Using Azure Event Hubs for real-time data ingestion

Posted on by Panther

Real-time data processing is a critical requirement for many systems today. It allows for near-instantaneous response to events as they occur, making it possible to react quickly to changing conditions, detect anomalous situations, or trigger immediate actions.

To support real-time data ingestion, Microsoft Azure provides a service called Event Hubs. This service allows you to receive and process millions of events per second in real-time, making it an excellent choice for applications that require high scalability and low latency.

In this tutorial, we will explore how to use Azure Event Hubs for real-time data ingestion, including the steps required to create an Event Hub, send data to it, and process the data using an Azure Function. We will also cover the best practices for using Event Hubs, as well as some of the limitations and trade-offs that you should be aware of when using this service.

Prerequisites

Before we start, you will need the following:

  • An Azure subscription
  • Azure CLI or Azure Portal

Getting Started with Azure Event Hubs

Azure Event Hubs is a fully managed, real-time data ingestion service. It allows you to receive and process millions of events per second in real-time, making it an excellent choice for applications that require high scalability and low latency.

To create an Event Hub, you will need to follow these steps:

  1. Create an Event Hubs namespace
  2. Create an Event Hub
  3. Send data to the Event Hub
  4. Process the data using an Azure Function

Step 1: Create an Event Hubs namespace

The first step is to create an Event Hubs namespace. This is the top-level container that holds all your Event Hubs. You can create an Event Hubs namespace using the Azure portal or Azure CLI.

To create an Event Hubs namespace using Azure portal, follow these steps:

  1. Log in to the Azure portal
  2. Click on “Create a resource” in the top-left corner of the portal
  3. Search for “Event Hubs” and select “Event Hubs namespaces” from the results
  4. Click on the “Create” button
  5. Enter a name for your Event Hubs namespace
  6. Select your subscription
  7. Choose a resource group or create a new one
  8. Select the location you want to create the namespace in
  9. Configure pricing and other settings as needed
  10. Click “Review + create” button
  11. Confirm that the settings are correct and click “Create”

To create an Event Hubs namespace using Azure CLI, follow these steps:

  1. Open a terminal window or PowerShell prompt
  2. Run the following command to create a new resource group (if necessary):
az group create --name myResourceGroup --location eastus
  1. Run the following command to create a new Event Hubs namespace:
az eventhubs namespace create --name myNamespace --resource-group myResourceGroup --location eastus

Step 2: Create an Event Hub

The next step is to create an Event Hub within your Event Hubs namespace. An Event Hub is a partitioned stream of events, and it is the basic unit of data ingestion in Azure Event Hubs.

To create an Event Hub, follow these steps:

  1. Go to your Event Hubs namespace in the Azure portal
  2. Click on “Event Hubs” in the left-hand menu
  3. Click on the “Add” button
  4. Enter a name for your Event Hub
  5. Choose the number of partitions you want to create
  6. Configure other settings as needed
  7. Click “Review + create” button
  8. Confirm that the settings are correct and click “Create”

To create an Event Hub using Azure CLI, follow these steps:

  1. Run the following command to create a new Event Hub:
az eventhubs eventhub create --name myEventHub --namespace-name myNamespace --resource-group myResourceGroup --message-retention 1 --partition-count 4

Step 3: Send data to the Event Hub

Once you have created an Event Hub, you can start sending data to it. Azure Event Hubs supports a variety of protocols for sending data, including AMQP and HTTPS/REST.

To send data to the Event Hub using Azure portal, follow these steps:

  1. Go to your Event Hub in the Azure portal
  2. Click on “Shared access policies” in the left-hand menu
  3. Click on the “Add” button
  4. Enter a name for your policy
  5. Choose the permissions you want to grant
  6. Click “Create” button
  7. Click on the policy you just created
  8. Copy the connection string with the primary key

To send data to the Event Hub using Azure CLI, follow these steps:

  1. Run the following command to get the connection string for the Event Hub:
az eventhubs namespace authorization-rule keys list --namespace-name myNamespace --resource-group myResourceGroup --name RootManageSharedAccessKey
  1. Copy the primary connection string from the output

Once you have the connection string, you can use it to send data to the Event Hub. Here is an example of how to send a batch of events using the REST API:

POST https://myNamespace.servicebus.windows.net/myEventHub/messages
Authorization: SharedAccessSignature sr=myNamespace.servicebus.windows.net&sig=...&skn=RootManageSharedAccessKey&se=...
Content-Type: application/vnd.microsoft.servicebus.json

[
  {"name": "John", "age": 32},
  {"name": "Jane", "age": 28},
  {"name": "Bob", "age": 45}
]

Step 4: Process the data using an Azure Function

Once you have sent data to the Event Hub, you can start processing it using an Azure Function. An Azure Function is a serverless compute service that allows you to run code in response to events.

To create an Azure Function, follow these steps:

  1. Go to the Azure portal
  2. Click on “Create a resource” in the top-left corner of the portal
  3. Search for “Function App” and select “Function App” from the results
  4. Click “Create” button
  5. Enter a name for your Function App
  6. Select your subscription
  7. Choose a resource group or create a new one
  8. Select the location you want to create the Function App in
  9. Click “Review + create” button
  10. Confirm that the settings are correct and click “Create”

Once you have created the Function App, you can create a new Azure Function to process the data from the Event Hub. Here is an example of how to create an Azure Function that processes data from the Event Hub:

  1. Go to your Function App in the Azure portal
  2. Click on “Functions” in the left-hand menu
  3. Click on “+ New Function” button
  4. Choose a template for your function, e.g., “Event Hub trigger”
  5. Enter a name for your function
  6. Choose the Event Hub you want to trigger on
  7. Configure other settings as needed
  8. Click “Create” button

Here is an example of how to process the events in Python:

import json
import logging

def main(event: Dict[str, Any], context: Optional[Context]) -> None:

    for m in event:
        logging.inf

o(f"Received Event: {json.dumps(m)}")

This will log each event to the Azure Function log.

Best practices for using Azure Event Hubs

When using Azure Event Hubs, there are several best practices that you should follow to ensure the best performance and reliability of your system. Here are some of the most important ones:

  1. Use partition keys to ensure ordering and scalability
  2. Use multiple event publishers to improve throughput
  3. Use different consumer groups to process events independently
  4. Monitor the Event Hub and its components using Azure Monitor or other tools
  5. Set appropriate thresholds for throughput and scaling
  6. Use batching and compression to reduce latency and improve throughput
  7. Avoid sending large messages or attachments
  8. Use message deduplication to handle duplicate events

Limitations and trade-offs

While Azure Event Hubs is an excellent choice for real-time data ingestion, there are some limitations and trade-offs that you should consider when choosing this service. Here are some of the most important ones:

  1. Event Hubs are limited to a maximum of 20 concurrent readers per partition
  2. Event Hubs have a maximum retention period of 7 days
  3. Event Hubs do not support transactions or atomic writes across partitions
  4. Event Hubs have a fixed capacity per partition, which cannot be increased dynamically
  5. Event Hubs are charged based on the number of events and the volume of data, which can become expensive at high volumes

Conclusion

Azure Event Hubs is a powerful and versatile service that can help you handle real-time data ingestion at scale. By following the best practices and understanding the limitations of this service, you can build reliable and robust systems that can react to events as they occur.

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