创建一个从AZURE读取数据的nodejs Web应用程序。 （流分析或事件中心或日志分析）

Question

I have connected several devices to Azure Stream Analytics that will send in various data. ( Temp, light, humidity and etc )

I am not sure how can I read data Azure Resources and display it on my web application that I've published on Azure . For example, reading device_name, device's data.

What I need is probably a sample code that reads some data from Azure and then display it on a simple 'h1' or 'p' tag.

PS: I've seen lots of tutorial that teaches how to publish web app to Azure. But there're hardly any tutorials that specifically teaches how to read and grab data from Azure Resources.

Answer 1

You can use Azure SDK for Node.js to manage Azure resources.

This is an example retrive information about an existing event hub. And here is the Azure Node SDK reference .

const msRestAzure = require('ms-rest-azure');
const EventHubManagement = require('azure-arm-eventhub');

const resourceGroupName = 'testRG';
const namespaceName = 'testNS';
const eventHubName = 'testEH';
const subscriptionId = 'your-subscription-id';

msRestAzure
  .interactiveLogin()
  .then(credentials => {
    const client = new EventHubManagement(credentials, subscriptionId);
    return client.eventHubs.get(resourceGroupName, namespaceName, eventHubName);
  })
  .then(zones => console.dir(zones, { depth: null, colors: true }))
  .catch(err => console.log(err));

Answer 2

I assume that you are using some shortcuts. And that you are sending events from devices to EventHub

So the architecture right now looks like this:

Device -> EventHub -> Azure StreamAnalytics

and AppService called my web application

Azure StreamAnalytics just help you to do some aggregation, calculation and so on. On the other hand, you can use eg Azure Function

I would suggest to store data in storage eg in Azure Storage

This is proposed architecture:

Device -> EventHub -> Azure StreamAnalytics or Azure Function -> Azure Table Storage

AppService <-> Azure Table Storage

And later display data in your web app from storage. Here is example from docs:

Retrieve an entity by key

tableSvc.retrieveEntity('mytable', 'hometasks', '1', function(error, result, response){
  if(!error){
    // result contains the entity
  }
});

Answer 3

The easiest way to visualize the output of Azure Stream Analytics is to use Power BI, if you have access to it. In few minutes you can create a dashboard and show values or graph. More info here . Your dashboard can be also embedded in your own app using "Power BI embedded". If you want to create your own application to visualize output, they are several possible ways depending of your latency requirements. Eg you can output to Cosmos DB or SQL and then use their client library. You can also output to Azure Function and use Signal R to create dynamic page. Let us know if you have any further question.