Communication between docker-compose and other images - docker

Question

I have this architecture:
- 1 docker component running nginx on the host's port 80
- app with 2 services: one node and one mongodb
the docker-compose file:
version: '2'
services:
backend:
build: ./back-end/
container_name: "app-back-end"
volumes:
- ./back-end/:/usr/src/dance-app-back
- /usr/src/app-back/node_modules
ports:
- "3000:3050"
links:
- mongodb
mongodb:
image: mongo:3.2.15
ports:
- "3100:27017"
volumes:
- ./data/mongodb:/data/db
The nginx config file
server {
listen 80;
server_name localhost;
#charset koi8-r;
#access_log /var/log/nginx/host.access.log main;
location /back_1 {
#proxy_pass http://172.17.0.2:5050/;
proxy_pass http://0.0.0.0:5050/;
}
#error_page 404 /404.html;
# redirect server error pages to the static page /50x.html
#
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root /usr/share/nginx/html;
}
}
The nginx container seems not to be able to reach the port 3000 on the host.
What I'm I doing wrong?

Answer 1

If you have port 3000 on your host and would like to map it to your container port, than you need to do that in your docker-compose file
Change:
backend:
build: ./back-end/
container_name: "app-back-end"
volumes:
- ./back-end/:/usr/src/dance-app-back
- /usr/src/app-back/node_modules
ports:
- "3000:3000"
links:
- mongodb
Then you can link nginx to your container that you want to proxy pass to.
Add to your compose file:
nginx:
restart: always
image: nginx:1.13.1
ports:
- "80:80"
depends_on:
- backend
links:
- backend:backend
And then in your nginx file mention the name of your application container that you would like to proxy to with the port of that container that is open.
server {
listen 80;
server_name localhost;
#charset koi8-r;
#access_log /var/log/nginx/host.access.log main;
location /back_1 {
proxy_pass http://backend:3000/;
}
#error_page 404 /404.html;
# redirect server error pages to the static page /50x.html
#
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root /usr/share/nginx/html;
}
}
Instead of the IP of the container inyour nginx, you can link the container name and the nginx config and docker will resolve those IPs for you.