There are two significant cases in Zuul where we may emit multi-line
log messages:
* Tracebacks
* Zuul config errors
When these are sent to a log file or stderr using the default
configurations, it can be difficult to work with those logs. Using
"grep" to search for messages or time periods will typically only
produce a single line of the error.
Further, on a busy system the error may be interleaved with other
log lines making extraction even harder.
To address both of these issues, add a formatter which formats every
line of a multi-line log message using the same format specifier.
This is quite readable when streaming or viewing a standard log file,
and it should cause all log lines to automatically appear in
ELK/splunk setups since they will all have the same message format.
(Though, those setups are probably better served with a native
logging configuration that sends the entire record together.)
It may be somewhat difficult if a multi-line log entry is recorded
on a busy system with multiple threads. However, some judicious
grepping should help with that since all related lineswill have the
exact same timestamp (including microseconds). Advanced users/devs
could specify a logging format with the thread id if necessary, though
I don't think we should do that by default.
Since this is implemented as a standard logging formatter, it can
be opted-out via logging config files. This enables it by default,
which I think is reasonable for new users, but if we decide that we
would prefer opt-in, that is a simple change.
Sample output:
2021-01-29 10:59:02,004 DEBUG zuul.Scheduler: Run handler awake
2021-01-29 10:59:02,004 ERROR zuul.Scheduler: Exception in run handler:
2021-01-29 10:59:02,004 ERROR zuul.Scheduler: Traceback (most recent call last):
2021-01-29 10:59:02,004 ERROR zuul.Scheduler: File "/home/corvus/git/zuul/zuul/zuul/scheduler.py", line 1254, in run
2021-01-29 10:59:02,004 ERROR zuul.Scheduler: raise Exception("Test")
2021-01-29 10:59:02,004 ERROR zuul.Scheduler: Exception: Test
2021-01-29 10:59:02,005 DEBUG zuul.Scheduler: Run handler sleeping
2021-01-29 10:59:41,956 WARNING zuul.ConfigLoader: 1 errors detected during zuultest tenant configuration loading
2021-01-29 10:59:41,956 WARNING zuul.ConfigLoader: Zuul encountered a syntax error while parsing its configuration in the
2021-01-29 10:59:41,956 WARNING zuul.ConfigLoader: repo local-project-config on branch master. The error was:
2021-01-29 10:59:41,956 WARNING zuul.ConfigLoader:
2021-01-29 10:59:41,956 WARNING zuul.ConfigLoader: extra keys not allowed @ data['trigger']['github']
2021-01-29 10:59:41,956 WARNING zuul.ConfigLoader:
2021-01-29 10:59:41,956 WARNING zuul.ConfigLoader: The error appears in the following pipeline stanza:
...
Change-Id: I6d7e7e7a9e19d46a744f9ffac8d532fc6b4bba01
16bb1bbf8c