Azure SignalR Javascript Negotiate "Unable to resolve ...ConnectionStringSetting"

Question

I started tinkering with Azure SignalR and ran into a problem with the negiotate trigger. I followed this official Microsoft guide:

Heres my Code:

local.settings.json

{
  "IsEncrypted": false,
  "Values": {
    "AzureSignalRConnectionString": "Endpoint=https://my.service.signalr.net;AccessKey=myKey=;Version=1.0;",
    "FUNCTIONS_WORKER_RUNTIME": "node"
  },
  "Host": {
    "LocalHttpPort": 7071,
    "CORS": "*",
    "CORSCredentials": true
  }
}

function.json

{
  "disabled": false,
  "bindings": [
    {
      "authLevel": "anonymous",
      "type": "httpTrigger",
      "direction": "in",
      "methods": [
        "get"
      ],
      "name": "req",
      "route": "negotiate"
    },
    {
      "type": "http",
      "direction": "out",
      "name": "res"
    },
    {
      "type": "SignalRConnectionInfo",
      "name": "connectionInfo",
      "hubName": "jitsi",
      "ConnectionStringSetting": "Endpoint=https://my.service.signalr.net;AccessKey=myKey;Version=1.0;",
      "direction": "in"
    }
  ]
}

index.js

module.exports = async function (context, req, connectionInfo) {
    context.res.body = connectionInfo;
};

It works fine locally (unfortunately thats where the guide ends). But if I visit the URL of the negotiate http-trigger I get "Internal Server Error 500". Logs contain following output.

2020-04-23T08:47:32  Welcome, you are now connected to log-streaming service. The default timeout is 2 hours. Change the timeout with the App Setting SCM_LOGSTREAM_TIMEOUT (in seconds). 
2020-04-23T08:47:52.070 [Information] Executing 'Functions.jitsiNegotiate' (Reason='This function was programmatically called via the host APIs.', Id=2b791d95-3775-47bb-ade1-ac9005929f61)
2020-04-23T08:47:52.238 [Error] Executed 'Functions.jitsiNegotiate' (Failed, Id=2b791d95-3775-47bb-ade1-ac9005929f61)
Unable to resolve the value for property 'SignalRConnectionInfoAttribute.ConnectionStringSetting'. Make sure the setting exists and has a valid value.

As you can see in my code I did provide the ConnectionStringSetting.

Some People suggested it's due to lower/upper case 'C' in ConnectionStringSetting. Others said to to edit local.settings.json. None of that had any effect for me and I can't find any useful information on the issue.

EDIT 1: I set "hubName":"jitsi". With jitsi being the name of my SignalR Service. As in 'jitsi.service.signalr.net'. I'm not sure if that's correct or not. Perhaps thats part of the issue?

EDIT 2: I tried with no value set for ConnectionStringSetting (so that it goes to default). Gave me same error. I also completely deleted any content of local.settings.json and then re-deployed to see what would happen. Same behaviour as before. My guess is The service only uses the file for local usage (hence the name). So with the local.settings.json being empty theres no place else where I defined the value for AzureSignalRConnectionString. I did some digging and apparently (according to this thread) you should define it under

'Configuration'->'Application Settings'

So I created a new setting with

name: Azure__SignalR__ConnectionString

value: myMaskedConnectionString

Which resulted in the following error:

The SignalR Service connection string must be set either via an 'AzureSignalRConnectionString' app setting, via an 'AzureSignalRConnectionString' environment variable, or directly in code via SignalROptions.ConnectionString or SignalRConnectionInfoAttribute.ConnectionStringSetting.

Answer 1

I found a resolution to this issue:

I got confused at first and thought the local.settings.json would serve as configuration for the live/non-local version of the function. That's not the case. It's only for local execution (could've guessed by the name of the file)

So the question remains: Where/How can I edit the required settings in the Azure Portal?

Answer:Home -> All Services -> Function-App -> MyFunctionApp -> Platform Features -> Configuration -> Application Settings -> Create New Application Setting

name: AzureSignalRConnectionString value MyMaskedConnectionString

Then in function.json like this:

{
  "disabled": false,
  "bindings": [
    {
      "authLevel": "anonymous",
      "type": "httpTrigger",
      "direction": "in",
      "methods": [
        "get"
      ],
      "name": "req",
      "route": "negotiate"
    },
    {
      "type": "http",
      "direction": "out",
      "name": "res"
    },
    {
      "type": "SignalRConnectionInfo",
      "name": "connectionInfo",
      "hubName": "jitsi",
      "direction": "in",
      "connectionStringSetting": "AzureSignalRConnectionString"
    }
  ]
}

With those settings it's working for me now.