Draft — paired with UiPath/hdens#7684. Neither side is useful alone. Ship this one first: it is inert until a caller sends resultCallbackSocket.

Summary

uipath server used to block for a whole job and leave its outcome on disk for the caller to find. StartJob now enqueues and returns; the server pushes logs while the job runs and the terminal result when it finishes.

Behaviour is a pure function of the request:

That is the whole compatibility story — an older caller cannot send the field, and could not serve the callback if it did. No handshake on the dispatch path.

POST {callback}/api/python/jobs/{jobKey}/result
POST {callback}/api/python/jobs/{jobKey}/logs

Execution stays serialised behind the process-wide lock: a job mutates process globals (logging handlers, OTel providers, env, cwd), so queueing changes who waits, not how many run.

Real cancellation

run/debug/eval each drive their own event loop via asyncio.run inside the to_thread worker — so a job is an event loop. They now go through run_job_loop, which publishes that loop to a JobControl carried on a ContextVar (to_thread propagates contextvars, so no monkeypatching, and it is asyncio.run verbatim when no control is in scope).

StopJob cancels the root task only, which unwinds the runtime cooperatively — its context managers still run, so output.json is still written and the file fallback still works. Cancelling every task would abort that cleanup mid-write. It escalates to a full sweep, then reports False rather than claiming a stop that did not happen.

A cancelled job is reported Stopped, not Faulted: the runtime records it as FAULTED/ERROR_CancelledError, which is the wrong story for a stop the caller asked for.

Also fixes two pre-existing defects

Both made the API result meaningless, and were masked only because the caller overwrote the status from the file afterwards:

1. _run_command_isolated hardcoded ExitCode: 0, while click returns ctx.exit(N)'s code under standalone_mode=False — so every ConsoleLogger.error path reported success.
2. The HTTP body now carries exitCode, which is the field the un-upgraded .NET handler already reads. That alone makes an old handler correct against a new runtime with no .NET change.

Worth a careful look

• Server diagnostics go to a stderr handle bound at import, not ConsoleLogger. ConsoleLogger resolves sys.stdout at call time, and the runtime's interceptor has replaced it with a writer feeding the job's execution.log — which the tailer reads and posts back. With the callback down that is a self-feeding loop.
• A 4xx from the callback is REJECTED, not UNREACHABLE. The caller is up and has moved on; retrying cannot help and must not trip the shutdown path.
• The log tailer holds back an unterminated tail. A logging handler writes the record and then flushes, so a poll can otherwise split one line into two entries that cannot be rejoined.
• StopJob takes resume_version as a trailing optional parameter, not a DTO. uipath-ipc ignores a surplus wire arg and defaults a missing one, so old and new peers interoperate both ways; a DTO would break an old venv loudly and a new one silently.
• Logs are tailed from the file, not captured via a handler. UiPathRuntimeLogsInterceptor._clean_all_handlers strips every handler but its own, and uipath-runtime ships on its own release train. The file is still written unchanged.

Testing

uv run pytest tests/cli green (~1400 tests; ~60 new across test_server_{result,async,logs,callbacks,cancellation}.py). ruff check, ruff format --check, mypy clean.

The cancellation tests use commands shaped like the real ones and assert the job's finally actually ran — an early cut used asyncio.run(loop_factory=...), which is 3.12+, and every one of them failed on the 3.11 venv. Now on asyncio.Runner.

Known gaps (deliberate)

• state.db stays on disk — agent code opens that path directly.
• A job wedged in a non-cancellable C call cannot be stopped; reported honestly rather than papered over.
• The shutdown-on-undeliverable-result path cannot recover jobs that never wrote a document.
• An accepted job has no timeout backstop on either side.

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