[Feature] Track Action by Event Field Values work

[rosemarYuan]

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Description

Summary

This umbrella issue tracks the CEL (Common Expression Language) action condition filtering work across the design discussion and follow-up pull requests. The change introduces an EventType constants/registry, unifies the @action / @Action trigger entry, and adds an ActionRouter that combines typed routing with CEL evaluation in both Java and Python.

Design Discussion

• Discussion: [Discussion] Trigger action by Event Field Values [Discussion] Trigger action by Event Field Values #726

Pull Requests

The work ships as a four-PR stack and must merge in order (PR1 → PR2 → PR3 → PR4).

• EventType constants and unified trigger entry: [api][java][python] Introduce EventType constants and unify Action trigger entry #756
• Java CEL implementation: [plan][runtime][java] Add CEL Action condition filtering #TBD-PR2
• Python CEL implementation: [plan][runtime][python] Add CEL Action condition filtering #TBD-PR3
• Documentation: [docs] Document CEL Action condition filtering #TBD-PR4

Current Status

• All four PRs are pending (will be opened sequentially as each parent merges).

Scope

• Public API rename: @Action(listenEventTypes = …) → @Action(…); @action(*listen_events) → @action(*trigger_conditions)
• New EventType constants and runtime registry for built-in and user-defined event types (Java + Python)
• CEL plan-time classifier (PlanCelClassifier): bare-ident → TypeMatch, otherwise → CelExpression
• CEL whitelist: only the has macro is allowed; exists / exists_one / all / filter / map are rejected
• AST rewriter that folds EventType.X, normalises type-equality aliases, qualifies bare identifiers under attributes., and rebuilds has calls
• CelExpressionFacade (Java) / cel_facade (Python) compile pipeline with a process-wide LRU program cache
• ActionRouter two-phase routing: typed-index fast path + CEL slow path, deduped across the union
• Wiring into ActionExecutionOperator (Java) and LocalRunner (Python)
• JSON serialization: listen_event_types → trigger_conditions, with backward-compat fallback in both deserializers
• Cross-language conformance fixture (cel_conformance_cases.json, disallowed-macros.txt) plus a CI workflow that diffs them and runs both evaluators
• User documentation in docs/content/docs/development/workflow_agent.md

Notes

• This issue is intended as a tracking umbrella for the work split across discussion and the four PRs above.
• Detailed design rationale (why CEL over alternatives, the supported expression subset, the macro whitelist) lives in [Discussion] Trigger action by Event Field Values #726 and should not be duplicated in each PR.
• This is an API-breaking change: @Action(listenEventTypes = …) no longer compiles. Migration is mechanical and covered in the PR1 description and the migrated examples.

Are you willing to submit a PR?

• I'm willing to submit a PR!