docker nginx failed to make connection with web container - django

Question

My docker nginx container failed to connect with gunicorn container. docker compose logs looks like,
dj | [2017-09-16 12:37:14 +0000] [22] [INFO] Starting gunicorn 19.7.1
dj | [2017-09-16 12:37:14 +0000] [22] [DEBUG] Arbiter booted
dj | [2017-09-16 12:37:14 +0000] [22] [INFO] Listening at: http://127.0.0.1:8000 (22)
dj | [2017-09-16 12:37:14 +0000] [22] [INFO] Using worker: sync
dj | [2017-09-16 12:37:14 +0000] [25] [INFO] Booting worker with pid: 25
dj | [2017-09-16 12:37:14 +0000] [22] [DEBUG] 1 workers
ng | 2017/09/16 12:37:22 [error] 8#8: *1 connect() failed (111: Connection refused) while connecting to upstream, client: 172.20.0.1, server: localhost, request: "GET /api HTTP/1.1", upstream: "http://127.0.0.1:8000/api/v1", host: "localhost"
ng | 172.20.0.1 - - [16/Sep/2017:12:37:22 +0000] "GET /api HTTP/1.1" 502 537 "-" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/52.0.2743.116 Chrome/52.0.2743.116 Safari/537.36" "-"
ng | 2017/09/16 12:37:31 [error] 8#8: *1 connect() failed (111: Connection refused) while connecting to upstream, client: 172.20.0.1, server: localhost, request: "GET /admin HTTP/1.1", upstream: "http://127.0.0.1:8000/api/admin", host: "localhost"
ng | 172.20.0.1 - - [16/Sep/2017:12:37:31 +0000] "GET /admin HTTP/1.1" 502 537 "-" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/52.0.2743.116 Chrome/52.0.2743.116 Safari/537.36" "-"
If I make a curl request inside django container, it shows the relevant html text.
$ docker-compose exec api bash
root#e29e3756916c:/code# curl http://127.0.0.1:8000
root#e29e3756916c:/code# curl http://127.0.0.1:8000/api/v1
root#e29e3756916c:/code# curl -L http://127.0.0.1:8000/api/v1
{"_type":"document","_meta":{"url":"http://127.0.0.1:8000/api/v1/","title":"Backend APIs"},"auth":{"convert-token":{"create":{"_type":"link","url":"/api/v1/auth/convert-token/","action":"post","description":"Implements an endpoint to convert a provider token to an access token\n\nThe endpoint is used in the following flows:\n\n* Authorization code\n* Client credentials"}},"revoke-token":{"create":{"_type":"link","url":"/api/v1/auth/revoke-token/","action":"post","description":"Implements an endpoint to revoke access or refresh tokens"}},"sign_in":{"create":{"_type":"link","url":"/api/v1/auth/sign_in/","action":"post","encoding":"application/json","fields":[{"name":"username","required":true,"location":"form","schema":{"_type":"string","title":"Username","description":""}},{"name":"password","required":true,"location":"form","schema":{"_type":"string","title":"Password","description":""}}]}},"sign_up":{"create":{"_type":"link","url":"/api/v1/auth/sign_up/","action":"post","encoding":"application/json","fields":[{"name":"first_name","location":"form","schema":{"_type":"string","title":"First name","description":""}},{"name":"last_name","location":"form","schema":{"_type":"string","title":"Last name","description":""}},{"name":"email","location":"form","schema":{"_type":"string","title":"Email address","description":""}},{"name":"username","required":true,"location":"form","schema":{"_type":"string","title":"Username","description":"Required. 150 characters or fewer. Letters, digits and #/./+/-/_ only."}},{"name":"password","required":true,"location":"form","schema":{"_type":"string","title":"Password","description":""}},{"name":"is_active","location":"form","schema":{"_type":"boolean","title":"Active","description":"Designates whether this user should be treated as active. Unselect this instead of deleting accounts."}}]}},"token":{"create":{"_type":"link","url":"/api/v1/auth/token/","action":"post","description":"Implements an endpoint to provide access tokens\n\nThe endpoint is used in the following flows:\n\n* Authorization code\n* Password\n* Client credentials"}}}}root#e29e3756916c:/code#
root#e29e3756916c:/code#
nginx.conf
server {
listen 80;
server_name localhost;
#charset koi8-r;
#access_log /var/log/nginx/host.access.log main;
#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;
}
proxy_force_ranges on;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $http_x_forwarded_proto;
location /admin {
proxy_pass http://127.0.0.1:8000/api/admin;
}
location /api {
proxy_pass http://127.0.0.1:8000/api/v1;
}
location /oauth {
proxy_pass http://127.0.0.1:8000/api/oauth;
}
location /static {
proxy_pass http://127.0.0.1:8000/static;
}
location / {
root /usr/share/nginx/html;
index index.html index.htm;
try_files $uri $uri/ /index.html;
}
}
Dockerfile for nginx container is,
FROM nginx:latest
#RUN apt-get update
ADD ./static /usr/share/nginx/html
ADD nginx.conf /etc/nginx/conf.d/default.conf
ENV NGINX_PORT 80
EXPOSE 80
CMD /bin/bash -c "nginx -g 'daemon off;'"
docker-compose.yaml
version: '2'
services:
nginx:
build: ./nginx
container_name: ng
ports:
- "80:80"
#volumes:
# - ./src:/src
# - ./config/nginx:/etc/nginx/conf.d
depends_on:
- api
links:
- api
volumes_from:
- api
api:
build: ./s2s_api
container_name: dj
command: bash ./wait_for_db.sh
restart: always
depends_on:
- db
ports:
- "8000:8000"
tty: true
links:
- db:mysql
db:
image: mysql
container_name: db
command: mysqld --user=root --verbose
volumes:
- ./dbcreation.sql:/tmp/dbcreation.sql
- ./import.sh:/tmp/import.sh
ports:
- "3306:3306"
restart: always
environment:
MYSQL_DATABASE: "S2S"
MYSQL_USER: "root"
MYSQL_PASSWORD: "avi"
MYSQL_ROOT_PASSWORD: "avi"
MYSQL_ALLOW_EMPTY_PASSWORD: "yes"
DB_PORT: 3306
DB_HOST: db
wait_for_db.sh
#!/bin/sh
# Wait for database to get available
M_LOOPS="10"
#wait for mysql
i=0
# http://stackoverflow.com/a/19956266/4848859
while ! curl db:3306 >/dev/null 2>&1 < /dev/null; do
i=`expr $i + 1`
if [ $i -ge $M_LOOPS ]; then
echo "$(date) - db:3306 still not reachable, giving up"
exit 1
fi
echo "$(date) - waiting for db:3306..."
sleep 3
done
echo "$(date) - db:3306 Reachable ! - Starting Daemon"
#start the daemon
#exec $START_CMD
python manage.py makemigrations
python manage.py migrate
gunicorn s2s_api.wsgi:application -b 127.0.0.1:8000 --log-level debug

Answer 1

You issue is obvious from the logs.
dj | [2017-09-16 12:37:14 +0000] [22] [INFO] Listening at: http://127.0.0.1:8000 (22)
ng | 2017/09/16 12:37:22 [error] 8#8: *1 connect() failed (111: Connection refused) while connecting to upstream, client: 172.20.0.1, server: localhost, request: "GET /api HTTP/1.1", upstream: "http://127.0.0.1:8000/api/v1", host: "localhost"
So there are two issues and both of them at 127.0.0.1. In your dj container, you should be running gunicorn on 0.0.0.0:8000 because the request will be forwarded by the nginx container and it is external to django container
127.0.0.1 in each container points to the container loop back itself. Now when you proxy_pass in nginx to 127.0.0.1:8000, nginx is expecting something to be running in the same container at port 8000. So it doesn't work. You need to change it to name of the service you used in docker-compose. Assuming it was api, you should use
proxy_pass http://api:8000/api/oauth;
Also on a side notem you shouldn't proxy pass static files to Gunicorn, they should be handled in nginx container itself