# if FD 1 is a TTY (that's the -t 1 check), trap SIGINT/Ctrl+C
# 1) restore the INT trap so it doesn't fire in a loop due to 2)
# 2) be nice to the caller and send SIGINT to ourselves (http://mywiki.wooledge.org/SignalTrap#Special_Note_On_SIGINT)
# 3) *do* exit after all to run the cleanup code from above (avoids duplication)
if[[-t 1 ]];then
trap'trap - INT; kill -INT $$; exit' INT;
# if FD 1 is not a TTY (e.g. when we're run through 'foreman start'), do nothing
# on SIGINT; the assumption is that the parent will send us a SIGTERM or
# something when this happens. With the trap above, Ctrl+C-ing out of a 'foreman
# start' run would trigger the INT trap both in Foreman and here (because Ctrl+C
# sends SIGINT to the entire process group, but there is no way to tell the two
# cases apart), and while the trap is still doing its shutdown work triggered by
# the SIGTERM from the Ctrl+C, Foreman would then send a SIGTERM because that's
# what it does when it receives a SIGINT itself.
else
trap'' INT;
fi
# we are now launching a subshell for each of the tasks (log tail, web server)
# 1) each subshell has a trap on EXIT that echos the command name to FD 3 (see the FIFO set up above)
# 1a) a 'read' at the end of the script will block on reading from that FD and then trigger the exit trap above, which does the cleanup
# 2) each subshell also has a trap on TERM that
# 2a) kills $! (the last process executed)
# 2b) ... which in turn will unblock the 'wait' in 4)
# 3) execute the command in the background
# 4) 'wait' on the command (wait is interrupted by an incoming TERM to the subshell, whereas running 3) in the foreground would wait for that 3) to finish before triggering the trap)
# 5) add the PID of the subshell to the array that the EXIT trap further above uses to clean everything up
echo"Starting log redirection...">&2
(
trap'echo "logs" >&3;' EXIT
trap'kill -TERM $! 2> /dev/null' TERM
mkdir-p logs
rm-f logs/access.log
mkfifo"logs/access.log"
cat"logs/access.log" 1>&2 &
wait
) & pids+=($!)
echo"Starting nginx...">&2
(
trap'echo "nginx" >&3;' EXIT
trap'kill -TERM $! 2> /dev/null' TERM
"${HERE}/nginx"-p.-c config/nginx.conf &
wait
) & pids+=($!)
# wait for something to come from the FIFO attached to FD 3, which means that
# the given process was killed or has failed this will be interrupted by a
# SIGTERM or SIGINT in the traps further up if the pipe unblocks and this
# executes, then we won't read it again, so if the traps further up kill the
# remaining subshells above, their writing to FD 3 will have no effect
read exitproc <&3
# we'll only reach this if one of the processes above has terminated
echo"Process exited unexpectedly: $exitproc">&2
# this will trigger the EXIT trap further up and kill all remaining children
