Send events from Android app to Microsoft Azure Event Hubs

Event Hubs is a highly scalable publish-subscribe ingestion system that can process millions of events per second. This article will explain how to publish event from an Android application to Azure event hub.

Create an Event Hub

  1. Log on to the Azure management portal, and click NEW at the bottom of the screen.
  2. Click App Services, then Service Bus, then Event Hub, then Quick Create.create_eventhub
  3. Enter the event hub name (eg:- AndroidHub) , select the region and namespace, and create the event hub.
  4. Select the newly created event hub, and select the Configure tab
  5. Create the shared access policy (eg:- android). We will require the policy name, key, namespace and event hub name at later stage to create the signature.shared_access_policy

Create Android application

Let us create anew_project simple android application using Android Studio. Select the minimum SDK (eg:- API 19), Blank Activity template, and  default activity (eg:- MainActivity), and then click “finish”to create the project.

Now add a button to the main layout to send sample event to Azure event hub.  Updated layout is given below.

We need to update the manifest file to support the network operation by including the following permission.

Connecting to EventHub:- Sending events to an Event Hub is accomplished either using HTTP POST or via an AMQP 1.0 connection. The choice of which to use when depends on the specific scenario being addressed. AMQP 1.0 connections are metered as brokered connections in Service Bus and are more appropriate in scenarios with frequent higher message volumes and lower latency requirements as they provide a persistent messaging channel. I will be using the HTTP post to publish the events.  I have been using the Android AsyncHttpClient library for a while to do asynchronous operation, and thought of using the same here as well. Let us update the build.gradle file with the following to add the AsyncHttpClient package.

Now update the button click handler with the following code.

Replace the namespace and eventhub name with the actual values from the Azure portal, and ClientId can be anything to identify the publisher. In real life scenario there will be multiple devices/apps publishing events to same event hub.   I have created another Azure website to generate the SAS signature, and let us use this site to create signature for this demo application.  In production application, it is better to generate the signature in Android app itself (or get it from a secure cloud service).

Once we update all the placeholders, it is time to execute the application, and eventhub_dashboardclick the button to send events. We should see the updates in Event hub dashboard as shown here. If not, check out the AsyncHttpClient callback handler and see the response from the server after the POST request.

Hope, many more Android apps will start publishing events to Azure Event hubs 🙂