Fix metrics timer stats deadlock

src/core/services/metrics_service.py

@@ -14,6 +14,28 @@
 _counters: dict[str, int] = defaultdict(int)
 _timers: dict[str, list[float]] = defaultdict(list)
 
+def _calculate_timer_stats(durations: list[float]) -> dict[str, Any]:
+    """Calculate statistics for the provided list of durations."""
+    if not durations:
+        return {
+            "count": 0,
+            "total": 0.0,
+            "average": 0.0,
+            "min": 0.0,
+            "max": 0.0,
+        }
+
+    total_duration = sum(durations)
+    count = len(durations)
+    return {
+        "count": count,
+        "total": total_duration,
+        "average": total_duration / count,
+        "min": min(durations),
+        "max": max(durations),
+    }
+
+
 
 def inc(name: str, by: int = 1) -> None:
     """Increment a counter metric by the specified amount.
@@ -90,23 +112,9 @@ def get_timer_stats(name: str) -> dict[str, Any]:
         A dictionary containing count, total, average, min, and max durations
     """
     with _lock:
-        durations = _timers.get(name, [])
-        if not durations:
-            return {
-                "count": 0,
-                "total": 0.0,
-                "average": 0.0,
-                "min": 0.0,
-                "max": 0.0,
-            }
+        durations = list(_timers.get(name, []))
 
-        return {
-            "count": len(durations),
-            "total": sum(durations),
-            "average": sum(durations) / len(durations),
-            "min": min(durations),
-            "max": max(durations),
-        }
+    return _calculate_timer_stats(durations)
 
 
 def get_all_timer_stats() -> dict[str, dict[str, Any]]:
@@ -116,7 +124,9 @@ def get_all_timer_stats() -> dict[str, dict[str, Any]]:
         A dictionary mapping timer names to their statistics
     """
     with _lock:
-        return {name: get_timer_stats(name) for name in _timers}
+        timers_snapshot = {name: list(durations) for name, durations in _timers.items()}
+
+    return {name: _calculate_timer_stats(durations) for name, durations in timers_snapshot.items()}
 
 
 def log_performance_stats() -> None:

tests/unit/core/services/aaa_test_metrics_service.py

@@ -1,121 +1,139 @@
-"""
-Unit tests for the metrics service.
-"""
-
-from __future__ import annotations
-
-import time
-
-from src.core.services import metrics_service
-
-
-class TestMetricsService:
-    """Test the metrics service functionality."""
-
-    def setup_method(self):
-        """Reset metrics before each test."""
-        # Clear counters and timers
-        with metrics_service._lock:
-            metrics_service._counters.clear()
-            metrics_service._timers.clear()
-
-    def test_counter_increment(self):
-        """Test basic counter increment functionality."""
-        metrics_service.inc("test.counter")
-        assert metrics_service.get("test.counter") == 1
-
-        metrics_service.inc("test.counter", by=5)
-        assert metrics_service.get("test.counter") == 6
-
-    def test_counter_get_nonexistent(self):
-        """Test getting a counter that doesn't exist returns 0."""
-        assert metrics_service.get("nonexistent.counter") == 0
-
-    def test_counter_snapshot(self):
-        """Test getting a snapshot of all counters."""
-        metrics_service.inc("counter1")
-        metrics_service.inc("counter2", by=3)
-        metrics_service.inc("counter3", by=10)
-
-        snapshot = metrics_service.snapshot()
-        assert snapshot["counter1"] == 1
-        assert snapshot["counter2"] == 3
-        assert snapshot["counter3"] == 10
-
-    def test_record_duration(self):
-        """Test recording duration measurements."""
-        metrics_service.record_duration("test.timer", 0.5)
-        metrics_service.record_duration("test.timer", 1.0)
-        metrics_service.record_duration("test.timer", 0.75)
-
-        stats = metrics_service.get_timer_stats("test.timer")
-        assert stats["count"] == 3
-        assert stats["total"] == 2.25
-        assert stats["average"] == 0.75
-        assert stats["min"] == 0.5
-        assert stats["max"] == 1.0
-
-    def test_timer_context_manager(self):
-        """Test the timer context manager."""
-        with metrics_service.timer("test.operation"):
-            time.sleep(0.01)  # Sleep for 10ms
-
-        stats = metrics_service.get_timer_stats("test.operation")
-        assert stats["count"] == 1
-        assert stats["total"] >= 0.01  # Should be at least 10ms
-        assert stats["average"] >= 0.01
-
-    def test_timer_stats_empty(self):
-        """Test getting stats for a timer with no measurements."""
-        stats = metrics_service.get_timer_stats("nonexistent.timer")
-        assert stats["count"] == 0
-        assert stats["total"] == 0.0
-        assert stats["average"] == 0.0
-        assert stats["min"] == 0.0
-        assert stats["max"] == 0.0
-
-    def test_get_all_timer_stats(self):
-        """Test getting stats for all timers."""
-        metrics_service.record_duration("timer1", 0.5)
-        metrics_service.record_duration("timer2", 1.0)
-
-        all_stats = metrics_service.get_all_timer_stats()
-        assert "timer1" in all_stats
-        assert "timer2" in all_stats
-        assert all_stats["timer1"]["count"] == 1
-        assert all_stats["timer2"]["count"] == 1
-
-    def test_tool_call_processing_metrics(self):
-        """Test metrics specific to tool call processing."""
-        # Simulate processing and skipping messages
-        metrics_service.inc("tool_call.messages.processed", by=5)
-        metrics_service.inc("tool_call.messages.skipped", by=45)
-
-        assert metrics_service.get("tool_call.messages.processed") == 5
-        assert metrics_service.get("tool_call.messages.skipped") == 45
-
-        # Calculate skip rate
-        total = 5 + 45
-        skip_rate = (45 / total) * 100
-        assert skip_rate == 90.0
-
-    def test_log_performance_stats_with_data(self, caplog):
-        """Test logging performance statistics with data."""
-        metrics_service.inc("tool_call.messages.processed", by=10)
-        metrics_service.inc("tool_call.messages.skipped", by=90)
-        metrics_service.record_duration("tool_call.processing.duration", 0.05)
-        metrics_service.record_duration("tool_call.processing.duration", 0.03)
-
-        metrics_service.log_performance_stats()
-
-        # Check that log messages were generated
-        assert any("processed=10" in record.message for record in caplog.records)
-        assert any("skipped=90" in record.message for record in caplog.records)
-        assert any("skip_rate=90.0%" in record.message for record in caplog.records)
-
-    def test_log_performance_stats_no_data(self, caplog):
-        """Test logging performance statistics with no data."""
-        metrics_service.log_performance_stats()
-
-        # Should not log anything when there's no data
-        assert len(caplog.records) == 0
+"""
+Unit tests for the metrics service.
+"""
+
+from __future__ import annotations
+
+import threading
+import time
+
+from src.core.services import metrics_service
+
+
+class TestMetricsService:
+    """Test the metrics service functionality."""
+
+    def setup_method(self):
+        """Reset metrics before each test."""
+        # Clear counters and timers
+        with metrics_service._lock:
+            metrics_service._counters.clear()
+            metrics_service._timers.clear()
+
+    def test_counter_increment(self):
+        """Test basic counter increment functionality."""
+        metrics_service.inc("test.counter")
+        assert metrics_service.get("test.counter") == 1
+
+        metrics_service.inc("test.counter", by=5)
+        assert metrics_service.get("test.counter") == 6
+
+    def test_counter_get_nonexistent(self):
+        """Test getting a counter that doesn't exist returns 0."""
+        assert metrics_service.get("nonexistent.counter") == 0
+
+    def test_counter_snapshot(self):
+        """Test getting a snapshot of all counters."""
+        metrics_service.inc("counter1")
+        metrics_service.inc("counter2", by=3)
+        metrics_service.inc("counter3", by=10)
+
+        snapshot = metrics_service.snapshot()
+        assert snapshot["counter1"] == 1
+        assert snapshot["counter2"] == 3
+        assert snapshot["counter3"] == 10
+
+    def test_record_duration(self):
+        """Test recording duration measurements."""
+        metrics_service.record_duration("test.timer", 0.5)
+        metrics_service.record_duration("test.timer", 1.0)
+        metrics_service.record_duration("test.timer", 0.75)
+
+        stats = metrics_service.get_timer_stats("test.timer")
+        assert stats["count"] == 3
+        assert stats["total"] == 2.25
+        assert stats["average"] == 0.75
+        assert stats["min"] == 0.5
+        assert stats["max"] == 1.0
+
+    def test_timer_context_manager(self):
+        """Test the timer context manager."""
+        with metrics_service.timer("test.operation"):
+            time.sleep(0.01)  # Sleep for 10ms
+
+        stats = metrics_service.get_timer_stats("test.operation")
+        assert stats["count"] == 1
+        assert stats["total"] >= 0.01  # Should be at least 10ms
+        assert stats["average"] >= 0.01
+
+    def test_timer_stats_empty(self):
+        """Test getting stats for a timer with no measurements."""
+        stats = metrics_service.get_timer_stats("nonexistent.timer")
+        assert stats["count"] == 0
+        assert stats["total"] == 0.0
+        assert stats["average"] == 0.0
+        assert stats["min"] == 0.0
+        assert stats["max"] == 0.0
+
+    def test_get_all_timer_stats(self):
+        """Test getting stats for all timers."""
+        metrics_service.record_duration("timer1", 0.5)
+        metrics_service.record_duration("timer2", 1.0)
+
+        all_stats = metrics_service.get_all_timer_stats()
+        assert "timer1" in all_stats
+        assert "timer2" in all_stats
+        assert all_stats["timer1"]["count"] == 1
+        assert all_stats["timer2"]["count"] == 1
+
+    def test_get_all_timer_stats_thread_safe(self):
+        """Ensure get_all_timer_stats does not deadlock when called from another thread."""
+        metrics_service.record_duration("timer1", 0.1)
+        metrics_service.record_duration("timer2", 0.2)
+
+        result: dict[str, dict[str, float]] = {}
+
+        def target() -> None:
+            result.update(metrics_service.get_all_timer_stats())
+
+        worker = threading.Thread(target=target)
+        worker.start()
+        worker.join(timeout=1)
+
+        assert not worker.is_alive(), "get_all_timer_stats deadlocked when called from another thread"
+        assert result, "Expected timer stats to be populated after thread execution"
+
+    def test_tool_call_processing_metrics(self):
+        """Test metrics specific to tool call processing."""
+        # Simulate processing and skipping messages
+        metrics_service.inc("tool_call.messages.processed", by=5)
+        metrics_service.inc("tool_call.messages.skipped", by=45)
+
+        assert metrics_service.get("tool_call.messages.processed") == 5
+        assert metrics_service.get("tool_call.messages.skipped") == 45
+
+        # Calculate skip rate
+        total = 5 + 45
+        skip_rate = (45 / total) * 100
+        assert skip_rate == 90.0
+
+    def test_log_performance_stats_with_data(self, caplog):
+        """Test logging performance statistics with data."""
+        metrics_service.inc("tool_call.messages.processed", by=10)
+        metrics_service.inc("tool_call.messages.skipped", by=90)
+        metrics_service.record_duration("tool_call.processing.duration", 0.05)
+        metrics_service.record_duration("tool_call.processing.duration", 0.03)
+
+        metrics_service.log_performance_stats()
+
+        # Check that log messages were generated
+        assert any("processed=10" in record.message for record in caplog.records)
+        assert any("skipped=90" in record.message for record in caplog.records)
+        assert any("skip_rate=90.0%" in record.message for record in caplog.records)
+
+    def test_log_performance_stats_no_data(self, caplog):
+        """Test logging performance statistics with no data."""
+        metrics_service.log_performance_stats()
+
+        # Should not log anything when there's no data
+        assert len(caplog.records) == 0