1. Mattermost

# https://docs.docker.com/compose/environment-variables/
services:
  postgres:
    image: postgres:${POSTGRES_IMAGE_TAG}
    restart: ${RESTART_POLICY}
    security_opt:
      - no-new-privileges:true
    # See https://docs.mattermost.com/administration-guide/scale/scaling-for-enterprise.html
    # for guidance on memory limits based on your deployment size.
    mem_limit: 16G
    read_only: true
    tmpfs:
      - /tmp
      - /var/run/postgresql
    volumes:
      - ${POSTGRES_DATA_PATH}:/var/lib/postgresql
    environment:
      # timezone inside container
      - TZ

      # necessary Postgres options/variables
      - POSTGRES_USER
      - POSTGRES_PASSWORD
      - POSTGRES_DB

  mattermost:
    depends_on:
      - postgres
    image: mattermost/${MATTERMOST_IMAGE}:${MATTERMOST_IMAGE_TAG}
    restart: ${RESTART_POLICY}
    security_opt:
      - no-new-privileges:true
    # See https://docs.mattermost.com/administration-guide/scale/scaling-for-enterprise.html
    # for guidance on memory limits based on your deployment size.
    mem_limit: 4G
    read_only: ${MATTERMOST_CONTAINER_READONLY}
    tmpfs:
      - /tmp
    volumes:
      - ${MATTERMOST_CONFIG_PATH}:/mattermost/config:rw
      - ${MATTERMOST_DATA_PATH}:/mattermost/data:rw
      - ${MATTERMOST_LOGS_PATH}:/mattermost/logs:rw
      - ${MATTERMOST_PLUGINS_PATH}:/mattermost/plugins:rw
      - ${MATTERMOST_CLIENT_PLUGINS_PATH}:/mattermost/client/plugins:rw
      - ${MATTERMOST_BLEVE_INDEXES_PATH}:/mattermost/bleve-indexes:rw
      # When you want to use SSO with GitLab, you have to add the cert pki chain of GitLab inside Alpine
      # to avoid Token request failed: certificate signed by unknown authority 
      # (link: https://github.com/mattermost/mattermost-server/issues/13059 and https://github.com/mattermost/docker/issues/34)
      # - ${GITLAB_PKI_CHAIN_PATH}:/etc/ssl/certs/pki_chain.pem:ro
    environment:
      # timezone inside container
      - TZ

      # necessary Mattermost options/variables (see env.example)
      - MM_SQLSETTINGS_DRIVERNAME
      - MM_SQLSETTINGS_DATASOURCE

      # necessary for bleve
      - MM_BLEVESETTINGS_INDEXDIR

      # additional settings
      - MM_SERVICESETTINGS_SITEURL