Fix init.d script to correctly set web server PID

This was still writing to unicorn.pid even after switching to puma.

changelogs/unreleased/213531-fix-init-d-web-server-pid.yml

+---
+title: Fix init.d script to correctly set web server PID
+merge_request: 29164
+author:
+type: fixed

doc/install/installation.md

@@ -966,7 +966,7 @@ If you want to switch back to Unicorn, follow these steps:
    sudo -u git -H cp config/unicorn.rb.example config/unicorn.rb
    ```
 
-1. Edit the system `init.d` script to set the `USE_UNICORN=1` flag. If you have `/etc/default/gitlab`, then you should edit it instead.
+1. Edit the system `init.d` script and set `USE_WEB_SERVER="unicorn"`. If you have `/etc/default/gitlab`, then you should edit it instead.
 1. Restart GitLab.
 
 ### Using Sidekiq instead of Sidekiq Cluster

lib/support/init.d/gitlab

@@ -23,11 +23,20 @@
 # An example defaults file can be found in lib/support/init.d/gitlab.default.example
 ###
 
-
 ### Environment variables
-RAILS_ENV="production"
-USE_UNICORN=""
-SIDEKIQ_WORKERS=1
+RAILS_ENV=${RAILS_ENV:-'production'}
+SIDEKIQ_WORKERS=${SIDEKIQ_WORKERS:-1}
+USE_WEB_SERVER=${USE_WEB_SERVER:-'puma'}
+
+case "${USE_WEB_SERVER}" in
+  puma|unicorn)
+    use_web_server="$USE_WEB_SERVER"
+    ;;
+  *)
+    echo "Unsupported web server '${USE_WEB_SERVER}' (Allowed: 'puma', 'unicorn')" 1>&2
+    exit 1
+    ;;
+esac
 
 # Script variable names should be lower-case not to conflict with
 # internal /bin/sh variables such as PATH, EDITOR or SHELL.
@@ -36,7 +45,7 @@ app_root="/home/$app_user/gitlab"
 pid_path="$app_root/tmp/pids"
 socket_path="$app_root/tmp/sockets"
 rails_socket="$socket_path/gitlab.socket"
-web_server_pid_path="$pid_path/unicorn.pid"
+web_server_pid_path="$pid_path/$use_web_server.pid"
 mail_room_enabled=false
 mail_room_pid_path="$pid_path/mail_room.pid"
 gitlab_workhorse_dir=$(cd $app_root/../gitlab-workhorse 2> /dev/null && pwd)
@@ -67,13 +76,6 @@ if ! cd "$app_root" ; then
  echo "Failed to cd into $app_root, exiting!";  exit 1
 fi
 
-# Select the web server to use
-if [ -z "$USE_UNICORN" ]; then
-  use_web_server="puma"
-else
-  use_web_server="unicorn"
-fi
-
 if [ -z "$SIDEKIQ_WORKERS" ]; then
   sidekiq_pid_path="$pid_path/sidekiq.pid"
 else

lib/support/init.d/gitlab.default.example

@@ -6,7 +6,7 @@
 RAILS_ENV="production"
 
 # Uncomment the line below to enable the Unicorn web server instead of Puma.
-# USE_UNICORN=1
+# use_web_server="unicorn"
 
 # app_user defines the user that GitLab is run as.
 # The default is "git".