Why I receive: 502 Bad Gateway? - node.js

Question

I have this Dockerfile I use to deploy my nodejs app together with nginx:
#Create our image from Node
FROM node:latest as builder
MAINTAINER Cristi Boariu <cristiboariu#gmail.com>
# use changes to package.json to force Docker not to use the cache
# when we change our application's nodejs dependencies:
ADD package.json /tmp/package.json
RUN cd /tmp && npm install
RUN mkdir -p /opt/app && cp -a /tmp/node_modules /opt/app/
# From here we load our application's code in, therefore the previous docker
# "layer" thats been cached will be used if possible
WORKDIR /opt/app
ADD . /opt/app
EXPOSE 8080
CMD npm start
### STAGE 2: Setup ###
FROM nginx:1.13.3-alpine
## Copy our default nginx config
RUN mkdir /etc/nginx/ssl
COPY nginx/default.conf /etc/nginx/conf.d/
COPY nginx/star_zuumapp_com.chained.crt /etc/nginx/ssl/
COPY nginx/star_zuumapp_com.key /etc/nginx/ssl/
RUN cd /etc/nginx && chmod -R 600 ssl/
RUN mkdir -p /opt/app
EXPOSE 80 443
CMD ["nginx", "-g", "daemon off;"]
and this is my nginx file:
upstream api-server {
server 127.0.0.1:8080;
}
server {
listen 80;
server_name example.com www.example.com;
access_log /var/log/nginx/dev.log;
error_log /var/log/nginx/dev.error.log debug;
location / {
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarder-For $proxy_add_x_forwarded_for;
proxy_set_header Host $http_host;
proxy_pass http://api-server;
proxy_redirect off;
}
}
server {
listen 443 default ssl;
server_name example.com www.example.com;
ssl on;
ssl_certificate /etc/nginx/ssl/star_example_com.chained.crt;
ssl_certificate_key /etc/nginx/ssl/star_example_com.key;
server_tokens off;
ssl_session_timeout 5m;
ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
ssl_ciphers 'EECDH+AESGCM:EDH+AESGCM:AES256+EECDH:AES256+EDH';
ssl_prefer_server_ciphers on;
location / {
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarder-For $proxy_add_x_forwarded_for;
proxy_set_header Host $host;
proxy_pass http://api-server;
proxy_redirect off;
}
}
I already spent a few hours debugging this without success.
Basically, I receive:
502 Bad Gateway
when trying to test it locally on:
https://localhost/docs/#
From docker logs:
172.17.0.1 - - [04/May/2018:05:35:36 +0000] "GET /docs/ HTTP/1.1" 502 166 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_4) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/11.1 Safari/605.1.15" "-"
2018/05/04 05:35:36 [error] 7#7: *1 connect() failed (111: Connection refused) while connecting to upstream, client: 172.17.0.1, server: example.com, request: "GET /docs/ HTTP/1.1", upstream: "http://127.0.0.1:8080/docs/", host: "localhost"
Can somebody help please?

Answer 1

You should configure:
server 172.17.42.1:8080;
172.17.42.1 is gateway ip address of docker.
or
server app_ipaddress_container:8080;
in nginx.conf file.
Because of port 8080 is listened on host, not on the container.