Skip to content

Materializers

zenml.materializers special

Initialization of ZenML materializers.

Materializers are used to convert a ZenML artifact into a specific format. They are most often used to handle the input or output of ZenML steps, and can be extended by building on the BaseMaterializer class.

base_materializer

Metaclass implementation for registering ZenML BaseMaterializer subclasses.

BaseMaterializer

Base Materializer to realize artifact data.

Source code in zenml/materializers/base_materializer.py
class BaseMaterializer(metaclass=BaseMaterializerMeta):
    """Base Materializer to realize artifact data."""

    ASSOCIATED_ARTIFACT_TYPE: ClassVar[ArtifactType] = ArtifactType.BASE
    ASSOCIATED_TYPES: ClassVar[Tuple[Type[Any], ...]] = ()

    # `SKIP_REGISTRATION` can be set to True to not register the class in the
    # materializer registry. This is primarily useful for defining base classes.
    # Subclasses will automatically have this set to False unless they override
    # it themselves.
    SKIP_REGISTRATION: ClassVar[bool] = True

    _DOCS_BUILDING_MODE: ClassVar[bool] = False

    def __init__(
        self, uri: str, artifact_store: Optional[BaseArtifactStore] = None
    ):
        """Initializes a materializer with the given URI.

        Args:
            uri: The URI where the artifact data will be stored.
            artifact_store: The artifact store used to store this artifact.
        """
        self.uri = uri
        self._artifact_store = artifact_store

    @property
    def artifact_store(self) -> BaseArtifactStore:
        """Returns the artifact store used to store this artifact.

        It either comes from the configuration of the materializer or from the
        active stack.

        Returns:
            The artifact store used to store this artifact.
        """
        if self._artifact_store:
            return self._artifact_store
        else:
            from zenml.client import Client

            return Client().active_stack.artifact_store

    # ================
    # Public Interface
    # ================

    def load(self, data_type: Type[Any]) -> Any:
        """Write logic here to load the data of an artifact.

        Args:
            data_type: What type the artifact data should be loaded as.

        Returns:
            The data of the artifact.
        """
        # read from a location inside self.uri
        return None

    def save(self, data: Any) -> None:
        """Write logic here to save the data of an artifact.

        Args:
            data: The data of the artifact to save.
        """
        # write `data` into self.uri

    def save_visualizations(self, data: Any) -> Dict[str, VisualizationType]:
        """Save visualizations of the given data.

        If this method is not overridden, no visualizations will be saved.

        When overriding this method, make sure to save all visualizations to
        files within `self.uri`.

        Example:
        ```
        visualization_uri = os.path.join(self.uri, "visualization.html")
        with self.artifact_store.open(visualization_uri, "w") as f:
            f.write("<html><body>data</body></html>")

        visualization_uri_2 = os.path.join(self.uri, "visualization.png")
        data.save_as_png(visualization_uri_2)

        return {
            visualization_uri: ArtifactVisualizationType.HTML,
            visualization_uri_2: ArtifactVisualizationType.IMAGE
        }
        ```

        Args:
            data: The data of the artifact to visualize.

        Returns:
            A dictionary of visualization URIs and their types.
        """
        # Optionally, save some visualizations of `data` inside `self.uri`.
        return {}

    def extract_metadata(self, data: Any) -> Dict[str, "MetadataType"]:
        """Extract metadata from the given data.

        This metadata will be tracked and displayed alongside the artifact.

        Example:
        ```
        return {
            "some_attribute_i_want_to_track": self.some_attribute,
            "pi": 3.14,
        }
        ```

        Args:
            data: The data to extract metadata from.

        Returns:
            A dictionary of metadata.
        """
        # Optionally, extract some metadata from `data` for ZenML to store.
        return {}

    # ================
    # Internal Methods
    # ================

    def validate_type_compatibility(self, data_type: Type[Any]) -> None:
        """Checks whether the materializer can read/write the given type.

        Args:
            data_type: The type to check.

        Raises:
            TypeError: If the materializer cannot read/write the given type.
        """
        if not self.can_handle_type(data_type):
            raise TypeError(
                f"Unable to handle type {data_type}. {self.__class__.__name__} "
                f"can only read/write artifacts of the following types: "
                f"{self.ASSOCIATED_TYPES}."
            )

    @classmethod
    def can_handle_type(cls, data_type: Type[Any]) -> bool:
        """Whether the materializer can read/write a certain type.

        Args:
            data_type: The type to check.

        Returns:
            Whether the materializer can read/write the given type.
        """
        return any(
            issubclass(data_type, associated_type)
            for associated_type in cls.ASSOCIATED_TYPES
        )

    def extract_full_metadata(self, data: Any) -> Dict[str, "MetadataType"]:
        """Extract both base and custom metadata from the given data.

        Args:
            data: The data to extract metadata from.

        Returns:
            A dictionary of metadata.
        """
        base_metadata = self._extract_base_metadata(data)
        custom_metadata = self.extract_metadata(data)
        return {**base_metadata, **custom_metadata}

    def _extract_base_metadata(self, data: Any) -> Dict[str, "MetadataType"]:
        """Extract metadata from the given data.

        This metadata will be extracted for all artifacts in addition to the
        metadata extracted by the `extract_metadata` method.

        Args:
            data: The data to extract metadata from.

        Returns:
            A dictionary of metadata.
        """
        from zenml.metadata.metadata_types import StorageSize

        storage_size = fileio.size(self.uri)
        if isinstance(storage_size, int):
            return {"storage_size": StorageSize(storage_size)}
        return {}
artifact_store: BaseArtifactStore property readonly

Returns the artifact store used to store this artifact.

It either comes from the configuration of the materializer or from the active stack.

Returns:

Type Description
BaseArtifactStore

The artifact store used to store this artifact.

__init__(self, uri, artifact_store=None) special

Initializes a materializer with the given URI.

Parameters:

Name Type Description Default
uri str

The URI where the artifact data will be stored.

required
artifact_store Optional[zenml.artifact_stores.base_artifact_store.BaseArtifactStore]

The artifact store used to store this artifact.

None
Source code in zenml/materializers/base_materializer.py
def __init__(
    self, uri: str, artifact_store: Optional[BaseArtifactStore] = None
):
    """Initializes a materializer with the given URI.

    Args:
        uri: The URI where the artifact data will be stored.
        artifact_store: The artifact store used to store this artifact.
    """
    self.uri = uri
    self._artifact_store = artifact_store
can_handle_type(data_type) classmethod

Whether the materializer can read/write a certain type.

Parameters:

Name Type Description Default
data_type Type[Any]

The type to check.

required

Returns:

Type Description
bool

Whether the materializer can read/write the given type.

Source code in zenml/materializers/base_materializer.py
@classmethod
def can_handle_type(cls, data_type: Type[Any]) -> bool:
    """Whether the materializer can read/write a certain type.

    Args:
        data_type: The type to check.

    Returns:
        Whether the materializer can read/write the given type.
    """
    return any(
        issubclass(data_type, associated_type)
        for associated_type in cls.ASSOCIATED_TYPES
    )
extract_full_metadata(self, data)

Extract both base and custom metadata from the given data.

Parameters:

Name Type Description Default
data Any

The data to extract metadata from.

required

Returns:

Type Description
Dict[str, MetadataType]

A dictionary of metadata.

Source code in zenml/materializers/base_materializer.py
def extract_full_metadata(self, data: Any) -> Dict[str, "MetadataType"]:
    """Extract both base and custom metadata from the given data.

    Args:
        data: The data to extract metadata from.

    Returns:
        A dictionary of metadata.
    """
    base_metadata = self._extract_base_metadata(data)
    custom_metadata = self.extract_metadata(data)
    return {**base_metadata, **custom_metadata}
extract_metadata(self, data)

Extract metadata from the given data.

This metadata will be tracked and displayed alongside the artifact.

Examples:

return {
    "some_attribute_i_want_to_track": self.some_attribute,
    "pi": 3.14,
}

Parameters:

Name Type Description Default
data Any

The data to extract metadata from.

required

Returns:

Type Description
Dict[str, MetadataType]

A dictionary of metadata.

Source code in zenml/materializers/base_materializer.py
def extract_metadata(self, data: Any) -> Dict[str, "MetadataType"]:
    """Extract metadata from the given data.

    This metadata will be tracked and displayed alongside the artifact.

    Example:
    ```
    return {
        "some_attribute_i_want_to_track": self.some_attribute,
        "pi": 3.14,
    }
    ```

    Args:
        data: The data to extract metadata from.

    Returns:
        A dictionary of metadata.
    """
    # Optionally, extract some metadata from `data` for ZenML to store.
    return {}
load(self, data_type)

Write logic here to load the data of an artifact.

Parameters:

Name Type Description Default
data_type Type[Any]

What type the artifact data should be loaded as.

required

Returns:

Type Description
Any

The data of the artifact.

Source code in zenml/materializers/base_materializer.py
def load(self, data_type: Type[Any]) -> Any:
    """Write logic here to load the data of an artifact.

    Args:
        data_type: What type the artifact data should be loaded as.

    Returns:
        The data of the artifact.
    """
    # read from a location inside self.uri
    return None
save(self, data)

Write logic here to save the data of an artifact.

Parameters:

Name Type Description Default
data Any

The data of the artifact to save.

required
Source code in zenml/materializers/base_materializer.py
def save(self, data: Any) -> None:
    """Write logic here to save the data of an artifact.

    Args:
        data: The data of the artifact to save.
    """
    # write `data` into self.uri
save_visualizations(self, data)

Save visualizations of the given data.

If this method is not overridden, no visualizations will be saved.

When overriding this method, make sure to save all visualizations to files within self.uri.

Examples:

visualization_uri = os.path.join(self.uri, "visualization.html")
with self.artifact_store.open(visualization_uri, "w") as f:
    f.write("<html><body>data</body></html>")

visualization_uri_2 = os.path.join(self.uri, "visualization.png")
data.save_as_png(visualization_uri_2)

return {
    visualization_uri: ArtifactVisualizationType.HTML,
    visualization_uri_2: ArtifactVisualizationType.IMAGE
}

Parameters:

Name Type Description Default
data Any

The data of the artifact to visualize.

required

Returns:

Type Description
Dict[str, zenml.enums.VisualizationType]

A dictionary of visualization URIs and their types.

Source code in zenml/materializers/base_materializer.py
def save_visualizations(self, data: Any) -> Dict[str, VisualizationType]:
    """Save visualizations of the given data.

    If this method is not overridden, no visualizations will be saved.

    When overriding this method, make sure to save all visualizations to
    files within `self.uri`.

    Example:
    ```
    visualization_uri = os.path.join(self.uri, "visualization.html")
    with self.artifact_store.open(visualization_uri, "w") as f:
        f.write("<html><body>data</body></html>")

    visualization_uri_2 = os.path.join(self.uri, "visualization.png")
    data.save_as_png(visualization_uri_2)

    return {
        visualization_uri: ArtifactVisualizationType.HTML,
        visualization_uri_2: ArtifactVisualizationType.IMAGE
    }
    ```

    Args:
        data: The data of the artifact to visualize.

    Returns:
        A dictionary of visualization URIs and their types.
    """
    # Optionally, save some visualizations of `data` inside `self.uri`.
    return {}
validate_type_compatibility(self, data_type)

Checks whether the materializer can read/write the given type.

Parameters:

Name Type Description Default
data_type Type[Any]

The type to check.

required

Exceptions:

Type Description
TypeError

If the materializer cannot read/write the given type.

Source code in zenml/materializers/base_materializer.py
def validate_type_compatibility(self, data_type: Type[Any]) -> None:
    """Checks whether the materializer can read/write the given type.

    Args:
        data_type: The type to check.

    Raises:
        TypeError: If the materializer cannot read/write the given type.
    """
    if not self.can_handle_type(data_type):
        raise TypeError(
            f"Unable to handle type {data_type}. {self.__class__.__name__} "
            f"can only read/write artifacts of the following types: "
            f"{self.ASSOCIATED_TYPES}."
        )

BaseMaterializerMeta (type)

Metaclass responsible for registering different BaseMaterializer subclasses.

Materializers are used for reading/writing artifacts.

Source code in zenml/materializers/base_materializer.py
class BaseMaterializerMeta(type):
    """Metaclass responsible for registering different BaseMaterializer subclasses.

    Materializers are used for reading/writing artifacts.
    """

    def __new__(
        mcs, name: str, bases: Tuple[Type[Any], ...], dct: Dict[str, Any]
    ) -> "BaseMaterializerMeta":
        """Creates a Materializer class and registers it at the `MaterializerRegistry`.

        Args:
            name: The name of the class.
            bases: The base classes of the class.
            dct: The dictionary of the class.

        Returns:
            The BaseMaterializerMeta class.

        Raises:
            MaterializerInterfaceError: If the class was improperly defined.
        """
        cls = cast(
            Type["BaseMaterializer"], super().__new__(mcs, name, bases, dct)
        )
        if not cls._DOCS_BUILDING_MODE:
            # Skip the following validation and registration for base classes.
            if cls.SKIP_REGISTRATION:
                # Reset the flag so subclasses don't have it set automatically.
                cls.SKIP_REGISTRATION = False
                return cls

            # Validate that the class is properly defined.
            if not cls.ASSOCIATED_TYPES:
                raise MaterializerInterfaceError(
                    f"Invalid materializer class '{name}'. When creating a "
                    f"custom materializer, make sure to specify at least one "
                    f"type in its ASSOCIATED_TYPES class variable.",
                    url="https://docs.zenml.io/how-to/handle-data-artifacts/handle-custom-data-types",
                )

            # Validate associated artifact type.
            if cls.ASSOCIATED_ARTIFACT_TYPE:
                try:
                    cls.ASSOCIATED_ARTIFACT_TYPE = ArtifactType(
                        cls.ASSOCIATED_ARTIFACT_TYPE
                    )
                except ValueError:
                    raise MaterializerInterfaceError(
                        f"Invalid materializer class '{name}'. When creating a "
                        f"custom materializer, make sure to specify a valid "
                        f"artifact type in its ASSOCIATED_ARTIFACT_TYPE class "
                        f"variable.",
                        url="https://docs.zenml.io/how-to/handle-data-artifacts/handle-custom-data-types",
                    )

            # Validate associated data types.
            for associated_type in cls.ASSOCIATED_TYPES:
                if not inspect.isclass(associated_type):
                    raise MaterializerInterfaceError(
                        f"Associated type {associated_type} for materializer "
                        f"{name} is not a class.",
                        url="https://docs.zenml.io/how-to/handle-data-artifacts/handle-custom-data-types",
                    )

            # Register the materializer.
            for associated_type in cls.ASSOCIATED_TYPES:
                materializer_registry.register_materializer_type(
                    associated_type, cls
                )

        return cls
__new__(mcs, name, bases, dct) special staticmethod

Creates a Materializer class and registers it at the MaterializerRegistry.

Parameters:

Name Type Description Default
name str

The name of the class.

required
bases Tuple[Type[Any], ...]

The base classes of the class.

required
dct Dict[str, Any]

The dictionary of the class.

required

Returns:

Type Description
BaseMaterializerMeta

The BaseMaterializerMeta class.

Exceptions:

Type Description
MaterializerInterfaceError

If the class was improperly defined.

Source code in zenml/materializers/base_materializer.py
def __new__(
    mcs, name: str, bases: Tuple[Type[Any], ...], dct: Dict[str, Any]
) -> "BaseMaterializerMeta":
    """Creates a Materializer class and registers it at the `MaterializerRegistry`.

    Args:
        name: The name of the class.
        bases: The base classes of the class.
        dct: The dictionary of the class.

    Returns:
        The BaseMaterializerMeta class.

    Raises:
        MaterializerInterfaceError: If the class was improperly defined.
    """
    cls = cast(
        Type["BaseMaterializer"], super().__new__(mcs, name, bases, dct)
    )
    if not cls._DOCS_BUILDING_MODE:
        # Skip the following validation and registration for base classes.
        if cls.SKIP_REGISTRATION:
            # Reset the flag so subclasses don't have it set automatically.
            cls.SKIP_REGISTRATION = False
            return cls

        # Validate that the class is properly defined.
        if not cls.ASSOCIATED_TYPES:
            raise MaterializerInterfaceError(
                f"Invalid materializer class '{name}'. When creating a "
                f"custom materializer, make sure to specify at least one "
                f"type in its ASSOCIATED_TYPES class variable.",
                url="https://docs.zenml.io/how-to/handle-data-artifacts/handle-custom-data-types",
            )

        # Validate associated artifact type.
        if cls.ASSOCIATED_ARTIFACT_TYPE:
            try:
                cls.ASSOCIATED_ARTIFACT_TYPE = ArtifactType(
                    cls.ASSOCIATED_ARTIFACT_TYPE
                )
            except ValueError:
                raise MaterializerInterfaceError(
                    f"Invalid materializer class '{name}'. When creating a "
                    f"custom materializer, make sure to specify a valid "
                    f"artifact type in its ASSOCIATED_ARTIFACT_TYPE class "
                    f"variable.",
                    url="https://docs.zenml.io/how-to/handle-data-artifacts/handle-custom-data-types",
                )

        # Validate associated data types.
        for associated_type in cls.ASSOCIATED_TYPES:
            if not inspect.isclass(associated_type):
                raise MaterializerInterfaceError(
                    f"Associated type {associated_type} for materializer "
                    f"{name} is not a class.",
                    url="https://docs.zenml.io/how-to/handle-data-artifacts/handle-custom-data-types",
                )

        # Register the materializer.
        for associated_type in cls.ASSOCIATED_TYPES:
            materializer_registry.register_materializer_type(
                associated_type, cls
            )

    return cls

built_in_materializer

Implementation of ZenML's builtin materializer.

BuiltInContainerMaterializer (BaseMaterializer)

Handle built-in container types (dict, list, set, tuple).

Source code in zenml/materializers/built_in_materializer.py
class BuiltInContainerMaterializer(BaseMaterializer):
    """Handle built-in container types (dict, list, set, tuple)."""

    ASSOCIATED_TYPES: ClassVar[Tuple[Type[Any], ...]] = (
        dict,
        list,
        set,
        tuple,
    )

    def __init__(
        self, uri: str, artifact_store: Optional[BaseArtifactStore] = None
    ):
        """Define `self.data_path` and `self.metadata_path`.

        Args:
            uri: The URI where the artifact data is stored.
            artifact_store: The artifact store where the artifact data is stored.
        """
        super().__init__(uri, artifact_store)
        self.data_path = os.path.join(self.uri, DEFAULT_FILENAME)
        self.metadata_path = os.path.join(self.uri, DEFAULT_METADATA_FILENAME)

    def load(self, data_type: Type[Any]) -> Any:
        """Reads a materialized built-in container object.

        If the data was serialized to JSON, deserialize it.

        Otherwise, reconstruct all elements according to the metadata file:
            1. Resolve the data type using `find_type_by_str()`,
            2. Get the materializer via the `default_materializer_registry`,
            3. Initialize the materializer with the desired path,
            4. Use `load()` of that materializer to load the element.

        Args:
            data_type: The type of the data to read.

        Returns:
            The data read.

        Raises:
            RuntimeError: If the data was not found.
        """
        # If the data was not serialized, there must be metadata present.
        if not self.artifact_store.exists(
            self.data_path
        ) and not self.artifact_store.exists(self.metadata_path):
            raise RuntimeError(
                f"Materialization of type {data_type} failed. Expected either"
                f"{self.data_path} or {self.metadata_path} to exist."
            )

        # If the data was serialized as JSON, deserialize it.
        if self.artifact_store.exists(self.data_path):
            outputs = yaml_utils.read_json(self.data_path)

        # Otherwise, use the metadata to reconstruct the data as a list.
        else:
            metadata = yaml_utils.read_json(self.metadata_path)
            outputs = []

            # Backwards compatibility for zenml <= 0.37.0
            if isinstance(metadata, dict):
                for path_, type_str in zip(
                    metadata["paths"], metadata["types"]
                ):
                    type_ = find_type_by_str(type_str)
                    materializer_class = materializer_registry[type_]
                    materializer = materializer_class(uri=path_)
                    element = materializer.load(type_)
                    outputs.append(element)

            # New format for zenml > 0.37.0
            elif isinstance(metadata, list):
                for entry in metadata:
                    path_ = entry["path"]
                    type_ = source_utils.load(entry["type"])
                    materializer_class = source_utils.load(
                        entry["materializer"]
                    )
                    materializer = materializer_class(uri=path_)
                    element = materializer.load(type_)
                    outputs.append(element)

            else:
                raise RuntimeError(f"Unknown metadata format: {metadata}.")

        # Cast the data to the correct type.
        if issubclass(data_type, dict) and not isinstance(outputs, dict):
            keys, values = outputs
            return data_type(zip(keys, values))
        if issubclass(data_type, tuple) and not isinstance(outputs, tuple):
            return data_type(outputs)
        if issubclass(data_type, set) and not isinstance(outputs, set):
            return data_type(outputs)
        return outputs

    def save(self, data: Any) -> None:
        """Materialize a built-in container object.

        If the object can be serialized to JSON, serialize it.

        Otherwise, use the `default_materializer_registry` to find the correct
        materializer for each element and materialize each element into a
        subdirectory.

        Tuples and sets are cast to list before materialization.

        For non-serializable dicts, materialize keys/values as separate lists.

        Args:
            data: The built-in container object to materialize.

        Raises:
            Exception: If any exception occurs, it is raised after cleanup.
        """
        # tuple and set: handle as list.
        if isinstance(data, tuple) or isinstance(data, set):
            data = list(data)

        # If the data is serializable, just write it into a single JSON file.
        if _is_serializable(data):
            yaml_utils.write_json(self.data_path, data)
            return

        # non-serializable dict: Handle as non-serializable list of lists.
        if isinstance(data, dict):
            data = [list(data.keys()), list(data.values())]

        # non-serializable list: Materialize each element into a subfolder.
        # Get path, type, and corresponding materializer for each element.
        metadata: List[Dict[str, str]] = []
        materializers: List[BaseMaterializer] = []
        try:
            for i, element in enumerate(data):
                element_path = os.path.join(self.uri, str(i))
                self.artifact_store.mkdir(element_path)
                type_ = type(element)
                materializer_class = materializer_registry[type_]
                materializer = materializer_class(uri=element_path)
                materializers.append(materializer)
                metadata.append(
                    {
                        "path": element_path,
                        "type": source_utils.resolve(type_).import_path,
                        "materializer": source_utils.resolve(
                            materializer_class
                        ).import_path,
                    }
                )
            # Write metadata as JSON.
            yaml_utils.write_json(self.metadata_path, metadata)
            # Materialize each element.
            for element, materializer in zip(data, materializers):
                materializer.validate_type_compatibility(type(element))
                materializer.save(element)
        # If an error occurs, delete all created files.
        except Exception as e:
            # Delete metadata
            if self.artifact_store.exists(self.metadata_path):
                self.artifact_store.remove(self.metadata_path)
            # Delete all elements that were already saved.
            for entry in metadata:
                self.artifact_store.rmtree(entry["path"])
            raise e

    def extract_metadata(self, data: Any) -> Dict[str, "MetadataType"]:
        """Extract metadata from the given built-in container object.

        Args:
            data: The built-in container object to extract metadata from.

        Returns:
            The extracted metadata as a dictionary.
        """
        if hasattr(data, "__len__"):
            return {"length": len(data)}
        return {}
__init__(self, uri, artifact_store=None) special

Define self.data_path and self.metadata_path.

Parameters:

Name Type Description Default
uri str

The URI where the artifact data is stored.

required
artifact_store Optional[zenml.artifact_stores.base_artifact_store.BaseArtifactStore]

The artifact store where the artifact data is stored.

None
Source code in zenml/materializers/built_in_materializer.py
def __init__(
    self, uri: str, artifact_store: Optional[BaseArtifactStore] = None
):
    """Define `self.data_path` and `self.metadata_path`.

    Args:
        uri: The URI where the artifact data is stored.
        artifact_store: The artifact store where the artifact data is stored.
    """
    super().__init__(uri, artifact_store)
    self.data_path = os.path.join(self.uri, DEFAULT_FILENAME)
    self.metadata_path = os.path.join(self.uri, DEFAULT_METADATA_FILENAME)
extract_metadata(self, data)

Extract metadata from the given built-in container object.

Parameters:

Name Type Description Default
data Any

The built-in container object to extract metadata from.

required

Returns:

Type Description
Dict[str, MetadataType]

The extracted metadata as a dictionary.

Source code in zenml/materializers/built_in_materializer.py
def extract_metadata(self, data: Any) -> Dict[str, "MetadataType"]:
    """Extract metadata from the given built-in container object.

    Args:
        data: The built-in container object to extract metadata from.

    Returns:
        The extracted metadata as a dictionary.
    """
    if hasattr(data, "__len__"):
        return {"length": len(data)}
    return {}
load(self, data_type)

Reads a materialized built-in container object.

If the data was serialized to JSON, deserialize it.

Otherwise, reconstruct all elements according to the metadata file: 1. Resolve the data type using find_type_by_str(), 2. Get the materializer via the default_materializer_registry, 3. Initialize the materializer with the desired path, 4. Use load() of that materializer to load the element.

Parameters:

Name Type Description Default
data_type Type[Any]

The type of the data to read.

required

Returns:

Type Description
Any

The data read.

Exceptions:

Type Description
RuntimeError

If the data was not found.

Source code in zenml/materializers/built_in_materializer.py
def load(self, data_type: Type[Any]) -> Any:
    """Reads a materialized built-in container object.

    If the data was serialized to JSON, deserialize it.

    Otherwise, reconstruct all elements according to the metadata file:
        1. Resolve the data type using `find_type_by_str()`,
        2. Get the materializer via the `default_materializer_registry`,
        3. Initialize the materializer with the desired path,
        4. Use `load()` of that materializer to load the element.

    Args:
        data_type: The type of the data to read.

    Returns:
        The data read.

    Raises:
        RuntimeError: If the data was not found.
    """
    # If the data was not serialized, there must be metadata present.
    if not self.artifact_store.exists(
        self.data_path
    ) and not self.artifact_store.exists(self.metadata_path):
        raise RuntimeError(
            f"Materialization of type {data_type} failed. Expected either"
            f"{self.data_path} or {self.metadata_path} to exist."
        )

    # If the data was serialized as JSON, deserialize it.
    if self.artifact_store.exists(self.data_path):
        outputs = yaml_utils.read_json(self.data_path)

    # Otherwise, use the metadata to reconstruct the data as a list.
    else:
        metadata = yaml_utils.read_json(self.metadata_path)
        outputs = []

        # Backwards compatibility for zenml <= 0.37.0
        if isinstance(metadata, dict):
            for path_, type_str in zip(
                metadata["paths"], metadata["types"]
            ):
                type_ = find_type_by_str(type_str)
                materializer_class = materializer_registry[type_]
                materializer = materializer_class(uri=path_)
                element = materializer.load(type_)
                outputs.append(element)

        # New format for zenml > 0.37.0
        elif isinstance(metadata, list):
            for entry in metadata:
                path_ = entry["path"]
                type_ = source_utils.load(entry["type"])
                materializer_class = source_utils.load(
                    entry["materializer"]
                )
                materializer = materializer_class(uri=path_)
                element = materializer.load(type_)
                outputs.append(element)

        else:
            raise RuntimeError(f"Unknown metadata format: {metadata}.")

    # Cast the data to the correct type.
    if issubclass(data_type, dict) and not isinstance(outputs, dict):
        keys, values = outputs
        return data_type(zip(keys, values))
    if issubclass(data_type, tuple) and not isinstance(outputs, tuple):
        return data_type(outputs)
    if issubclass(data_type, set) and not isinstance(outputs, set):
        return data_type(outputs)
    return outputs
save(self, data)

Materialize a built-in container object.

If the object can be serialized to JSON, serialize it.

Otherwise, use the default_materializer_registry to find the correct materializer for each element and materialize each element into a subdirectory.

Tuples and sets are cast to list before materialization.

For non-serializable dicts, materialize keys/values as separate lists.

Parameters:

Name Type Description Default
data Any

The built-in container object to materialize.

required

Exceptions:

Type Description
Exception

If any exception occurs, it is raised after cleanup.

Source code in zenml/materializers/built_in_materializer.py
def save(self, data: Any) -> None:
    """Materialize a built-in container object.

    If the object can be serialized to JSON, serialize it.

    Otherwise, use the `default_materializer_registry` to find the correct
    materializer for each element and materialize each element into a
    subdirectory.

    Tuples and sets are cast to list before materialization.

    For non-serializable dicts, materialize keys/values as separate lists.

    Args:
        data: The built-in container object to materialize.

    Raises:
        Exception: If any exception occurs, it is raised after cleanup.
    """
    # tuple and set: handle as list.
    if isinstance(data, tuple) or isinstance(data, set):
        data = list(data)

    # If the data is serializable, just write it into a single JSON file.
    if _is_serializable(data):
        yaml_utils.write_json(self.data_path, data)
        return

    # non-serializable dict: Handle as non-serializable list of lists.
    if isinstance(data, dict):
        data = [list(data.keys()), list(data.values())]

    # non-serializable list: Materialize each element into a subfolder.
    # Get path, type, and corresponding materializer for each element.
    metadata: List[Dict[str, str]] = []
    materializers: List[BaseMaterializer] = []
    try:
        for i, element in enumerate(data):
            element_path = os.path.join(self.uri, str(i))
            self.artifact_store.mkdir(element_path)
            type_ = type(element)
            materializer_class = materializer_registry[type_]
            materializer = materializer_class(uri=element_path)
            materializers.append(materializer)
            metadata.append(
                {
                    "path": element_path,
                    "type": source_utils.resolve(type_).import_path,
                    "materializer": source_utils.resolve(
                        materializer_class
                    ).import_path,
                }
            )
        # Write metadata as JSON.
        yaml_utils.write_json(self.metadata_path, metadata)
        # Materialize each element.
        for element, materializer in zip(data, materializers):
            materializer.validate_type_compatibility(type(element))
            materializer.save(element)
    # If an error occurs, delete all created files.
    except Exception as e:
        # Delete metadata
        if self.artifact_store.exists(self.metadata_path):
            self.artifact_store.remove(self.metadata_path)
        # Delete all elements that were already saved.
        for entry in metadata:
            self.artifact_store.rmtree(entry["path"])
        raise e

BuiltInMaterializer (BaseMaterializer)

Handle JSON-serializable basic types (bool, float, int, str).

Source code in zenml/materializers/built_in_materializer.py
class BuiltInMaterializer(BaseMaterializer):
    """Handle JSON-serializable basic types (`bool`, `float`, `int`, `str`)."""

    ASSOCIATED_ARTIFACT_TYPE: ClassVar[ArtifactType] = ArtifactType.DATA
    ASSOCIATED_TYPES: ClassVar[Tuple[Type[Any], ...]] = BASIC_TYPES

    def __init__(
        self, uri: str, artifact_store: Optional[BaseArtifactStore] = None
    ):
        """Define `self.data_path`.

        Args:
            uri: The URI where the artifact data is stored.
            artifact_store: The artifact store where the artifact data is stored.
        """
        super().__init__(uri, artifact_store)
        self.data_path = os.path.join(self.uri, DEFAULT_FILENAME)

    def load(
        self, data_type: Union[Type[bool], Type[float], Type[int], Type[str]]
    ) -> Any:
        """Reads basic primitive types from JSON.

        Args:
            data_type: The type of the data to read.

        Returns:
            The data read.
        """
        contents = yaml_utils.read_json(self.data_path)
        if type(contents) is not data_type:
            # TODO [ENG-142]: Raise error or try to coerce
            logger.debug(
                f"Contents {contents} was type {type(contents)} but expected "
                f"{data_type}"
            )
        return contents

    def save(self, data: Union[bool, float, int, str]) -> None:
        """Serialize a basic type to JSON.

        Args:
            data: The data to store.
        """
        yaml_utils.write_json(self.data_path, data)

    def extract_metadata(
        self, data: Union[bool, float, int, str]
    ) -> Dict[str, "MetadataType"]:
        """Extract metadata from the given built-in container object.

        Args:
            data: The built-in container object to extract metadata from.

        Returns:
            The extracted metadata as a dictionary.
        """
        # For boolean and numbers, add the string representation as metadata.
        # We don't to this for strings because they can be arbitrarily long.
        if isinstance(data, (bool, float, int)):
            return {"string_representation": str(data)}

        return {}
__init__(self, uri, artifact_store=None) special

Define self.data_path.

Parameters:

Name Type Description Default
uri str

The URI where the artifact data is stored.

required
artifact_store Optional[zenml.artifact_stores.base_artifact_store.BaseArtifactStore]

The artifact store where the artifact data is stored.

None
Source code in zenml/materializers/built_in_materializer.py
def __init__(
    self, uri: str, artifact_store: Optional[BaseArtifactStore] = None
):
    """Define `self.data_path`.

    Args:
        uri: The URI where the artifact data is stored.
        artifact_store: The artifact store where the artifact data is stored.
    """
    super().__init__(uri, artifact_store)
    self.data_path = os.path.join(self.uri, DEFAULT_FILENAME)
extract_metadata(self, data)

Extract metadata from the given built-in container object.

Parameters:

Name Type Description Default
data Union[bool, float, int, str]

The built-in container object to extract metadata from.

required

Returns:

Type Description
Dict[str, MetadataType]

The extracted metadata as a dictionary.

Source code in zenml/materializers/built_in_materializer.py
def extract_metadata(
    self, data: Union[bool, float, int, str]
) -> Dict[str, "MetadataType"]:
    """Extract metadata from the given built-in container object.

    Args:
        data: The built-in container object to extract metadata from.

    Returns:
        The extracted metadata as a dictionary.
    """
    # For boolean and numbers, add the string representation as metadata.
    # We don't to this for strings because they can be arbitrarily long.
    if isinstance(data, (bool, float, int)):
        return {"string_representation": str(data)}

    return {}
load(self, data_type)

Reads basic primitive types from JSON.

Parameters:

Name Type Description Default
data_type Union[Type[bool], Type[float], Type[int], Type[str]]

The type of the data to read.

required

Returns:

Type Description
Any

The data read.

Source code in zenml/materializers/built_in_materializer.py
def load(
    self, data_type: Union[Type[bool], Type[float], Type[int], Type[str]]
) -> Any:
    """Reads basic primitive types from JSON.

    Args:
        data_type: The type of the data to read.

    Returns:
        The data read.
    """
    contents = yaml_utils.read_json(self.data_path)
    if type(contents) is not data_type:
        # TODO [ENG-142]: Raise error or try to coerce
        logger.debug(
            f"Contents {contents} was type {type(contents)} but expected "
            f"{data_type}"
        )
    return contents
save(self, data)

Serialize a basic type to JSON.

Parameters:

Name Type Description Default
data Union[bool, float, int, str]

The data to store.

required
Source code in zenml/materializers/built_in_materializer.py
def save(self, data: Union[bool, float, int, str]) -> None:
    """Serialize a basic type to JSON.

    Args:
        data: The data to store.
    """
    yaml_utils.write_json(self.data_path, data)

BytesMaterializer (BaseMaterializer)

Handle bytes data type, which is not JSON serializable.

Source code in zenml/materializers/built_in_materializer.py
class BytesMaterializer(BaseMaterializer):
    """Handle `bytes` data type, which is not JSON serializable."""

    ASSOCIATED_ARTIFACT_TYPE: ClassVar[ArtifactType] = ArtifactType.DATA
    ASSOCIATED_TYPES: ClassVar[Tuple[Type[Any], ...]] = (bytes,)

    def __init__(
        self, uri: str, artifact_store: Optional[BaseArtifactStore] = None
    ):
        """Define `self.data_path`.

        Args:
            uri: The URI where the artifact data is stored.
            artifact_store: The artifact store where the artifact data is stored.
        """
        super().__init__(uri, artifact_store)
        self.data_path = os.path.join(self.uri, DEFAULT_BYTES_FILENAME)

    def load(self, data_type: Type[Any]) -> Any:
        """Reads a bytes object from file.

        Args:
            data_type: The type of the data to read.

        Returns:
            The data read.
        """
        with self.artifact_store.open(self.data_path, "rb") as file_:
            return file_.read()

    def save(self, data: Any) -> None:
        """Save a bytes object to file.

        Args:
            data: The data to store.
        """
        with self.artifact_store.open(self.data_path, "wb") as file_:
            file_.write(data)
__init__(self, uri, artifact_store=None) special

Define self.data_path.

Parameters:

Name Type Description Default
uri str

The URI where the artifact data is stored.

required
artifact_store Optional[zenml.artifact_stores.base_artifact_store.BaseArtifactStore]

The artifact store where the artifact data is stored.

None
Source code in zenml/materializers/built_in_materializer.py
def __init__(
    self, uri: str, artifact_store: Optional[BaseArtifactStore] = None
):
    """Define `self.data_path`.

    Args:
        uri: The URI where the artifact data is stored.
        artifact_store: The artifact store where the artifact data is stored.
    """
    super().__init__(uri, artifact_store)
    self.data_path = os.path.join(self.uri, DEFAULT_BYTES_FILENAME)
load(self, data_type)

Reads a bytes object from file.

Parameters:

Name Type Description Default
data_type Type[Any]

The type of the data to read.

required

Returns:

Type Description
Any

The data read.

Source code in zenml/materializers/built_in_materializer.py
def load(self, data_type: Type[Any]) -> Any:
    """Reads a bytes object from file.

    Args:
        data_type: The type of the data to read.

    Returns:
        The data read.
    """
    with self.artifact_store.open(self.data_path, "rb") as file_:
        return file_.read()
save(self, data)

Save a bytes object to file.

Parameters:

Name Type Description Default
data Any

The data to store.

required
Source code in zenml/materializers/built_in_materializer.py
def save(self, data: Any) -> None:
    """Save a bytes object to file.

    Args:
        data: The data to store.
    """
    with self.artifact_store.open(self.data_path, "wb") as file_:
        file_.write(data)

find_materializer_registry_type(type_)

For a given type, find the type registered in the registry.

This can be either the type itself, or a superclass of the type.

Parameters:

Name Type Description Default
type_ Type[Any]

The type to find.

required

Returns:

Type Description
Type[Any]

The type registered in the registry.

Exceptions:

Type Description
RuntimeError

If the type could not be resolved.

Source code in zenml/materializers/built_in_materializer.py
def find_materializer_registry_type(type_: Type[Any]) -> Type[Any]:
    """For a given type, find the type registered in the registry.

    This can be either the type itself, or a superclass of the type.

    Args:
        type_: The type to find.

    Returns:
        The type registered in the registry.

    Raises:
        RuntimeError: If the type could not be resolved.
    """
    # Check that a unique materializer is registered for this type
    materializer_registry[type_]

    # Check if the type itself is registered
    registered_types = materializer_registry.materializer_types.keys()
    if type_ in registered_types:
        return type_

    # Check if a superclass of the type is registered
    for registered_type in registered_types:
        if issubclass(type_, registered_type):
            return registered_type

    # Raise an error otherwise - this should never happen since
    # `default_materializer_registry[type_]` should have raised an error already
    raise RuntimeError(
        f"Cannot find a materializer for type '{type_}' in the "
        f"materializer registry."
    )

find_type_by_str(type_str)

Get a Python type, given its string representation.

E.g., "" should resolve to int.

Currently this is implemented by checking all artifact types registered in the default_materializer_registry. This means, only types in the registry can be found. Any other types will cause a RunTimeError.

Parameters:

Name Type Description Default
type_str str

The string representation of a type.

required

Exceptions:

Type Description
RuntimeError

If the type could not be resolved.

Returns:

Type Description
Type[Any]

The type whose string representation is type_str.

Source code in zenml/materializers/built_in_materializer.py
def find_type_by_str(type_str: str) -> Type[Any]:
    """Get a Python type, given its string representation.

    E.g., "<class 'int'>" should resolve to `int`.

    Currently this is implemented by checking all artifact types registered in
    the `default_materializer_registry`. This means, only types in the registry
    can be found. Any other types will cause a `RunTimeError`.

    Args:
        type_str: The string representation of a type.

    Raises:
        RuntimeError: If the type could not be resolved.

    Returns:
        The type whose string representation is `type_str`.
    """
    registered_types = materializer_registry.materializer_types.keys()
    type_str_mapping = {str(type_): type_ for type_ in registered_types}
    if type_str in type_str_mapping:
        return type_str_mapping[type_str]
    raise RuntimeError(f"Cannot resolve type '{type_str}'.")

cloudpickle_materializer

Implementation of ZenML's cloudpickle materializer.

CloudpickleMaterializer (BaseMaterializer)

Materializer using cloudpickle.

This materializer can materialize (almost) any object, but does so in a non-reproducble way since artifacts cannot be loaded from other Python versions. It is recommended to use this materializer only as a last resort.

That is also why it has SKIP_REGISTRATION set to True and is currently only used as a fallback materializer inside the materializer registry.

Source code in zenml/materializers/cloudpickle_materializer.py
class CloudpickleMaterializer(BaseMaterializer):
    """Materializer using cloudpickle.

    This materializer can materialize (almost) any object, but does so in a
    non-reproducble way since artifacts cannot be loaded from other Python
    versions. It is recommended to use this materializer only as a last resort.

    That is also why it has `SKIP_REGISTRATION` set to True and is currently
    only used as a fallback materializer inside the materializer registry.
    """

    ASSOCIATED_TYPES: ClassVar[Tuple[Type[Any], ...]] = (object,)
    ASSOCIATED_ARTIFACT_TYPE: ClassVar[ArtifactType] = ArtifactType.DATA
    SKIP_REGISTRATION: ClassVar[bool] = True

    def load(self, data_type: Type[Any]) -> Any:
        """Reads an artifact from a cloudpickle file.

        Args:
            data_type: The data type of the artifact.

        Returns:
            The loaded artifact data.
        """
        # validate python version
        source_python_version = self._load_python_version()
        current_python_version = Environment().python_version()
        if source_python_version != current_python_version:
            logger.warning(
                f"Your artifact was materialized under Python version "
                f"'{source_python_version}' but you are currently using "
                f"'{current_python_version}'. This might cause unexpected "
                "behavior since pickle is not reproducible across Python "
                "versions. Attempting to load anyway..."
            )

        # load data
        filepath = os.path.join(self.uri, DEFAULT_FILENAME)
        with self.artifact_store.open(filepath, "rb") as fid:
            data = cloudpickle.load(fid)
        return data

    def _load_python_version(self) -> str:
        """Loads the Python version that was used to materialize the artifact.

        Returns:
            The Python version that was used to materialize the artifact.
        """
        filepath = os.path.join(self.uri, DEFAULT_PYTHON_VERSION_FILENAME)
        if os.path.exists(filepath):
            return read_file_contents_as_string(filepath)
        return "unknown"

    def save(self, data: Any) -> None:
        """Saves an artifact to a cloudpickle file.

        Args:
            data: The data to save.
        """
        # Log a warning if this materializer was not explicitly specified for
        # the given data type.
        if type(self) is CloudpickleMaterializer:
            logger.warning(
                f"No materializer is registered for type `{type(data)}`, so "
                "the default Pickle materializer was used. Pickle is not "
                "production ready and should only be used for prototyping as "
                "the artifacts cannot be loaded when running with a different "
                "Python version. Please consider implementing a custom "
                f"materializer for type `{type(data)}` according to the "
                "instructions at https://docs.zenml.io/how-to/handle-data-artifacts/handle-custom-data-types"
            )

        # save python version for validation on loading
        self._save_python_version()

        # save data
        filepath = os.path.join(self.uri, DEFAULT_FILENAME)
        with self.artifact_store.open(filepath, "wb") as fid:
            cloudpickle.dump(data, fid)

    def _save_python_version(self) -> None:
        """Saves the Python version used to materialize the artifact."""
        filepath = os.path.join(self.uri, DEFAULT_PYTHON_VERSION_FILENAME)
        current_python_version = Environment().python_version()
        write_file_contents_as_string(filepath, current_python_version)
load(self, data_type)

Reads an artifact from a cloudpickle file.

Parameters:

Name Type Description Default
data_type Type[Any]

The data type of the artifact.

required

Returns:

Type Description
Any

The loaded artifact data.

Source code in zenml/materializers/cloudpickle_materializer.py
def load(self, data_type: Type[Any]) -> Any:
    """Reads an artifact from a cloudpickle file.

    Args:
        data_type: The data type of the artifact.

    Returns:
        The loaded artifact data.
    """
    # validate python version
    source_python_version = self._load_python_version()
    current_python_version = Environment().python_version()
    if source_python_version != current_python_version:
        logger.warning(
            f"Your artifact was materialized under Python version "
            f"'{source_python_version}' but you are currently using "
            f"'{current_python_version}'. This might cause unexpected "
            "behavior since pickle is not reproducible across Python "
            "versions. Attempting to load anyway..."
        )

    # load data
    filepath = os.path.join(self.uri, DEFAULT_FILENAME)
    with self.artifact_store.open(filepath, "rb") as fid:
        data = cloudpickle.load(fid)
    return data
save(self, data)

Saves an artifact to a cloudpickle file.

Parameters:

Name Type Description Default
data Any

The data to save.

required
Source code in zenml/materializers/cloudpickle_materializer.py
def save(self, data: Any) -> None:
    """Saves an artifact to a cloudpickle file.

    Args:
        data: The data to save.
    """
    # Log a warning if this materializer was not explicitly specified for
    # the given data type.
    if type(self) is CloudpickleMaterializer:
        logger.warning(
            f"No materializer is registered for type `{type(data)}`, so "
            "the default Pickle materializer was used. Pickle is not "
            "production ready and should only be used for prototyping as "
            "the artifacts cannot be loaded when running with a different "
            "Python version. Please consider implementing a custom "
            f"materializer for type `{type(data)}` according to the "
            "instructions at https://docs.zenml.io/how-to/handle-data-artifacts/handle-custom-data-types"
        )

    # save python version for validation on loading
    self._save_python_version()

    # save data
    filepath = os.path.join(self.uri, DEFAULT_FILENAME)
    with self.artifact_store.open(filepath, "wb") as fid:
        cloudpickle.dump(data, fid)

materializer_registry

Implementation of a default materializer registry.

MaterializerRegistry

Matches a Python type to a default materializer.

Source code in zenml/materializers/materializer_registry.py
class MaterializerRegistry:
    """Matches a Python type to a default materializer."""

    def __init__(self) -> None:
        """Initialize the materializer registry."""
        self.default_materializer: Optional[Type["BaseMaterializer"]] = None
        self.materializer_types: Dict[Type[Any], Type["BaseMaterializer"]] = {}

    def register_materializer_type(
        self, key: Type[Any], type_: Type["BaseMaterializer"]
    ) -> None:
        """Registers a new materializer.

        Args:
            key: Indicates the type of object.
            type_: A BaseMaterializer subclass.
        """
        if key not in self.materializer_types:
            self.materializer_types[key] = type_
            logger.debug(f"Registered materializer {type_} for {key}")
        else:
            logger.debug(
                f"Found existing materializer class for {key}: "
                f"{self.materializer_types[key]}. Skipping registration of "
                f"{type_}."
            )

    def register_and_overwrite_type(
        self, key: Type[Any], type_: Type["BaseMaterializer"]
    ) -> None:
        """Registers a new materializer and also overwrites a default if set.

        Args:
            key: Indicates the type of object.
            type_: A BaseMaterializer subclass.
        """
        self.materializer_types[key] = type_
        logger.debug(f"Registered materializer {type_} for {key}")

    def __getitem__(self, key: Type[Any]) -> Type["BaseMaterializer"]:
        """Get a single materializers based on the key.

        Args:
            key: Indicates the type of object.

        Returns:
            `BaseMaterializer` subclass that was registered for this key.
        """
        for class_ in key.__mro__:
            materializer = self.materializer_types.get(class_, None)
            if materializer:
                return materializer
        return self.get_default_materializer()

    def get_default_materializer(self) -> Type["BaseMaterializer"]:
        """Get the default materializer that is used if no other is found.

        Returns:
            The default materializer.
        """
        from zenml.materializers.cloudpickle_materializer import (
            CloudpickleMaterializer,
        )

        if self.default_materializer:
            return self.default_materializer

        return CloudpickleMaterializer

    def get_materializer_types(
        self,
    ) -> Dict[Type[Any], Type["BaseMaterializer"]]:
        """Get all registered materializer types.

        Returns:
            A dictionary of registered materializer types.
        """
        return self.materializer_types

    def is_registered(self, key: Type[Any]) -> bool:
        """Returns if a materializer class is registered for the given type.

        Args:
            key: Indicates the type of object.

        Returns:
            True if a materializer is registered for the given type, False
            otherwise.
        """
        return any(issubclass(key, type_) for type_ in self.materializer_types)
__getitem__(self, key) special

Get a single materializers based on the key.

Parameters:

Name Type Description Default
key Type[Any]

Indicates the type of object.

required

Returns:

Type Description
Type[BaseMaterializer]

BaseMaterializer subclass that was registered for this key.

Source code in zenml/materializers/materializer_registry.py
def __getitem__(self, key: Type[Any]) -> Type["BaseMaterializer"]:
    """Get a single materializers based on the key.

    Args:
        key: Indicates the type of object.

    Returns:
        `BaseMaterializer` subclass that was registered for this key.
    """
    for class_ in key.__mro__:
        materializer = self.materializer_types.get(class_, None)
        if materializer:
            return materializer
    return self.get_default_materializer()
__init__(self) special

Initialize the materializer registry.

Source code in zenml/materializers/materializer_registry.py
def __init__(self) -> None:
    """Initialize the materializer registry."""
    self.default_materializer: Optional[Type["BaseMaterializer"]] = None
    self.materializer_types: Dict[Type[Any], Type["BaseMaterializer"]] = {}
get_default_materializer(self)

Get the default materializer that is used if no other is found.

Returns:

Type Description
Type[BaseMaterializer]

The default materializer.

Source code in zenml/materializers/materializer_registry.py
def get_default_materializer(self) -> Type["BaseMaterializer"]:
    """Get the default materializer that is used if no other is found.

    Returns:
        The default materializer.
    """
    from zenml.materializers.cloudpickle_materializer import (
        CloudpickleMaterializer,
    )

    if self.default_materializer:
        return self.default_materializer

    return CloudpickleMaterializer
get_materializer_types(self)

Get all registered materializer types.

Returns:

Type Description
Dict[Type[Any], Type[BaseMaterializer]]

A dictionary of registered materializer types.

Source code in zenml/materializers/materializer_registry.py
def get_materializer_types(
    self,
) -> Dict[Type[Any], Type["BaseMaterializer"]]:
    """Get all registered materializer types.

    Returns:
        A dictionary of registered materializer types.
    """
    return self.materializer_types
is_registered(self, key)

Returns if a materializer class is registered for the given type.

Parameters:

Name Type Description Default
key Type[Any]

Indicates the type of object.

required

Returns:

Type Description
bool

True if a materializer is registered for the given type, False otherwise.

Source code in zenml/materializers/materializer_registry.py
def is_registered(self, key: Type[Any]) -> bool:
    """Returns if a materializer class is registered for the given type.

    Args:
        key: Indicates the type of object.

    Returns:
        True if a materializer is registered for the given type, False
        otherwise.
    """
    return any(issubclass(key, type_) for type_ in self.materializer_types)
register_and_overwrite_type(self, key, type_)

Registers a new materializer and also overwrites a default if set.

Parameters:

Name Type Description Default
key Type[Any]

Indicates the type of object.

required
type_ Type[BaseMaterializer]

A BaseMaterializer subclass.

required
Source code in zenml/materializers/materializer_registry.py
def register_and_overwrite_type(
    self, key: Type[Any], type_: Type["BaseMaterializer"]
) -> None:
    """Registers a new materializer and also overwrites a default if set.

    Args:
        key: Indicates the type of object.
        type_: A BaseMaterializer subclass.
    """
    self.materializer_types[key] = type_
    logger.debug(f"Registered materializer {type_} for {key}")
register_materializer_type(self, key, type_)

Registers a new materializer.

Parameters:

Name Type Description Default
key Type[Any]

Indicates the type of object.

required
type_ Type[BaseMaterializer]

A BaseMaterializer subclass.

required
Source code in zenml/materializers/materializer_registry.py
def register_materializer_type(
    self, key: Type[Any], type_: Type["BaseMaterializer"]
) -> None:
    """Registers a new materializer.

    Args:
        key: Indicates the type of object.
        type_: A BaseMaterializer subclass.
    """
    if key not in self.materializer_types:
        self.materializer_types[key] = type_
        logger.debug(f"Registered materializer {type_} for {key}")
    else:
        logger.debug(
            f"Found existing materializer class for {key}: "
            f"{self.materializer_types[key]}. Skipping registration of "
            f"{type_}."
        )

numpy_materializer

Implementation of the ZenML NumPy materializer.

NumpyMaterializer (BaseMaterializer)

Materializer to read data to and from pandas.

Source code in zenml/materializers/numpy_materializer.py
class NumpyMaterializer(BaseMaterializer):
    """Materializer to read data to and from pandas."""

    ASSOCIATED_TYPES: ClassVar[Tuple[Type[Any], ...]] = (np.ndarray,)
    ASSOCIATED_ARTIFACT_TYPE: ClassVar[ArtifactType] = ArtifactType.DATA

    def load(self, data_type: Type[Any]) -> "Any":
        """Reads a numpy array from a `.npy` file.

        Args:
            data_type: The type of the data to read.


        Raises:
            ImportError: If pyarrow is not installed.

        Returns:
            The numpy array.
        """
        numpy_file = os.path.join(self.uri, NUMPY_FILENAME)

        if self.artifact_store.exists(numpy_file):
            with self.artifact_store.open(numpy_file, "rb") as f:
                return np.load(f, allow_pickle=True)
        elif self.artifact_store.exists(os.path.join(self.uri, DATA_FILENAME)):
            logger.warning(
                "A legacy artifact was found. "
                "This artifact was created with an older version of "
                "ZenML. You can still use it, but it will be "
                "converted to the new format on the next materialization."
            )
            try:
                # Import old materializer dependencies
                import pyarrow as pa  # type: ignore
                import pyarrow.parquet as pq  # type: ignore

                from zenml.utils import yaml_utils

                # Read numpy array from parquet file
                shape_dict = yaml_utils.read_json(
                    os.path.join(self.uri, SHAPE_FILENAME)
                )
                shape_tuple = tuple(shape_dict.values())
                with self.artifact_store.open(
                    os.path.join(self.uri, DATA_FILENAME), "rb"
                ) as f:
                    input_stream = pa.input_stream(f)
                    data = pq.read_table(input_stream)
                vals = getattr(data.to_pandas(), DATA_VAR).values
                return np.reshape(vals, shape_tuple)
            except ImportError:
                raise ImportError(
                    "You have an old version of a `NumpyMaterializer` ",
                    "data artifact stored in the artifact store ",
                    "as a `.parquet` file, which requires `pyarrow` for reading. ",
                    "You can install `pyarrow` by running `pip install pyarrow`.",
                )

    def save(self, arr: "NDArray[Any]") -> None:
        """Writes a np.ndarray to the artifact store as a `.npy` file.

        Args:
            arr: The numpy array to write.
        """
        with self.artifact_store.open(
            os.path.join(self.uri, NUMPY_FILENAME), "wb"
        ) as f:
            np.save(f, arr)

    def save_visualizations(
        self, arr: "NDArray[Any]"
    ) -> Dict[str, VisualizationType]:
        """Saves visualizations for a numpy array.

        If the array is 1D, a histogram is saved. If the array is 2D or 3D with
        3 or 4 channels, an image is saved.

        Args:
            arr: The numpy array to visualize.

        Returns:
            A dictionary of visualization URIs and their types.
        """
        if not np.issubdtype(arr.dtype, np.number):
            return {}

        try:
            # Save histogram for 1D arrays
            if len(arr.shape) == 1:
                histogram_path = os.path.join(self.uri, "histogram.png")
                histogram_path = histogram_path.replace("\\", "/")
                self._save_histogram(histogram_path, arr)
                return {histogram_path: VisualizationType.IMAGE}

            # Save as image for 3D arrays with 3 or 4 channels
            if len(arr.shape) == 3 and arr.shape[2] in [3, 4]:
                image_path = os.path.join(self.uri, "image.png")
                image_path = image_path.replace("\\", "/")
                self._save_image(image_path, arr)
                return {image_path: VisualizationType.IMAGE}

        except ImportError:
            logger.info(
                "Skipping visualization of numpy array because matplotlib "
                "is not installed. To install matplotlib, run "
                "`pip install matplotlib`."
            )

        return {}

    def _save_histogram(self, output_path: str, arr: "NDArray[Any]") -> None:
        """Saves a histogram of a numpy array.

        Args:
            output_path: The path to save the histogram to.
            arr: The numpy array of which to save the histogram.
        """
        import matplotlib.pyplot as plt

        plt.hist(arr)
        with self.artifact_store.open(output_path, "wb") as f:
            plt.savefig(f)
        plt.close()

    def _save_image(self, output_path: str, arr: "NDArray[Any]") -> None:
        """Saves a numpy array as an image.

        Args:
            output_path: The path to save the image to.
            arr: The numpy array to save.
        """
        from matplotlib.image import imsave

        with self.artifact_store.open(output_path, "wb") as f:
            imsave(f, arr)

    def extract_metadata(
        self, arr: "NDArray[Any]"
    ) -> Dict[str, "MetadataType"]:
        """Extract metadata from the given numpy array.

        Args:
            arr: The numpy array to extract metadata from.

        Returns:
            The extracted metadata as a dictionary.
        """
        if np.issubdtype(arr.dtype, np.number):
            return self._extract_numeric_metadata(arr)
        elif np.issubdtype(arr.dtype, np.unicode_) or np.issubdtype(
            arr.dtype, np.object_
        ):
            return self._extract_text_metadata(arr)
        else:
            return {}

    def _extract_numeric_metadata(
        self, arr: "NDArray[Any]"
    ) -> Dict[str, "MetadataType"]:
        """Extracts numeric metadata from a numpy array.

        Args:
            arr: The numpy array to extract metadata from.

        Returns:
            A dictionary of metadata.
        """
        min_val = np.min(arr).item()
        max_val = np.max(arr).item()

        numpy_metadata: Dict[str, "MetadataType"] = {
            "shape": tuple(arr.shape),
            "dtype": DType(arr.dtype.type),
            "mean": np.mean(arr).item(),
            "std": np.std(arr).item(),
            "min": min_val,
            "max": max_val,
        }
        return numpy_metadata

    def _extract_text_metadata(
        self, arr: "NDArray[Any]"
    ) -> Dict[str, "MetadataType"]:
        """Extracts text metadata from a numpy array.

        Args:
            arr: The numpy array to extract metadata from.

        Returns:
            A dictionary of metadata.
        """
        text = " ".join(arr)
        words = text.split()
        word_counts = Counter(words)
        unique_words = len(word_counts)
        total_words = len(words)
        most_common_word, most_common_count = word_counts.most_common(1)[0]

        text_metadata: Dict[str, "MetadataType"] = {
            "shape": tuple(arr.shape),
            "dtype": DType(arr.dtype.type),
            "unique_words": unique_words,
            "total_words": total_words,
            "most_common_word": most_common_word,
            "most_common_count": most_common_count,
        }
        return text_metadata
extract_metadata(self, arr)

Extract metadata from the given numpy array.

Parameters:

Name Type Description Default
arr NDArray[Any]

The numpy array to extract metadata from.

required

Returns:

Type Description
Dict[str, MetadataType]

The extracted metadata as a dictionary.

Source code in zenml/materializers/numpy_materializer.py
def extract_metadata(
    self, arr: "NDArray[Any]"
) -> Dict[str, "MetadataType"]:
    """Extract metadata from the given numpy array.

    Args:
        arr: The numpy array to extract metadata from.

    Returns:
        The extracted metadata as a dictionary.
    """
    if np.issubdtype(arr.dtype, np.number):
        return self._extract_numeric_metadata(arr)
    elif np.issubdtype(arr.dtype, np.unicode_) or np.issubdtype(
        arr.dtype, np.object_
    ):
        return self._extract_text_metadata(arr)
    else:
        return {}
load(self, data_type)

Reads a numpy array from a .npy file.

Parameters:

Name Type Description Default
data_type Type[Any]

The type of the data to read.

required

Exceptions:

Type Description
ImportError

If pyarrow is not installed.

Returns:

Type Description
Any

The numpy array.

Source code in zenml/materializers/numpy_materializer.py
def load(self, data_type: Type[Any]) -> "Any":
    """Reads a numpy array from a `.npy` file.

    Args:
        data_type: The type of the data to read.


    Raises:
        ImportError: If pyarrow is not installed.

    Returns:
        The numpy array.
    """
    numpy_file = os.path.join(self.uri, NUMPY_FILENAME)

    if self.artifact_store.exists(numpy_file):
        with self.artifact_store.open(numpy_file, "rb") as f:
            return np.load(f, allow_pickle=True)
    elif self.artifact_store.exists(os.path.join(self.uri, DATA_FILENAME)):
        logger.warning(
            "A legacy artifact was found. "
            "This artifact was created with an older version of "
            "ZenML. You can still use it, but it will be "
            "converted to the new format on the next materialization."
        )
        try:
            # Import old materializer dependencies
            import pyarrow as pa  # type: ignore
            import pyarrow.parquet as pq  # type: ignore

            from zenml.utils import yaml_utils

            # Read numpy array from parquet file
            shape_dict = yaml_utils.read_json(
                os.path.join(self.uri, SHAPE_FILENAME)
            )
            shape_tuple = tuple(shape_dict.values())
            with self.artifact_store.open(
                os.path.join(self.uri, DATA_FILENAME), "rb"
            ) as f:
                input_stream = pa.input_stream(f)
                data = pq.read_table(input_stream)
            vals = getattr(data.to_pandas(), DATA_VAR).values
            return np.reshape(vals, shape_tuple)
        except ImportError:
            raise ImportError(
                "You have an old version of a `NumpyMaterializer` ",
                "data artifact stored in the artifact store ",
                "as a `.parquet` file, which requires `pyarrow` for reading. ",
                "You can install `pyarrow` by running `pip install pyarrow`.",
            )
save(self, arr)

Writes a np.ndarray to the artifact store as a .npy file.

Parameters:

Name Type Description Default
arr NDArray[Any]

The numpy array to write.

required
Source code in zenml/materializers/numpy_materializer.py
def save(self, arr: "NDArray[Any]") -> None:
    """Writes a np.ndarray to the artifact store as a `.npy` file.

    Args:
        arr: The numpy array to write.
    """
    with self.artifact_store.open(
        os.path.join(self.uri, NUMPY_FILENAME), "wb"
    ) as f:
        np.save(f, arr)
save_visualizations(self, arr)

Saves visualizations for a numpy array.

If the array is 1D, a histogram is saved. If the array is 2D or 3D with 3 or 4 channels, an image is saved.

Parameters:

Name Type Description Default
arr NDArray[Any]

The numpy array to visualize.

required

Returns:

Type Description
Dict[str, zenml.enums.VisualizationType]

A dictionary of visualization URIs and their types.

Source code in zenml/materializers/numpy_materializer.py
def save_visualizations(
    self, arr: "NDArray[Any]"
) -> Dict[str, VisualizationType]:
    """Saves visualizations for a numpy array.

    If the array is 1D, a histogram is saved. If the array is 2D or 3D with
    3 or 4 channels, an image is saved.

    Args:
        arr: The numpy array to visualize.

    Returns:
        A dictionary of visualization URIs and their types.
    """
    if not np.issubdtype(arr.dtype, np.number):
        return {}

    try:
        # Save histogram for 1D arrays
        if len(arr.shape) == 1:
            histogram_path = os.path.join(self.uri, "histogram.png")
            histogram_path = histogram_path.replace("\\", "/")
            self._save_histogram(histogram_path, arr)
            return {histogram_path: VisualizationType.IMAGE}

        # Save as image for 3D arrays with 3 or 4 channels
        if len(arr.shape) == 3 and arr.shape[2] in [3, 4]:
            image_path = os.path.join(self.uri, "image.png")
            image_path = image_path.replace("\\", "/")
            self._save_image(image_path, arr)
            return {image_path: VisualizationType.IMAGE}

    except ImportError:
        logger.info(
            "Skipping visualization of numpy array because matplotlib "
            "is not installed. To install matplotlib, run "
            "`pip install matplotlib`."
        )

    return {}

pandas_materializer

Materializer for Pandas.

PandasMaterializer (BaseMaterializer)

Materializer to read data to and from pandas.

Source code in zenml/materializers/pandas_materializer.py
class PandasMaterializer(BaseMaterializer):
    """Materializer to read data to and from pandas."""

    ASSOCIATED_TYPES: ClassVar[Tuple[Type[Any], ...]] = (
        pd.DataFrame,
        pd.Series,
    )
    ASSOCIATED_ARTIFACT_TYPE: ClassVar[ArtifactType] = ArtifactType.DATA

    def __init__(
        self, uri: str, artifact_store: Optional[BaseArtifactStore] = None
    ):
        """Define `self.data_path`.

        Args:
            uri: The URI where the artifact data is stored.
            artifact_store: The artifact store where the artifact data is stored.
        """
        super().__init__(uri, artifact_store)
        try:
            import pyarrow  # type: ignore # noqa

            self.pyarrow_exists = True
        except ImportError:
            self.pyarrow_exists = False
            logger.warning(
                "By default, the `PandasMaterializer` stores data as a "
                "`.csv` file. If you want to store data more efficiently, "
                "you can install `pyarrow` by running "
                "'`pip install pyarrow`'. This will allow `PandasMaterializer` "
                "to automatically store the data as a `.parquet` file instead."
            )
        finally:
            self.parquet_path = os.path.join(self.uri, PARQUET_FILENAME)
            self.csv_path = os.path.join(self.uri, CSV_FILENAME)

    def load(self, data_type: Type[Any]) -> Union[pd.DataFrame, pd.Series]:
        """Reads `pd.DataFrame` or `pd.Series` from a `.parquet` or `.csv` file.

        Args:
            data_type: The type of the data to read.

        Raises:
            ImportError: If pyarrow or fastparquet is not installed.

        Returns:
            The pandas dataframe or series.
        """
        if self.artifact_store.exists(self.parquet_path):
            if self.pyarrow_exists:
                with self.artifact_store.open(
                    self.parquet_path, mode="rb"
                ) as f:
                    df = pd.read_parquet(f)
            else:
                raise ImportError(
                    "You have an old version of a `PandasMaterializer` "
                    "data artifact stored in the artifact store "
                    "as a `.parquet` file, which requires `pyarrow` "
                    "for reading, You can install `pyarrow` by running "
                    "'`pip install pyarrow fastparquet`'."
                )
        else:
            with self.artifact_store.open(self.csv_path, mode="rb") as f:
                df = pd.read_csv(f, index_col=0, parse_dates=True)

        # validate the type of the data.
        def is_dataframe_or_series(
            df: Union[pd.DataFrame, pd.Series],
        ) -> Union[pd.DataFrame, pd.Series]:
            """Checks if the data is a `pd.DataFrame` or `pd.Series`.

            Args:
                df: The data to check.

            Returns:
                The data if it is a `pd.DataFrame` or `pd.Series`.
            """
            if issubclass(data_type, pd.Series):
                # Taking the first column if its a series as the assumption
                # is that there will only be one
                assert len(df.columns) == 1
                df = df[df.columns[0]]
                return df
            else:
                return df

        return is_dataframe_or_series(df)

    def save(self, df: Union[pd.DataFrame, pd.Series]) -> None:
        """Writes a pandas dataframe or series to the specified filename.

        Args:
            df: The pandas dataframe or series to write.
        """
        if isinstance(df, pd.Series):
            df = df.to_frame(name="series")

        if self.pyarrow_exists:
            with self.artifact_store.open(self.parquet_path, mode="wb") as f:
                df.to_parquet(f, compression=COMPRESSION_TYPE)
        else:
            with self.artifact_store.open(self.csv_path, mode="wb") as f:
                df.to_csv(f, index=True)

    def save_visualizations(
        self, df: Union[pd.DataFrame, pd.Series]
    ) -> Dict[str, VisualizationType]:
        """Save visualizations of the given pandas dataframe or series.

        Args:
            df: The pandas dataframe or series to visualize.

        Returns:
            A dictionary of visualization URIs and their types.
        """
        describe_uri = os.path.join(self.uri, "describe.csv")
        describe_uri = describe_uri.replace("\\", "/")
        with self.artifact_store.open(describe_uri, mode="wb") as f:
            df.describe().to_csv(f)
        return {describe_uri: VisualizationType.CSV}

    def extract_metadata(
        self, df: Union[pd.DataFrame, pd.Series]
    ) -> Dict[str, "MetadataType"]:
        """Extract metadata from the given pandas dataframe or series.

        Args:
            df: The pandas dataframe or series to extract metadata from.

        Returns:
            The extracted metadata as a dictionary.
        """
        pandas_metadata: Dict[str, "MetadataType"] = {"shape": df.shape}

        if isinstance(df, pd.Series):
            pandas_metadata["dtype"] = DType(df.dtype.type)
            pandas_metadata["mean"] = float(df.mean().item())
            pandas_metadata["std"] = float(df.std().item())
            pandas_metadata["min"] = float(df.min().item())
            pandas_metadata["max"] = float(df.max().item())

        else:
            pandas_metadata["dtype"] = {
                str(key): DType(value.type) for key, value in df.dtypes.items()
            }
            for stat_name, stat in {
                "mean": df.mean,
                "std": df.std,
                "min": df.min,
                "max": df.max,
            }.items():
                pandas_metadata[stat_name] = {
                    str(key): float(value)
                    for key, value in stat(numeric_only=True).to_dict().items()
                }

        return pandas_metadata
__init__(self, uri, artifact_store=None) special

Define self.data_path.

Parameters:

Name Type Description Default
uri str

The URI where the artifact data is stored.

required
artifact_store Optional[zenml.artifact_stores.base_artifact_store.BaseArtifactStore]

The artifact store where the artifact data is stored.

None
Source code in zenml/materializers/pandas_materializer.py
def __init__(
    self, uri: str, artifact_store: Optional[BaseArtifactStore] = None
):
    """Define `self.data_path`.

    Args:
        uri: The URI where the artifact data is stored.
        artifact_store: The artifact store where the artifact data is stored.
    """
    super().__init__(uri, artifact_store)
    try:
        import pyarrow  # type: ignore # noqa

        self.pyarrow_exists = True
    except ImportError:
        self.pyarrow_exists = False
        logger.warning(
            "By default, the `PandasMaterializer` stores data as a "
            "`.csv` file. If you want to store data more efficiently, "
            "you can install `pyarrow` by running "
            "'`pip install pyarrow`'. This will allow `PandasMaterializer` "
            "to automatically store the data as a `.parquet` file instead."
        )
    finally:
        self.parquet_path = os.path.join(self.uri, PARQUET_FILENAME)
        self.csv_path = os.path.join(self.uri, CSV_FILENAME)
extract_metadata(self, df)

Extract metadata from the given pandas dataframe or series.

Parameters:

Name Type Description Default
df Union[pandas.core.frame.DataFrame, pandas.core.series.Series]

The pandas dataframe or series to extract metadata from.

required

Returns:

Type Description
Dict[str, MetadataType]

The extracted metadata as a dictionary.

Source code in zenml/materializers/pandas_materializer.py
def extract_metadata(
    self, df: Union[pd.DataFrame, pd.Series]
) -> Dict[str, "MetadataType"]:
    """Extract metadata from the given pandas dataframe or series.

    Args:
        df: The pandas dataframe or series to extract metadata from.

    Returns:
        The extracted metadata as a dictionary.
    """
    pandas_metadata: Dict[str, "MetadataType"] = {"shape": df.shape}

    if isinstance(df, pd.Series):
        pandas_metadata["dtype"] = DType(df.dtype.type)
        pandas_metadata["mean"] = float(df.mean().item())
        pandas_metadata["std"] = float(df.std().item())
        pandas_metadata["min"] = float(df.min().item())
        pandas_metadata["max"] = float(df.max().item())

    else:
        pandas_metadata["dtype"] = {
            str(key): DType(value.type) for key, value in df.dtypes.items()
        }
        for stat_name, stat in {
            "mean": df.mean,
            "std": df.std,
            "min": df.min,
            "max": df.max,
        }.items():
            pandas_metadata[stat_name] = {
                str(key): float(value)
                for key, value in stat(numeric_only=True).to_dict().items()
            }

    return pandas_metadata
load(self, data_type)

Reads pd.DataFrame or pd.Series from a .parquet or .csv file.

Parameters:

Name Type Description Default
data_type Type[Any]

The type of the data to read.

required

Exceptions:

Type Description
ImportError

If pyarrow or fastparquet is not installed.

Returns:

Type Description
Union[pandas.core.frame.DataFrame, pandas.core.series.Series]

The pandas dataframe or series.

Source code in zenml/materializers/pandas_materializer.py
def load(self, data_type: Type[Any]) -> Union[pd.DataFrame, pd.Series]:
    """Reads `pd.DataFrame` or `pd.Series` from a `.parquet` or `.csv` file.

    Args:
        data_type: The type of the data to read.

    Raises:
        ImportError: If pyarrow or fastparquet is not installed.

    Returns:
        The pandas dataframe or series.
    """
    if self.artifact_store.exists(self.parquet_path):
        if self.pyarrow_exists:
            with self.artifact_store.open(
                self.parquet_path, mode="rb"
            ) as f:
                df = pd.read_parquet(f)
        else:
            raise ImportError(
                "You have an old version of a `PandasMaterializer` "
                "data artifact stored in the artifact store "
                "as a `.parquet` file, which requires `pyarrow` "
                "for reading, You can install `pyarrow` by running "
                "'`pip install pyarrow fastparquet`'."
            )
    else:
        with self.artifact_store.open(self.csv_path, mode="rb") as f:
            df = pd.read_csv(f, index_col=0, parse_dates=True)

    # validate the type of the data.
    def is_dataframe_or_series(
        df: Union[pd.DataFrame, pd.Series],
    ) -> Union[pd.DataFrame, pd.Series]:
        """Checks if the data is a `pd.DataFrame` or `pd.Series`.

        Args:
            df: The data to check.

        Returns:
            The data if it is a `pd.DataFrame` or `pd.Series`.
        """
        if issubclass(data_type, pd.Series):
            # Taking the first column if its a series as the assumption
            # is that there will only be one
            assert len(df.columns) == 1
            df = df[df.columns[0]]
            return df
        else:
            return df

    return is_dataframe_or_series(df)
save(self, df)

Writes a pandas dataframe or series to the specified filename.

Parameters:

Name Type Description Default
df Union[pandas.core.frame.DataFrame, pandas.core.series.Series]

The pandas dataframe or series to write.

required
Source code in zenml/materializers/pandas_materializer.py
def save(self, df: Union[pd.DataFrame, pd.Series]) -> None:
    """Writes a pandas dataframe or series to the specified filename.

    Args:
        df: The pandas dataframe or series to write.
    """
    if isinstance(df, pd.Series):
        df = df.to_frame(name="series")

    if self.pyarrow_exists:
        with self.artifact_store.open(self.parquet_path, mode="wb") as f:
            df.to_parquet(f, compression=COMPRESSION_TYPE)
    else:
        with self.artifact_store.open(self.csv_path, mode="wb") as f:
            df.to_csv(f, index=True)
save_visualizations(self, df)

Save visualizations of the given pandas dataframe or series.

Parameters:

Name Type Description Default
df Union[pandas.core.frame.DataFrame, pandas.core.series.Series]

The pandas dataframe or series to visualize.

required

Returns:

Type Description
Dict[str, zenml.enums.VisualizationType]

A dictionary of visualization URIs and their types.

Source code in zenml/materializers/pandas_materializer.py
def save_visualizations(
    self, df: Union[pd.DataFrame, pd.Series]
) -> Dict[str, VisualizationType]:
    """Save visualizations of the given pandas dataframe or series.

    Args:
        df: The pandas dataframe or series to visualize.

    Returns:
        A dictionary of visualization URIs and their types.
    """
    describe_uri = os.path.join(self.uri, "describe.csv")
    describe_uri = describe_uri.replace("\\", "/")
    with self.artifact_store.open(describe_uri, mode="wb") as f:
        df.describe().to_csv(f)
    return {describe_uri: VisualizationType.CSV}

pydantic_materializer

Implementation of ZenML's pydantic materializer.

PydanticMaterializer (BaseMaterializer)

Handle Pydantic BaseModel objects.

Source code in zenml/materializers/pydantic_materializer.py
class PydanticMaterializer(BaseMaterializer):
    """Handle Pydantic BaseModel objects."""

    ASSOCIATED_ARTIFACT_TYPE: ClassVar[ArtifactType] = ArtifactType.DATA
    ASSOCIATED_TYPES: ClassVar[Tuple[Type[Any], ...]] = (BaseModel,)

    def load(self, data_type: Type[BaseModel]) -> Any:
        """Reads BaseModel from JSON.

        Args:
            data_type: The type of the data to read.

        Returns:
            The data read.
        """
        data_path = os.path.join(self.uri, DEFAULT_FILENAME)
        contents = yaml_utils.read_json(data_path)
        return data_type.model_validate_json(contents)

    def save(self, data: BaseModel) -> None:
        """Serialize a BaseModel to JSON.

        Args:
            data: The data to store.
        """
        data_path = os.path.join(self.uri, DEFAULT_FILENAME)
        yaml_utils.write_json(data_path, data.model_dump_json())

    def extract_metadata(self, data: BaseModel) -> Dict[str, "MetadataType"]:
        """Extract metadata from the given BaseModel object.

        Args:
            data: The BaseModel object to extract metadata from.

        Returns:
            The extracted metadata as a dictionary.
        """
        return {"schema": data.schema()}
extract_metadata(self, data)

Extract metadata from the given BaseModel object.

Parameters:

Name Type Description Default
data BaseModel

The BaseModel object to extract metadata from.

required

Returns:

Type Description
Dict[str, MetadataType]

The extracted metadata as a dictionary.

Source code in zenml/materializers/pydantic_materializer.py
def extract_metadata(self, data: BaseModel) -> Dict[str, "MetadataType"]:
    """Extract metadata from the given BaseModel object.

    Args:
        data: The BaseModel object to extract metadata from.

    Returns:
        The extracted metadata as a dictionary.
    """
    return {"schema": data.schema()}
load(self, data_type)

Reads BaseModel from JSON.

Parameters:

Name Type Description Default
data_type Type[pydantic.main.BaseModel]

The type of the data to read.

required

Returns:

Type Description
Any

The data read.

Source code in zenml/materializers/pydantic_materializer.py
def load(self, data_type: Type[BaseModel]) -> Any:
    """Reads BaseModel from JSON.

    Args:
        data_type: The type of the data to read.

    Returns:
        The data read.
    """
    data_path = os.path.join(self.uri, DEFAULT_FILENAME)
    contents = yaml_utils.read_json(data_path)
    return data_type.model_validate_json(contents)
save(self, data)

Serialize a BaseModel to JSON.

Parameters:

Name Type Description Default
data BaseModel

The data to store.

required
Source code in zenml/materializers/pydantic_materializer.py
def save(self, data: BaseModel) -> None:
    """Serialize a BaseModel to JSON.

    Args:
        data: The data to store.
    """
    data_path = os.path.join(self.uri, DEFAULT_FILENAME)
    yaml_utils.write_json(data_path, data.model_dump_json())

service_materializer

Implementation of a materializer to read and write ZenML service instances.

ServiceMaterializer (BaseMaterializer)

Materializer to read/write service instances.

Source code in zenml/materializers/service_materializer.py
class ServiceMaterializer(BaseMaterializer):
    """Materializer to read/write service instances."""

    ASSOCIATED_TYPES: ClassVar[Tuple[Type[Any], ...]] = (BaseService,)
    ASSOCIATED_ARTIFACT_TYPE: ClassVar[ArtifactType] = ArtifactType.SERVICE

    def load(self, data_type: Type[Any]) -> BaseService:
        """Creates and returns a service.

        This service is instantiated from the serialized service configuration
        and last known status information saved as artifact.

        Args:
            data_type: The type of the data to read.

        Returns:
            A ZenML service instance.
        """
        filepath = os.path.join(self.uri, SERVICE_CONFIG_FILENAME)
        with self.artifact_store.open(filepath, "r") as f:
            service_id = f.read().strip()

        service = Client().get_service(name_id_or_prefix=uuid.UUID(service_id))
        return BaseDeploymentService.from_model(service)

    def save(self, service: BaseService) -> None:
        """Writes a ZenML service.

        The configuration and last known status of the input service instance
        are serialized and saved as an artifact.

        Args:
            service: A ZenML service instance.
        """
        filepath = os.path.join(self.uri, SERVICE_CONFIG_FILENAME)
        with self.artifact_store.open(filepath, "w") as f:
            f.write(str(service.uuid))

    def extract_metadata(
        self, service: BaseService
    ) -> Dict[str, "MetadataType"]:
        """Extract metadata from the given service.

        Args:
            service: The service to extract metadata from.

        Returns:
            The extracted metadata as a dictionary.
        """
        from zenml.metadata.metadata_types import Uri

        if prediction_url := service.get_prediction_url() or None:
            return {"uri": Uri(prediction_url)}
        return {}
extract_metadata(self, service)

Extract metadata from the given service.

Parameters:

Name Type Description Default
service BaseService

The service to extract metadata from.

required

Returns:

Type Description
Dict[str, MetadataType]

The extracted metadata as a dictionary.

Source code in zenml/materializers/service_materializer.py
def extract_metadata(
    self, service: BaseService
) -> Dict[str, "MetadataType"]:
    """Extract metadata from the given service.

    Args:
        service: The service to extract metadata from.

    Returns:
        The extracted metadata as a dictionary.
    """
    from zenml.metadata.metadata_types import Uri

    if prediction_url := service.get_prediction_url() or None:
        return {"uri": Uri(prediction_url)}
    return {}
load(self, data_type)

Creates and returns a service.

This service is instantiated from the serialized service configuration and last known status information saved as artifact.

Parameters:

Name Type Description Default
data_type Type[Any]

The type of the data to read.

required

Returns:

Type Description
BaseService

A ZenML service instance.

Source code in zenml/materializers/service_materializer.py
def load(self, data_type: Type[Any]) -> BaseService:
    """Creates and returns a service.

    This service is instantiated from the serialized service configuration
    and last known status information saved as artifact.

    Args:
        data_type: The type of the data to read.

    Returns:
        A ZenML service instance.
    """
    filepath = os.path.join(self.uri, SERVICE_CONFIG_FILENAME)
    with self.artifact_store.open(filepath, "r") as f:
        service_id = f.read().strip()

    service = Client().get_service(name_id_or_prefix=uuid.UUID(service_id))
    return BaseDeploymentService.from_model(service)
save(self, service)

Writes a ZenML service.

The configuration and last known status of the input service instance are serialized and saved as an artifact.

Parameters:

Name Type Description Default
service BaseService

A ZenML service instance.

required
Source code in zenml/materializers/service_materializer.py
def save(self, service: BaseService) -> None:
    """Writes a ZenML service.

    The configuration and last known status of the input service instance
    are serialized and saved as an artifact.

    Args:
        service: A ZenML service instance.
    """
    filepath = os.path.join(self.uri, SERVICE_CONFIG_FILENAME)
    with self.artifact_store.open(filepath, "w") as f:
        f.write(str(service.uuid))

structured_string_materializer

Implementation of HTMLString materializer.

StructuredStringMaterializer (BaseMaterializer)

Materializer for HTML or Markdown strings.

Source code in zenml/materializers/structured_string_materializer.py
class StructuredStringMaterializer(BaseMaterializer):
    """Materializer for HTML or Markdown strings."""

    ASSOCIATED_TYPES = (CSVString, HTMLString, MarkdownString)
    ASSOCIATED_ARTIFACT_TYPE = ArtifactType.DATA_ANALYSIS

    def load(self, data_type: Type[STRUCTURED_STRINGS]) -> STRUCTURED_STRINGS:
        """Loads the data from the HTML or Markdown file.

        Args:
            data_type: The type of the data to read.

        Returns:
            The loaded data.
        """
        with self.artifact_store.open(self._get_filepath(data_type), "r") as f:
            return data_type(f.read())

    def save(self, data: STRUCTURED_STRINGS) -> None:
        """Save data as an HTML or Markdown file.

        Args:
            data: The data to save as an HTML or Markdown file.
        """
        with self.artifact_store.open(
            self._get_filepath(type(data)), "w"
        ) as f:
            f.write(data)

    def save_visualizations(
        self, data: STRUCTURED_STRINGS
    ) -> Dict[str, VisualizationType]:
        """Save visualizations for the given data.

        Args:
            data: The data to save visualizations for.

        Returns:
            A dictionary of visualization URIs and their types.
        """
        filepath = self._get_filepath(type(data))
        filepath = filepath.replace("\\", "/")
        visualization_type = self._get_visualization_type(type(data))
        return {filepath: visualization_type}

    def _get_filepath(self, data_type: Type[STRUCTURED_STRINGS]) -> str:
        """Get the file path for the given data type.

        Args:
            data_type: The type of the data.

        Returns:
            The file path for the given data type.

        Raises:
            ValueError: If the data type is not supported.
        """
        if issubclass(data_type, CSVString):
            filename = CSV_FILENAME
        elif issubclass(data_type, HTMLString):
            filename = HTML_FILENAME
        elif issubclass(data_type, MarkdownString):
            filename = MARKDOWN_FILENAME
        else:
            raise ValueError(
                f"Data type {data_type} is not supported by this materializer."
            )
        return os.path.join(self.uri, filename)

    def _get_visualization_type(
        self, data_type: Type[STRUCTURED_STRINGS]
    ) -> VisualizationType:
        """Get the visualization type for the given data type.

        Args:
            data_type: The type of the data.

        Returns:
            The visualization type for the given data type.

        Raises:
            ValueError: If the data type is not supported.
        """
        if issubclass(data_type, CSVString):
            return VisualizationType.CSV
        elif issubclass(data_type, HTMLString):
            return VisualizationType.HTML
        elif issubclass(data_type, MarkdownString):
            return VisualizationType.MARKDOWN
        else:
            raise ValueError(
                f"Data type {data_type} is not supported by this materializer."
            )
load(self, data_type)

Loads the data from the HTML or Markdown file.

Parameters:

Name Type Description Default
data_type Type[Union[zenml.types.CSVString, zenml.types.HTMLString, zenml.types.MarkdownString]]

The type of the data to read.

required

Returns:

Type Description
Union[zenml.types.CSVString, zenml.types.HTMLString, zenml.types.MarkdownString]

The loaded data.

Source code in zenml/materializers/structured_string_materializer.py
def load(self, data_type: Type[STRUCTURED_STRINGS]) -> STRUCTURED_STRINGS:
    """Loads the data from the HTML or Markdown file.

    Args:
        data_type: The type of the data to read.

    Returns:
        The loaded data.
    """
    with self.artifact_store.open(self._get_filepath(data_type), "r") as f:
        return data_type(f.read())
save(self, data)

Save data as an HTML or Markdown file.

Parameters:

Name Type Description Default
data Union[zenml.types.CSVString, zenml.types.HTMLString, zenml.types.MarkdownString]

The data to save as an HTML or Markdown file.

required
Source code in zenml/materializers/structured_string_materializer.py
def save(self, data: STRUCTURED_STRINGS) -> None:
    """Save data as an HTML or Markdown file.

    Args:
        data: The data to save as an HTML or Markdown file.
    """
    with self.artifact_store.open(
        self._get_filepath(type(data)), "w"
    ) as f:
        f.write(data)
save_visualizations(self, data)

Save visualizations for the given data.

Parameters:

Name Type Description Default
data Union[zenml.types.CSVString, zenml.types.HTMLString, zenml.types.MarkdownString]

The data to save visualizations for.

required

Returns:

Type Description
Dict[str, zenml.enums.VisualizationType]

A dictionary of visualization URIs and their types.

Source code in zenml/materializers/structured_string_materializer.py
def save_visualizations(
    self, data: STRUCTURED_STRINGS
) -> Dict[str, VisualizationType]:
    """Save visualizations for the given data.

    Args:
        data: The data to save visualizations for.

    Returns:
        A dictionary of visualization URIs and their types.
    """
    filepath = self._get_filepath(type(data))
    filepath = filepath.replace("\\", "/")
    visualization_type = self._get_visualization_type(type(data))
    return {filepath: visualization_type}