Use VScode to remote debug Go lang code in Docker container

Question

I believe there might be an issue in this scenario. Here's what I've done:

1. Create an empty folder c:\repos\demo
2. In that folder I run go mod init demo, here is the mod file

   module demo
   go 1.22.0
   

3. Add a simple main.go file in the folder

   package main
   import (
       "fmt"
       "net/http"
   )
   func main() {
       http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
           fmt.Fprintf(w, "Hello, World!")
       })
       http.ListenAndServe(":8080", nil)
   }
   

4. Test the VScode debugging works fine, and I can put break point in my code and use browser access the http://localhost:8080 to hit my breakpoint.
5. Add a Dockerfile to build the debugging image

   FROM golang:1.22.0
   WORKDIR /app
   COPY . .
   RUN go install github.com/go-delve/delve/cmd/dlv@latest
   EXPOSE 40000 8080
   CMD ["dlv", "debug", "--headless", "--listen=:40000", "--api-version=2", "--accept-multiclient", "--log"]
   

6. Add VS code remote debugging launch.json

   {
     "version": "0.2.0",
     "configurations": [
       {
         "name": "Connect to server",
         "type": "go",
         "request": "attach",
         "mode": "remote",
         "port": 40000,
         "host": "127.0.0.1"
       }
     ]
   }
   

7. Build the docker image and run it

   docker build -t demo .
   docker run -p 40000:40000 -p 8080:8080 demo
   

8. Now I can see the dlv is running and click the VScode Connect to server to remote debug

    PS C:\repos\demo> docker run -p 40000:40000 -p 8080:8080 demo     
    2024-02-16T04:46:42Z warning layer=rpc Listening for remote connections (connections are not authenticated nor encrypted)
    2024-02-16T04:46:42Z info layer=debugger launching process with args: [./__debug_bin4263375465]
    API server listening at: [::]:40000
    2024-02-16T04:46:42Z debug layer=debugger Adding target 1534 "/app/__debug_bin4263375465"
    2024-02-16T04:46:50Z debug layer=debugger continuing
    2024-02-16T04:46:50Z debug layer=debugger ContinueOnce
   

9. Now my code is running the remote debugger is attached. I can use my browser to hit the my "Hello, world!" end-point. However, I cannot set break point on my code, the VScode said could not find code c:\repos\demo\main.go, If click in the VScode try to set a breakpoint, the docker log said:

    2024-02-16T04:46:59Z debug layer=debugger halting
    2024-02-16T04:46:59Z warning layer=debugger gnu_debuglink link "ce4e6e4ef08fa58a3535f7437bd3e592db5ac0.debug" not found in any debug info directory
    2024-02-16T04:46:59Z warning layer=debugger gnu_debuglink link "e7d4a67acf053c794b3b8094e6900b5163f37d.debug" not found in any debug info directory
    2024-02-16T04:46:59Z debug layer=debugger callInjection protocol on:
    2024-02-16T04:46:59Z debug layer=debugger       1534 PC=0x405e8e
    2024-02-16T04:46:59Z debug layer=debugger       1542 PC=0x4795a3
    2024-02-16T04:46:59Z debug layer=debugger       1543 PC=0x4795a3
    2024-02-16T04:46:59Z debug layer=debugger       1544 PC=0x4795a3
    2024-02-16T04:46:59Z debug layer=debugger       1545 PC=0x4795a3
    2024-02-16T04:46:59Z debug layer=debugger continuing (direction congruent)
    2024-02-16T04:46:59Z debug layer=debugger ContinueOnce
   

I attempted to run the same code about a month ago, and everything worked perfectly. However, this time it seems to be broken. I'm not certain if anything has changed recently.

Answer 1

That worked for me - open VSCode user's settings.json file and add there:

"go.delveConfig": {
    "debugAdapter": "legacy",
},