fix template when running docker-gen and nginx in separate containers

Since commit 658e20f, the template makes the assumption that the container running docker-gen is the container running nginx while checking that upstream containers are reachable.
By introducint the `NGINX_CONTAINER` environment variable, users are now able to indicate which container is actually running nginx when running docker-gen and nginx in separated containers.

.gitignore

@@ -1,2 +1,3 @@
 **/__pycache__/
 **/.cache/
+*.pyc

README.md

@@ -135,13 +135,17 @@ First start nginx with a volume:
 
     $ docker run -d -p 80:80 --name nginx -v /tmp/nginx:/etc/nginx/conf.d -t nginx
 
-Then start the docker-gen container with the shared volume and template:
+Then start the docker-gen container with:
+- the `NGINX_CONTAINER` environment variable set to the name of the container running nginx
+- the shared volume
+- the template
 
 ```
 $ docker run --volumes-from nginx \
+    -e NGINX_CONTAINER=nginx \
     -v /var/run/docker.sock:/tmp/docker.sock:ro \
     -v $(pwd):/etc/docker-gen/templates \
-    -t jwilder/docker-gen -notify-sighup nginx -watch /etc/docker-gen/templates/nginx.tmpl /etc/nginx/conf.d/default.conf
+    -t jwilder/docker-gen -notify-sighup nginx -only-exposed -watch /etc/docker-gen/templates/nginx.tmpl /etc/nginx/conf.d/default.conf
 ```
 
 Finally, start your containers with `VIRTUAL_HOST` environment variables.

docker-compose-separate-containers.yml

@@ -10,12 +10,14 @@ services:
 
   dockergen:
     image: jwilder/docker-gen
-    command: -notify-sighup nginx -watch /etc/docker-gen/templates/nginx.tmpl /etc/nginx/conf.d/default.conf
+    command: -notify-sighup nginx -only-exposed -watch /etc/docker-gen/templates/nginx.tmpl /etc/nginx/conf.d/default.conf
     volumes_from:
       - nginx
     volumes:
       - /var/run/docker.sock:/tmp/docker.sock:ro
       - ./nginx.tmpl:/etc/docker-gen/templates/nginx.tmpl
+    environment:
+      - NGINX_CONTAINER=nginx
 
   whoami:
     image: jwilder/whoami

nginx.tmpl

@@ -1,4 +1,23 @@
 {{ $CurrentContainer := where $ "ID" .Docker.CurrentContainerID | first }}
+{{ $NginxContainerName := coalesce $.Env.NGINX_CONTAINER $CurrentContainer.Name }}
+{{ $NginxContainer := where $ "Name" $NginxContainerName | first }}
+# -----------------------------------------------------------------------------
+# $.Env.NGINX_CONTAINER: {{ $.Env.NGINX_CONTAINER }}
+# Docker-gen container name: {{ $CurrentContainer.Name }}
+# Nginx container name: {{ $NginxContainerName }}
+# Nginx container found: {{ if $NginxContainer }}yes{{ else }}no{{ end }}
+# Nginx networks: {{ json $NginxContainer.Networks }}
+# -----------------------------------------------------------------------------
+
+{{ if not $NginxContainer }}
+###############################################################################
+#                                                                             #
+# Could not determine which container is running nginx.                       #
+# Make sure to provide a correct value for the `NGINX_CONTAINER` environment  #
+# variable.                                                                   #
+#                                                                             #
+###############################################################################
+{{ end }}
 
 {{ define "upstream" }}
 	{{ if .Address }}
@@ -106,7 +125,7 @@ upstream {{ $upstream_name }} {
 {{ range $container := $containers }}
 	{{ $addrLen := len $container.Addresses }}
 
-	{{ range $knownNetwork := $CurrentContainer.Networks }}
+	{{ range $knownNetwork := $NginxContainer.Networks }}
 		{{ range $containerNetwork := $container.Networks }}
 			{{ if eq $knownNetwork.Name $containerNetwork.Name }}
 				## Can be connect with "{{ $containerNetwork.Name }}" network
@@ -268,6 +287,5 @@ server {
 	ssl_certificate_key /etc/nginx/certs/default.key;
 }
 {{ end }}
-
 {{ end }}
 {{ end }}

test/.gitignore

@@ -0,0 +1 @@
+/nginx.tmpl

test/README.md

@@ -47,6 +47,7 @@ This test suite uses [pytest](http://doc.pytest.org/en/latest/). The [conftest.p
 
 - docker_compose
 - nginxproxy
+- nginx_tmpl
 
 
 ### docker_compose fixture
@@ -96,6 +97,10 @@ Furthermore, the nginxproxy methods accept an additional keyword parameter: `ipv
         assert r.text == "answer from port 81\n"
 
 
+### nginx_tmpl fixture
+
+The `nginx_tmpl` fixture extracts the `nginx.tmpl` template file from the `jwilder/nginx-proxy:test` image and copy it into the `test` directory. This is useful for tests which requires to mount the template file into a container as a volume.
+
 
 ### The web docker image
 

test/conftest.py

@@ -370,7 +370,8 @@ def disconnect_from_network(network=None):
 
 def connect_to_all_networks():
     """
-    If we are running from a container, connect our container to all current docker networks.
+    If we are running from a container, connect our container to all current docker networks but the 'bridge' and
+    'none' networks.
 
     :return: a list of networks we connected to
     """
@@ -378,7 +379,7 @@ def connect_to_all_networks():
         return []
     else:
         # find the list of docker networks
-        networks = filter(lambda network: len(network.containers) > 0 and network.name != 'bridge', docker_client.networks.list())
+        networks = filter(lambda network: len(network.containers) > 0 and network.name not in ('bridge', 'none'), docker_client.networks.list())
         return [connect_to_network(network) for network in networks]
 
 
@@ -429,6 +430,27 @@ def nginxproxy():
     yield requests_for_docker()
 
 
+@pytest.yield_fixture(scope="module")
+def nginx_tmpl():
+    """
+    pytest fixture which extracts the the nginx config template from
+    the jwilder/nginx-proxy:test image into the test directory
+    """
+    script_dir = os.path.dirname(__file__)
+    logging.info("extracting nginx.tmpl from jwilder/nginx-proxy:test")
+    print(docker_client.containers.run(
+        image='jwilder/nginx-proxy:test',
+        remove=True,
+        volumes=['{current_dir}:{current_dir}'.format(current_dir=script_dir)],
+        entrypoint='sh',
+        command='-xc "cp /app/nginx.tmpl {current_dir} && chmod 777 {current_dir}/nginx.tmpl"'.format(
+            current_dir=script_dir),
+        stderr=True))
+    yield os.path.join(script_dir, 'nginx.tmpl')
+    logging.info("removing nginx.tmpl")
+    os.remove(os.path.join(script_dir, "nginx.tmpl"))
+
+
 ###############################################################################
 # 
 # Py.test hooks

test/test_dockergen/.gitignore

@@ -1 +0,0 @@
-nginx.tmpl

test/test_dockergen/test_dockergen_v2.py

@@ -1,38 +0,0 @@
-import os
-import docker
-import logging
-import pytest
-
-
-@pytest.yield_fixture(scope="module")
-def nginx_tmpl():
-    """
-    pytest fixture which extracts the the nginx config template from
-    the jwilder/nginx-proxy:test image
-    """
-    script_dir = os.path.dirname(__file__)
-    logging.info("extracting nginx.tmpl from jwilder/nginx-proxy:test")
-    docker_client = docker.from_env()
-    print(docker_client.containers.run(
-        image='jwilder/nginx-proxy:test',
-        remove=True,
-        volumes=['{current_dir}:{current_dir}'.format(current_dir=script_dir)],
-        entrypoint='sh',
-        command='-xc "cp /app/nginx.tmpl {current_dir} && chmod 777 {current_dir}/nginx.tmpl"'.format(
-            current_dir=script_dir),
-        stderr=True))
-    yield
-    logging.info("removing nginx.tmpl")
-    os.remove(os.path.join(script_dir, "nginx.tmpl"))
-
-
-def test_unknown_virtual_host_is_503(nginx_tmpl, docker_compose, nginxproxy):
-    r = nginxproxy.get("http://unknown.nginx.container.docker/")
-    assert r.status_code == 503
-
-
-def test_forwards_to_whoami(nginx_tmpl, docker_compose, nginxproxy):
-    r = nginxproxy.get("http://whoami.nginx.container.docker/")
-    assert r.status_code == 200
-    whoami_container = docker_compose.containers.get("whoami")
-    assert r.text == "I'm %s\n" % whoami_container.id[:12]

test/test_dockergen_v2/test_dockergen_v2.py

@@ -0,0 +1,18 @@
+from time import sleep
+
+
+def test_nginx_is_running(nginx_tmpl, docker_compose):
+    sleep(3)
+    assert docker_compose.containers.get("nginx").status == "running"
+
+
+def test_unknown_virtual_host_is_503(nginx_tmpl, docker_compose, nginxproxy):
+    r = nginxproxy.get("http://unknown.nginx.container.docker/")
+    assert r.status_code == 503
+
+
+def test_forwards_to_whoami(nginx_tmpl, docker_compose, nginxproxy):
+    r = nginxproxy.get("http://whoami.nginx.container.docker/")
+    assert r.status_code == 200
+    whoami_container = docker_compose.containers.get("whoami")
+    assert r.text == "I'm %s\n" % whoami_container.id[:12]

test/test_dockergen_v2/test_dockergen_v2.yml

@@ -14,7 +14,7 @@ services:
       - nginx
     volumes:
       - /var/run/docker.sock:/tmp/docker.sock:ro
-      - ./nginx.tmpl:/etc/docker-gen/templates/nginx.tmpl
+      - ../nginx.tmpl:/etc/docker-gen/templates/nginx.tmpl
 
   web:
     image: web

test/test_dockergen_v3/test_dockergen_v3.py

@@ -1,6 +1,5 @@
-import os
+from time import sleep
 import docker
-import logging
 import pytest
 
 
@@ -27,26 +26,9 @@ pytestmark = pytest.mark.skipif(
     reason="Docker compose syntax v3 requires docker engine v1.13 or later (got %s)" % raw_version)
 
 
-@pytest.yield_fixture(scope="module")
-def nginx_tmpl():
-    """
-    pytest fixture which extracts the the nginx config template from
-    the jwilder/nginx-proxy:test image
-    """
-    script_dir = os.path.dirname(__file__)
-    logging.info("extracting nginx.tmpl from jwilder/nginx-proxy:test")
-    docker_client = docker.from_env()
-    print(docker_client.containers.run(
-        image='jwilder/nginx-proxy:test',
-        remove=True,
-        volumes=['{current_dir}:{current_dir}'.format(current_dir=script_dir)],
-        entrypoint='sh',
-        command='-xc "cp /app/nginx.tmpl {current_dir} && chmod 777 {current_dir}/nginx.tmpl"'.format(
-            current_dir=script_dir),
-        stderr=True))
-    yield
-    logging.info("removing nginx.tmpl")
-    os.remove(os.path.join(script_dir, "nginx.tmpl"))
+def test_nginx_is_running(nginx_tmpl, docker_compose):
+    sleep(3)
+    assert docker_compose.containers.get("nginx").status == "running"
 
 
 def test_unknown_virtual_host_is_503(nginx_tmpl, docker_compose, nginxproxy):
@@ -59,8 +41,3 @@ def test_forwards_to_whoami(nginx_tmpl, docker_compose, nginxproxy):
     assert r.status_code == 200
     whoami_container = docker_compose.containers.get("whoami")
     assert r.text == "I'm %s\n" % whoami_container.id[:12]
-
-
-if __name__ == '__main__':
-    import doctest
-    doctest.testmod()

test/test_dockergen_v3/test_dockergen_v3.yml

@@ -1,4 +1,5 @@
 version: '3'
+
 services:
   nginx:
     image: nginx
@@ -11,7 +12,7 @@ services:
     command: -notify-sighup nginx -watch /etc/docker-gen/templates/nginx.tmpl /etc/nginx/conf.d/default.conf
     volumes:
       - /var/run/docker.sock:/tmp/docker.sock:ro
-      - ./nginx.tmpl:/etc/docker-gen/templates/nginx.tmpl
+      - ../nginx.tmpl:/etc/docker-gen/templates/nginx.tmpl
       - nginx_conf:/etc/nginx/conf.d
 
   web:

test/test_separate_no_net/test_no_network_for_dockergen.py

@@ -0,0 +1,18 @@
+from time import sleep
+
+
+def test_nginx_is_running(nginx_tmpl, docker_compose):
+    sleep(3)
+    assert docker_compose.containers.get("nginx").status == "running"
+
+
+def test_unknown_virtual_host_is_503(nginx_tmpl, docker_compose, nginxproxy):
+    r = nginxproxy.get("http://unknown.nginx.container.docker/")
+    assert r.status_code == 503
+
+
+def test_forwards_to_whoami(nginx_tmpl, docker_compose, nginxproxy):
+    r = nginxproxy.get("http://whoami.nginx.container.docker/")
+    assert r.status_code == 200
+    whoami_container = docker_compose.containers.get("whoami")
+    assert r.text == "I'm %s\n" % whoami_container.id[:12]

test/test_separate_no_net/test_no_network_for_dockergen.yml

@@ -0,0 +1,50 @@
+# In this compose file, we define a dockergen container which has no network.
+# This should not be an issue since the docker-gen process is not binding to any port or isn't making any
+# network connection to any other container.
+
+---
+
+version: '2'
+
+networks:
+  nginx-net: {}
+
+
+volumes:
+  nginx_conf: {}
+  nginx_certs: {}
+
+services:
+  nginx:
+    image: nginx
+    container_name: nginx
+    volumes:
+      - nginx_conf:/etc/nginx/conf.d
+      - nginx_certs:/etc/nginx/certs
+    networks:
+      - nginx-net
+
+  dockergen:
+    image: jwilder/docker-gen
+    command: -notify-sighup nginx -watch /etc/docker-gen/templates/nginx.tmpl /etc/nginx/conf.d/default.conf
+    volumes_from:
+      - nginx
+    volumes:
+      - /var/run/docker.sock:/tmp/docker.sock:ro
+      - nginx_conf:/etc/nginx/conf.d
+      - nginx_certs:/etc/nginx/certs
+      - ../nginx.tmpl:/etc/docker-gen/templates/nginx.tmpl
+    environment:
+      NGINX_CONTAINER: nginx
+    networks: []
+
+  web:
+    image: web
+    container_name: whoami
+    expose:
+      - "80"
+    environment:
+      WEB_PORTS: 80
+      VIRTUAL_HOST: whoami.nginx.container.docker
+    networks:
+      - nginx-net

test/test_separate_only_exposed/test_only-exposed.py

@@ -0,0 +1,18 @@
+from time import sleep
+
+
+def test_nginx_is_running(nginx_tmpl, docker_compose):
+    sleep(3)
+    assert docker_compose.containers.get("nginx").status == "running"
+
+
+def test_unknown_virtual_host_is_503(nginx_tmpl, docker_compose, nginxproxy):
+    r = nginxproxy.get("http://unknown.nginx.container.docker/")
+    assert r.status_code == 503
+
+
+def test_forwards_to_whoami(nginx_tmpl, docker_compose, nginxproxy):
+    r = nginxproxy.get("http://whoami.nginx.container.docker/")
+    assert r.status_code == 200
+    whoami_container = docker_compose.containers.get("whoami")
+    assert r.text == "I'm %s\n" % whoami_container.id[:12]

test/test_separate_only_exposed/test_only-exposed.yml

@@ -0,0 +1,45 @@
+# In this compose file we define a dockergen container which is running the docker-gen process with the
+# `-only-exposed` option. This should not be an issue since the template for the nginx config file should only
+# have to deal with upstream containers which are required to have at least one port exposed, and since the nginx
+# container with no exposed port makes no sense.
+---
+
+version: '2'
+
+networks:
+  default: {}
+
+
+volumes:
+  nginx_conf: {}
+  nginx_certs: {}
+
+services:
+  nginx:
+    image: nginx
+    container_name: nginx
+    volumes:
+      - nginx_conf:/etc/nginx/conf.d
+      - nginx_certs:/etc/nginx/certs
+
+  dockergen:
+    image: jwilder/docker-gen
+    command: -notify-sighup nginx -only-exposed -watch /etc/docker-gen/templates/nginx.tmpl /etc/nginx/conf.d/default.conf
+    volumes_from:
+      - nginx
+    volumes:
+      - /var/run/docker.sock:/tmp/docker.sock:ro
+      - nginx_conf:/etc/nginx/conf.d
+      - nginx_certs:/etc/nginx/certs
+      - ../nginx.tmpl:/etc/docker-gen/templates/nginx.tmpl
+    environment:
+      NGINX_CONTAINER: nginx
+
+  web:
+    image: web
+    container_name: whoami
+    expose:
+      - "80"
+    environment:
+      WEB_PORTS: 80
+      VIRTUAL_HOST: whoami.nginx.container.docker