Support opt-in sidekiq-cluster in bin/background_jobs script

It simplifies the interface of `bin/background_jobs` as:

1. start - Starting sidekiq or sidekiq-cluster on background.
2. restart - Kill all existing processes and start them
again (in background).
3. start_foreground - Starts sidekiq or sidekiq-cluster on foreground.
4. stop - Well, stops the process.

Here we also split the script into two `bin/background_jobs_sk` and
`bin/background_jobs_sk_cluster`. If `SIDEKIQ_WORKERS` env var is
given we use the `bin/background_jobs_sk_cluster`, which has
basically the same API of the sidekiq counterpart.

bin/background_jobs

 #!/bin/sh
 
 cd $(dirname $0)/..
-app_root=$(pwd)
-sidekiq_pidfile="$app_root/tmp/pids/sidekiq.pid"
-sidekiq_logfile="$app_root/log/sidekiq.log"
-sidekiq_config="$app_root/config/sidekiq_queues.yml"
-gitlab_user=$(ls -l config.ru | awk '{print $3}')
 
-warn()
-{
-  echo "$@" 1>&2
-}
-
-stop()
-{
-  bundle exec sidekiqctl stop $sidekiq_pidfile >> $sidekiq_logfile 2>&1
-}
-
-killall()
-{
-  pkill -u $gitlab_user -f 'sidekiq [0-9]'
-}
-
-restart()
-{
-  if [ -f $sidekiq_pidfile ]; then
-    stop
-  fi
-  killall
-  start_sidekiq -P $sidekiq_pidfile -d -L $sidekiq_logfile >> $sidekiq_logfile 2>&1
-}
-
-start_no_deamonize()
-{
-  start_sidekiq >> $sidekiq_logfile 2>&1
-}
-
-start_sidekiq()
-{
-  cmd="exec"
-  chpst=$(which chpst)
-
-  if [ -n "$chpst" ]; then
-    cmd="${cmd} ${chpst} -P"
-  fi
-
-  ${cmd} bundle exec sidekiq -C "${sidekiq_config}" -e $RAILS_ENV "$@"
-}
-
-load_ok()
-{
-  sidekiq_pid=$(cat $sidekiq_pidfile)
-  if [ -z "$sidekiq_pid" ] ; then
-    warn "Could not find a PID in $sidekiq_pidfile"
-    exit 0
-  fi
-
-  if (ps -p $sidekiq_pid -o args | grep '\([0-9]\+\) of \1 busy' 1>&2) ; then
-    warn "Too many busy Sidekiq workers"
-    exit 1
-  fi
-
-  exit 0
-}
-
-case "$1" in
-  stop)
-    stop
-    ;;
-  start)
-    restart
-    ;;
-  start_no_deamonize)
-    start_no_deamonize
-    ;;
-  start_foreground)
-    start_sidekiq
-    ;;
-  restart)
-    restart
-    ;;
-  killall)
-    killall
-    ;;
-  load_ok)
-    load_ok
-    ;;
-  *)
-    echo "Usage: RAILS_ENV=your_env $0 {stop|start|start_no_deamonize|restart|killall|load_ok}"
-esac
+if [ -n "$SIDEKIQ_WORKERS" ] ; then
+  exec bin/background_jobs_sk_cluster "$@"
+else
+  exec bin/background_jobs_sk "$@"
+fi

bin/background_jobs_sk

+#!/bin/sh
+
+cd $(dirname $0)/..
+app_root=$(pwd)
+sidekiq_pidfile="$app_root/tmp/pids/sidekiq.pid"
+sidekiq_logfile="$app_root/log/sidekiq.log"
+sidekiq_config="$app_root/config/sidekiq_queues.yml"
+gitlab_user=$(ls -l config.ru | awk '{print $3}')
+
+warn()
+{
+  echo "$@" 1>&2
+}
+
+stop()
+{
+  bundle exec sidekiqctl stop $sidekiq_pidfile >> $sidekiq_logfile 2>&1
+}
+
+restart()
+{
+  if [ -f $sidekiq_pidfile ]; then
+    stop
+  fi
+
+  pkill -u $gitlab_user -f 'sidekiq [0-9]'
+  start_sidekiq -P $sidekiq_pidfile -d -L $sidekiq_logfile >> $sidekiq_logfile 2>&1
+}
+
+# Starts on foreground but output to the logfile instead stdout.
+start_silent()
+{
+  start_sidekiq >> $sidekiq_logfile 2>&1
+}
+
+start_sidekiq()
+{
+  cmd="exec"
+  chpst=$(which chpst)
+
+  if [ -n "$chpst" ]; then
+    cmd="${cmd} ${chpst} -P"
+  fi
+
+  ${cmd} bundle exec sidekiq -C "${sidekiq_config}" -e $RAILS_ENV "$@"
+}
+
+case "$1" in
+  stop)
+    stop
+    ;;
+  start)
+    restart
+    ;;
+  start_silent)
+    warn "Deprecated: Will be removed at 13.0 (see https://gitlab.com/gitlab-org/gitlab/-/issues/196731)."
+    start_silent
+    ;;
+  start_foreground)
+    start_sidekiq
+    ;;
+  restart)
+    restart
+    ;;
+  *)
+    echo "Usage: RAILS_ENV=<env> $0 {stop|start|start_silent|start_foreground|restart}"
+esac

bin/background_jobs_sk_cluster

+#!/bin/sh
+
+cd $(dirname $0)/..
+app_root=$(pwd)
+sidekiq_pidfile="$app_root/tmp/pids/sidekiq-cluster.pid"
+sidekiq_logfile="$app_root/log/sidekiq.log"
+gitlab_user=$(ls -l config.ru | awk '{print $3}')
+
+warn()
+{
+  echo "$@" 1>&2
+}
+
+get_sidekiq_pid() 
+{
+  if [ ! -f $sidekiq_pidfile ]; then
+    warn "No pidfile found at $sidekiq_pidfile; is Sidekiq running?"
+    return
+  fi
+
+  cat $sidekiq_pidfile
+}
+
+stop()
+{
+  sidekiq_pid=$(get_sidekiq_pid)
+
+  if [ $sidekiq_pid ]; then
+    kill -TERM $sidekiq_pid
+  fi
+}
+
+restart()
+{
+  if [ -f $sidekiq_pidfile ]; then
+    stop
+  fi
+
+  warn "Sidekiq output will be written to $sidekiq_logfile"
+  start_sidekiq >> $sidekiq_logfile 2>&1
+}
+
+start_sidekiq()
+{
+  cmd="exec"
+  chpst=$(which chpst)
+
+  if [ -n "$chpst" ]; then
+    cmd="${cmd} ${chpst} -P"
+  fi
+
+  # sidekiq-cluster expects '*' '*' arguments (one wildcard for each process).
+  for (( i=1; i<=$SIDEKIQ_WORKERS; i++ ))
+  do
+    processes_args+=("*")
+  done
+
+  ${cmd} bin/sidekiq-cluster "${processes_args[@]}" -P $sidekiq_pidfile -e $RAILS_ENV
+}
+
+case "$1" in
+  stop)
+    stop
+    ;;
+  start)
+    restart &
+    ;;
+  start_foreground)
+    start_sidekiq
+    ;;
+  restart)
+    restart &
+    ;;
+  *)
+    echo "Usage: RAILS_ENV=<env> SIDEKIQ_WORKERS=<n> $0 {stop|start|start_foreground|restart}"
+esac

changelogs/unreleased/osw-support-opt-in-cluster-in-bg-jobs-script.yml

+---
+title: Support sidekiq-cluster supervision through bin/background_jobs
+merge_request: 27042
+author:
+type: added

lib/tasks/sidekiq.rake

@@ -33,6 +33,6 @@ namespace :sidekiq do
   task :launchd do
     deprecation_warning!
 
-    system(*%w(bin/background_jobs start_no_deamonize))
+    system(*%w(bin/background_jobs start_silent))
   end
 end