feat: Add user customizable default root response

Dockerfile

@@ -1,5 +1,5 @@
 # setup build arguments for version of dependencies to use
-ARG DOCKER_GEN_VERSION=0.7.7
+ARG DOCKER_GEN_VERSION=main
 ARG FOREGO_VERSION=v0.17.0
 
 # Use a specific version of golang to build both binaries

Dockerfile.alpine

@@ -1,5 +1,5 @@
 # setup build arguments for version of dependencies to use
-ARG DOCKER_GEN_VERSION=0.7.7
+ARG DOCKER_GEN_VERSION=main
 ARG FOREGO_VERSION=v0.17.0
 
 # Use a specific version of golang to build both binaries

README.md

@@ -123,6 +123,16 @@ You can have multiple containers proxied by the same `VIRTUAL_HOST` by adding a
 
 The full request URI will be forwarded to the serving container in the `X-Forwarded-Path` header.
 
+**NOTE**: Your application needs to be able to generate links starting with `VIRTUAL_PATH`. This can be achieved by it being natively on this path or havin an option to prepend this path. The application does not need to expect this path in the request.
+
+#### DEFAULT_ROOT
+
+This environment variable of the nginx proxy container can be used to customize the return error page if no matching path is found. Furthermore it is possible to use anything which is compatible with the `return` statement of nginx.
+
+For example `DEFAUL_ROOT=418` will return a 418 error page instead of the normal 404 one.
+Another example is `DEFAULT_ROOT="301 https://github.com/nginx-proxy/nginx-proxy/blob/main/README.md"` which would redirect an invalid request to this documentation.
+
+
 ### Multiple Networks
 
 With the addition of [overlay networking](https://docs.docker.com/engine/userguide/networking/get-started-overlay/) in Docker 1.9, your `nginx-proxy` container may need to connect to backend containers on multiple networks. By default, if you don't pass the `--net` flag when your `nginx-proxy` container is created, it will only be attached to the default `bridge` network. This means that it will not be able to connect to containers on networks other than `bridge`.

nginx.tmpl

@@ -5,6 +5,7 @@
 {{ $external_https_port := coalesce $.Env.HTTPS_PORT "443" }}
 {{ $debug_all := $.Env.DEBUG }}
 {{ $sha1_upstream_name := parseBool (coalesce $.Env.SHA1_UPSTREAM_NAME "false") }}
+{{ $default_root_response := coalesce $.Env.DEFAULT_ROOT "404" }}
 
 {{ define "ssl_policy" }}
 	{{ if eq .ssl_policy "Mozilla-Modern" }}
@@ -392,6 +393,11 @@ server {
 			{{ $upstream := printf "%s-%s" $upstream_name $sum }}
 			{{ template "location" (dict "Path" $path "Proto" $proto "Upstream" $upstream "Host" $host "Vhostroot" $vhost_root) }}
 		{{ end }}
+		{{ if (not (contains $paths "/")) }}
+			location / {
+				return {{ $default_root_response }};
+			}
+		{{ end }}
 	{{ end }}
 }
 
@@ -429,6 +435,11 @@ server {
 			{{ $upstream := printf "%s-%s" $upstream_name $sum }}
 			{{ template "location" (dict "Path" $path "Proto" $proto "Upstream" $upstream "Host" $host "Vhostroot" $vhost_root) }}
 		{{ end }}
+		{{ if (not (contains $paths "/")) }}
+			location / {
+				return {{ $default_root_response }};
+			}
+		{{ end }}
 	{{ end }}
 }
 

test/test_virtual-path/test_custom_conf.py

@@ -0,0 +1,6 @@
+import pytest
+
+def test_default_root_response(docker_compose, nginxproxy):
+    r = nginxproxy.get("http://nginx-proxy.test/")
+    assert r.status_code == 418
+

test/test_virtual-path/test_custom_conf.yml

@@ -0,0 +1,24 @@
+web1:
+  image: web
+  expose:
+    - "81"
+  environment:
+    WEB_PORTS: "81"
+    VIRTUAL_HOST: "nginx-proxy.test"
+    VIRTUAL_PATH: "/web1/"
+
+web2:
+  image: web
+  expose:
+    - "82"
+  environment:
+    WEB_PORTS: "82"
+    VIRTUAL_HOST: "nginx-proxy.test"
+    VIRTUAL_PATH: "/web2/"
+sut:
+  image: nginxproxy/nginx-proxy:test
+  environment:
+    DEFAULT_ROOT: 418
+  volumes:
+    - /var/run/docker.sock:/tmp/docker.sock:ro
+    - ../lib/ssl/dhparam.pem:/etc/nginx/dhparam/dhparam.pem:ro