How can I reverse proxy my API requests with nginx? - docker

Question

To add some context:
I'm running an Angular PWA with Node.js backend.
They run on different ports:
· Front-end: Hosted by nginx on port 80
· Back-end: Hosted by Node.js on port 3939
nginx is within a Docker container.
Thing is, I plan to redirect all traffic related to /api from port 80 to port 3939 internally via reverse proxy. I'm testing with /api/agenda to see if it works, but it isn't.
Here's the default.conf file I'm using:
server {
listen 80;
listen [::]:80;
server_name localhost;
#access_log /var/log/nginx/host.access.log main;
location / {
root /usr/share/nginx/html;
index index.html index.htm;
}
location /api/agenda {
proxy_pass http://localhost:3939;
}
#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;
}
}
I'm testing with Postman to see if redirect works, but I'm getting a 404 while accessing with this url:
http://localhost:80/api/agenda
If I access it using its original port, I do get the desired results, but that's not what I want to do.
http://localhost:3939/api/agenda
Edit: Here's the error logs I get in my docker console when I try to access http://localhost:80/api/agenda
1 | 172.19.0.1 - - [22/Jun/2022:07:13:50 +0000] "GET /api/agenda HTTP/1.1" 404 555 "http://localhost/" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/102.0.0.0 Safari/537.36" "-"
nginx-conf-web-1 | 2022/06/22 07:55:18 [error] 28#28: *8 connect() failed (111: Connection refused) while connecting to upstream, client: 172.19.0.1, server: localhost, request: "GET /api/agenda HTTP/1.1", upstream: "http://127.0.0.1:3939/api/agenda", host: "localhost:80"
Thanks in advance for your help.

Answer 1

One of the comments worked for me, regarding #Ivan Shatsky.
Switching: "https://localhost:port/api
to: https://host.docker.internal:port/api
Thank you to the people in the comments.