This sample demonstrates a basic producer and consumer application using Azure Event Hubs with C#. The producer sends events to an Event Hub, and the consumer reads and processes those events.
This is a fundamental pattern for building real-time data processing pipelines, microservices communication, and telemetry ingestion.
1. Create a new .NET Console Application:
dotnet new console -n EventHubsSample
cd EventHubsSample2. Add the Azure Event Hubs SDK NuGet package:
dotnet add package Azure.Messaging.EventHubs3. Configure your connection string:
It's recommended to use environment variables or a configuration file for sensitive information like connection strings. For this sample, we'll assume you'll set an environment variable named EVENTHUB_CONNECTION_STRING.
Replace the contents of Program.cs with the following producer code:
using Azure.Messaging.EventHubs;
using Azure.Messaging.EventHubs.Producer;
using System;
using System.Text;
using System.Threading.Tasks;
namespace EventHubsSample
{
class Program
{
// Replace with your actual Event Hubs connection string
// Or set it as an environment variable: EVENTHUB_CONNECTION_STRING
private const string connectionString = "YOUR_EVENT_HUBS_CONNECTION_STRING";
private const string eventHubName = "YOUR_EVENT_HUB_NAME"; // Optional, if not in connection string
static async Task Main(string[] args)
{
Console.WriteLine("Azure Event Hubs Producer Sample");
string envConnectionString = Environment.GetEnvironmentVariable("EVENTHUB_CONNECTION_STRING");
string finalConnectionString = string.IsNullOrEmpty(connectionString) ? envConnectionString : connectionString;
if (string.IsNullOrEmpty(finalConnectionString))
{
Console.ForegroundColor = ConsoleColor.Red;
Console.WriteLine("Error: Event Hubs connection string is not configured.");
Console.WriteLine("Please set the EVENTHUB_CONNECTION_STRING environment variable or update the 'connectionString' constant.");
Console.ResetColor();
return;
}
// Using a producer client that automatically polls and discovers partitions
await using (var producer = new EventHubProducerClient(finalConnectionString, eventHubName))
{
try
{
Console.WriteLine("Sending events...");
for (int i = 0; i < 10; i++)
{
var eventBody = $"{{ \"messageId\": {i}, \"timestamp\": \"{DateTime.UtcNow:O}\", \"content\": \"Hello Event Hubs! Event #{i}\" }}";
var eventData = new EventData(Encoding.UTF8.GetBytes(eventBody));
await producer.SendAsync(new[] { eventData });
Console.WriteLine($"Sent: {eventBody}");
await Task.Delay(100); // Small delay between events
}
Console.WriteLine("Finished sending events.");
}
catch (Exception ex)
{
Console.ForegroundColor = ConsoleColor.Red;
Console.WriteLine($"An error occurred: {ex.Message}");
Console.ResetColor();
}
}
Console.WriteLine("\nPress any key to exit...");
Console.ReadKey();
}
}
}
Note: Update "YOUR_EVENT_HUBS_CONNECTION_STRING" and optionally "YOUR_EVENT_HUB_NAME" if they are not set via environment variable.
To run the consumer, you will need a separate project or modify Program.cs to handle consumption. For simplicity, let's create a new console app for the consumer. If you prefer, you can combine them, but separate projects are often cleaner.
1. Create a new .NET Console Application for the Consumer:
cd ..
dotnet new console -n EventHubsConsumer
cd EventHubsConsumer2. Add the Azure Event Hubs SDK NuGet package:
dotnet add package Azure.Messaging.EventHubsReplace the contents of EventHubsConsumer/Program.cs with the following consumer code:
using Azure.Messaging.EventHubs;
using Azure.Messaging.EventHubs.Consumer;
using System;
using System.Text;
using System.Threading.Tasks;
namespace EventHubsConsumer
{
class Program
{
// Replace with your actual Event Hubs connection string
// Or set it as an environment variable: EVENTHUB_CONNECTION_STRING
private const string connectionString = "YOUR_EVENT_HUBS_CONNECTION_STRING";
private const string eventHubName = "YOUR_EVENT_HUB_NAME"; // Optional, if not in connection string
private const string consumerGroup = EventHubConsumerClient.DefaultConsumerGroupName; // Or specify your own consumer group
static async Task Main(string[] args)
{
Console.WriteLine("Azure Event Hubs Consumer Sample");
string envConnectionString = Environment.GetEnvironmentVariable("EVENTHUB_CONNECTION_STRING");
string finalConnectionString = string.IsNullOrEmpty(connectionString) ? envConnectionString : connectionString;
if (string.IsNullOrEmpty(finalConnectionString))
{
Console.ForegroundColor = ConsoleColor.Red;
Console.WriteLine("Error: Event Hubs connection string is not configured.");
Console.WriteLine("Please set the EVENTHUB_CONNECTION_STRING environment variable or update the 'connectionString' constant.");
Console.ResetColor();
return;
}
// Create a consumer client
await using (var consumerClient = new EventHubConsumerClient(consumerGroup, finalConnectionString, eventHubName))
{
Console.WriteLine($"Listening to Event Hub: {eventHubName} in consumer group: {consumerGroup}");
Console.WriteLine("Press Ctrl+C to stop.");
try
{
// Process events in batches
await foreach (PartitionEvent batch in consumerClient.ReadEventsAsync())
{
Console.WriteLine($"Received event from partition {batch.Partition.Id}:");
var messageBody = Encoding.UTF8.GetString(batch.Data.EventBody.ToArray());
Console.WriteLine($" Body: {messageBody}");
Console.WriteLine($" Sequence Number: {batch.Data.SequenceNumber}");
Console.WriteLine($" Offset: {batch.Data.Offset}");
Console.WriteLine($" Enqueued Time: {batch.Data.EnqueuedTime}");
Console.WriteLine("---");
}
}
catch (TaskCanceledException)
{
Console.WriteLine("Consumer stopped by user.");
}
catch (Exception ex)
{
Console.ForegroundColor = ConsoleColor.Red;
Console.WriteLine($"An error occurred: {ex.Message}");
Console.ResetColor();
}
}
Console.WriteLine("\nPress any key to exit...");
Console.ReadKey();
}
}
}
Note: Update "YOUR_EVENT_HUBS_CONNECTION_STRING" and optionally "YOUR_EVENT_HUB_NAME" if they are not set via environment variable. Also, consider specifying a dedicated consumer group for your application.
1. Set the Connection String:
Before running, ensure your Event Hubs connection string is available. You can set it as an environment variable:
set EVENTHUB_CONNECTION_STRING="YOUR_EVENT_HUBS_CONNECTION_STRING"$env:EVENTHUB_CONNECTION_STRING="YOUR_EVENT_HUBS_CONNECTION_STRING"export EVENTHUB_CONNECTION_STRING="YOUR_EVENT_HUBS_CONNECTION_STRING"Replace "YOUR_EVENT_HUBS_CONNECTION_STRING" with your actual connection string.
2. Run the Producer:
cd EventHubsSample
dotnet runYou should see output indicating events being sent.
3. Run the Consumer:
In a separate terminal window, navigate to the consumer project directory and run it:
cd ../EventHubsConsumer
dotnet runYou should see output indicating events being received from the Event Hub.
Press Ctrl+C in the consumer's terminal to stop it.