A Docker entrypoint for starting Foreman with multiple Sidekiq processes

docker_entrypoint_sidekiq.sh

#!/usr/bin/env bash
#
# A Docker entrypoint for starting Foreman with multiple Sidekiq processes
#
# Required in the Dockerfile:
#
#   gem install foreman --no-document


echo_stderr() {
    echo "$@" 1>&2
}

on_exit() {
  echo_stderr "exiting"
}

trap on_exit EXIT

SIDEKIQ_WORKERS=${SIDEKIQ_WORKERS:-1}

echo_stderr "Starting $SIDEKIQ_WORKERS Sidekiq worker(s)"

procfile_template=$(cat <<EOF
worker: bundle exec sidekiq -C config/sidekiq.yml -e ${RAILS_ENV:-development}
EOF
)

echo "$procfile_template" > Procfile

exec foreman start -f Procfile --formation worker=$SIDEKIQ_WORKERS