.NET Core Service Fabric IoT Sample project

Since Microsoft recommends building new applications based on .NET Core, the topic of this blog is simple Service Fabric IoT example based on .NET Core.
The idea is similar and is based on the official Sevice Fabric IoT Example that is .NET Framework based.
This blog will point on some of the differences and will offer a full solution on Github.
Service fabric will contain stateful services for consuming messages from the IoT Hub partitions. One stateful service partition per one IoT Hub partition. That way the scaling is achieved. The state of the service will keep information about event hub queue offset, and epoch.
Epoch ensures that there is only one receiver per consumer group, with the following rules:
a) If there is no existing receiver on a consumer group then the user can create a receiver with any epoch value.
b) If there is a receiver with epoch value e1 and a new receiver is created with an epoch value e2 where e1 <= e2 then receiver with e1 will be disconnected automatically, receiver with e2 get created successfully.
c) If there is a receiver with epoch value e1 and a new receiver is created with an epoch value e2 where e1 > e2 then the creation of e2 with fail with the error “A receiver with epoch e1 already exists”
The offset represents the date which is used to read all messages that arrived to the IoT Hub after that date.


Official Service Fabric IoT Example(Iot.Ingestion.RouterService) is using NuGet packages with WindowsAzure prefix, which causes some incompatibilities in .NET Core based project.
That is why .NET Core IoT based applications prefer to use packages with Microsoft.Azure prefix.
Service Fabric IoT Sample, based on .NET Core, is using the following packages:
1. Microsoft.Azure.EventHubs
2. Microsoft.Azure.ServiceBus
These packages require slightly different implementation when it comes to reading messages from IoT Hub partitions.
Following code represents how the method for creating the event hub receiver should be implemented with .NET core related packages:

The code and other changes are available on Github.


1. Explaination for event hub epochs: https://blogs.msdn.microsoft.com/gyan/2014/09/02/event-hubs-receiver-epoch/
2. Service Fabric Sample IoT solution based on .NET Framework: https://github.com/Azure-Samples/service-fabric-dotnet-iot

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