PR #13021 fixed serial starvation by adding ThreadPoolExecutor to tick(), but kept as_completed(timeout=600) which still blocks the ticker thread until the slowest job finishes. This causes the same starvation pattern: when one job runs long (15+ min), other jobs' next_run_at expires past the grace window and they get perpetually fast-forwarded instead of running. This PR decouples dispatch from completion: - Persistent ThreadPoolExecutor (reused across ticks, no auto-join) - Fire-and-forget dispatch: tick submits and returns immediately - Running-job guard: prevents re-dispatching active jobs - sync parameter: defaults to True (backward compatible), callers opt into sync=False for non-blocking behavior - atexit shutdown handler for clean pool teardown - gateway/run.py: production ticker opts into sync=False Refs #33315 (complementary — that issue's PRs fix grace handling in jobs.py; this PR prevents the grace from expiring in the first place)
172 lines
6.0 KiB
Python
172 lines
6.0 KiB
Python
"""Tests for the persistent parallel pool and running-job guard in cron/scheduler.py.
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These verify the fix for the tick-blocking issue where as_completed(timeout=600)
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prevented the ticker thread from firing, causing all other jobs to be fast-forwarded.
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"""
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import concurrent.futures
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import threading
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import time
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from unittest.mock import patch
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import pytest
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class TestPersistentPool:
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"""_get_parallel_pool returns a persistent ThreadPoolExecutor."""
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def test_pool_is_reused(self, monkeypatch):
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"""Same pool instance returned when max_workers doesn't change."""
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import cron.scheduler as sched
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# Reset module state.
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sched._parallel_pool = None
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sched._parallel_pool_max_workers = None
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pool1 = sched._get_parallel_pool(4)
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pool2 = sched._get_parallel_pool(4)
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assert pool1 is pool2
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# Cleanup.
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sched._shutdown_parallel_pool()
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def test_pool_is_recreated_on_worker_change(self, monkeypatch):
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"""New pool when max_workers changes."""
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import cron.scheduler as sched
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sched._parallel_pool = None
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sched._parallel_pool_max_workers = None
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pool1 = sched._get_parallel_pool(2)
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pool2 = sched._get_parallel_pool(4)
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assert pool1 is not pool2
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sched._shutdown_parallel_pool()
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def test_shutdown_clears_pool(self, monkeypatch):
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"""_shutdown_parallel_pool resets state."""
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import cron.scheduler as sched
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sched._parallel_pool = None
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sched._parallel_pool_max_workers = None
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sched._get_parallel_pool(2)
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sched._shutdown_parallel_pool()
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assert sched._parallel_pool is None
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assert sched._parallel_pool_max_workers is None
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class TestRunningJobGuard:
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"""_running_job_ids prevents double-dispatch of active jobs."""
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def test_running_set_prevents_double_dispatch(self, tmp_path, monkeypatch):
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"""A job already in _running_job_ids is skipped on the next tick."""
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import cron.scheduler as sched
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# Reset state.
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sched._parallel_pool = None
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sched._parallel_pool_max_workers = None
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sched._running_job_ids.clear()
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job = {
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"id": "guard-job",
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"name": "guard-test",
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"prompt": "test",
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"schedule": "every 5m",
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"enabled": True,
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"next_run_at": "2020-01-01T00:00:00",
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"deliver": "local",
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}
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# Simulate the job already running.
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sched._running_job_ids.add("guard-job")
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dispatched = []
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monkeypatch.setattr(sched, "get_due_jobs", lambda: [job])
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monkeypatch.setattr(sched, "advance_next_run", lambda *_a, **_kw: None)
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monkeypatch.setattr(sched, "run_job", lambda j: dispatched.append(j["id"]) or (True, "out", "resp", None))
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monkeypatch.setattr(sched, "save_job_output", lambda *_a, **_kw: None)
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monkeypatch.setattr(sched, "mark_job_run", lambda *_a, **_kw: None)
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monkeypatch.setattr(sched, "_deliver_result", lambda *_a, **_kw: None)
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n = sched.tick(verbose=False)
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assert n == 0 # skipped, not dispatched
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assert dispatched == []
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sched._running_job_ids.discard("guard-job")
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sched._shutdown_parallel_pool()
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class TestSyncMode:
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"""tick() blocks by default (sync=True); tick(sync=False) returns immediately."""
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def test_sync_true_blocks_and_returns_correct_count(self, tmp_path, monkeypatch):
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"""sync=True waits for jobs and returns actual results."""
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import cron.scheduler as sched
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sched._parallel_pool = None
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sched._parallel_pool_max_workers = None
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sched._running_job_ids.clear()
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jobs = [
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{"id": f"job-{i}", "name": f"Job {i}", "prompt": "test",
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"schedule": "every 5m", "enabled": True,
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"next_run_at": "2020-01-01T00:00:00", "deliver": "local"}
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for i in range(3)
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]
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monkeypatch.setattr(sched, "get_due_jobs", lambda: jobs)
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monkeypatch.setattr(sched, "advance_next_run", lambda *_a, **_kw: None)
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monkeypatch.setattr(sched, "run_job", lambda j: (True, "out", "resp", None))
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monkeypatch.setattr(sched, "save_job_output", lambda *_a, **_kw: "/tmp/out")
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monkeypatch.setattr(sched, "mark_job_run", lambda *_a, **_kw: None)
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monkeypatch.setattr(sched, "_deliver_result", lambda *_a, **_kw: None)
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n = sched.tick(verbose=False)
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assert n == 3
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sched._shutdown_parallel_pool()
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def test_sync_false_returns_immediately(self, tmp_path, monkeypatch):
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"""sync=False returns before parallel jobs finish (optimistic count)."""
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import cron.scheduler as sched
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sched._parallel_pool = None
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sched._parallel_pool_max_workers = None
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sched._running_job_ids.clear()
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job = {
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"id": "slow-job",
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"name": "slow",
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"prompt": "test",
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"schedule": "every 5m",
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"enabled": True,
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"next_run_at": "2020-01-01T00:00:00",
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"deliver": "local",
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}
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barrier = threading.Barrier(2, timeout=5)
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def slow_run(j):
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barrier.wait() # blocks until test thread also waits
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return True, "out", "resp", None
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monkeypatch.setattr(sched, "get_due_jobs", lambda: [job])
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monkeypatch.setattr(sched, "advance_next_run", lambda *_a, **_kw: None)
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monkeypatch.setattr(sched, "run_job", slow_run)
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monkeypatch.setattr(sched, "save_job_output", lambda *_a, **_kw: "/tmp/out")
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monkeypatch.setattr(sched, "mark_job_run", lambda *_a, **_kw: None)
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monkeypatch.setattr(sched, "_deliver_result", lambda *_a, **_kw: None)
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start = time.monotonic()
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n = sched.tick(verbose=False, sync=False) # opt-in: non-blocking
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elapsed = time.monotonic() - start
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assert n == 1 # optimistic count
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assert elapsed < 1.0 # returned immediately, didn't wait for slow_run
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# Let the job finish so cleanup works.
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barrier.wait()
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time.sleep(0.1)
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sched._shutdown_parallel_pool()
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