Stored file position contains "NaN" / invalid position.

[sematext]

Stored file position contains "NaN" / invalid position.

[megastef]

I doubt that this is related to exit handlers.
Signals are recognized (SIGINT, SIGQUIT, SIGTERM).
https://github.com/sematext/logagent-js/blob/1.x/bin/logagent.js#L524-#L526

The invalid position is from the tailForever.unwatch() (or a bug in reading the postion before it gets stored). https://github.com/sematext/logagent-js/blob/master/lib/fileManager.js#L141

Was the file renamed? How can this error be re-produced?

[megastef]

You could get some more log messages (on stderr, stored e.g. in /var/log/upstart/logagent.log when you use the upstart service). Set following environment variables

export LOG_TAIL_FILE_INFO=1
export DEBUG=1

[erik-stephens]

Thanks, that will help. By the way, I'm running this as a spawned process in the shell and not daemonized. Not renaming files, although I ran it multiple times against different files (full log file vs a small subset). I'll figure out how to reproduce and probably submit a PR. A PR for this should go against 1.x branch?

[megastef]

Yes please 1.x - 2.x needs to get in shape, working on plugins.

Do you use --diskBufferDir /tmp/logagent ? The file is always stored in this directory. So you run it with different file sets. I could imagine that an old file gets into the list (it was stored), but LA never started a tail process on it, then it tries to unwatch - but I did not check this.

[erik-stephens]

I think I was able to narrow down the issue. My nodejs-fu is not strong enough to add much more insight at this point. I worry about getting a response since that repo has no commits for almost 2 years. Hopefully someone here has some insight.

[megastef]

Published on npm - I will watch the tailF repository. We should consider a fork or alternative library.

[erik-stephens]

Thanks for the workaround but I worry it will try to read the entire file into memory since maxSize defaults to -1. I think I have a fix in this PR.

[megastef]

Thanks for catching this! Please ping when a new npm version is available. So I will remove "bufferSize: -1" again.

[megastef]

Oh, its on npm already:tail-forever 0.3.12 :)

[megastef]

Made a quick test and release with updated dependency. Release: 1.2.25.