import logging
import types
import threading
import time
import queue as q
import core.telemetry as telemetry
def test_telemetry_queue_backpressure_and_single_worker(monkeypatch, caplog):
# Directly attach caplog's handler to the telemetry logger so that
# earlier tests calling logging.basicConfig() can't steal the records
# via a root handler before caplog sees them.
tel_logger = logging.getLogger("unity-mcp-telemetry")
tel_logger.addHandler(caplog.handler)
try:
caplog.set_level("DEBUG", logger="unity-mcp-telemetry")
collector = telemetry.TelemetryCollector()
# Force-enable telemetry regardless of env settings from conftest
collector.config.enabled = True
# Wake existing worker once so it observes the new queue on the next loop
collector.record(telemetry.RecordType.TOOL_EXECUTION, {"i": -1})
# Replace queue with tiny one to trigger backpressure quickly
small_q = q.Queue(maxsize=2)
collector._queue = small_q
# Give the worker time to finish processing the seeded item and
# re-enter _queue.get() on the new small queue
time.sleep(0.2)
# Make sends slow to build backlog and exercise worker
def slow_send(self, rec):
time.sleep(0.05)
collector._send_telemetry = types.MethodType(slow_send, collector)
# Fire many events quickly; record() should not block even when queue fills
start = time.perf_counter()
for i in range(50):
collector.record(telemetry.RecordType.TOOL_EXECUTION, {"i": i})
elapsed_ms = (time.perf_counter() - start) * 1000.0
# Should be fast despite backpressure (non-blocking enqueue or drop)
# Threshold set high (500ms) to accommodate CI environments with variable load.
# The key assertion is that 50 record() calls don't block on a full queue;
# even under heavy CI load, non-blocking calls should complete well under 500ms.
assert elapsed_ms < 500.0, f"Took {elapsed_ms:.1f}ms (expected <500ms for non-blocking calls)"
# Allow worker to process some
time.sleep(0.3)
# Verify drops were logged (queue full backpressure)
dropped_logs = [
m for m in caplog.messages if "Telemetry queue full; dropping" in m]
assert len(dropped_logs) >= 1
# Ensure only one worker thread exists and is alive
assert collector._worker.is_alive()
worker_threads = [
t for t in threading.enumerate() if t is collector._worker]
assert len(worker_threads) == 1
finally:
if caplog.handler in tel_logger.handlers:
tel_logger.removeHandler(caplog.handler)
