static void Main(string[] args)
{
var config = new Dictionary <string, object>
{
{ "group.id", "sample-consumer" },
{ "bootstrap.servers", "127.0.0.1:9092" },
{ "enable.auto.commit", "false" }
};
var topic = "my-topic";
Console.WriteLine($"reads messages in {topic}");
using (var consumer = new Consumer <Null, string>(config, null, new StringDeserializer(Encoding.UTF8)))
{
consumer.Subscribe(new string[] { topic });
consumer.OnError += (_, e) =>
{
Console.WriteLine(e.Reason);
};
consumer.OnMessage += (_, msg) =>
{
Console.WriteLine($"Topic: {msg.Topic} Partition: {msg.Partition} Offset: {msg.Offset} {msg.Value}");
consumer.CommitAsync(msg);
};
while (true)
{
consumer.Poll(100);
}
}
}
public Task ConsumeNewMessageAsync()
{
_tcs = new TaskCompletionSource <int>();
Task <int> t = _tcs.Task;
_consumer.Poll(TimeSpan.FromMilliseconds(100));
return(t);
}
static void Main(string[] args)
{
var typeName = typeof(Program).Assembly.GetName();
Console.WriteLine($"Starting {typeName.Name} v{typeName.Version}...");
// Create the consumer configuration
var config = new Dictionary <string, object>
{
{ "group.id", Common.GetConfigValue("group.id") },
{ "bootstrap.servers", Common.GetConfigValue("bootstrap.servers") },
{ "auto.commit.interval.ms", Common.GetConfigValue("auto.commit.interval.ms") },
{ "auto.offset.reset", Common.GetConfigValue("auto.offset.reset") }
};
Console.WriteLine($"Connecting consumer to '{Common.GetConfigValue("bootstrap.servers")}' kafka endpoint...");
// Create the consumer
using (var consumer = new Consumer <Null, string>(config, null, new StringDeserializer(Encoding.UTF8)))
{
// Subscribe to the OnMessage event
consumer.OnMessage += (obj, msg) =>
{
Console.WriteLine($"Received: {msg.Value}. Offset: {msg.Offset}. Partition: {msg.Partition}");
};
// Subscribe to the Kafka topic
consumer.Subscribe(new List <string>()
{
Common.GetConfigValue("topic")
});
// Handle Cancel Keypress
var cancelled = false;
Console.CancelKeyPress += (_, e) =>
{
e.Cancel = true; // prevent the process from terminating.
cancelled = true;
};
Console.WriteLine("Ctrl-C to exit.");
// Poll for messages
while (!cancelled)
{
consumer.Poll(TimeSpan.FromMilliseconds(100));
}
}
}
/// <summary>
// In this example:
/// - offsets are auto commited.
/// - consumer.Poll / OnMessage is used to consume messages.
/// - no extra thread is created for the Poll loop.
/// </summary>
public static void Run_Poll(string brokerList, List <string> topics)
{
var config = new Dictionary <string, object>
{
{ "bootstrap.servers", brokerList },
{ "group.id", "csharp-consumer" },
{ "enable.auto.commit", true }, // this is the default
{ "auto.commit.interval.ms", 5000 },
{ "statistics.interval.ms", 60000 },
{ "session.timeout.ms", 6000 },
{ "auto.offset.reset", "smallest" }
};
using (var consumer = new Consumer <Ignore, string>(config, null, new StringDeserializer(Encoding.UTF8)))
{
// Note: All event handlers are called on the main thread.
consumer.OnMessage += (_, msg)
=> Console.WriteLine($"Topic: {msg.Topic} Partition: {msg.Partition} Offset: {msg.Offset} {msg.Value}");
consumer.OnPartitionEOF += (_, end)
=> Console.WriteLine($"Reached end of topic {end.Topic} partition {end.Partition}, next message will be at offset {end.Offset}");
consumer.OnError += (_, error)
=> Console.WriteLine($"Error: {error}");
// Raised on deserialization errors or when a consumed message has an error != NoError.
consumer.OnConsumeError += (_, msg)
=> Console.WriteLine($"Error consuming from topic/partition/offset {msg.Topic}/{msg.Partition}/{msg.Offset}: {msg.Error}");
consumer.OnOffsetsCommitted += (_, commit)
=> Console.WriteLine(
commit.Error
? $"Failed to commit offsets: {commit.Error}"
: $"Successfully committed offsets: [{string.Join(", ", commit.Offsets)}]");
// Raised when the consumer is assigned a new set of partitions.
consumer.OnPartitionsAssigned += (_, partitions) =>
{
Console.WriteLine($"Assigned partitions: [{string.Join(", ", partitions)}], member id: {consumer.MemberId}");
// If you don't add a handler to the OnPartitionsAssigned event,
// the below .Assign call happens automatically. If you do, you
// must call .Assign explicitly in order for the consumer to
// start consuming messages.
consumer.Assign(partitions);
};
// Raised when the consumer's current assignment set has been revoked.
consumer.OnPartitionsRevoked += (_, partitions) =>
{
Console.WriteLine($"Revoked partitions: [{string.Join(", ", partitions)}]");
// If you don't add a handler to the OnPartitionsRevoked event,
// the below .Unassign call happens automatically. If you do,
// you must call .Unassign explicitly in order for the consumer
// to stop consuming messages from it's previously assigned
// partitions.
consumer.Unassign();
};
consumer.OnStatistics += (_, json)
=> Console.WriteLine($"Statistics: {json}");
consumer.Subscribe(topics);
Console.WriteLine($"Subscribed to: [{string.Join(", ", consumer.Subscription)}]");
var cancelled = false;
Console.CancelKeyPress += (_, e) => {
e.Cancel = true; // prevent the process from terminating.
cancelled = true;
};
Console.WriteLine("Ctrl-C to exit.");
while (!cancelled)
{
consumer.Poll(TimeSpan.FromMilliseconds(100));
}
}
}
