Cannot access url on my dockerized web app endpoint - docker

Question

I have started my .net core 3.1 web app under docker container and I'm having info from docker desktop client
Now listening on: http://[::]:80
info: Microsoft.Hosting.Lifetime[0]
Application started. Press Ctrl+C to shut down.
info: Microsoft.Hosting.Lifetime[0]
Hosting environment: Development
info: Microsoft.Hosting.Lifetime[0]
Content root path: /app
My controller looks like this
[Route("hello/[controller]")]
public class WorldController : ControllerBase
{
[HttpGet]
public IActionResult Get()
{
return Ok();
}
}
since my container is running on port 80 I'm trying to access controller action using
http://localhost/hello/world
but I'm getting HTTP Error 404.0 - Not Found
Am I missing something? Any suggestions?
Update:
Dockerfile
...
ENV ASPNETCORE_URLS http://*:57362
EXPOSE 57362
Even though I'm explicitly exposing 57362 docker still gives the message Now listening on: http://[::]:80

Answer 1

You can change the port ASPNETCORE will listen with the following directive in the Dockerfile:
ENV ASPNETCORE_URLS=http://+:80;https://+:443
If you want to change the default HTTP port to be 57362 you should do:
ENV ASPNETCORE_URLS=http://+:57362
After building the docker image, the application will run under port 57362 inside the container. To forward any port of your computer to the container port you need to run the container with the -p parameter as follows:
docker run -tid -p <host_port>:<container_port> my_image:<my_tag>
In your case it should be the following:
docker run -tid -p 80:57362 my_image:<my_tag>
If you're running this script on Windows on Docker for Desktop, it will only allow the binding of port 80 from an elevated prompt. If not running on an elevated prompt you can change it to port 8080 or any other.

Answer 2

You will need to map port 80 to 57362. This would look something like this inside a docker-compose.yml file if you have a docker-compose file thats to say and using the docker-compose up -build command
ports:
80:57362