feat(handler): add support to buffer logs from external libraries

Author: acascell

aws_lambda_powertools/logging/buffer/handler.py

@@ -0,0 +1,60 @@
+from __future__ import annotations
+
+import logging
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from aws_lambda_powertools.logging.buffer.cache import LoggerBufferCache
+    from aws_lambda_powertools.logging.buffer.config import LoggerBufferConfig
+    from aws_lambda_powertools.logging.logger import Logger
+
+
+class BufferingHandler(logging.Handler):
+    """
+    Handler that buffers logs from external libraries using the source logger's buffer.
+
+    The handler intercepts log records from external libraries and
+    stores them in the source logger's buffer using the same tracer_id mechanism.
+    Logs are flushed when an error occurs or when explicitly requested.
+    """
+
+    def __init__(
+        self,
+        buffer_cache: LoggerBufferCache,
+        buffer_config: LoggerBufferConfig,
+        source_logger: Logger,
+    ):
+        """
+        Initialize the BufferingHandler.
+
+        Parameters
+        ----------
+        buffer_cache : LoggerBufferCache
+            Shared buffer cache from the source logger
+        buffer_config : LoggerBufferConfig
+            Buffer configuration from the source logger
+        source_logger : Logger
+            The Powertools Logger instance to delegate buffering logic to
+        """
+        super().__init__()
+        self.buffer_cache = buffer_cache
+        self.buffer_config = buffer_config
+        self.source_logger = source_logger
+
+    def emit(self, record: logging.LogRecord) -> None:
+        """
+        Buffer the log record by delegating to source logger's buffering logic.
+        Call source logger to add a structured record to the buffer.
+
+        Parameters
+        ----------
+        record : logging.LogRecord
+            The log record from an external logger
+        """
+        self.source_logger._add_log_record_to_buffer(
+            level=record.levelno,
+            msg=record.getMessage(),
+            args=(),
+            exc_info=record.exc_info,
+            stack_info=False,
+        )