logging: Add option to show the PID in each log message.

zerver/lib/logging_util.py

@@ -177,11 +177,17 @@ class ZulipFormatter(logging.Formatter):
     # Used in the base implementation.  Default uses `,`.
     default_msec_format = '%s.%03d'
 
-    _fmt = '%(asctime)s %(zulip_level_abbrev)-4s [%(zulip_origin)s] %(message)s'
-
     def __init__(self):
         # type: () -> None
-        super().__init__(fmt=self._fmt)
+        super().__init__(fmt=self._compute_fmt())
+
+    def _compute_fmt(self):
+        # type: () -> str
+        pieces = ['%(asctime)s', '%(zulip_level_abbrev)-4s']
+        if settings.LOGGING_SHOW_PID:
+            pieces.append('pid:%(process)d')
+        pieces.extend(['[%(zulip_origin)s]', '%(message)s'])
+        return ' '.join(pieces)
 
     def format(self, record):
         # type: (logging.LogRecord) -> str

zproject/prod_settings_template.py

@@ -173,6 +173,11 @@ FEEDBACK_EMAIL = ZULIP_ADMINISTRATOR
 # mysterious log message, but a little verbose.
 #LOGGING_SHOW_MODULE = False
 
+# If True, each log message in the server logs will identify the
+# process ID.  Useful for correlating logs with information from
+# system-level monitoring tools.
+#LOGGING_SHOW_PID = False
+
 # Controls whether or not Zulip will provide inline image preview when
 # a link to an image is referenced in a message.  Note: this feature
 # can also be disabled in a realm's organization settings.

zproject/settings.py

@@ -135,6 +135,7 @@ DEFAULT_SETTINGS = {
     'ERROR_REPORTING': True,
     'BROWSER_ERROR_REPORTING': False,
     'LOGGING_SHOW_MODULE': False,
+    'LOGGING_SHOW_PID': False,
 
     # File uploads and avatars
     'DEFAULT_AVATAR_URI': '/static/images/default-avatar.png',