Can't access Node.js app running in docker through browser

Question

I am trying to run a Node.js app on docker. I am using WSL and have successfully run the app on docker. Now the problem is that when I try to access the app on the browser, it's showing as no response. I can't access it in the browser. I also have another Reactjs app running on the docker and I can access that app through the browser. What am I doing wrong? Why Nodejs app is not accessible in the windows browser? Below is the Dockerfile for Node.js

# pull official base image
FROM node:12.18.3-alpine

# set working directory
WORKDIR /app

# add `/app/node_modules/.bin` to $PATH
ENV PATH /app/node_modules/.bin:$PATH

# install app dependencies
COPY package.json ./
COPY package-lock.json ./
RUN npm install --silent

# add app
COPY . ./


# start app
CMD ["npm", "run", "dev"]

Below is the command used for running the app image in docker

docker build -t gdns/node-app .

winpty docker run \
    -it \
    --rm \
    -v ${PWD}:/app \
    -v /app/node_modules \
    -p 4000:4000 \
    -e CHOKIDAR_USEPOLLING=true \
    gdns/node-app

Node.js app is running, I can view the log as below

Please help

Can you verify the app is running in the container by logging into the terminal of container? Can you access the app on port 4000 within the container? — v1shva, Nov 24 '21 at 09:29
@v1shva The app is running. I can view the log. Updated the question. How can I access the app within the container? — Akhilesh, Nov 24 '21 at 09:35
You probably have `server.listen(4000)` in your javascript. It needs to be `server.listen(4000, "0.0.0.0")` — Hans Kilian, Nov 24 '21 at 09:49
use `docker exec -it {containerId} bash` and then `curl localhost:4000` — v1shva, Nov 24 '21 at 09:49
@Akhilesh your app is listening on localhost which is why you can't access it. As pointed out, you should listen on `0.0.0.0`. — Stefan Golubović, Nov 24 '21 at 09:53

score 4 · Accepted Answer · answered Nov 25 '21 at 04:47

4

I have changed the code in the Node.js app to listen on "0.0.0.0".

const hostname = '0.0.0.0';
const port = 4000;
server.listen(port, hostname, () => {
    console.log(`Server running at http://${hostname}:${port}/`);
});

answered Nov 25 '21 at 04:47

Akhilesh

1,243
4
16
49

i think its not the recommanded way. check my answer https://stackoverflow.com/a/70096563/6881773 – S.Sachith Nov 26 '21 at 20:13

score 1 · Answer 2 · answered Nov 24 '21 at 09:19

1

Okay. You are running a docker in a wsl. WSL is a virtual box on top of windows os. So it has its own network adapters. So please find the wsl's IP by the "ifconfig" command. It will tell you wsl's IP.

Then you can connect that IP from your browser

http://wsl-ip:4000

answered Nov 24 '21 at 09:19

Kumar Albert

280
1
5

Then how my react app is accessible in browser? – Akhilesh Nov 24 '21 at 09:29
Any way react app will run on another port right. So you can listen to WSL's IP with the respective port. – Kumar Albert Nov 24 '21 at 11:36

S.Sachith · Answer 3 · 2021-11-25T03:50:37.383

You have to expose your nodejs port inside the container. you just open host port 4000 to the container but the container is not opened the port 4000, for that you have to changein your Dockerfile

changed Dockerfile

# pull official base image
FROM node:12.18.3-alpine

# set working directory
WORKDIR /app

# add `/app/node_modules/.bin` to $PATH
ENV PATH /app/node_modules/.bin:$PATH

# install app dependencies
COPY package.json ./
COPY package-lock.json ./
RUN npm install --silent

# add app
COPY . ./

EXPOSE 4000

# start app
CMD ["npm", "run", "dev"]

Can't access Node.js app running in docker through browser

3 Answers3