Figure out handling of unexpected SIGTERM

[maruel]

We have cases where something sends an undesired SIGTERM to bot_main. It could be the task being run, OOM killer, whatever. It doesn't matter why, the fact it happens is the problem here. In any case, we'd like to differentiate between:

• User on machine desiring to terminate the bot who sends a SIGTERM to the bot.
• Undesired SIGTERM.

Alternatives are:

• Replace SIGTERM with SIGUSR1 and disable SIGTERM handling.

The main problem with the smart SIGUSR1 idea is that it needs an alternative on Windows; which https://msdn.microsoft.com/ms683242.aspx can help but it's more pain work to implement.

[shishkander]

Replace SIGTERM with SIGUSR1

do you mean update docs to send SIGUSR1 if a user wants to kill the bot?

[maruel]

Both updating the doc and the code.

[techtonik]

Why rely on intricacies of system signals? Is it possible to provide an OS independent channel for communication?