It’s quite easy since Grafana containers already have the respecting parameters you only need 3 files and 1 crontab entry.

• modify your docker-compose.yml like this

    grafana-render:
  hostname: grafana-render
  image: grafana/grafana-image-renderer:latest
  ports:
  - "127.0.0.1:8081:8081"
  
  #        - ./data/graphite.htpasswd:/etc/nginx/.htpasswd
  grafana:
  #    image: grafana/grafana:4.2.0
  image: grafana/grafana:4.6.5
  ports:
  - "127.0.0.1:3000:3000"
  volumes:
  - ./data/grafana:/var/lib/grafana
  #    links:
  #        - graphite
  environment:
  - GF_EXTERNAL_IMAGE_STORAGE_PROVIDER=webdav
  - GF_EXTERNAL_IMAGE_STORAGE_PUBLIC_URL=https://my.domain.lan/grafana-uploads/media
  - GF_EXTERNAL_IMAGE_STORAGE_PUBLICURL=https://my.domain.lan/grafana-uploads/media
  - GF_EXTERNAL_IMAGE_STORAGE_WEBDAV_PUBLICURL=https://my.domain.lan/grafana-uploads/media
  - GF_EXTERNAL_IMAGE_STORAGE_WEBDAV_PUBLIC_URL=https://my.domain.lan/grafana-uploads/media
  - GF_EXTERNAL_IMAGE_STORAGE_WEBDAV_URL=http://webdav.my.domain.lan/media
  - GF_EXTERNAL_IMAGE_STORAGE_WEBDAV_USERNAME=grafana
  - GF_EXTERNAL_IMAGE_STORAGE_WEBDAV_PASSWORD=PassSharedGrafanaWebdav_CHANGE_ME
  - GF_RENDERING_SERVER_URL=http://grafana-render:8081/render
  - GF_SERVER_ROOT_URL=https://my.domain.lan
  - GF_SECURITY_ADMIN_PASSWORD=N0B0dyKnows_You_SHOULD_CHANGE_ME
  - GF_SMTP_ENABLED=true
  - GF_SMTP_HOST=smtp.mydomain.lan
  - GF_SMTP_USER=sensors@mydomain.lan
  - GF_SMTP_PASSWORD=mySMTP_PASSWORD_You_SHOULD_CHANGE_ME
  - GF_LOG_FILTERS=rendering:debug
  
  restart: unless-stopped
  
  webdav.my.domain.lan:
  restart: unless-stopped
  hostname: webdav.my.domain.lan
  container_name: webdav.my.domain.lan
  build:
  context: ./
  #      dockerfile: Dockerfile-alternate
  dockerfile: Dockerfile.webdav
  ports:
  - "127.0.0.1:8008:80"
  volumes:
  - "/opt/docker-compose/general/myproject_services/my.domain.lan/uploads/grafana-uploads/:/media"
  environment:
  USERNAME: grafana
  PASSWORD: PassSharedGrafanaWebdav_CHANGE_ME
  

• create Dockerfile.webdav

  FROM thefoundation/upgraded-operating-systems:ubuntu-bionic
  RUN ln -s /usr/share/zoneinfo/Europe/Berlin
  RUN apt-get update && apt-get install -y nginx nginx-extras apache2-utils
  
  VOLUME /media
  EXPOSE 80
  COPY webdav.conf /etc/nginx/conf.d/default.conf
  RUN rm /etc/nginx/sites-enabled/*
  
  COPY entrypoint-webdav.sh /
  RUN chmod +x entrypoint-webdav.sh
  CMD /entrypoint-webdav.sh && nginx -g "daemon off;"
  

• create entrypoint-webdav.sh

  #!/bin/bash
  
  if [[ -n "$USERNAME" ]] && [[ -n "$PASSWORD" ]]
  then
  htpasswd -bc /etc/nginx/htpasswd $USERNAME $PASSWORD
  echo Done.
  else
  echo Using no auth.
  sed -i 's%auth_basic "Restricted";% %g' /etc/nginx/conf.d/default.conf
  sed -i 's%auth_basic_user_file htpasswd;% %g' /etc/nginx/conf.d/default.conf
  

• find the folder of your webdav-images ( docker-compose config ) and add a cron entry

  #Grafana webDAV cleanup
  15 */2  * * *   find /opt/docker-compose/general/my_services/my.grafana.lan/uploads/grafana-uploads/media -type f -name "*.png" -mtime +2 -delete &>/dev/null || true
  

• setup your grafana to include the images

• have fun