Python API reference
source >> target | target << source | source.task_pool_call(target, pool=...)Stream and Link objects
Runtime graph nodes and optional persisted execution metadata for an existing edge.
When to use
Keep returned Stream objects in variables so graph wiring and explicit link options remain readable.
Behavior
>>sets a primary source and returns the target, allowing chains.<<appends an additional source and returns the target, allowing merge chains.from_sources(*sources)replaces a complete multi-source list.- Typed call methods register FunctionCall, TaskPool, PriorityTaskPool, or ParallelCall metadata and return Link.
on_error(error_stream)assigns a dedicated Error stream to the source.
Stream fields properties
Normally populated by Pipeline factories.
PropertyTypeDescription
key / name / typestrStable symbolic identity, display name, and selected transformation.
service / pipelineService / PipelineImmutable graph ownership context.
source / sourcesStream | list[Stream]Primary and additional incoming graph references.
endpoint / functionEndpoint | Function | NoneBoundary or callback metadata when supported.
appearanceAppearanceOptional Designer coordinates and supported color.
Typed call methods properties
Persisted execution overrides.
PropertyTypeDescription
function_call(target, async_=None)LinkDirect FunctionCall edge.
task_pool_call(target, pool)LinkTaskPool edge using a registered Pool.
priority_task_pool_call(target, pool, priority)LinkPriorityTaskPool edge with an integer priority.
parallel_call(target)LinkParallelCall edge without unrelated options.
on_error(error_stream)StreamAssign the dedicated Error relationship.
Python example
incoming >> validate >> publish
merge << cache_result << database_result
validate.priority_task_pool_call(publish, pool=workers, priority=5)
validate >> validation_error
validate.on_error(validation_error)