feat: move log filter attachment to init

Author: Alex Wang

packages/aws-durable-execution-sdk-python-examples/src/otel/otel_logger_example.py

@@ -1,10 +1,12 @@
 """Demonstrates OTel-enriched logging in a durable execution.
 
-The DurableExecutionOtelPlugin wraps the execution logger (enrich_logger=True
-by default) so every log line emitted through context.logger / step_context.logger
-is automatically enriched with the active OpenTelemetry trace context
-(otel.trace_id, otel.span_id, otel.trace_sampled). This lets logs correlate to
-the spans the plugin emits without any user code changes.
+The DurableExecutionOtelPlugin installs a logging filter on the root logger
+(enrich_logger=True by default) when the plugin is constructed. The filter
+stamps the active OpenTelemetry trace context (otel_trace_id, otel_span_id,
+otel_trace_sampled) onto every log record that flows through the root handler.
+This includes logs emitted via context.logger / step_context.logger as well as
+direct logging.getLogger() calls and third-party library logs, so logs
+correlate to the spans the plugin emits without any user code changes.
 
 Logs emitted:
 - at the top level correlate to the invocation span

packages/aws-durable-execution-sdk-python-otel/src/aws_durable_execution_sdk_python_otel/plugin.py

@@ -117,6 +117,13 @@ def __init__(
         self._operation_spans: dict[str | None, Span] = {}
         self._operation_spans_lock = threading.RLock()
 
+        if self._enrich_logger:
+            # Install the root-logger filter so every log record is stamped with
+            # the active span context. The Lambda runtime attaches its root
+            # handler before the handler module is imported (and thus before the
+            # plugin is constructed), so the handlers are available here.
+            install_log_filter(self)
+
     def _set_span(self, operation_id: str | None, span: Span) -> None:
         """Register the active span for an operation ID."""
         with self._operation_spans_lock:
@@ -284,12 +291,6 @@ def on_invocation_start(self, info: InvocationStartInfo) -> None:
         self._extracted_context = self._context_extractor(info)
         self._id_generator.set_trace_id(self._execution_arn, info.start_time)
 
-        if self._enrich_logger:
-            # Install (idempotently) the root-logger filter so every log record
-            # emitted during this invocation is stamped with the active span
-            # context. Safe to call on every invocation, including warm reuse.
-            install_log_filter(self)
-
         self._start_span(
             operation_id=None,
             name="invocation",

packages/aws-durable-execution-sdk-python-otel/tests/test_log_filter.py

@@ -200,14 +200,13 @@ def test_install_log_filter_returns_none_without_handlers():
     assert install_log_filter(plugin, target_logger=target) is None
 
 
-def test_on_invocation_start_installs_filter_on_root_logger():
-    """The plugin installs the filter on the root logger at invocation start."""
-    plugin, _ = _create_plugin(enrich_logger=True)
+def test_plugin_installs_filter_on_root_logger_at_construction():
+    """The plugin installs the filter on the root logger when constructed."""
     root = logging.getLogger()
     handler = logging.NullHandler()
     root.addHandler(handler)
     try:
-        plugin.on_invocation_start(_invocation_start_info())
+        _create_plugin(enrich_logger=True)
 
         assert any(isinstance(f, OtelContextLogFilter) for f in handler.filters)
     finally:
@@ -216,14 +215,13 @@ def test_on_invocation_start_installs_filter_on_root_logger():
         root.removeHandler(handler)
 
 
-def test_on_invocation_start_skips_filter_when_disabled():
+def test_plugin_skips_filter_when_disabled():
     """No filter is installed when enrich_logger is disabled."""
-    plugin, _ = _create_plugin(enrich_logger=False)
     root = logging.getLogger()
     handler = logging.NullHandler()
     root.addHandler(handler)
     try:
-        plugin.on_invocation_start(_invocation_start_info())
+        _create_plugin(enrich_logger=False)
 
         assert not any(isinstance(f, OtelContextLogFilter) for f in handler.filters)
     finally: