SWARM multi node multi container compatible

The idea:
 - all nodes generate their config in /etc/nginx/node.conf.d/HOSTNAME.conf
 - a python script can read all configs and merge them into one and reload nginx
 - using entr in Procfile, anytime any of these config change, they are merged immediately
 - the default nginx reload on notify is being removed to prevent from reloading twice

.gitignore

@@ -1,3 +1,4 @@
 **/__pycache__/
 **/.cache/
 .idea/
+venv

Dockerfile

@@ -1,18 +1,26 @@
 FROM nginx:1.17.8
-LABEL maintainer="Jason Wilder mail@jasonwilder.com"
+MAINTAINER Jonathan Adami <contact@jadami.com>
+LABEL creator="Jason Wilder mail@jasonwilder.com"
 
-# Install wget and install/updates certificates
+# Install python with crossplane, wget, entr and install/updates certificates
 RUN apt-get update \
  && apt-get install -y -q --no-install-recommends \
     ca-certificates \
     wget \
+    entr \
+    python3 python3-pip \
+ && pip3 crossplane \
+ && apt-get purge -y python3-pip \
+ && apt autoremove -y
  && apt-get clean \
  && rm -r /var/lib/apt/lists/*
 
-
 # Configure Nginx and apply fix for very long server names
 RUN echo "daemon off;" >> /etc/nginx/nginx.conf \
- && sed -i 's/worker_processes  1/worker_processes  auto/' /etc/nginx/nginx.conf
+ && sed -i 's/worker_processes  1/worker_processes  auto/' /etc/nginx/nginx.conf \
+ && rm /etc/nginx/conf.d/default.conf \
+ && mkdir /etc/nginx/node.conf.d \
+ && echo "http { include ./*.conf; }" > /etc/nginx/node.conf.d/swarm.conf
 
 # Install Forego
 ADD https://github.com/jwilder/forego/releases/download/v0.16.1/forego /usr/local/bin/forego
@@ -31,7 +39,7 @@ WORKDIR /app/
 
 ENV DOCKER_HOST unix:///tmp/docker.sock
 
-VOLUME ["/etc/nginx/certs", "/etc/nginx/dhparam", "/etc/nginx/static_files"]
+VOLUME ["/etc/nginx/certs", "/etc/nginx/dhparam", "/etc/nginx/static_files", "/etc/nginx/node.conf.d"]
 
 ENTRYPOINT ["/app/docker-entrypoint.sh"]
 CMD ["forego", "start", "-r"]

Procfile

@@ -1,2 +1,3 @@
-dockergen: docker-gen -watch -notify "nginx -s reload" /app/nginx.tmpl /etc/nginx/conf.d/default.conf
+swarmmerge: while true; do ls -d /etc/nginx/node.conf.d/*.conf | entr -d python3 /app/mergeswarm.py; done
+dockergen: docker-gen -watch /app/nginx.tmpl /etc/nginx/node.conf.d/`hostname`.conf
 nginx: nginx

mergeswarm.py

@@ -0,0 +1,28 @@
+# -*- coding: utf-8 -*-
+
+import subprocess
+import sys
+from crossplane import parse, build
+
+SWARM_CONFIG_FILE = '/etc/nginx/node.conf.d/swarm.conf'
+NGINX_OUTPUT = '/etc/nginx/conf.d/default'
+NGINX_RELOAD = 'nginx -s reload'
+
+nginx_config = []
+swarm_config = parse(SWARM_CONFIG_FILE)['config']
+nodes = [f['parsed'] for f in swarm_config[1:-1]]
+
+for node in nodes:
+    for statement in node:
+        if statement not in nginx_config:
+            nginx_config.append(statement)
+
+with open(NGINX_OUTPUT, 'w') as f:
+    f.write(build(nginx_config))
+
+process = subprocess.Popen(NGINX_RELOAD.split(), stdout=subprocess.PIPE)
+output, error = process.communicate()
+if output:
+    sys.stdout.write(output)
+if error:
+    sys.stderr.write(error)

nginx.tmpl

@@ -13,7 +13,7 @@
 		{{/* If there is no swarm node or the port is not published on host, use container's IP:PORT */}}
 		{{ else if .Network }}
 			# {{ .Container.Name }}
-			server {{ .Network.IP }}:{{ .Address.Port }};
+			server {{ (first (split .Container.Name "." )) }}:{{ .Address.Port }};
 		{{ end }}
 	{{ else if .Network }}
 		# {{ .Container.Name }}

swarm.stack.yml

@@ -0,0 +1,50 @@
+version: '3.8'
+
+services:
+
+    proxy:
+        deploy:
+            mode: global
+        build:
+            context: .
+        image: test-proxy:1.0
+        networks:
+            - proxy
+        ports:
+            - "80:80"
+        volumes:
+            - /var/run/docker.sock:/tmp/docker.sock:ro
+            - /tmp/proxyconf:/var/nginx/node.conf.d/
+
+    whoami1:
+        deploy:
+            replicas: 1
+        image: jwilder/whoami
+        networks:
+            - proxy
+        environment:
+            - VIRTUAL_HOST=1.whoami.local
+
+
+    whoami2:
+        deploy:
+            replicas: 2
+        image: jwilder/whoami
+        networks:
+            - proxy
+        environment:
+            - VIRTUAL_HOST=2.whoami.local
+
+
+    whoami3:
+        deploy:
+            replicas: 3
+        image: jwilder/whoami
+        networks:
+            - proxy
+        environment:
+            - VIRTUAL_HOST=3.whoami.local
+
+networks:
+    proxy:
+        name: proxy