How do I ensure a process is running, even if it kills itself? (it needs to be restarted then)
- by le_me
I'm using linux. I want a process (an irc bot) to run every time I start the computer. But I've got a problem: The network is bad and it disconnects often, so I need to manually restart the bot a few times a day. How do I automate that?
Additional information:
The bot creates a pid file, called bot.pid
The bot reconnects itself, but only a few times. The network is too bad, so the bot kills itself sometimes because it gets no response.
What I do currently (aka my approach ;) )
I have a cron job executing startbot.rb every 5 minutes. (The script itself is in the same directory as the bot)
The script:
#!/usr/bin/ruby
require 'fileutils'
if File.exists?(File.expand_path('tmp/bot.pid'))
@pid = File.read(File.expand_path('tmp/bot.pid')).chomp!.to_i
begin
raise "ouch" if Process.kill(0, @pid) != 1
rescue
puts "Removing abandoned pid file"
FileUtils.rm(File.expand_path('tmp/bot.pid'))
puts "Starting the bot!"
Kernel.exec(File.expand_path('./bot.rb'))
else
puts "Bot up and running!"
end
else
puts "Starting the bot!"
Kernel.exec(File.expand_path('./bot.rb'))
end
What this does:
It checks if the pid file exists, if that's true it checks if kill -s 0 BOT_PID == 1 (if the bot's running) and starts the bot if one of the two checks fail/are not true.
My approach seems to be quite dirty so how do I do it better?
