Investigation report of how to set up debugging of aspnetcore:2 containerised app in @VScode

Dockerfile.debug

FROM microsoft/aspnetcore-build:2
ENV NUGET_XMLDOC_MODE skip
WORKDIR /vsdbg
RUN 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

RUN mkdir /app
WORKDIR /app

COPY Banco.Orders.Api.csproj /app
RUN dotnet restore

COPY . /app
RUN dotnet publish -c Debug -o out

ENV ASPNETCORE_URLS http://*:5000
EXPOSE 5000
ENTRYPOINT ["/bin/bash", "-c", "if [ -z \"$REMOTE_DEBUGGING\" ]; then dotnet out/Banco.Orders.Api.dll; else sleep infinity; fi"]

dockerTask.sh

imageName="banco.orders.api"
projectName="banco"
serviceName="orders.api"
containerName="${projectName}.${serviceName}_1"
publicPort=5000
url="http://localhost:$publicPort"
runtimeID="debian.8-x64"
framework="netcoreapp2.0"
workdir="src/Banco.Orders.Api"

# Kills all running containers of an image and then removes them.
cleanAll () {
  if [[ -z $ENVIRONMENT ]]; then
    ENVIRONMENT="debug"
  fi

  dockerFileName="Dockerfile"
  if [[ $ENVIRONMENT != "release" ]]; then
    dockerFileName="Dockerfile.$ENVIRONMENT"
  fi

  echo "$workdir/$dockerFileName"
  if [[ ! -f "$workdir/$dockerFileName" ]]; then
    echo "$ENVIRONMENT is not a valid parameter. File '$dockerFileName' does not exist."
  else
    docker stop $containerName
    docker rmi -f $imageName

    # Remove any dangling images (from previous builds)
    danglingImages=$(docker images -q --filter 'dangling=true')
    if [[ ! -z $danglingImages ]]; then
      docker rmi -f $danglingImages
    fi
  fi
}

# Builds the Docker image.
buildImage () {
  if [[ -z $ENVIRONMENT ]]; then
    ENVIRONMENT="debug"
  fi

  dockerFileName="Dockerfile"
  if [[ $ENVIRONMENT != "release" ]]; then
    dockerFileName="Dockerfile.$ENVIRONMENT"
  fi

  if [[ ! -f "$workdir/$dockerFileName" ]]; then
    echo "$ENVIRONMENT is not a valid parameter. File '$dockerFileName' does not exist."
  else
    echo "Building the image $imageName ($ENVIRONMENT)."
    docker build -t $imageName -f "$workdir/$dockerFileName" $workdir
  fi
}

runContainer () {
    echo "Running a new container $containerName"
    if [[ -z $(docker images -q $imageName) ]]; then
        echo "Couldn not find an image named $imageName"
    else
        containerId=$(docker ps -f "name=$containerName" -q -n=1)
        if [[ ! -z $containerId ]]; then
            docker stop $containerId
            docker rm $containerId
        fi
        docker run -d -p $publicPort:5000 --name $containerName $imageName
    fi
}

# Shows the usage for the script.
showUsage () {
  echo "Usage: dockerTask.sh [COMMAND] (ENVIRONMENT)"
  echo "    Runs build or compose using specific environment (if not provided, debug environment is used)"
  echo ""
  echo "Commands:"
  echo "    build: Builds a Docker image ('$imageName')."
  echo "    compose: Runs docker-compose."
  echo "    clean: Removes the image '$imageName' and kills all containers based on that image."
  echo "    composeForDebug: Builds the image and runs docker-compose."
  echo "    startDebugging: Finds the running container and starts the debugger inside of it."
  echo ""
  echo "Environments:"
  echo "    debug: Uses debug environment."
  echo "    release: Uses release environment."
  echo ""
  echo "Example:"
  echo "    ./dockerTask.sh build debug"
  echo ""
  echo "    This will:"
  echo "        Build a Docker image named $imageName using debug environment."
}

if [ $# -eq 0 ]; then
  showUsage
else
  case "$1" in
    "buildForDebug")
            ENVIRONMENT=$(echo $2 | tr "[:upper:]" "[:lower:]")
            export REMOTE_DEBUGGING=1
            buildImage
            runContainer
            ;;
    "clean")
            ENVIRONMENT=$(echo $2 | tr "[:upper:]" "[:lower:]")
            cleanAll
            ;;
    *)
            showUsage
            ;;
  esac
fi

Investigation.md

The goal of this investigation to find out the way to build aspnet core app inside Docker container and use VS Code to debug it remotely.

*** Useful links

https://github.com/OmniSharp/omnisharp-vscode/wiki https://github.com/OmniSharp/omnisharp-vscode/wiki/Attaching-to-remote-processes https://github.com/Microsoft/vscode-docker https://blogs.msdn.microsoft.com/stevelasker/2016/09/29/building-optimized-docker-images-with-asp-net-core/ microsoft/generator-docker#130

*** Docker commands to be able to debug

docker run -it --rm -v $(pwd):/app microsoft/aspnetcore-build:2 -it means keep the container running in interactive mode --rm means remove the container when complete -v $(pwd):/sln means volume mount the present working directory to a root folder in the Linux image named app

launch.json

{
   // Use IntelliSense to find out which attributes exist for C# debugging
   // Use hover for the description of the existing attributes
   // For further information visit https://github.com/OmniSharp/omnisharp-vscode/blob/master/debugger-launchjson.md
   "version": "0.2.0",
   "configurations": [
        {            
            "name": ".NET Core Docker Attach (web)",
            "type": "coreclr",
            "request": "attach",
            "preLaunchTask": "dockerBuildForDebug",
            "processName": "dotnet",
            "sourceFileMap": {
                "/app": "${workspaceRoot}/src/Banco.Orders.Api"
            },
            "launchBrowser": {
                "enabled": true,
                "args": "${auto-detect-url}/swagger",
                "osx": {
                    "command": "open"
                }
            },
            "pipeTransport": {
                "pipeProgram": "docker",
                "pipeCwd": "${workspaceRoot}",
                "pipeArgs": [
                    "exec", "-i", "banco.orders.api_1"
                ],
                "quoteArgs": false,
                "debuggerPath": "/vsdbg/vsdbg"
            }
        }
    ]
}

tasks.json

{
    "version": "0.1.0",
    "command": "/bin/bash",
    "options": {
        "cwd": "${workspaceRoot}"
    },
    "tasks": [
        {
            "taskName": "dockerBuildForDebug",
            "suppressTaskName": true,
            "args": [
                "-c",
                "./scripts/dockerTask.sh buildForDebug debug"
            ],
            "isBuildCommand": false,
            "showOutput": "always"
        }
    ]
}