In preparation for the exam DP-420 Designing and Implementing Native Applications Using Microsoft Azure Cosmos DB, it’s essential to understand the functionalities of Azure Functions and Azure Event Hubs and how they can facilitate in event-driven programming.
Integrating Events with Azure Functions
Azure Functions serve as the cornerstone of serverless architecture, allowing developers to write less code, maintain less infrastructure, and save costs. They provide an environment to write code that responds to a triggering event.
To integrate events, create an Azure function that gets automatically invoked when an event source emits an event. This could be a file change, a message on azure service bus, or a change stream event from Azure Cosmos DB. Azure functions can be set up to listen to these events and trigger the necessary processes.
Azure Function Example:
module.exports = async function (context, myQueueItem) {
context.log('Processed work item', myQueueItem);
};
In this example, the function is triggered by a new message added to the Queue storage and the payload of the message is provided to the function in ‘myQueueItem’.
Integrating Events with Azure Event Hubs
Azure Event Hubs is a real-time data ingestion service that can receive and process millions of events per second. This can be hooked up to an Azure Function, which can be triggered each time an event is sent to the hub.
Azure Event Hubs Example:
// Connection string to the event hub namespace
const connectionString = '<< CONNECTION STRING TO EVENT HUB NAMESPACE >>';
// Name of the event hub
const eventHubsName = '<< NAME OF EVENT HUB >>';
const client = new EventHubProducerClient(connectionString, eventHubsName);
async function main() {
const eventDataBatch = await client.createBatch();
eventDataBatch.tryAdd({ body: 'First event' });
eventDataBatch.tryAdd({ body: 'Second event' });
// Send the batch to the event hub.
await client.sendBatch(eventDataBatch);
await client.close();
}
main().catch(console.error);
In this example, an Event Hubs producer is created that sends two events (“First event” and “Second event”) to the Event Hubs. If an Azure Function was listening to this Event Hubs, it would trigger twice.
Azure Functions and Azure Event Hubs working together
The interoperability of Azure Functions and Azure Event Hubs lies in their capacity to react dynamically to events. An Azure Function can be configured to trigger when an event is published onto Event Hubs. Therefore, any applications that publish to Azure Event Hubs can trigger Azure Functions, allowing complex, distributed workflows to be implemented as code that runs only in response to events.
Hence, integrating Azure Functions and Azure Event Hubs is incredibly useful for real-time analytics, IoT, and many other types of applications and services. Understanding this integration is a significant aspect of preparing and being successful in the DP-420 Exam: Designing and Implementing Native Applications Using Microsoft Azure Cosmos DB.
Practice Test
True or False: Azure Functions can be used to integrate events with other applications.
- True
- False
Answer: True.
Explanation: Azure Functions is a serverless compute service that enables you to run code in response to events without having to provision or manage infrastructure, making it ideal for integrating events with other applications.
Which of the following components of Azure are used to integrate events with other applications?
- A. Azure Power BI
- B. Azure Event Hubs
- C. Azure Logic Apps
- D. Azure SQL Database
Answer: B. Azure Event Hubs, C. Azure Logic Apps.
Explanation: Azure Event Hubs and Azure Logic Apps are used to create a real-time analytics pipeline and automate workflows, respectively, making them critical components for integrating events with other applications.
True or False: Azure Cosmos DB cannot trigger an Azure Function.
- True
- False
Answer: False.
Explanation: Azure Functions can be triggered by a change in the state of a document in Azure Cosmos DB, allowing real-time processing.
Which of the following Azure services can be used to ingest massive amounts of telemetry data?
- A. Azure Function
- B. Azure Data Lake
- C. Azure Event Hubs
- D. Azure SQL Database
Answer: C. Azure Event Hubs.
Explanation: Azure Event Hubs is Azure’s real-time data ingestion service and can handle millions of events per second.
True or False: Azure Functions run in a server-based environment.
- True
- False
Answer: False.
Explanation: Azure Functions allow for serverless computing. Code is run in response to events without having to provision or manage server-based infrastructure.
Which of the following can Azure Event Hubs store and process?
- A. Database transactions
- B. Sensor readings
- C. Social media feeds
- D. All of the above
Answer: D. All of the above.
Explanation: Azure Event Hubs can process and analyze data from all these sources and more to derive real-time analytics and insights.
True or False: Azure Cosmos DB requires you to manage your infrastructure.
- True
- False
Answer: False.
Explanation: Azure Cosmos DB is a fully managed NoSQL database service.
The stream processing engine that connects to Azure Event Hubs is called:
- A. Azure Functions
- B. Azure Stream Analytics
- C. Azure Logic Apps
- D. Azure Power BI
Answer: B. Azure Stream Analytics.
Explanation: Azure Stream Analytics is an event processing engine that can connect to Azure Event Hubs to analyze real-time data streams.
Which of the following allows you to execute your code in a serverless environment in Azure?
- A. Azure Cosmos DB
- B. Azure Functions
- C. Azure Event Hubs
- D. Azure SQL Database
Answer: B. Azure Functions.
Explanation: Azure Functions is a serverless compute service that lets you run your code in Azure’s serverless environment.
True or False: Azure Functions cannot integrate with Azure Logic Apps.
- True
- False
Answer: False.
Explanation: Azure Functions can integrate with Azure Logic Apps to compute responses to HTTP triggers or timer-based events.
Interview Questions
What is Azure Functions?
Azure Functions is a serverless compute service that allows you to run small pieces of code (called functions) without worrying about application infrastructure. You can develop in your choice of language, with functionality being triggered by a range of events including HTTP requests, database operations, and Event Hubs Targets.
What is the use of Azure Event Hubs?
Azure Event Hubs is a big data streaming platform and event ingestion service, capable of receiving and processing millions of events per second. It can process and analyze the data produced by your cloud infrastructure, and react to information in real-time.
What are some examples of how you might use Azure Event Hubs and Azure Functions together?
Azure Functions can be triggered by events in Azure Event Hubs. This allows for executing code and processing data in real time as data flows through Azure Event Hubs. Examples might include real-time analytics, data transformations, and IoT workloads.
What is the use of Azure Cosmos DB?
Azure Cosmos DB is a globally distributed, multi-model database service. It provides support for NoSQL choices, offers five consistency models, guarantees single-digit-millisecond read and write latencies at the 99th percentile and offers 99.999-percent high availability with multi-homing anywhere in the world—all backed by industry-leading, comprehensive service level agreements (SLAs).
How can you use Azure Cosmos DB with Azure Functions?
Azure Functions supports Azure Cosmos DB bindings. The Azure Cosmos DB trigger allows you to create functions that react to data changes in your Azure Cosmos DB database. Azure Functions can also output data to Azure Cosmos DB.
Can you scale Azure Functions and Azure Event Hubs independently?
Yes, Azure Functions and Azure Event Hubs can both be scaled independently to match your application needs.
How do you setup the function.json file to connect Azure Functions and Azure Event Hubs?
To connect Azure Functions and Azure Event Hubs, you need to set up certain parameters in the function.json file. These include “Type”, “Name”, “EventHubName”, and “ConnectionStringSetting”.
How can Database operations be handled in Azure Functions?
In Azure Functions, you can use input and output bindings to automatically read from and write to Azure Cosmos DB documents without needing to write the code to interact with the Azure Cosmos DB SDK directly.
Can Azure Functions be written in any programming language?
Azure Functions support multiple programming languages such as C#, Java, JavaScript (Node.js), and Python.
Is it possible to test Azure Functions locally before deploying?
Yes, Azure Functions provides a local development experience for testing and debugging your functions in your local development environment before deploying them to the cloud.
How does Azure Event Hubs manage and process large amounts of events per second?
Azure Event Hubs uses a partitioned consumer pattern for processing these events allowing the data stream to be divided into potentially many partitions that can be consumed independently, enabling massive scale.
Can Azure Cosmos DB handle real-time analytics?
Yes, Azure Cosmos DB offers real-time analytics over operational data. It also provides comprehensive service level agreements (SLAs) for throughput, latency, consistency, and availability.
What is the role of Azure functions in the integration of events with applications?
Azure Functions operates as a serverless computing service, which allows the execution of code upon the triggering of specified events, such as incoming HTTP requests or messages on a queue, making it highly valuable in integrating events with applications.
What is the benefit of combining Azure Event Hubs, Azure Functions, and Azure Cosmos DB in an application?
By combining Azure Event Hubs, Azure Functions and Azure Cosmos DB, developers can build highly scalable and distributed apps that react to changes in data in real time. These apps can handle massive amounts of data ingress, process information in parallel, and store and retrieve data at large scales.
How is data accessed and delivered in Azure Event Hubs?
The data in Azure Event Hubs is accessed via consumer groups which enable multiple consuming applications to each have a separate view of the event stream, and to read the stream independently at their own pace and from their own position.
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