Flushing logs when log line is bigger than buffer size

Author: leandrodamascena

aws_lambda_powertools/logging/logger.py

@@ -536,7 +536,9 @@ def decorate(event, context, *args, **kwargs):
                 # Re-raise any exceptions that occur during handler execution
                 raise
             finally:
-                self._buffer_cache.clear()
+                # Clear the cache after invocation is complete
+                if self._buffer_config:
+                    self._buffer_cache.clear()
 
         return decorate
 
@@ -1117,7 +1119,7 @@ def _add_log_record_to_buffer(
         # Determine tracer ID, defaulting to first invoke marker
         tracer_id = get_tracer_id()
 
-        if tracer_id:
+        if tracer_id and self._buffer_config:
             log_record: dict[str, Any] = _create_buffer_record(
                 level=level,
                 msg=msg,
@@ -1130,7 +1132,7 @@ def _add_log_record_to_buffer(
                 self._buffer_cache.add(tracer_id, log_record)
             except BufferError:
                 warnings.warn(
-                    message=f"Cannot add item to the buffer. "
+                    message="Cannot add item to the buffer. "
                     f"Item size exceeds total cache size {self._buffer_config.max_size} bytes",
                     category=PowertoolsUserWarning,
                     stacklevel=2,
@@ -1182,6 +1184,19 @@ def flush_buffer(self) -> None:
         # Clear the entire cache
         self._buffer_cache.clear()
 
+    def clear_buffer(self) -> None:
+        """
+        Clear the internal buffer cache.
+
+        This method removes all items from the buffer cache, effectively resetting it to an empty state.
+
+        Returns
+        -------
+        None
+        """
+        if self._buffer_config:
+            self._buffer_cache.clear()
+
 
 def set_package_logger(
     level: str | int = logging.DEBUG,

tests/functional/logger/required_dependencies/test_powertools_logger_buffer.py

@@ -190,6 +190,23 @@ def test_ensure_log_location_after_flush_buffer(stdout, service_name, monkeypatc
     assert "test_ensure_log_location_after_flush_buffer" in log[0]["location"]
 
 
+def test_clear_buffer_during_execution(stdout, service_name, monkeypatch):
+    monkeypatch.setenv(constants.XRAY_TRACE_ID_ENV, "1-67c39786-5908a82a246fb67f3089263f")
+
+    # GIVEN A logger configured with a sufficiently large buffer
+    logger_buffer_config = LoggerBufferConfig(max_size=10240)
+    logger = Logger(level="DEBUG", service=service_name, stream=stdout, logger_buffer=logger_buffer_config)
+
+    # WHEN we clear the buffer during the execution
+    logger.debug("this log line will be flushed")
+    logger.clear_buffer()
+
+    # THEN not log is flushed
+    logger.flush_buffer()
+    log = capture_multiple_logging_statements_output(stdout)
+    assert not log
+
+
 def test_exception_logging_during_buffer_flush(stdout, service_name, monkeypatch):
     monkeypatch.setenv(constants.XRAY_TRACE_ID_ENV, "1-67c39786-5908a82a246fb67f3089263f")