trap sigterm to exit container faster

[edaniszewski]

fixes #205

[marcoceppi]

We think there is a better way to do this, let me pull up some of my old run.sh files

[codecov]

Codecov Report

Merging #206 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #206   +/-   ##
=======================================
  Coverage   82.76%   82.76%           
=======================================
  Files          44       44           
  Lines        1300     1300           
=======================================
  Hits         1076     1076           
  Misses        224      224

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[edaniszewski]

@marcoceppi I hope there is. This felt a little janky to me, but it worked, so its got that going for it.

[marcoceppi]

It is embarrassing how annoying this is in Docker. I've used this in a lot of projects; just carrying it around from code to code.

#!/bin/bash

child=1

_handle_term() {
  echo "Caught SIGTERM, forwarding to pid $child"
  kill -TERM "$child" 2>/dev/null
}

_handle_usr2() {
  echo "Caught SIGUSR2, forwarding to pid $child"
  kill -USR2 "$child" 2>/dev/null
}

_handle_quit() {
  echo "Caught SIGQUIT, forwarding to pid $child"
  kill -QUIT "$child" 2>/dev/null
}

_handle_int() {
  exec_after_terminate=bash
  echo "Caught SIGINT, forwarding to pid $child"
  kill -INT "$child" 2>/dev/null
}

trap _handle_term SIGTERM
trap _handle_quit SIGQUIT
trap _handle_usr2 SIGUSR2
trap _handle_int SIGINT

wrap() {
  declare desc="Proxy signals to the child process. Invoke shell on SIGINT"
  echo "Starting the child process, watching for SIGINT"

  echo "\$ $@ &"
  $@ &
  child=$!

  echo "Child process started has pid $child"
  wait $child
  wait $child
  echo "Child process $child exited with status $?"

  if [ -n "$exec_after_terminate" ]
  then
    echo "Running exec_after_terminate: '$exec_after_terminate'"
    exec $exec_after_terminate
  fi
}

get-command() {
  declare desc="Get the command mapping for a command word"
  declare type="$1"

  echo "$1"
}

run-commands() {
  declare desc="Run command words"
  declare type="$1"

  if [ "$(eval echo $(get-command "$1"))" = "$1" ]; then
    # if the first command is the same as the first argument, then the command
    # was not found (or it was identical to the command)
    echo "Command word '$1' not found, running the whole string '$@' as a single command"

    cmd="$CMD_PREFIX$(eval echo $@)"
    exec $cmd
  else
    # loop through the command words and handle appropriately
    until [ -z "$1" ]
    do
      cmd="$CMD_PREFIX$(eval echo $(get-command "$1"))"

      if [ "$#" -gt "1" ]; then
        echo "Only one command word at a time"
        exit 1
      else
        echo "entrypoint: Command word is '"$1"', running '$cmd'"

        if [ "$$" = "1" ]
        then
          wrap "$cmd"
        else
          exec $cmd
        fi
      fi

      shift
    done
  fi
}

main() {
  declare desc="Kick off the entrypoint script"
  declare type="$@"

  if [ $# -eq 0 ]; then
    echo "No command words specified. Exiting"
  else
    run-commands "$@"
  fi
}

main "$@"

My Dockerfile ends up like this

ENTRYPOINT ["/code/run.sh", "python3"]
CMD ["app.py"]

[edaniszewski]

closing this in preference of #207 (which also simplifies the image build process)