Add operation mode to docker container for scaled deployments

[nyanmark]

Is there an existing feature request for this?

• [X] I have searched the existing issues before opening this feature request.

Describe the feature you would like to see.

Having an environmental variable, such as SERVER_MODE which will allow you to select between mode MASTER and SLAVE. As I understand only one container can be running the cron and queue worker so it would be nice to have an option where when the env variable is set the docker container would disable those services in the container. This would then allow that small amount of users running docker swarm or k8s to scale their deployment.

Describe the solution you'd like.

This can be implemented through editing the entrypoint.sh file and adding an additional configuration fire for supervisord without the queue worker which would replace the default one just like the nginx file. My bash ain't perfect but this is how I image a solution would look like.

#!/bin/ash -e
cd /app

mkdir -p /var/log/panel/logs/ /var/log/supervisord/ /var/log/nginx/ /var/log/php7/ \
  && chmod 777 /var/log/panel/logs/ \
  && ln -s /var/log/panel/logs/ /app/storage/logs/

## Set mode to master if not set
if [[ -z $SERVER_MODE ]]; then
  echo -e "SERVER_MODE not specified, defaulting to MASTER"
  SERVER_MODE=MASTER
fi

## check for .env file and generate app keys if missing
if [ -f /app/var/.env ]; then
  echo "external vars exist."
  rm -rf /app/.env
  ln -s /app/var/.env /app/
else
  echo "external vars don't exist."
  rm -rf /app/.env
  touch /app/var/.env

  ## manually generate a key because key generate --force fails
  if [ "$SERVER_MODE" == "MASTER" ]; then
    if [ -z $APP_KEY ]; then
      echo -e "Generating key."
      APP_KEY=$(cat /dev/urandom | tr -dc 'a-zA-Z0-9' | fold -w 32 | head -n 1)
      echo -e "Generated app key: $APP_KEY"
      echo -e "APP_KEY=$APP_KEY" > /app/var/.env
    else
      echo -e "APP_KEY exists in environment, using that."
      echo -e "APP_KEY=$APP_KEY" > /app/var/.env
    fi
  else
    if [ -z $APP_KEY ]; then
      echo -e "No APP_KEY will not work in slave mode"
    else
      echo -e "APP_KEY exists in environment, using that."
      echo -e "APP_KEY=$APP_KEY" > /app/var/.env
    fi
  fi
  ln -s /app/var/.env /app/
fi

echo "Checking if https is required."
if [ -f /etc/nginx/http.d/panel.conf ]; then
  echo "Using nginx config already in place."
  if [ $LE_EMAIL ]; then
    echo "Checking for cert update"
    certbot certonly -d $(echo $APP_URL | sed 's~http[s]*://~~g')  --standalone -m $LE_EMAIL --agree-tos -n
  else
    echo "No letsencrypt email is set"
  fi
else
  echo "Checking if letsencrypt email is set."
  if [ -z $LE_EMAIL ]; then
    echo "No letsencrypt email is set using http config."
    cp .github/docker/default.conf /etc/nginx/http.d/panel.conf
  else
    echo "writing ssl config"
    cp .github/docker/default_ssl.conf /etc/nginx/http.d/panel.conf
    echo "updating ssl config for domain"
    sed -i "s|<domain>|$(echo $APP_URL | sed 's~http[s]*://~~g')|g" /etc/nginx/http.d/panel.conf
    echo "generating certs"
    certbot certonly -d $(echo $APP_URL | sed 's~http[s]*://~~g')  --standalone -m $LE_EMAIL --agree-tos -n
  fi
  echo "Removing the default nginx config"
  rm -rf /etc/nginx/http.d/default.conf
fi

if [[ -z $DB_PORT ]]; then
  echo -e "DB_PORT not specified, defaulting to 3306"
  DB_PORT=3306
fi

## check for DB up before starting the panel
echo "Checking database status."
until nc -z -v -w30 $DB_HOST $DB_PORT
do
  echo "Waiting for database connection..."
  # wait for 1 seconds before check again
  sleep 1
done

## make sure the db is set up
if [ "$SERVER_MODE" == "MASTER" ]; then
  echo -e "Migrating and Seeding D.B"
  php artisan migrate --seed --force

  ## start cronjobs for the queue
  echo -e "Starting cron jobs."
  crond -L /var/log/crond -l 5
fi

if [ "$SERVER_MODE" == "SLAVE" ]; then
  ## remove queue worker from /etc/supervisord.conf
  rm -rf /etc/supervisord.conf
  ## copy supervisord slave config without the queue worker
  cp .github/docker/supervisord-slave.conf /etc/supervisord.conf
fi

echo -e "Starting supervisord."
exec "$@"

Additional context to this request.

I just built a container with this entrypoint and an additional supervisord file and it seems to work.