prefect.blocks.system

Classes

Secret ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/blocks/system.py#L26" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

A block that represents a secret value. The value stored in this block will be obfuscated when this block is viewed or edited in the UI.

Attributes:

• value: A value that should be kept secret.

Methods:

adelete ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/blocks/core.py#L1893" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

adelete(cls, name: str, client: Optional['PrefectClient'] = None) -> None

Asynchronously deletes the block document with the specified name.

Args:

• name: The name of the block document to delete.
• client: The client to use to delete the block document. If not provided, the default client will be injected.

aload ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/blocks/core.py#L1057" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

aload(cls, name: str, validate: bool = True, client: Optional['PrefectClient'] = None) -> 'Self'

Retrieves data from the block document with the given name for the block type that corresponds with the current class and returns an instantiated version of the current class with the data stored in the block document.

If a block document for a given block type is saved with a different schema than the current class calling aload, a warning will be raised.

If the current class schema is a subset of the block document schema, the block can be loaded as normal using the default validate = True.

If the current class schema is a superset of the block document schema, aload must be called with validate set to False to prevent a validation error. In this case, the block attributes will default to None and must be set manually and saved to a new block document before the block can be used as expected.

Args:

• name: The name or slug of the block document. A block document slug is a string with the format <block_type_slug>/<block_document_name>
• validate: If False, the block document will be loaded without Pydantic validating the block schema. This is useful if the block schema has changed client-side since the block document referred to by name was saved.
• client: The client to use to load the block document. If not provided, the default client will be injected.

Raises:

• ValueError: If the requested block document is not found.

Returns:

• An instance of the current class hydrated with the data stored in the
• block document with the specified name.

Examples:

Load from a Block subclass with a block document name:

class Custom(Block):
    message: str

Custom(message="Hello!").save("my-custom-message")

loaded_block = await Custom.aload("my-custom-message")

Load from Block with a block document slug:

class Custom(Block):
    message: str

Custom(message="Hello!").save("my-custom-message")

loaded_block = await Block.aload("custom/my-custom-message")

Migrate a block document to a new schema:

# original class
class Custom(Block):
    message: str

Custom(message="Hello!").save("my-custom-message")

# Updated class with new required field
class Custom(Block):
    message: str
    number_of_ducks: int

loaded_block = await Custom.aload("my-custom-message", validate=False)

# Prints UserWarning about schema mismatch

loaded_block.number_of_ducks = 42

loaded_block.save("my-custom-message", overwrite=True)

aload_from_ref ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/blocks/core.py#L1244" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

aload_from_ref(cls, ref: Union[str, UUID, dict[str, Any]], validate: bool = True, client: 'PrefectClient | None' = None) -> Self

Asynchronously retrieves data from the block document by given reference for the block type that corresponds with the current class and returns an instantiated version of the current class with the data stored in the block document.

Provided reference can be a block document ID, or a reference data in dictionary format. Supported dictionary reference formats are:

• {"block_document_id": <block_document_id>}
• {"block_document_slug": <block_document_slug>}

If a block document for a given block type is saved with a different schema than the current class calling aload_from_ref, a warning will be raised.

If the current class schema is a subset of the block document schema, the block can be loaded as normal using the default validate = True.

If the current class schema is a superset of the block document schema, aload_from_ref must be called with validate set to False to prevent a validation error. In this case, the block attributes will default to None and must be set manually and saved to a new block document before the block can be used as expected.

Args:

• ref: The reference to the block document. This can be a block document ID, or one of supported dictionary reference formats.
• validate: If False, the block document will be loaded without Pydantic validating the block schema. This is useful if the block schema has changed client-side since the block document referred to by name was saved.
• client: The client to use to load the block document. If not provided, the default client will be injected.

Raises:

• ValueError: If invalid reference format is provided.
• ValueError: If the requested block document is not found.

Returns:

• An instance of the current class hydrated with the data stored in the
• block document with the specified name.

annotation_refers_to_block_class ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/blocks/core.py#L1442" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

annotation_refers_to_block_class(annotation: Any) -> bool

aregister_type_and_schema ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/blocks/core.py#L1455" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

aregister_type_and_schema(cls, client: Optional['PrefectClient'] = None) -> None

Asynchronously makes block available for configuration with current Prefect API. Recursively registers all nested blocks. Registration is idempotent.

Args:

• client: Optional client to use for registering type and schema with the Prefect API. A new client will be created and used if one is not provided.

asave ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/blocks/core.py#L1842" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

asave(self, name: Optional[str] = None, overwrite: bool = False, client: Optional['PrefectClient'] = None) -> UUID

Asynchronously saves the values of a block as a block document.

Args:

• name: User specified name to give saved block document which can later be used to load the block document.
• overwrite: Boolean value specifying if values should be overwritten if a block document with the specified name already exists.
• client: The client to use to save the block document. If not provided, the default client will be injected.

Returns:

• The ID of the saved block document.

block_initialization ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/blocks/core.py#L381" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

block_initialization(self) -> None

delete ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/blocks/core.py#L1914" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

delete(cls, name: str, client: Optional['PrefectClient'] = None) -> None

Deletes the block document with the specified name.

This function will dispatch to adelete when called from an async context.

Args:

• name: The name of the block document to delete.
• client: The client to use to delete the block document. If not provided, the default client will be injected. This is ignored when called from a synchronous context.

get ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/blocks/system.py#L72" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

get(self) -> T | str

get_block_capabilities ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/blocks/core.py#L477" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

get_block_capabilities(cls) -> FrozenSet[str]

Returns the block capabilities for this Block. Recursively collects all block capabilities of all parent classes into a single frozenset.

get_block_class_from_key ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/blocks/core.py#L902" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

get_block_class_from_key(cls: type[Self], key: str) -> type[Self]

Retrieve the block class implementation given a key.

get_block_class_from_schema ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/blocks/core.py#L895" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

get_block_class_from_schema(cls: type[Self], schema: BlockSchema) -> type[Self]

Retrieve the block class implementation given a schema.

get_block_placeholder ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/blocks/core.py#L1934" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

get_block_placeholder(self) -> str

Returns the block placeholder for the current block which can be used for templating.

Returns:

• The block placeholder for the current block in the format prefect.blocks.{block_type_name}.{block_document_name}

Raises:

• BlockNotSavedError: Raised if the block has not been saved.

If a block has not been saved, the return value will be None.

get_block_schema_version ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/blocks/core.py#L507" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

get_block_schema_version(cls) -> str

get_block_type_name ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/blocks/core.py#L469" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

get_block_type_name(cls) -> str

get_block_type_slug ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/blocks/core.py#L473" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

get_block_type_slug(cls) -> str

get_code_example ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/blocks/core.py#L750" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

get_code_example(cls) -> Optional[str]

Returns the code example for the given block. Attempts to parse code example from the class docstring if an override is not provided.

get_description ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/blocks/core.py#L727" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

get_description(cls) -> Optional[str]

Returns the description for the current block. Attempts to parse description from class docstring if an override is not defined.

is_block_class ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/blocks/core.py#L1438" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

is_block_class(block: Any) -> TypeGuard[type['Block']]

load ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/blocks/core.py#L1146" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

load(cls, name: str, validate: bool = True, client: Optional['PrefectClient'] = None) -> 'Self'

Retrieves data from the block document with the given name for the block type that corresponds with the current class and returns an instantiated version of the current class with the data stored in the block document.

If a block document for a given block type is saved with a different schema than the current class calling load, a warning will be raised.

If the current class schema is a subset of the block document schema, the block can be loaded as normal using the default validate = True.

If the current class schema is a superset of the block document schema, load must be called with validate set to False to prevent a validation error. In this case, the block attributes will default to None and must be set manually and saved to a new block document before the block can be used as expected.

Args:

• name: The name or slug of the block document. A block document slug is a string with the format <block_type_slug>/<block_document_name>
• validate: If False, the block document will be loaded without Pydantic validating the block schema. This is useful if the block schema has changed client-side since the block document referred to by name was saved.
• client: The client to use to load the block document. If not provided, the default client will be injected.

Raises:

• ValueError: If the requested block document is not found.

Returns:

• An instance of the current class hydrated with the data stored in the
• block document with the specified name.

Examples:

Load from a Block subclass with a block document name:

class Custom(Block):
    message: str

Custom(message="Hello!").save("my-custom-message")

loaded_block = Custom.load("my-custom-message")

Load from Block with a block document slug:

class Custom(Block):
    message: str

Custom(message="Hello!").save("my-custom-message")

loaded_block = Block.load("custom/my-custom-message")

Migrate a block document to a new schema:

# original class
class Custom(Block):
    message: str

Custom(message="Hello!").save("my-custom-message")

# Updated class with new required field
class Custom(Block):
    message: str
    number_of_ducks: int

loaded_block = Custom.load("my-custom-message", validate=False)

# Prints UserWarning about schema mismatch

loaded_block.number_of_ducks = 42

loaded_block.save("my-custom-message", overwrite=True)

load_from_ref ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/blocks/core.py#L1311" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

load_from_ref(cls, ref: Union[str, UUID, dict[str, Any]], validate: bool = True, client: 'PrefectClient | None' = None) -> Self

Retrieves data from the block document by given reference for the block type that corresponds with the current class and returns an instantiated version of the current class with the data stored in the block document.

This function will dispatch to aload_from_ref when called from an async context.

Provided reference can be a block document ID, or a reference data in dictionary format. Supported dictionary reference formats are:

• {"block_document_id": <block_document_id>}
• {"block_document_slug": <block_document_slug>}

If a block document for a given block type is saved with a different schema than the current class calling load_from_ref, a warning will be raised.

If the current class schema is a subset of the block document schema, the block can be loaded as normal using the default validate = True.

If the current class schema is a superset of the block document schema, load_from_ref must be called with validate set to False to prevent a validation error. In this case, the block attributes will default to None and must be set manually and saved to a new block document before the block can be used as expected.

Args:

• ref: The reference to the block document. This can be a block document ID, or one of supported dictionary reference formats.
• validate: If False, the block document will be loaded without Pydantic validating the block schema. This is useful if the block schema has changed client-side since the block document referred to by name was saved.
• client: The client to use to load the block document. If not provided, the default client will be injected. This is ignored when called from a synchronous context.

Raises:

• ValueError: If invalid reference format is provided.
• ValueError: If the requested block document is not found.

Returns:

• An instance of the current class hydrated with the data stored in the
• block document with the specified name.

model_dump ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/blocks/core.py#L2063" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

model_dump(self) -> dict[str, Any]

model_json_schema ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/blocks/core.py#L2005" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

model_json_schema(cls, by_alias: bool = True, ref_template: str = '#/definitions/{model}', schema_generator: type[GenerateJsonSchema] = GenerateJsonSchema, mode: Literal['validation', 'serialization'] = 'validation') -> dict[str, Any]

TODO: stop overriding this method - use GenerateSchema in ConfigDict instead?

model_validate ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/blocks/core.py#L2038" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

model_validate(cls: type[Self], obj: dict[str, Any] | Any) -> Self

register_type_and_schema ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/blocks/core.py#L1554" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

register_type_and_schema(cls, client: Optional['PrefectClient'] = None) -> None

Makes block available for configuration with current Prefect API. Recursively registers all nested blocks. Registration is idempotent.

This function will dispatch to aregister_type_and_schema when called from an async context.

Args:

• client: Optional client to use for registering type and schema with the Prefect API. A new client will be created and used if one is not provided. This is ignored when called from a synchronous context.

save ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/blocks/core.py#L1866" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

save(self, name: Optional[str] = None, overwrite: bool = False, client: Optional['PrefectClient'] = None) -> UUID

Saves the values of a block as a block document.

This function will dispatch to asave when called from an async context.

Args:

• name: User specified name to give saved block document which can later be used to load the block document.
• overwrite: Boolean value specifying if values should be overwritten if a block document with the specified name already exists.
• client: The client to use to save the block document. If not provided, the default client will be injected. This is ignored when called from a synchronous context.

Returns:

• The ID of the saved block document.

ser_model ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/blocks/core.py#L424" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

ser_model(self, handler: SerializerFunctionWrapHandler, info: SerializationInfo) -> Any

validate_block_type_slug ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/blocks/core.py#L365" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

validate_block_type_slug(cls, values: Any) -> Any

Validates that the block_type_slug in the input values matches the expected block type slug for the class. This helps pydantic to correctly discriminate between different Block subclasses when validating Union types of Blocks.

validate_value ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/blocks/system.py#L64" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

validate_value(cls, value: Union[T, SecretStr, PydanticSecret[T]]) -> Union[SecretStr, PydanticSecret[T]]