public async Task SubscribeToTopicAsync(string brokerList, string topicName)
{
await _dao.EnsureTableCreated(_consumerGroup);
var config = new Dictionary <string, object>
{
{ "group.id", _consumerGroup },
{ "bootstrap.servers", brokerList },
{ "enable.auto.commit", EnableAutoCommit? "true" : "false" },
{ "auto.offset.reset", "earliest" }
};
_consumer = new Consumer <string, string>(config, new StringDeserializer(Encoding.UTF8), new StringDeserializer(Encoding.UTF8));
_consumer.OnMessage += async(_, msg) =>
{
await ExecuteProcessMessage(async() =>
{
await ProcessMessageAsync(msg, _consumer);
});
if (!EnableAutoCommit)
{
await ExecuteCommitOffset(async() =>
{
await CommitMessageAsync(_consumer);
});
}
;
_tcs.SetResult(1);
};
_consumer.OnPartitionsAssigned += (_, partitions) =>
{
Console.WriteLine($"Assigned partitions: [{string.Join(", ", partitions)}]");
_consumer.Assign(partitions);
};
_consumer.OnPartitionsRevoked += (_, partitions) =>
{
Console.WriteLine($"Revoked partitions: [{string.Join(", ", partitions)}]");
_consumer.Unassign();
};
_consumer.Subscribe(topicName);
//var cancelled = false;
//Console.CancelKeyPress += (_, e) =>
//{
// e.Cancel = true; // prevent the process from terminating.
// cancelled = true;
//};
}
/// <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));
}
}
}
