MM23 Twelve Factor Lab Final State

consul/client.json

@@ -0,0 +1,10 @@
+{
+  "node_name": "consul-client",
+  "data_dir": "/consul/data",
+  "retry_join": [
+    "consul-server"
+  ],
+  "addresses": {
+    "http": "0.0.0.0"
+  }
+}

consul/server.json

@@ -0,0 +1,12 @@
+{
+  "node_name": "consul-server",
+  "server": true,
+  "bootstrap": true,
+  "ui_config": {
+    "enabled": true
+  },
+  "data_dir": "/consul/data",
+  "addresses": {
+    "http": "0.0.0.0"
+  }
+}

docker-compose.yml

@@ -14,6 +14,30 @@ services:
     networks:
       - mm_2023
 
+  consul-server:
+    image: hashicorp/consul:1.14.4
+    container_name: consul-server
+    restart: always
+    volumes:
+      - ./consul/server.json:/consul/config/server.json:ro
+    ports:
+      - "8500:8500"
+      - "8600:8600/tcp"
+      - "8600:8600/udp"
+    command: "agent"
+    networks:
+      - mm_2023
+
+  consul-client:
+    image: hashicorp/consul:1.14.4
+    container_name: consul-client
+    restart: always
+    volumes:
+      - ./consul/client.json:/consul/config/client.json:ro
+    command: "agent"
+    networks:
+      - mm_2023
+
 volumes:
   rabbit-data:
   rabbit-log:

load_balancer/Dockerfile

@@ -0,0 +1,30 @@
+FROM nginx:1.23.1
+
+ARG CONSUL_TEMPLATE_VERSION=0.30.0
+
+# Set an environment variable for the location of the Consul
+# cluster. By default, it tries to resolve to consul-client:8500
+# which is the behavior if Consul is running as a container in the 
+# same host and linked to this NGINX container (with the alias 
+# consul, of course). But this environment variable can also be
+# overridden as the container starts if we want to resolve to
+# another address.
+
+ENV CONSUL_URL consul-client:8500
+
+# Download the specified version of Consul template
+ADD https://releases.hashicorp.com/consul-template/${CONSUL_TEMPLATE_VERSION}/consul-template_${CONSUL_TEMPLATE_VERSION}_linux_amd64.zip /tmp
+
+RUN apt-get update \
+  && apt-get install -y --no-install-recommends dumb-init unzip \
+  && unzip /tmp/consul-template_${CONSUL_TEMPLATE_VERSION}_linux_amd64.zip -d /usr/local/bin \
+  && rm -rf /tmp/consul-template_${CONSUL_TEMPLATE_VERSION}_linux_amd64.zip
+
+COPY consul-template-config.hcl ./consul-template-config.hcl
+COPY nginx.ctmpl /usr/templates/nginx.ctmpl
+
+EXPOSE 8085
+
+STOPSIGNAL SIGQUIT
+
+CMD ["dumb-init", "consul-template", "-config=consul-template-config.hcl"]

load_balancer/consul-template-config.hcl

@@ -0,0 +1,15 @@
+consul {
+  address = "consul-client:8500"
+
+  retry {
+    enabled  = true
+    attempts = 12
+    backoff  = "250ms"
+  }
+}
+template {
+  source      = "/usr/templates/nginx.ctmpl"
+  destination = "/etc/nginx/conf.d/default.conf"
+  perms       = 0600
+  command     = "if [ -e /var/run/nginx.pid ]; then nginx -s reload; else nginx; fi"
+}

load_balancer/nginx.ctmpl

@@ -0,0 +1,15 @@
+upstream messenger_service {
+    {{- range service "messenger" }}
+    server {{ .Address }}:{{ .Port }};
+    {{- end }}
+}
+
+server {
+    listen 8085;
+    server_name localhost;
+
+    location / {
+        proxy_pass http://messenger_service;
+        add_header Upstream-Host $upstream_addr;
+    }
+}