+ To attach journal MESSAGE_ID, an extra field is supported:
+
+ >>> import uuid
+ >>> mid = uuid.UUID('0123456789ABCDEF0123456789ABCDEF')
+ >>> log.warn("Message with ID", extra={'MESSAGE_ID': mid})
+
+ Fields to be attached to all messages sent through this
+ handler can be specified as keyword arguments. This probably
+ makes sense only for SYSLOG_IDENTIFIER and similar fields
+ which are constant for the whole program:
+
+ >>> journal.JournalHandler(SYSLOG_IDENTIFIER='my-cool-app')
+