Debug with docker containers

[galvesribeiro]

What is the proper way to install the debugger on a dotnet image and get it debugging from VSCode?

Currently there are multiple (messy) ways to work with old project.json and containers like for example, that bunch of scripts generated by yo docker.

Is there any guidance on how to create a debug container for .net apps?

Thank you

[MichaelSimons]

@galvesribeiro, Good question. The yo docker experience is definitely out of date. We currently don't have any guidance on this. Let me dig around a little and see what I can come up with.

[galvesribeiro]

Thanks @MichaelSimons I appreciate that. I'm struggling to get it to work here. Even if I use VS2017 which has that Add Docker Support function, it works, but there is no docs on how that works whatsoever so I can't try reproduce it on VSCode. Looking forward to hear from you, thanks!

[MichaelSimons]

For my own exercise, I went through the yo docker experience. Even though it was out of date, I was able to get it working with a few tweaks.

1. mkdir DockerDebugApp
2. cd DockerDebugApp
3. dotnet new -t Console1.1
4. yo docker (used defaults)
5. Ignore project.json file does not exist error
6. Open DockerDebugAdd in VSCode
7. add the following to the csproj

         <ItemGroup>
     <None Update="Dockerfile">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>
     <None Update="Dockerfile.Debug">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>
     <None Update="docker-compose.yml">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>
     <None Update="docker-compose.debug.yml">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>
   </ItemGroup>
   

8. Update the two Dockerfiles to reference the appropriate base images
   a. microsoft/dotnet:1.1-sdk-msbuild
   b. microsoft/dotnet:1.1-runtime
9. Update the Dockerfile.debug to install unzip before the GetClrDbg logic

       RUN apt-get update \
       && apt-get install -y --no-install-recommends \
           unzip \
       && rm -rf /var/lib/apt/lists/*
   

10. Set the $framework variables of the dockerTask script to match your csproj
    a. netcoreapp1.1
11. dotnet restore -r debian.8-x64
12. Build
13. Set breakpoint in program
14. F5

[galvesribeiro]

Was about to ping you... I did similar thing and it work :)

However, that is not close to what we have with VS2017, where you can run/debug multiple projects using the solution-level docker-compose files...

[MichaelSimons]

I moved this to microsoft/generator-docker#130 since the underlying issue is not specific to the Docker image rather it is with the broken yo docker experience.

[dasMulli]

@MichaelSimons most of the fuss is about downloading clrdbg into the containers. Does it make sense to create a public image that already includes the correct debugger? (e.g. microsoft/dotnet:1.1-sdk-msbuild-debug).

[galvesribeiro]

@dasMulli if you look at simple apps with a single container yes, people don't know that the SDK doesn't come with the debugger. However, when you have multiple containers (i.e. docker-compose based projects) the problem goes far from just that. Look at the new issue @MichaelSimons just created.