Provide way to rotate logs without being disruptive

As far as I can tell, the only way to rotate logs is to issue a restart of the service, which causes all clients to disconnect, it also initiates a full recheck of the npm and dependencies, which slows things down (e.g. /etc/init.d/etherpad-lite restart).

It would be ideal if we could do a 'kill -HUP' to a process to cause it to close the log file handle and open a new one, as this is the least disruptive mechanism for rotating logs, and is pretty common for services to use.

I tried to do a kill -HUP on the server.js process, but that just killed things outright.

[Pita]

afaik supports log4js logrotating. You may wanna dig into the documentation of log4js and do a pull request https://github.com/csausdev/log4js-node

Else this feature won't made it into 1.1

This shows a snippet with automatic logrotation built in: https://github.com/csausdev/log4js-node/blob/master/test/with-log-rolling.json

[Pita]

please implement it if you want that

It might be that this is supported already by log4js, but I haven't yet figured out how to make it work.

According to the log4js documentation, you should be able to drop a file called 'log4js.json' in "the current directory" (whatever that is), or in the require paths, and then log4js will pick it up automatically, by default, the configuration file is checked for changes every 60 seconds, and if changed, reloaded. This allows changes to logging levels to occur without restarting the application.

The logrotation 'snippit' in the comment above is supposed to be one of those log4js.json files that you could put somewhere and get logrotation for free. However, I've tried to put that in every location that I could think of, and it did not work. See my issue filed with log4js: https://github.com/csausdev/log4js-node/issues/47

[jhollinger]

For what it's worth, several well-established projects (e.g. Ruby on Rails) do not offer this functionality, but instead recommend using logrotate with the "copytruncatae" setting. Basically it will copy your log, then delete the contents of the original. I imagine it would look like this on the command line: "cp ep.log ep.log.1 && cat /dev/null > ep.log". Obviously it's non-disruptive, but I don't know if there's a Windows equivalent.

thanks for the suggestion for copytruncate, I had forgotten about that option. I use that instead of trying to get log4js to work.