Add support printing TID to logs (#323)

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 - Feature:
   - Users now can specify the `SW_AGENT_ASYNCIO_ENHANCEMENT` environment variable to enable the performance enhancement with asyncio (#316)
+  - Support printing Trace IDs (TID) to collected application logs (#323)
 
 - Plugins:
   - Add neo4j plugin.(#312)

docs/en/setup/advanced/LogReporter.md

@@ -103,4 +103,10 @@ Will result in:
     }
   ]
 }
-```
+```
+
+## Print trace ID in your logs
+To print out the trace IDs in the logs, simply add `%(tid)s` to the `agent_log_reporter_layout`.
+
+You can take advantage of this feature to print out the trace IDs on any channel you desire, not limited to reporting logs to OAP,
+this can be achieved by using any formatter you prefer in your own application logic.

skywalking/agent/__init__.py

@@ -268,7 +268,6 @@ def start(self) -> None:
             logger.info(f'SkyWalking sync agent instance {config.agent_instance_name} starting in pid-{os.getpid()}.')
 
             # Install log reporter core
-            # TODO - Add support for printing traceID/ context in logs
             if config.agent_log_reporter_active:
                 from skywalking import log
                 log.install()
@@ -502,7 +501,6 @@ async def __start_event_loop_async(self) -> None:
         self._finished = asyncio.Event()
 
         # Install log reporter core
-        # TODO - Add support for printing traceID/ context in logs
         if config.agent_log_reporter_active:
             from skywalking import log
             log.install()

skywalking/log/sw_logging.py

@@ -75,6 +75,9 @@ def build_log_tags() -> LogTags:
 
         context = get_context()
 
+        if '%(tid)s' in layout:
+            record.tid = str(context.segment.related_traces[0])
+
         active_span_id = -1
         primary_endpoint_name = ''