apache_beam.typehints.typecheck module

Runtime type checking support.

For internal use only; no backwards-compatibility guarantees.

class apache_beam.typehints.typecheck.AbstractDoFnWrapper(dofn)

Bases: apache_beam.transforms.core.DoFn

An abstract class to create wrapper around DoFn

wrapper(method, args, kwargs)

setup()

start_bundle(*args, **kwargs)

process(*args, **kwargs)

finish_bundle(*args, **kwargs)

teardown()

class apache_beam.typehints.typecheck.OutputCheckWrapperDoFn(dofn, full_label)

Bases: apache_beam.typehints.typecheck.AbstractDoFnWrapper

A DoFn that verifies against common errors in the output type.

wrapper(method, args, kwargs)

class apache_beam.typehints.typecheck.TypeCheckWrapperDoFn(dofn, type_hints, label=None)

Bases: apache_beam.typehints.typecheck.AbstractDoFnWrapper

A wrapper around a DoFn which performs type-checking of input and output.

wrapper(method, args, kwargs)

process(*args, **kwargs)

static type_check(type_constraint, datum, is_input)

Typecheck a PTransform related datum according to a type constraint.

This function is used to optionally type-check either an input or an output to a PTransform.

Parameters:

• type_constraint – An instance of a typehints.TypeContraint, one of the white-listed builtin Python types, or a custom user class.
• datum – An instance of a Python object.
• is_input – True if ‘datum’ is an input to a PTransform’s DoFn. False otherwise.

Raises:

TypeError – If ‘datum’ fails to type-check according to ‘type_constraint’.

class apache_beam.typehints.typecheck.TypeCheckCombineFn(combinefn, type_hints, label=None)

Bases: apache_beam.transforms.core.CombineFn

A wrapper around a CombineFn performing type-checking of input and output.

create_accumulator(*args, **kwargs)

add_input(accumulator, element, *args, **kwargs)

merge_accumulators(accumulators, *args, **kwargs)

compact(accumulator, *args, **kwargs)

extract_output(accumulator, *args, **kwargs)

class apache_beam.typehints.typecheck.TypeCheckVisitor

Bases: apache_beam.pipeline.PipelineVisitor

enter_composite_transform(applied_transform)

leave_composite_transform(applied_transform)

visit_transform(applied_transform)

class apache_beam.typehints.typecheck.PerformanceTypeCheckVisitor

Bases: apache_beam.pipeline.PipelineVisitor

visit_transform(applied_transform)

get_input_type_hints(transform)

get_output_type_hints(transform)