Logging traceback for fatal errors (#1064)

azure_functions_worker/dispatcher.py

@@ -29,7 +29,7 @@
 from .logging import disable_console_logging, enable_console_logging
 from .logging import enable_debug_logging_recommendation
 from .logging import (logger, error_logger, is_system_log_category,
-                      CONSOLE_LOG_PREFIX)
+                      CONSOLE_LOG_PREFIX, format_exception)
 from .utils.common import get_app_setting, is_envvar_true
 from .utils.dependency import DependencyManager
 from .utils.tracing import marshall_exception_trace
@@ -745,7 +745,9 @@ def gen(resp_queue):
             if ex is grpc_req_stream:
                 # Yes, this is how grpc_req_stream iterator exits.
                 return
-            error_logger.exception('unhandled error in gRPC thread')
+            error_logger.exception(
+                'unhandled error in gRPC thread. Exception: {0}'.format(
+                    format_exception(ex)))
             raise
 
 

azure_functions_worker/logging.py

@@ -4,6 +4,7 @@
 import logging
 import logging.handlers
 import sys
+import traceback
 from typing import Optional
 
 # Logging Prefixes
@@ -20,6 +21,13 @@
 error_handler: Optional[logging.Handler] = None
 
 
+def format_exception(exception):
+    msg = str(exception) + "\n"
+    msg += ''.join(traceback.format_exception(
+        etype=type(exception), value=exception, tb=exception.__traceback__))
+    return msg
+
+
 def setup(log_level, log_destination):
     # Since handler and error_handler are moved to the global scope,
     # before assigning to these handlers, we should define 'global' keyword

azure_functions_worker/main.py

@@ -36,7 +36,7 @@ def main():
 
     from . import logging
     from ._thirdparty import aio_compat
-    from .logging import error_logger, logger
+    from .logging import error_logger, logger, format_exception
 
     args = parse_args()
     logging.setup(log_level=args.log_level, log_destination=args.log_to)
@@ -48,8 +48,10 @@ def main():
     try:
         return aio_compat.run(start_async(
             args.host, args.port, args.worker_id, args.request_id))
-    except Exception:
-        error_logger.exception('unhandled error in functions worker')
+    except Exception as ex:
+        error_logger.exception(
+            'unhandled error in functions worker: {0}'.format(
+                format_exception(ex)))
         raise