How to rotate log files while running server with pm2?

Question

We are using node module pm2 to run the server and capturing application logs.

But as the traffic is very huge, huge data is getting stored in single file which are around more than 100Gb.

Is there any possibility that we change the file every 1 hour or every 1Gb file without restarting server?

Currently we are manually doing this, restarting server and renaming the existing file which is creating issue.

Answer 1

You can use pm2-logrotate

pm2 install pm2-logrotate

# max log size is 1GB
pm2 set pm2-logrotate:max_size 1G

# compress logs when rotated (optional)
pm2 set pm2-logrotate:compress true

# force rotate every hours
pm2 set pm2-logrotate:rotateInterval '0 * * * *'

Answer 2

I personally do not use pm2-logrotate because it is no longer maintained, and even worse, it is quite buggy. One time I used it on my production server, and it immediately and repeatedly created large log files leading to 0% space and crashed the server. That was not a good day.

PM2 website has a section called "Setting up a native logrotate" wherein it tells you to run:

sudo pm2 logrotate -u user

Obviously change user to the actual user that is running pm2. It will create a file at /etc/logrotate.d/pm2-user and edit it so that it looks like this:

/home/user/.pm2/pm2.log /home/user/.pm2/logs/*.log {
        su user user
        rotate 12
        weekly
        missingok
        notifempty
        compress
        delaycompress
        copytruncate
        create 0640 user user
}

The most important part is su user user part. Logrotate runs as root, and it does not like creating log files that non-root users can view, so it will fail, often times silently. And this runs against npm philosophy, which prefers to run things generally without sudo privileges. By specifying the user in the logrotate config file, you get around this problem.

It took me a while to figure this out - hope it helps someone.