Suite log, out, err rotation should be synchronized

[hjoliver]

Currently these are rotated independently according to file size. It would be better to rotate all files with the log (which is biggest), so that the content matches across them all.

[arjclark]

+1 - Very much agreed.

[matthewrmshin]

See also #386.

[matthewrmshin]

I must admit I am a bit confused by the current setting with these multiple modules:

• cylc.suite_logging, which deals with log and err.
• cylc.suite_log_interface, which provides a Pyro interface to err via cylc.suite_logging.
• cylc.suite_output, which deals with out and err.

We need to do something to rationalise these.

[hjoliver]

(a late-night look-in here)

We need to do something to rationalise these.

Yes, hence #386 (2 yrs old, gack).

In historical context it's not completely insane, however: cylc.suite_logging just configures the standard python logging facility (log message format etc.), which (as configured) happens to write WARNING and CRITICAL messages to stderr as well as the event log; cylc.suite_output redirects sys.std(out|err) to the suite log directory (this was added when the server became daemonizable?); and cylc.suite_log_interface is the new(ish) Pyro interface to the err log (this is used only by the gcylc info bar to highlight warnings and errors).

[matthewrmshin]

See also #846.

[hjoliver]

We agreed this should still be done.