logs to both custom log and twistd.log

[Robert Collins]

This is because log.startLoggingWithObserver isn't being called.

We should use either a custom log, or twistd.log, but not both. There will be interactions with twistd I suspect - bug see what we do in other LP daemons.

[Robert Collins (lifeless)]

to reproduce:
bin/txlongpoll amqp-longpoll -l mylog -u guest -a guest1 -f 9999 -r .
note that there is then both
mylog
and
twistd.log

[Julian Edwards (julian-edwards)]

It's not because log.startLoggingWithObserver isn't being called. See twisted bug 638 - there is no way of overriding application log observers from a TAP, so you end up with not only the observers we add to the service, the application gets a default whether you want it or not!

It was recently "fixed" in this changeset, I am yet to investigate whether we can backport it until it's properly released.

http://twistedmatrix.com/trac/changeset/32397

[Julian Edwards (julian-edwards)]

http://twistedmatrix.com/trac/ticket/638

[Julian Edwards (julian-edwards)]

I've backported that twisted changeset and I am now getting a single log file. However, that change is bloody hideous - it requires you to write --logger=python.file.function_that_returns_observer - which means the log file name has to be hard coded in the logger! I've worked around that, but now have a new problem

This application's log observer *has* to be set up to receive all logging, otherwise the default observer takes over and you end up with 2 log files. Which means that oops_twisted's fallback observer is now doing the logging twice, so I need a way of making it only log failures there.

[Robert Collins (lifeless)]

Create a function which returns an observer.
Set that as the '--logger=python.file.function_that_returns_observer' thing.

It should return an OOPSObserver with fallback set.

(This is the intended use: the oopsobserver receives *everything*,
translates failures to oopses and forwards non-failures unaltered.)

[Julian Edwards (julian-edwards)]

Gavin and I decided that this --logger option is so awful that we're not going to use it any more. The answer to this problem is to invoke the process like this:

twistd --logfile=/dev/null amqp-longpoll -u guest -a guest -f 34366 -l mylogname.log

which effectively removes the default logger.