private static Message ReadMessage(BrokerRouter router, string topic, int messageIndex, int maxBytes = 32768)
{
Message message = null;
long offset = router.LatestOffset(topic) - (2 - messageIndex);
List<Message> messages = router.Fetch(topic, 0, offset, maxBytes)?.Messages;
if ((messages?.Count ?? 0) > 0)
message = messages?[0];
if ((object)message == null)
throw new InvalidOperationException("No Kafka record to consume");
return message;
}
/// <summary>
/// Writes time-series metadata to specified Kafka <paramref name="topic"/>.
/// </summary>
/// <param name="metadata">Source time-series metadata object to write to Kafka.</param>
/// <param name="router">Kafka router connection.</param>
/// <param name="topic">Kafka topic.</param>
public static void WriteToKafka(TimeSeriesMetadata metadata, BrokerRouter router, string topic)
{
if ((object)metadata == null)
throw new ArgumentNullException(nameof(metadata));
if ((object)router == null)
throw new ArgumentNullException(nameof(router));
if (string.IsNullOrWhiteSpace(topic))
throw new ArgumentNullException(nameof(topic));
using (MemoryStream stream = new MemoryStream())
{
Serialize(metadata, stream, true);
using (Producer producer = new Producer(router))
{
Message[] messages = new Message[2];
byte[] timeKey = BitConverter.GetBytes(DateTime.UtcNow.Ticks);
// First message used to serialize metadata size (since metadata messages can be large)
messages[SizeMessage] = new Message
{
Key = timeKey,
Value = BitConverter.GetBytes(stream.Length)
};
// Second message used to serialize metadata value
messages[ValueMessage] = new Message
{
Key = timeKey,
Value = stream.ToArray()
};
// Send meta-data to Kafka
producer.SendMessageAsync(topic, messages).Wait();
}
}
}
/// <summary>
/// Reads latest time-series metadata from specified Kafka <paramref name="topic"/>.
/// </summary>
/// <param name="router">Kafka router connection.</param>
/// <param name="topic">Kafka topic.</param>
/// <param name="serializationTime">Serialization time.</param>
/// <param name="statusMessage">Status message function.</param>
/// <returns>Latest <see cref="TimeSeriesMetadata"/> instance read from Kafka.</returns>
public static TimeSeriesMetadata ReadFromKafka(BrokerRouter router, string topic, Action<string> statusMessage, out Ticks serializationTime)
{
if ((object)router == null)
throw new ArgumentNullException(nameof(router));
if (string.IsNullOrWhiteSpace(topic))
throw new ArgumentNullException(nameof(topic));
Message sizeMessage = ReadMessage(router, topic, SizeMessage);
serializationTime = BitConverter.ToInt64(sizeMessage.Key, 0);
Message valueMessage = ReadMessage(router, topic, ValueMessage, (int)Math.Ceiling(BitConverter.ToInt64(sizeMessage.Value, 0) / 4096.0D) * 4096);
if (serializationTime != BitConverter.ToInt64(valueMessage.Key, 0))
statusMessage?.Invoke("WARNING: Timestamp keys for metadata size and value records are mismatched...");
using (MemoryStream stream = new MemoryStream(valueMessage.Value))
return Deserialize(stream);
}
/// <summary>
/// Attempts to disconnect from data output stream.
/// </summary>
/// <remarks>
/// Derived classes should attempt disconnect from data output stream here. Any exceptions thrown
/// by this implementation will be reported to host via <see cref="AdapterBase.ProcessException"/> event.
/// </remarks>
protected override void AttemptDisconnection()
{
if ((object)m_producer != null)
{
m_producer.Dispose();
m_producer = null;
}
if ((object)m_router != null)
{
m_router.Dispose();
m_router = null;
}
}
/// <summary>
/// Executes the metadata refresh in a synchronous fashion.
/// </summary>
protected override void ExecuteMetadataRefresh()
{
if (!Initialized || !Enabled || !SerializeMetadata)
return;
try
{
using (BrokerRouter router = new BrokerRouter(new KafkaOptions(m_servers)
{
Log = new TimeSeriesLogger
(
(status, args) => OnStatusMessage(MessageLevel.Info, string.Format(status, args)),
ex => OnProcessException(MessageLevel.Warning, new InvalidOperationException($"[{MetadataTopic}]: {ex.Message}", ex))
)
}))
{
// Attempt to retrieve last known metadata record from Kafka
if ((object)m_metadata == null)
{
try
{
Ticks serializationTime;
OnStatusMessage(MessageLevel.Info, "Reading latest time-series metadata records from Kafka...");
m_metadata = TimeSeriesMetadata.ReadFromKafka(router, MetadataTopic, status => OnStatusMessage(MessageLevel.Info, status), out serializationTime);
OnStatusMessage(MessageLevel.Info, $"Deserialized {m_metadata.Count:N0} Kafka time-series metadata records, version {m_metadata.Version:N0}, from \"{MetadataTopic}\" serialized at {serializationTime.ToString(MetadataRecord.DateTimeFormat)}");
}
catch (Exception ex)
{
OnStatusMessage(MessageLevel.Warning, $"Failed to read any existing Kafka time-series metadata records from topic \"{MetadataTopic}\": {ex.Message}");
}
}
// Create new meta-data object based on newly loaded configuration
TimeSeriesMetadata metadata = new TimeSeriesMetadata();
try
{
foreach (DataRow row in DataSource.Tables["ActiveMeasurements"].AsEnumerable())
{
MeasurementKey key;
if (MeasurementKey.TryParse(row.Field<string>("ID") ?? MeasurementKey.Undefined.ToString(), out key))
{
metadata.Records.Add(new MetadataRecord
{
ID = key.ID,
Source = key.Source,
UniqueID = row.Field<object>("SignalID").ToString(),
PointTag = row.Field<string>("PointTag"),
Device = row.Field<string>("Device"),
Longitude = row.ConvertField("Longitude", 0.0F),
Latitude = row.ConvertField("Latitude", 0.0F),
Protocol = row.Field<string>("Protocol"),
SignalType = row.Field<string>("SignalType"),
EngineeringUnits = row.Field<string>("EngineeringUnits"),
PhasorType = row.Field<string>("PhasorType"),
Phase = row.Field<string>("Phase"),
Description = row.Field<string>("Description"),
LastUpdate = row.Field<DateTime>("UpdatedOn").ToString(MetadataRecord.DateTimeFormat)
});
}
}
}
catch (Exception ex)
{
OnProcessException(MessageLevel.Warning, new InvalidOperationException($"Failed to serialize current time-series metadata records: {ex.Message}", ex));
}
if (metadata.Count > 0)
{
// See if metadata has not been created yet or is different from last known Kafka record
if ((object)m_metadata == null || m_metadata.CalculateChecksum() != metadata.CalculateChecksum())
{
// Update local metadata reference
m_metadata = metadata;
// Send updated metadata to Kafka
TimeSeriesMetadata.WriteToKafka(m_metadata, router, MetadataTopic);
// Cache metadata locally, if configured
m_cacheMetadataLocally?.RunOnceAsync();
m_metadataUpdateCount++;
OnStatusMessage(MessageLevel.Info, $"Updated \"{MetadataTopic}\" with {m_metadata.Count:N0} Kafka time-series metadata records...");
}
else
{
OnStatusMessage(MessageLevel.Info, $"Latest \"{MetadataTopic}\" is up to date with current time-series metadata records...");
}
}
else
{
OnStatusMessage(MessageLevel.Warning, "No available local time-series metadata available to serialize...");
}
}
}
catch (Exception ex)
{
OnProcessException(MessageLevel.Warning, new InvalidOperationException($"Failed to update \"{MetadataTopic}\" with current time-series metadata records: {ex.Message}", ex));
}
}
/// <summary>
/// Attempts to connect to data output stream.
/// </summary>
/// <remarks>
/// Derived classes should attempt connection to data output stream here. Any exceptions thrown
/// by this implementation will result in restart of the connection cycle.
/// </remarks>
protected override void AttemptConnection()
{
m_router = new BrokerRouter(new KafkaOptions(m_servers)
{
Log = new TimeSeriesLogger
(
(status, args) => OnStatusMessage(MessageLevel.Info, string.Format(status, args)),
ex => OnProcessException(MessageLevel.Warning, ex)
)
});
m_producer = new Producer(m_router);
MetadataRefreshOperation.RunOnceAsync();
}
static void Main(string[] args)
{
var options = new KafkaOptions(new Uri("http://kafka1:9092"), new Uri("http://kafka2:9092"))
{
Log = new ConsoleLog()
};
var router = new BrokerRouter(options);
var client = new Producer(router);
var timing = new RollingQueue<double>(50);
var rate = new RollingQueue<double>(50);
var second = DateTime.Now.Second;
var count = 0;
Task.Run(() =>
{
var consumer = new Consumer(new ConsumerOptions("latencies", router));
var position = consumer.GetTopicOffsetAsync("latencies");
position.Wait();
consumer.SetOffsetPosition(
position.Result
.Select(p => new OffsetPosition(p.PartitionId, p.Offsets.First()))
.ToArray()
);
foreach (var data in consumer.Consume())
{
count++;
var rtt = (DateTime.Now - new DateTime(
long.Parse(Encoding.UTF8.GetString(data.Value))
)).TotalMilliseconds;
if (rtt < 1000)
timing.Enqueue(rtt);
if (second != DateTime.Now.Second)
{
second = DateTime.Now.Second;
rate.Enqueue(count);
count = 0;
Console.WriteLine("Rate: {0} pps.\t{1} ",
rate.Average().ToString("N2") , (rtt < 1000)
? "RTT: " + timing.Average().ToString("N2") + " ms."
: string.Empty
);
}
}
});
while (true)
{
client.SendMessageAsync("latencies", new[] {
new Message(DateTime.Now.Ticks.ToString()),
new Message(DateTime.Now.Ticks.ToString()),
new Message(DateTime.Now.Ticks.ToString()),
new Message(DateTime.Now.Ticks.ToString()),
new Message(DateTime.Now.Ticks.ToString()),
new Message(DateTime.Now.Ticks.ToString()),
new Message(DateTime.Now.Ticks.ToString()),
new Message(DateTime.Now.Ticks.ToString()),
new Message(DateTime.Now.Ticks.ToString()),
new Message(DateTime.Now.Ticks.ToString())
}, 1);
Thread.Sleep(1);
}
client.Dispose();
router.Dispose();
}
// Update metadata from latest Kafka records
private void UpdateMetadata()
{
// Attempt to retrieve last known metadata record from Kafka
try
{
using (BrokerRouter router = new BrokerRouter(new KafkaOptions(m_servers)
{
Log = new TimeSeriesLogger(
(status, args) => OnStatusMessage(MessageLevel.Info, string.Format(status, args)),
ex => OnProcessException(MessageLevel.Warning, new InvalidOperationException($"[{MetadataTopic}]: {ex.Message}", ex)))
}))
{
Ticks serializationTime;
OnStatusMessage(MessageLevel.Info, "Reading latest time-series metadata records from Kafka...");
TimeSeriesMetadata metadata = TimeSeriesMetadata.ReadFromKafka(router, MetadataTopic, status => OnStatusMessage(MessageLevel.Info, status), out serializationTime);
if ((object)metadata != null)
{
m_metadata = metadata;
OnStatusMessage(MessageLevel.Info, $"Deserialized {m_metadata.Count:N0} Kafka time-series metadata records, version {m_metadata.Version:N0}, from \"{MetadataTopic}\" serialized at {serializationTime.ToString(MetadataRecord.DateTimeFormat)}");
if (m_lastMetadataVersion != MetadataVersion)
{
m_lastMetadataVersion = MetadataVersion;
m_metadataUpdateCount++;
}
// Cache metadata locally, if configured
m_cacheMetadataLocally?.RunOnceAsync();
}
}
}
catch (Exception ex)
{
if (Enabled)
{
// Treat exception as a warning if metadata already exists
if ((object)m_metadata == null)
throw;
OnStatusMessage(MessageLevel.Warning, $"Failed to read latest Kafka time-series metadata records from topic \"{MetadataTopic}\": {ex.Message}");
}
}
}
/// <summary>
/// Attempts to disconnect from data output stream.
/// </summary>
/// <remarks>
/// Derived classes should attempt disconnect from data output stream here. Any exceptions thrown
/// by this implementation will be reported to host via <see cref="AdapterBase.ProcessException"/> event.
/// </remarks>
protected override void AttemptDisconnection()
{
if ((object)m_processingThreads != null)
{
foreach (Thread processingThread in m_processingThreads)
processingThread.Abort();
m_processingThreads = null;
}
if ((object)m_router != null)
{
m_router.Dispose();
m_router = null;
}
lock (m_consumers)
m_consumers.Clear();
}
/// <summary>
/// Attempts to connect to data output stream.
/// </summary>
/// <remarks>
/// Derived classes should attempt connection to data output stream here. Any exceptions thrown
/// by this implementation will result in restart of the connection cycle.
/// </remarks>
protected override void AttemptConnection()
{
m_router = new BrokerRouter(new KafkaOptions(m_servers)
{
Log = new TimeSeriesLogger
(
(status, args) => OnStatusMessage(MessageLevel.Info, string.Format(status, args)),
ex => OnProcessException(MessageLevel.Warning, ex)
)
});
m_processingThreads = new Thread[Partitions];
for (int partition = 0; partition < m_processingThreads.Length; partition++)
{
m_processingThreads[partition] = new Thread(ProcessPartitionMessages) { IsBackground = true };
m_processingThreads[partition].Start(partition);
}
// Kick off process to update metadata
m_updateMetadata.RunOnceAsync();
}
