/// <summary>
/// This is the main entry point for your service replica.
/// This method executes when this replica of your service becomes primary and has write status.
/// </summary>
/// <param name="cancellationToken">Canceled when Service Fabric needs to shut down this service replica.</param>
protected override async Task RunAsync(CancellationToken cancellationToken)
{
// Get the IoT Hub connection string from the Settings.xml config file
// from a configuration package named "Config"
string iotHubConnectionString =
this.Context.CodePackageActivationContext
.GetConfigurationPackageObject("Config")
.Settings
.Sections["IoTHubConfigInformation"]
.Parameters["ConnectionString"]
.Value;
string iotHubProcessOnlyFutureEvents =
this.Context.CodePackageActivationContext
.GetConfigurationPackageObject("Config")
.Settings
.Sections["IoTHubConfigInformation"]
.Parameters["ProcessOnlyFutureEvents"]
.Value.ToLower();
ServiceEventSource.Current.ServiceMessage(this.Context, $"RouterService - {ServiceUniqueId} - RunAsync - Starting service - Process Only Future Events[{iotHubProcessOnlyFutureEvents}] - IoTHub Connection String[{iotHubConnectionString}]");
// These Reliable Dictionaries are used to keep track of our position in IoT Hub.
// If this service fails over, this will allow it to pick up where it left off in the event stream.
IReliableDictionary <string, string> offsetDictionary =
await this.StateManager.GetOrAddAsync <IReliableDictionary <string, string> >(OffsetDictionaryName);
IReliableDictionary <string, long> epochDictionary =
await this.StateManager.GetOrAddAsync <IReliableDictionary <string, long> >(EpochDictionaryName);
// Each partition of this service corresponds to a partition in IoT Hub.
// IoT Hub partitions are numbered 0..n-1, up to n = 32.
// This service needs to use an identical partitioning scheme.
// The low key of every partition corresponds to an IoT Hub partition.
Int64RangePartitionInformation partitionInfo = (Int64RangePartitionInformation)this.Partition.PartitionInfo;
long servicePartitionKey = partitionInfo.LowKey;
EventHubReceiver eventHubReceiver = null;
MessagingFactory messagingFactory = null;
try
{
// HttpClient is designed as a shared object.
// A single instance should be used throughout the lifetime of RunAsync.
using (HttpClient httpClient = new HttpClient(new HttpServiceClientHandler()))
{
int offsetIteration = 0;
bool IsConnected = false;
while (true)
{
cancellationToken.ThrowIfCancellationRequested();
if (!IsConnected)
{
// Get an EventHubReceiver and the MessagingFactory used to create it.
// The EventHubReceiver is used to get events from IoT Hub.
// The MessagingFactory is just saved for later so it can be closed before RunAsync exits.
Tuple <EventHubReceiver, MessagingFactory> iotHubInfo = await this.ConnectToIoTHubAsync(iotHubConnectionString, servicePartitionKey, epochDictionary, offsetDictionary, iotHubProcessOnlyFutureEvents);
eventHubReceiver = iotHubInfo.Item1;
messagingFactory = iotHubInfo.Item2;
IsConnected = true;
}
Uri postUrl = null;
try
{
// It's important to set a low wait time here in lieu of a cancellation token
// so that this doesn't block RunAsync from exiting when Service Fabric needs it to complete.
// ReceiveAsync is a long-poll operation, so the timeout should not be too low,
// yet not too high to block RunAsync from exiting within a few seconds.
using (EventData eventData = await eventHubReceiver.ReceiveAsync(TimeSpan.FromSeconds(5)))
{
if (eventData == null)
{
ServiceEventSource.Current.ServiceMessage(this.Context, $"RouterService - {ServiceUniqueId} - RunAsync - No event data available on hub '{eventHubReceiver.Name}'");
await Task.Delay(global::Iot.Common.Names.IoTHubRetryWaitIntervalsInMills);
continue;
}
else
{
ServiceEventSource.Current.ServiceMessage(this.Context, $"RouterService - {ServiceUniqueId} - RunAsync - Received event data from hub '{eventHubReceiver.Name}' - Enqueued Time[{eventData.EnqueuedTimeUtc}] - Partition '{eventData.PartitionKey}' Sequence # '{eventData.SequenceNumber}'");
}
string targetSite = (string)eventData.Properties[global::Iot.Common.Names.EventKeyFieldTargetSite];
string deviceId = (string)eventData.Properties[global::Iot.Common.Names.EventKeyFieldDeviceId];
// This is the named service instance of the target site data service that the event should be sent to.
// The targetSite id is part of the named service instance name.
// The incoming device data stream specifie which target site the data belongs to.
string prefix = global::Iot.Common.Names.InsightApplicationNamePrefix;
string serviceName = global::Iot.Common.Names.InsightDataServiceName;
Uri targetSiteServiceName = new Uri($"{prefix}/{targetSite}/{serviceName}");
long targetSiteServicePartitionKey = FnvHash.Hash(deviceId);
ServiceEventSource.Current.ServiceMessage(this.Context, $"RouterService - {ServiceUniqueId} - RunAsync - About to post data to Insight Data Service from device '{deviceId}' to target site '{targetSite}' - partitionKey '{targetSiteServicePartitionKey}' - Target Service Name '{targetSiteServiceName}'");
// The target site data service exposes an HTTP API.
// For incoming device events, the URL is /api/events/{deviceId}
// This sets up a URL and sends a POST request with the device JSON payload.
postUrl = new HttpServiceUriBuilder()
.SetServiceName(targetSiteServiceName)
.SetPartitionKey(targetSiteServicePartitionKey)
.SetServicePathAndQuery($"/api/events/{deviceId}")
.Build();
ServiceEventSource.Current.ServiceMessage(this.Context, $"RouterService - {ServiceUniqueId} - RunAsync - Ready to post data to Insight Data Service from device '{deviceId}' to taget site '{targetSite}' - partitionKey '{targetSiteServicePartitionKey}' - Target Service Name '{targetSiteServiceName}' - url '{postUrl.PathAndQuery}'");
// The device stream payload isn't deserialized and buffered in memory here.
// Instead, we just can just hook the incoming stream from Iot Hub right into the HTTP request stream.
using (Stream eventStream = eventData.GetBodyStream())
{
using (StreamContent postContent = new StreamContent(eventStream))
{
postContent.Headers.ContentType = new MediaTypeHeaderValue("application/json");
HttpResponseMessage response = await httpClient.PostAsync(postUrl, postContent, cancellationToken);
if (response.StatusCode == System.Net.HttpStatusCode.BadRequest)
{
// This service expects the receiving target site service to return HTTP 400 if the device message was malformed.
// In this example, the message is simply logged.
// Your application should handle all possible error status codes from the receiving service
// and treat the message as a "poison" message.
// Message processing should be allowed to continue after a poison message is detected.
string responseContent = await response.Content.ReadAsStringAsync();
ServiceEventSource.Current.ServiceMessage(
this.Context,
$"RouterService - {ServiceUniqueId} - RunAsync - Insight service '{targetSiteServiceName}' returned HTTP 400 due to a bad device message from device '{deviceId}'. Error message: '{responseContent}'");
}
ServiceEventSource.Current.ServiceMessage(
this.Context,
$"RouterService - {ServiceUniqueId} - RunAsync - Sent event data to Insight service '{targetSiteServiceName}' with partition key '{targetSiteServicePartitionKey}'. Result: {response.StatusCode.ToString()}");
}
}
// Save the current Iot Hub data stream offset.
// This will allow the service to pick up from its current location if it fails over.
// Duplicate device messages may still be sent to the the target site service
// if this service fails over after the message is sent but before the offset is saved.
if (++offsetIteration % OffsetInterval == 0)
{
ServiceEventSource.Current.ServiceMessage(
this.Context,
$"RouterService - {ServiceUniqueId} - RunAsync - Saving offset {eventData.Offset}");
using (ITransaction tx = this.StateManager.CreateTransaction())
{
await offsetDictionary.SetAsync(tx, "offset", eventData.Offset);
await tx.CommitAsync();
}
offsetIteration = 0;
}
}
}
catch (Microsoft.ServiceBus.Messaging.ReceiverDisconnectedException rde)
{
// transient error. Retry.
ServiceEventSource.Current.ServiceMessage(this.Context, $"RouterService - {ServiceUniqueId} - RunAsync - Receiver Disconnected Exception in RunAsync: {rde.ToString()}");
IsConnected = false;
}
catch (TimeoutException te)
{
// transient error. Retry.
ServiceEventSource.Current.ServiceMessage(this.Context, $"RouterService - {ServiceUniqueId} - RunAsync - TimeoutException in RunAsync: {te.ToString()}");
}
catch (FabricTransientException fte)
{
// transient error. Retry.
ServiceEventSource.Current.ServiceMessage(this.Context, $"RouterService - {ServiceUniqueId} - RunAsync - FabricTransientException in RunAsync: {fte.ToString()}");
}
catch (FabricNotPrimaryException fnpe)
{
ServiceEventSource.Current.ServiceMessage(this.Context, $"RouterService - {ServiceUniqueId} - RunAsync - FabricNotPrimaryException Exception - Message=[{fnpe}]");
// not primary any more, time to quit.
return;
}
catch (Exception ex)
{
IsConnected = false;
string url = postUrl == null ? "Url undefined" : postUrl.ToString();
//ServiceEventSource.Current.ServiceMessage(this.Context, $"RouterService - {ServiceUniqueId} - RunAsync - General Exception Url=[{url}]- Message=[{ex}] - Inner Exception=[{ex.InnerException.Message ?? "ex.InnerException is null"}] Call Stack=[{ex.StackTrace ?? "ex.StackTrace is null"}] - Stack trace of inner exception=[{ex.InnerException.StackTrace ?? "ex.InnerException.StackTrace is null"}]");
ServiceEventSource.Current.ServiceMessage(this.Context, $"RouterService - {ServiceUniqueId} - RunAsync - General Exception Message[{ex.Message}] for url[{url}]");
}
}
}
}
finally
{
if (messagingFactory != null)
{
await messagingFactory.CloseAsync();
}
}
}