Unable to debug Azure Functions Core Tools in VSCode - azure

Question

I am currently having trouble to debug my Azure Functions Core Tools in VS Code.
I am using the npm package azure-functions-core-tools#2.
As i read on many resources func host start / func start should always start the node process in with --inspect=9229. As you can see this is not the case in my setup:
[4/30/19 4:51:25 AM] Starting language worker process:node "/usr/lib/node_modules/azure-functions-core-tools/bin/workers/node/dist/src/nodejsWorker.js" --host 127.0.0.1 --port 50426 --workerId 3e909143-72a3-4779-99c7-376ab3aba92b --requestId 656a9413-e705-4db8-b09f-da44fb1f991d --grpcMaxMessageLength 134217728
[4/30/19 4:51:25 AM] node process with Id=92 started
[4/30/19 4:51:25 AM] Generating 1 job function(s)
[...]
[4/30/19 4:51:25 AM] Job host started
Hosting environment: Production
Also all attempts of changing the hosting environment failed. I tried to add FUNCTIONS_CORETOOLS_ENVIRONMENT to my local configuration, resulting in an error:
An item with the same key has already been added. Key: FUNCTIONS_CORETOOLS_ENVIRONMENT
I tried to add several environment variables in my launch and task settings, using --debug, changing project settings. Nothing works.
I am currently running this on the Windows Subsystem for Linux (WSL) and except this it works really well.
Anyone has a clue on what i am doing wrong here?

Answer 1

I don't think debug is enabled by default. You will have to set the language worker arguments for this to work as documented.
In local.settings.json
To debug locally, add "languageWorkers:node:arguments": "--inspect=5858" under Values in your local.settings.json file and attach a debugger to port 5858.
With func CLI
You could set this by using the --language-worker argument
func host start --language-worker -- --inspect=5858
In VS Code
If you are developing using VS Code and the Azure Functions extension, the --inspect is added automatically as the corresponding environment variable is set in .vscode/tasks.json
{
"version": "2.0.0",
"tasks": [
{
"label": "runFunctionsHost",
"type": "shell",
"command": "func host start",
"isBackground": true,
"presentation": {
"reveal": "always"
},
"problemMatcher": "$func-watch",
"options": {
"env": {
"languageWorkers__node__arguments": "--inspect=5858"
}
},
"dependsOn": "installExtensions"
},
{
"label": "installExtensions",
"command": "func extensions install",
"type": "shell",
"presentation": {
"reveal": "always"
}
}
]
}
You could also set this environment variable directly if you'd like instead of adding it in local.settings.json too.