template nginx.tmpl error : nil pointer evaluating interface {}.Networks

[genestouxguy]

Hello,

I got the following error:
Template error: template: nginx.tmpl:24:39: executing "nginx.tmpl" at <$globals.CurrentContainer.Networks>: nil pointer evaluating interface {}.Networks

The nginx.tmpl is https://github.com/nginx-proxy/nginx-proxy/blob/main/nginx.tmpl

my docker-compose.yml is :

version: '3.9'

services:
  portail:
    image: nginx:alpine
    container_name: nginx
    restart: unless-stopped
    logging:
        driver: "json-file"
        options:
            max-size: "200k"
            max-file: "10"
    volumes:
      - porte_conf:/etc/nginx/conf.d:ro
      - porte_htpasswd:/etc/nginx/htpasswd:ro
      - porte_vhost:/etc/nginx/vhost.d:ro
      - porte_html:/usr/share/nginx/html:ro
      - certif_certs:/etc/nginx/certs:ro
    ports:
      - 80:80
      - 443:443
    networks:
      - net-front
    labels:
      com.github.jrcs.letsencrypt_nginx_proxy_companion.nginx_proxy: 'true'

  docker-gen:
    image: nginxproxy/docker-gen:0.10.1
    restart: unless-stopped
    logging:
        driver: "json-file"
        options:
            max-size: "200k"
            max-file: "10"
    depends_on:
      - portail
    container_name: portail_gen
    volumes:
      - /var/run/docker.sock:/tmp/docker.sock:ro
      - certif_certs:/etc/nginx/certs:ro
      - porte_conf:/etc/nginx/conf.d:rw
      - porte_html:/usr/share/nginx/html:rw
      - porte_htpasswd:/etc/nginx/htpasswd:rw
      - porte_templates:/etc/docker-gen/templates:ro
      - porte_vhost:/etc/nginx/vhost.d:rw
    command: -notify-sighup nginx -watch -only-exposed -wait 5s:30s /etc/docker-gen/templates/nginx.tmpl /etc/nginx/conf.d/default.conf
    labels:
      com.github.jrcs.letsencrypt_nginx_proxy_companion.docker_gen: 'true'
    networks:
      - net-front

  certif:
    image: nginxproxy/acme-companion:2.2.6
    container_name: portail_certif
    restart: unless-stopped
    logging:
        driver: "json-file"
        options:
            max-size: "200k"
            max-file: "10"
    depends_on:
      - docker-gen
    volumes:
      - certif_certs:/etc/nginx/certs:rw
      - /var/run/docker.sock:/var/run/docker.sock:ro
      - porte_conf:/etc/nginx/conf.d
      - porte_vhost:/etc/nginx/vhost.d
      - porte_html:/usr/share/nginx/html
    networks:
      - net-front
    environment:
      NGINX_PROXY_CONTAINER: 'nginx'
      NGINX_DOCKER_GEN_CONTAINER: 'portail_gen'
      DEBUG: 'false'
  vim:
    image: disp/vim
    volumes:
      - porte_conf:/etc/nginx/conf.d:rw
      - porte_html:/usr/share/nginx/html:rw
      - porte_htpasswd:/etc/nginx/htpasswd:rw
      - porte_templates:/etc/docker-gen/templates:rw
      - porte_vhost:/etc/nginx/vhost.d:rw

networks:
  net-front:
    external:
      name: net-proxy

volumes:
  certif_certs:
  porte_conf:
  porte_html:
  porte_htpasswd:
  porte_templates:
  porte_vhost:

docker version
Client: Docker Engine - Community
 Version:           23.0.1
 API version:       1.42
 Go version:        go1.19.5
 Git commit:        a5ee5b1
 Built:             Thu Feb  9 19:47:01 2023
 OS/Arch:           linux/amd64
 Context:           default

Server: Docker Engine - Community
 Engine:
  Version:          23.0.1
  API version:      1.42 (minimum version 1.12)
  Go version:       go1.19.5
  Git commit:       bc3805a
  Built:            Thu Feb  9 19:47:01 2023
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          1.6.18
  GitCommit:        2456e983eb9e37e47538f59ea18f2043c9a73640
 runc:
  Version:          1.1.4
  GitCommit:        v1.1.4-0-g5fd4c4d
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

And I run the following container :
docker run --env VIRTUAL_HOST=test.example.com --env VIRTUAL_PORT=8000 --env LETSENCRYPT_HOST=test.example.com --env WWW='no-www' --network=net-proxy jwilder/whoami

Could you tell me why this error please ?

[SchoNie]

The network in your compose is net-front
But your whoami container is attached to net-proxy

So the containers cannot reach eachother. That is probably why it is giving a nil pointers as there are zero (nil) available networks.

[genestouxguy]

Thanks for your response.

The network net-front is only a reference to the neworks section where I specify net-front is external and the name is net-proxy but I changed all net-front by net-proxy and I got the same error :/

[SchoNie]

Yes sorry, you are right. I missed the name part.
I tried your config and indeed same issue. (only with docker-gen as separate container)

I narrowed it down to commit bcec2d9075c053b9930de52a32a712d69961a213 if that helps @rhansen

If you need a quick fix, you could use the nginx.tmpl from the commit before that.

[genestouxguy]

Thanks for your response. It works, thanks.

I let you decide when you want to close the issue.

[genestouxguy]

For information, I changed line 13 in nginx.tmpl by {{- $_ := set $globals "CurrentContainer" (where $globals.containers "Name" "nginx" | first) }}.

With this change the actual template works.

[rhansen]

I think I understand what's going wrong. I don't think the commit @SchoNie identified is wrong; instead, I think that it exposed nginx-proxy/docker-gen#458 in certain setups where that bug wasn't exposed before. Specifically, if there are no containers with VIRTUAL_HOST set, then $globals.CurrentContainer.Networks was never evaluated. Now it is.

As a workaround, I believe it would be sufficient to remove -only-exposed from the arguments passed to docker-gen. Can you confirm @genestouxguy?

[SchoNie]

As a workaround, I believe it would be sufficient to remove -only-exposed from the arguments passed to docker-gen. Can you confirm @genestouxguy?

Yes for me it already works, with the copied config from @genestouxguy

[genestouxguy]

Sorry I didn't get enough time today to try. I try monday. Have a nice weekend.

[genestouxguy]

Hi,

It works also for me.

Thanks.