Docker compose port forwarding Linux asp net core

Question

I have a handful of docker images that work fine. Except for the ports that are always 5000 (the default on asp.net core), everything works. I have tried multiple methods to get around this, but I am out of ideas now.

The containers are running on Debian 9- Hosted on Linode

Ran my build with

docker-compose -f docker-compose.yml up

My docker-compose.yml

#Api  Service
API:
 build:
  context: .
  #Use the DockerFile in that Directory
  dockerfile: Dockerfile
  #This Service Depends on the database service specifed above
  depends_on:
  - database
#Map port 8888 in the docker container to port 80 in the Api
ports:
  - "5000:80"
restart: always
#Specify Environment Variables for the Api Service
environment:
  - DBHOST=database
  - ASPNETCORE_ENVIRONMENT=Production

Content for DockerFile

FROM mcr.microsoft.com/dotnet/aspnet:5.0 AS base
WORKDIR /app
EXPOSE 80/tcp

FROM mcr.microsoft.com/dotnet/sdk:5.0 AS build

WORKDIR /src
COPY ["TestApi.csproj", "./"]
RUN dotnet restore "TestApi.csproj"
COPY . .
WORKDIR "/src/."
RUN dotnet build "TestApi.csproj" -c Release -o /app/build

FROM build AS publish
RUN dotnet publish "TestApi.csproj" -c Release -o /app/publish


FROM base AS final
WORKDIR /app
COPY --from=publish /app/publish .
ENTRYPOINT ["dotnet", "TestApi.dll"]

File content docker-compose.debug.yml

version: '3.4'

services:
  testapi:
    image: testapi
    build:
      context: .
      dockerfile: ./Dockerfile
    ports:
      - 80
      - 5000
    environment:
      - ASPNETCORE_ENVIRONMENT=Production
      - ASPNETCORE_URLS=http://+:80
    volumes:
      - ~/.aspnet/https:/https:ro

Answer 1

ASP.NET Core apps run on port 5000 by default (or 5001 for TLS). You may modify this in a number ways, the simplest of which is to set the ASPNETCORE URLS environment option, for example, if you want to run on HTTP/S ports 80/443:

environment:
  - ASPNETCORE_URLS=https://+:443;http://+:80

That being said, I don't see why you'd want to do it. Why don't you just bind your container to port 5000? For instance, instead of 5000:80, use 5000:5000.