Cannot access localhost with dockerized app - docker

Question

MacOS Monterey
I have a simple Dockerfile
FROM denoland/deno:1.29.1
EXPOSE 4200
WORKDIR /app
ADD . /app
RUN deno cache ./src/index.ts
CMD ["run", "--allow-net", "--allow-read", "./src/index.ts"]
And the most simple deno code
const handler = (request: Request) => {
return new Response("heyo", { status: 200 });
};
DenoServer.serve(handler, { hostname: HOST, port: PORT });
Running the application locally works fine and I can reach localhost:4200. However when I run the app with docker the request fails
I use
docker run --publish 4200:4200 frontend
└───> curl http://localhost:4200
curl: (52) Empty reply from server
I can see the container running and trying to hit the {{ .NetworkSettings.IPAddress }} doesn't work either
docker container running on localhost

Answer 1

It appears that the necessary environment variables were not included in the docker run command. To specify the host and port, you can use the -e option in the docker command.
docker build -t deno-sample .
docker run -e HOST=localhost -e PORT=4200 -p 4200:4200 deno-sample
For more information, please refer to the Docker documentation at the following link: https://docs.docker.com/engine/reference/commandline/run/
FROM denoland/deno:1.29.1
EXPOSE 4200
WORKDIR /app
COPY . /app
# RUN deno cache ./src/index.ts
RUN ls
CMD ["deno", "run", "--allow-net", "--allow-read", "app.ts"]
Here is my app.ts in same path as of dockerfile
function requestHandler() {
console.log(">>>>>")
return new Response("Hey, I'm a server")
}
serve(requestHandler, { hostname: '0.0.0.0', port: 4200 })