Debugging .NET Core in Docker Container with Visual Studio Code. Based on https://github.com/Microsoft/generator-docker/issues/130#issuecomment-287222915

docker-compose.yml

version: '3.5'

services:
  MY_PROJECT:
    container_name: MY_PROJECT
    image: MY_PROJECT:dev
    build:
      context: ./src
      dockerfile: Dockerfile
      target: debug
      args:
        buildconfig: debug
    ports:
      - "5001:80"
    environment: 
      - ASPNETCORE_ENVIRONMENT=Development
      - DOTNET_USE_POLLING_FILE_WATCHER=1
    entrypoint: tail -f /dev/null
    volumes: 
      - ./src/MY_PROJECT/bin/Docker/:/app
      - ~/.nuget/packages:/root/.nuget/packages:ro

Dockerfile

FROM mcr.microsoft.com/dotnet/core/aspnet:2.2 AS base

WORKDIR /app
EXPOSE 80

# DEBUG

FROM mcr.microsoft.com/dotnet/core/sdk:2.2 AS debug

WORKDIR /app
EXPOSE  80

ARG buildconfig

# limit messages
ENV DEBIAN_FRONTEND noninteractive 

RUN if [ "${buildconfig}" = "debug" ]; then \
        apt-get update && \
        apt-get install -y --no-install-recommends unzip && \
        rm -rf /var/lib/apt/lists/* && \
        curl -sSL https://aka.ms/getvsdbgsh | bash /dev/stdin -v latest -l /vsdbg; \
     else \
        echo "*Skipping Debugger Installion *"; \
    fi

ENV DEBIAN_FRONTEND teletype

# PUBLISH

FROM debug AS build

WORKDIR /src
COPY ./MY_PROJECT/MY_PROJECT.csproj ./MY_PROJECT/
COPY ./MY_PROJECT.Core/MY_PROJECT.Core.csproj ./MY_PROJECT.Core/
RUN dotnet restore "MY_PROJECT/MY_PROJECT.csproj"

COPY . .
WORKDIR /src/MY_PROJECT

RUN dotnet publish "./MY_PROJECT.csproj" -o /publish -c Release;

# FINAL

FROM base AS final

WORKDIR /app
COPY --from=build /publish .

ENTRYPOINT ["dotnet", "MY_PROJECT.dll"]

launch.json

{
   "version": "0.2.0",
   "configurations": [
        {
            "name": "Docker: MY_PROJECT launch",
            "type": "coreclr",
            "request": "launch",
            "preLaunchTask": "publish",
            "cwd": "/app",
            "program": "/app/MY_PROJECT.dll",
            "sourceFileMap": {
                "/app": "${workspaceRoot}/src/MY_PROJECT"
            },
            "pipeTransport": {
                "debuggerPath": "/vsdbg/vsdbg",
                "pipeProgram": "/bin/bash",
                "pipeCwd": "${workspaceRoot}",
                "pipeArgs": [
                    "-c",
                    "docker exec -i MY_PROJECT /vsdbg/vsdbg --interpreter=vscode"
                ]
            }
        }
    ]
}

tasks.json

{
    "version": "2.0.0",
    "tasks": [
        {
            "label": "publish",
            "command": "dotnet",
            "type": "process",
            "args": [
                "publish",
                "${workspaceFolder}/src/MY_PROJECT/MY_PROJECT.csproj", "-c", "Debug", "-o", "bin/Docker"
            ],
            "problemMatcher": "$msCompile"
        }
    ]
}