feat(workflow): add NewEmittingFunctionNode for streaming and HITL function node#1000
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feat(workflow): add NewEmittingFunctionNode for streaming and HITL function node#1000wolo-lab wants to merge 9 commits into
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…on nodes FunctionNode previously emitted exactly one event with the function's return value, leaving HITL prompts and progress streaming impossible from a plain function body — users had to drop down to a custom Node or wrap logic in an AgentNode. This mirrors the gap with adk-python, where a generator-style function node can yield RequestInput, Content, or Event objects mid-execution. Add NewEmittingFunctionNode and NewEmittingFunctionNodeWithSchema that accept an EmittingFunctionFn[IN, OUT] whose body receives an emit callback. The shape and HITL contract mirror DynamicFn from dynamic_node.go: the body may emit any number of intermediate events (typically via NewRequestInputEvent for HITL), and returns ErrNodeInterrupted as the sentinel meaning "pause event already forwarded; do not emit a terminal event". Any other returned error fails the node — matching the precedence already tested for bare nodes in TestScheduler_HitlNode_ErrorAfterRequestFails. A nil return without error suppresses the auto-emitted terminal event for nodes whose entire payload was sent inline. No scheduler, resume, or persistence changes are needed: the emit helper and ErrNodeInterrupted sentinel already power dynamicNode, so the existing pause/handoff/re-entry machinery applies unchanged. Default NodeConfig.RerunOnResume keeps handoff semantics consistent with adk-python's rerun_on_resume=False default in _function_node.py. The classic NewFunctionNode constructor and signature are unchanged. Tests cover the same scenarios as hitl_test.go (pause+forward, auto-generated InterruptID, multiple parked requests, error precedence) plus a non-HITL streaming case (intermediate content event alongside the terminal output). Simplify the workflow examples that previously hand-rolled a workflow.BaseNode subclass solely to emit a single custom event: hitl_simple and dynamic/hitl (RequestInput for HITL), and all three routing examples int/string/llm (Event.Routes). All now use NewEmittingFunctionNode.
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…node # Conflicts: # workflow/function_node.go
| yield(nil, err) | ||
| return | ||
| } | ||
| if output == nil { |
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For a no-op function there is no trace of completion. To be considered: emit an event with invocation id and no content
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Valid point. It makes sense. I've updated it for dynamic_nodes as well.
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I will handle it in a follow-up PR as it is a bigger change.
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…node # Conflicts: # examples/workflow/dynamic/hitl/main.go # examples/workflow/hitl_simple/main.go # examples/workflow/routing/int/main.go # examples/workflow/routing/llm/main.go # examples/workflow/routing/string/main.go # workflow/function_node.go
examples/quickstart/main was a 35MB ELF build artifact tracked in the repo (alongside its main.go source). Remove it; the source is unaffected.
…ode API The emitting FunctionNode API (EmittingFunctionFn, the emittingFn field, and the internal wrapper) used the NodeContext alias; switch it to agent.Context directly. Updates the NewEmittingFunctionNode callers in tests and examples to match. DynamicFn keeps NodeContext (out of scope).
The emitting function node callbacks now take agent.Context, so the nc (node context) parameter name no longer fits; rename to ctx. DynamicFn callbacks keep nc (still NodeContext).
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Problem
A
FunctionNodeemits exactly one event built from its return value, soa plain function body cannot emit a HITL
RequestInput, a routing event(
Event.Routes), or progress updates. Authors who needed any of these hadto drop down to a custom
workflow.Node(BaseNodesubclass) just to callyield. adk-python supports this directly via generator-style functionnodes; adk-go had no equivalent.
Solution
Add
NewEmittingFunctionNode/NewEmittingFunctionNodeWithSchematakingan
EmittingFunctionFn[IN, OUT]whose body receives anemitcallback. Theshape and HITL contract mirror
DynamicFn: emit any number of intermediateevents, and return
ErrNodeInterruptedafter aRequestInputto pause. Noscheduler/resume/persistence changes are needed — the existing
pause/handoff machinery applies unchanged.
NewFunctionNodeis untouched.Simplifies five workflow examples (hitl_simple, dynamic/hitl, routing
int/string/llm) that previously hand-rolled a
BaseNodesubclass solely toemit a single custom event.