Run Laravel schedule in docker image using supervisord (#6606)

* docker: Rename /entrypoint.sh to /startup.sh

This script is not configured as the docker image ENTRYPOINT, thus it is
misleading to name it so.

* docker: Terminate supervisord if a process enters the FATAL state

By terminating PID 1, this will also terminate the Docker container.

* docker: Use supervisord to start up apache and cron

Note that this uses `apache2ctl -DFOREGROUND` rather than manually
sourcing /etc/apache2/envvars and running apache2, as recommended at
https://advancedweb.hu/2018/07/03/supervisor_docker/.

* docker: Add artisan schedule:run to crontab

This also switches to executing /var/www/html/artisan directly.

* docker: Run artisan schedule:run directly from supervisor

This has the following benefits over using cron:
- Cron doesn't need to be installed
- Docker-provided environment variables are preserved
- It's easy and explicit to run as the docker user

docker/startup.sh

@@ -5,7 +5,7 @@ if [ -z "$APP_KEY" ]
 then
   echo "Please re-run this container with an environment variable \$APP_KEY"
   echo "An example APP_KEY you could use is: "
-  php artisan key:generate --show
+  /var/www/html/artisan key:generate --show
   exit
 fi
 
@@ -47,5 +47,4 @@ then
   cp -ax /var/www/html/vendor/laravel/passport/database/migrations/* /var/www/html/database/migrations/
 fi
 
-. /etc/apache2/envvars 
-exec apache2 -DNO_DETACH < /dev/null
+exec supervisord -c /supervisord.conf

docker/supervisor-exit-event-listener

@@ -0,0 +1,19 @@
+#!/usr/bin/env python
+# A supervisor event listener which terminates supervisord if any of its child
+# processes enter the FATAL state.
+# https://stackoverflow.com/a/37527488/119527
+import os
+import signal
+
+from supervisor import childutils
+
+def main():
+    while True:
+        headers, payload = childutils.listener.wait()
+        childutils.listener.ok()
+        if headers['eventname'] != 'PROCESS_STATE_FATAL':
+            continue
+        os.kill(os.getppid(), signal.SIGTERM)
+
+if __name__ == "__main__":
+    main()

docker/supervisord.conf

@@ -0,0 +1,27 @@
+[supervisord]
+nodaemon=true
+
+[program:apache]
+; https://advancedweb.hu/2018/07/03/supervisor_docker/
+command=apache2ctl -DFOREGROUND
+killasgroup=true
+stopasgroup=true
+stdout_logfile=/dev/stdout
+stdout_logfile_maxbytes=0
+stderr_logfile=/dev/stderr
+stderr_logfile_maxbytes=0
+
+[program:run_schedule]
+; Simply run the Laravel command scheduler every minute
+command=/bin/bash -c "while true; do /var/www/html/artisan schedule:run; sleep 1m; done"
+user=docker
+stdout_logfile=/dev/stdout
+stdout_logfile_maxbytes=0
+stderr_logfile=/dev/stderr
+stderr_logfile_maxbytes=0
+
+
+; https://stackoverflow.com/a/37527488/119527
+[eventlistener:exit_on_any_fatal]
+command=supervisor-exit-event-listener
+events=PROCESS_STATE_FATAL