feat: allow nginx / docker-gen network segregation

README.md

@@ -295,6 +295,12 @@ Finally, start your containers with `VIRTUAL_HOST` environment variables.
 docker run -e VIRTUAL_HOST=foo.bar.com  ...
 ```
 
+To allow for network segregation of the nginx and docker-gen containers, the label `com.github.nginx-proxy.nginx-proxy.nginx` must be applied to the nginx container, otherwise it is assumed that nginx and docker-gen share the same network:
+
+```console
+docker run -d -p 80:80 --name nginx -l "com.github.nginx-proxy.nginx-proxy.nginx" -v /tmp/nginx:/etc/nginx/conf.d -t nginx
+```
+
 ### SSL Support using an ACME CA
 
 [acme-companion](https://github.com/nginx-proxy/acme-companion) is a lightweight companion container for the nginx-proxy. It allows the automated creation/renewal of SSL certificates using the ACME protocol.

nginx.tmpl

@@ -11,6 +11,7 @@
 {{- $_ := set $globals "Env" $.Env }}
 {{- $_ := set $globals "Docker" $.Docker }}
 {{- $_ := set $globals "CurrentContainer" (where $globals.containers "ID" $globals.Docker.CurrentContainerID | first) }}
+{{- $_ := set $globals "NginxContainer" (whereLabelExists $globals.containers "com.github.nginx-proxy.nginx-proxy.nginx" | first) }}
 {{- $_ := set $globals "default_cert_ok" (and (exists "/etc/nginx/certs/default.crt") (exists "/etc/nginx/certs/default.key")) }}
 {{- $_ := set $globals "external_http_port" (coalesce $globals.Env.HTTP_PORT "80") }}
 {{- $_ := set $globals "external_https_port" (coalesce $globals.Env.HTTPS_PORT "443") }}
@@ -22,14 +23,21 @@
 {{- $_ := set $globals "ssl_policy" (or ($globals.Env.SSL_POLICY) "Mozilla-Intermediate") }}
 {{- $_ := set $globals "vhosts" (dict) }}
 {{- $_ := set $globals "networks" (dict) }}
-# Networks available to the container running docker-gen (which are assumed to
+# Networks available to the container labeled "com.github.nginx-proxy.nginx-proxy.nginx-proxy" or the one running docker-gen (which are assumed to
 # match the networks available to the container running nginx):
 {{- /*
      * Note: $globals.CurrentContainer may be nil in some circumstances due to
      * <https://github.com/nginx-proxy/docker-gen/issues/458>.  For more context
      * see <https://github.com/nginx-proxy/nginx-proxy/issues/2189>.
      */}}
-{{- if $globals.CurrentContainer }}
+{{- if $globals.NginxContainer }}
+    {{- range sortObjectsByKeysAsc $globals.NginxContainer.Networks "Name" }}
+        {{- $_ := set $globals.networks .Name . }}
+#     {{ .Name }}
+    {{- else }}
+#     (none)
+    {{- end }}
+{{- else if $globals.CurrentContainer }}
     {{- range sortObjectsByKeysAsc $globals.CurrentContainer.Networks "Name" }}
         {{- $_ := set $globals.networks .Name . }}
 #     {{ .Name }}