CODEWITHSUNDEEP
javascriptazureadt
SJS Bowley
SJS Bowley

Reputation: 51

Tring to connect to Azure Digital Twins from Visual Studio Code: DefaultAzureCredential(); .getToken error

I'm trying to connect to an Azure Digital wins Instance from Visual Studio Code, using Javascript API for Azure Digital Twins.

I have ran npm install @azure/identity and npm install @azure/digital-twins-core.

I can login to Azure portal using az login from the Powershell terminal in VS Code. It finds my account and subscription and logs in.

az account get-access-token --output json returns my token.

Here's the code I'm trying to run. It should create two models in the Azure Digital Twins instance:

    const { DefaultAzureCredential } = require("@azure/identity");
    const { DigitalTwinsClient } = require("@azure/digital-twins-core");
    const { v4 } = require("uuid");
    const { inspect } = require("util");
    
    
    async function main() {
      const modelId = `dtmi:model_${v4()
        .split("-")
        .join("")};1`;
      const componentId = `dtmi:component_${v4()
        .split("-")
        .join("")};1`;
      const digitalTwinId = `digitalTwin-${v4()}`;
    
      const temporaryComponent = {
        "@id": componentId,
        "@type": "Interface",
        "@context": "dtmi:dtdl:context;2",
        displayName: "Component1",
        contents: [
          {
            "@type": "Property",
            name: "ComponentProp1",
            schema: "string"
          }
        ]
      };
    
      const temporaryModel = {
        "@id": modelId,
        "@type": "Interface",
        "@context": "dtmi:dtdl:context;2",
        displayName: "TempModel",
        contents: [
          {
            "@type": "Property",
            name: "Prop1",
            schema: "double"
          },
          {
            "@type": "Component",
            name: "Component1",
            schema: componentId
          }
        ]
      };
    
      const temporaryTwin = {
        $dtId: digitalTwinId,
        $metadata: {
          $model: modelId
        },
        Prop1: 42,
        Component1: {
          $metadata: {},
          ComponentProp1: "value1"
        }
      };
    
      // AZURE_DIGITALTWINS_URL: The URL to your Azure Digital Twins instance
      const url = 'https://ParADIM-ADT-Dev.api.wcus.digitaltwins.azure.net';
      if (url === undefined) {
        throw new Error("Required environment variable AZURE_DIGITALTWINS_URL is not set.");
      }
    
      // DefaultAzureCredential is provided by @azure/identity. It supports
      // different authentication mechanisms and determines the appropriate
      // credential type based of the environment it is executing in. See
      // https://www.npmjs.com/package/@azure/identity for more information on
      // authenticating with DefaultAzureCredential or other implementations of
      // TokenCredential.
      const credential = new DefaultAzureCredential();
      const serviceClient = new DigitalTwinsClient(url, credential);
    
      // Create models
      const newModels = [temporaryComponent, temporaryModel];
      const models = await serviceClient.createModels(newModels);
      //console.log(`Created Models:`);
      //console.log(inspect(models));
      
    }
    
    main().catch((err) => {
      console.log("error code: ", err.code);
      console.log("error message: ", err.message);
      console.log("error stack: ", err.stack);
    });

Here's the error I'm getting:

C:\Program Files\nodejs\node.exe .\index.js
error code:  undefined
error message:  Unexpected end of JSON input
error stack:  Error: Unexpected end of JSON input
    at AzureCliCredential.getToken (c:\ADTProject\node_modules\@azure\identity\dist\index.js:1529:27)
    at processTicksAndRejections (internal/process/task_queues.js:95:5)
    at async DefaultAzureCredential.getToken (c:\ADTProject\node_modules\@azure\identity\dist\index.js:1358:25)

So, an unexpected end of JSON input. This error is coming from @azure\identity\dist\index.js which is part of the azure\identity package, so not code I wrote. The code I'm using is from a tutorial, and the JSON is compliant. Seems it's getting an error executing the getToken function.

Any help appreciated! I've hit a wall on this one!

Upvotes: 0

Views: 202

Answers (1)

SaiKarri-MT
SaiKarri-MT

Reputation: 1301

As the code pulled from the documentation, looking into the error trace it got failed to retrieve a token from specified credentials, might be issue in how we are passing it. Below is how we usually connect in JavaScript:

const client = new SecretClient(keyVaultUrl, new DefaultAzureCredential());

Below is the sample code to communicate with Cosmos and storage:

import { SecretClient } from '@azure/keyvault-secrets';
import { DefaultAzureCredential } from '@azure/identity';
import { CosmosClient } from '@azure/cosmos';

const keyVaultUrl = process.env('APP_KEY_VAULT_URI');
const credential = new DefaultAzureCredential();
let storageClient;
let cosmosClient;

async function configureClients() {
    const kvClient = new SecretClient(keyVaultUrl, credential);
    const storageUri = await client.getSecret('storageUri');
    const cosmosDbConnectionString = await client.getSecret('cosmosDb');

    cosmosClient = new CosmosClient(cosmosDbConnectonString);
    storageClient = new BlobServiceClient(storageUri, credential);
}

For more information about environmental variables, setting keyvault refer to azure sdk blog to know about Authentication

Upvotes: 0

Related Questions