How to make irb quit after long idle? - ruby

Question

I'm a DBA, and I stumbled upon such case: developers run irb sessions (from Ruby on Rails app). This irb keeps database connection open. Sometimes - they forget about it, and it keeps on "running" - not doign anything, but still using one db connection.
I'd like to add some kind of "idle timeout" to their irb config. Is it possible? How to do it?

Answer 1

Here's a quick hack how you might implement this.
Note that this does not take into account that the user might be executing some long-running task inside the irb session. It simply looks at the time stamp of the last input; if it has not changed then it just flat out kills the process:
Update: it now checks if irb is currently running a command and ignores any timeouts if that is the case.
# Add some methods to IRB::Context and IRB::Irb
# for easier timeout implementation.
class IRB::Irb
def status
#signal_status
end
end
class IRB::Context
attr_reader :irb
attr_reader :line_no
def is_evaluating?
self.irb.status == :IN_EVAL
end
end
# Implement an auto exit timer thread. Timeout is given in seconds.
module IRB
def self.auto_exit_after(timeout = 60)
Thread.new {
context = IRB.conf[:MAIN_CONTEXT]
last_input = Time.now
last_line = context.line_no
loop {
sleep 10
# Check if irb is running a command
if context.is_evaluating?
# Reset the input time and ignore any timeouts
last_input = Time.now
next
end
# Check for new input
if last_line != context.line_no
# Got new input
last_line = context.line_no
last_input = Time.now
next
end
# No new input, check if idle time exceeded
if Time.now - last_input > timeout
$stderr.puts "\n** IRB exiting due to idle timeout. Goodbye..."
Process.kill("KILL", Process.pid)
end
}
}
end
end
To use it add the code to .irbrc, or some other place that auto-loads when irb is started, and then just start the timer:
IRB.auto_exit_after(60)