Debug not works with "Sam local start-api" with "--debug-port" and "--warm-containers"

With this command: sam local start-api --template-file template.yml --region eu-west-1 --debug-port 5555 --warm-containers EAGER

and this launch.json

{
      "name": "Attach to SAM CLI",
      "type": "node",
      "request": "attach",
      "address": "localhost",
      "port": 5555,
      "localRoot": "${fileDirname}",
      "remoteRoot": "/var/task",
      "protocol": "inspector",
      "stopOnEntry": false
    }

my Visual Studio Code doesn’t attach to container, I have no error or log, simply after 5 seconds the debug’s topbar disappear. The terminal logs doesn’t show “Debugging listening on…” when I try lo execute an HTTP request.

All works fine removing --warm-containers param.

[jaedenharris]

I also cannot start the debugger mode with or without the --warm-containers option

sam local start-api --warm-containers LAZY -p 3001 -d 9999

[jonkipu]

@CeccoCQ Regarding the original issue using start-api, I had to dive into the code a bit to find out the following:

If the template contains several functions (could be generated functions besides your original lambda, such as log retention related lambdas), a warning will be output: Warning: you supplied debugging options but you did not specify the --debug-function option. To specify which function you want to debug, please use the --debug-function <function-name>

What’s non-intuitive about this code path is that it will disable setting of the debug port rendering debugging useless in this case. If you have one function and don’t specifiy --debug-function AWS SAM will assume you meant to debug your one and only function, when using ---warm-containers the code path will disable debugging if the function being executed isn’t the one specified by --debug-function, however the code uses different identifiers of said function to check, again rendering debugging useless, this honestly seems like a bug.

To make sure you can debug your function use --debug-function with your current flags, but specify the function name as specified in your template, e.g: MyFunction1A65A8F as opposed to just MyFunction