apache_beam.transforms.external module

Defines Transform whose expansion is implemented elsewhere.

No backward compatibility guarantees. Everything in this module is experimental.

apache_beam.transforms.external.iter_urns(coder, context=None)

class apache_beam.transforms.external.PayloadBuilder

Bases: object

Abstract base class for building payloads to pass to ExternalTransform.

build()

Returns:ExternalConfigurationPayload

payload()

The serialized ExternalConfigurationPayload

Returns:bytes

class apache_beam.transforms.external.SchemaBasedPayloadBuilder(values, schema)

Bases: apache_beam.transforms.external.PayloadBuilder

Base class for building payloads based on a schema that provides type information for each configuration value to encode.

Note that if the schema defines a type as Optional, the corresponding value will be omitted from the encoded payload, and thus the native transform will determine the default.

Parameters:

• values – mapping of config names to values
• schema – mapping of config names to types

build()

Returns:ExternalConfigurationPayload

class apache_beam.transforms.external.ImplicitSchemaPayloadBuilder(values)

Bases: apache_beam.transforms.external.SchemaBasedPayloadBuilder

Build a payload that generates a schema from the provided values.

class apache_beam.transforms.external.NamedTupleBasedPayloadBuilder(tuple_instance)

Bases: apache_beam.transforms.external.SchemaBasedPayloadBuilder

Build a payload based on a NamedTuple schema.

Parameters:tuple_instance – an instance of a typing.NamedTuple

class apache_beam.transforms.external.AnnotationBasedPayloadBuilder(transform, **values)

Bases: apache_beam.transforms.external.SchemaBasedPayloadBuilder

Build a payload based on an external transform’s type annotations.

Supported in python 3 only.

Parameters:

• transform – a PTransform instance or class. type annotations will be gathered from its __init__ method
• values – values to encode

class apache_beam.transforms.external.DataclassBasedPayloadBuilder(transform)

Bases: apache_beam.transforms.external.SchemaBasedPayloadBuilder

Build a payload based on an external transform that uses dataclasses.

Supported in python 3 only.

Parameters:transform – a dataclass-decorated PTransform instance from which to gather type annotations and values

class apache_beam.transforms.external.ExternalTransform(urn, payload, expansion_service=None)

Bases: apache_beam.transforms.ptransform.PTransform

External provides a cross-language transform via expansion services in foreign SDKs.

Experimental; no backwards compatibility guarantees.

Wrapper for an external transform with the given urn and payload.

Parameters:

• urn – the unique beam identifier for this transform
• payload – the payload, either as a byte string or a PayloadBuilder
• expansion_service – an expansion service implementing the beam ExpansionService protocol, either as an object with an Expand method or an address (as a str) to a grpc server that provides this method.

default_label()

classmethod get_local_namespace()

classmethod outer_namespace(namespace)

expand(pvalueish)

to_runner_api_transform(context, full_label)

class apache_beam.transforms.external.JavaJarExpansionService(path_to_jar, extra_args=None)

Bases: object

An expansion service based on an Java Jar file.

This can be passed into an ExternalTransform as the expansion_service argument which will spawn a subprocess using this jar to expand the transform.

Expand(request, context)

class apache_beam.transforms.external.BeamJarExpansionService(gradle_target, extra_args=None, gradle_appendix=None)

Bases: apache_beam.transforms.external.JavaJarExpansionService

An expansion service based on an Beam Java Jar file.

Attempts to use a locally-build copy of the jar based on the gradle target, if it exists, otherwise attempts to download and cache the released artifact corresponding to this version of Beam from the apache maven repository.

apache_beam.transforms.external.memoize(func)