• SIGINT - “Sorry to interrupt you, sir, but you need to come with Us.”
• SIGTERM - “Your contract have been terminated, security will lead you out.”
• SIGKILL - BAM!!!

SIGINT is supposed to be related to killing a process from inputting characters on the terminal. So if you CTRL+ C'd a process, that should send a SIGINT.

I think SIGTERM is a more of a “hey, let’s shut down this process gracefully” but this is meant to be triggered by another process, such as a process manager.

SIGKILL on the other hand is a non-graceful event. The OS won’t wait for your process to run any exit routines and will just kill it on the spot. That’s what happens when you run kill -9 on a process.

For the record, migrating from Elixir 1.10.1 to 1.10.2 fixed the problem with the Logger.

This seems like bug in the Logger. Could you report it and I will check that out.

In general you want to use SIGTERM unless specified otherwise.

Ok, I dug more and here is what I found:

On Unix systems, the Erlang runtime will interpret two types of signals.

SIGUSR1

    A SIGUSR1 signal forces a crash dump.
SIGTERM

    A SIGTERM will produce a stop message to the init process. This is equivalent to a init:stop/0 call.

    Introduced in ERTS 8.3 (Erlang/OTP 19.3)

source: https://erlang.org/doc/man/erl.html#signals

So I guess, that is the documentation I was looking for.