Just an updated example following the steps from this Medium post
Steps:
- Clone the repo locally
- Open it with VSCode
- Build the image and running it, like this
$ docker build -t delve-playground .
$ docker run --rm --publish 38081:38081 --publish 38080:38080 --security-opt=seccomp:unconfined --name delve-playground delve-playground
At this point the dummy app is running but not debugger process attached to it
- In VSCode, set some breakpoints in main.go
For example: go to line 21 and press F9 or click in the left side of the line number). This toggle a breakpoint
- Start debugging (F5)
Attach the debbuger from VSCode using the Delve Docker configuration.
Notice that F5 uses the last configuration, Shift+Cmd+D for opening Run and Debug where you will find the dropdown for configurations.
(Your debugging window will show something like ..."Starting Web server")
- Send a request to it
For example:
$ curl http://127.0.0.1:38081/go
You will see how VSCode pauses the execution at that line... Now it's your turn, debug it!
To restart the debugger you have to:
- Stop the contanier (which uses Delvev for running your app)
- Stop the debugging session in VSCode (shift + F5)
- Start the container again (
docker run...) and attach the debug session from VSCode (F5)
This restart is necessary in case you add or remove breakpoints or if something goes wrong (you might see errors like trying to read from a closed connection or stuff like that, etc...).
If you don't need Docker and you can just debug your code locally (this program is a good example), then just:
$ dlv debug ./main.go --listen=:38081 --headless=true --api-version=2 --log
on your terminal, and attach the debbuger from VSCode using the Delve Local configuration. Of course it requires Delve to be installed on your machine.