Sponsor: Using RabbitMQ or Azure Service Bus in your .NET systems? Well, you could just use their SDKs and roll your own serialization, routing, outbox, retries, and telemetry. I mean, seriously, how hard could it be?
I discovered the Orleans Smart Cache Pattern by listening to a talk by John Azariah and Sergey Bykov. The idea is that you can use Orleans as a distributed cache in front of (permanent) storage. This is really ideal if you have a read heavy system, which most are. You could optionally also choose to buffer your writes when you make state changes. Ultimately you will reduce load on your storage by accessing data/state from memory.
Blog Post Series:
- Part 1 – Practical Orleans
- Part 2 – Grains and Silos
- Part 3 – Smart Cache Pattern
- Part 4 – Event Sourced Grain
- Part 5 – EventStore for Grain Persistence
Video Tutorial
State Holder Grain
The idea is we are going to create a Grain that will be used for holding/containing our state. There are just two methods, setting and getting our state as defined inIStateHolderGrain<T>
Implementation
For this example, I’m creating a POCOCustomerState to hold some customer data.
Then create a ICustomerGrain that just extends IStateHolderGrain where T is our POCO CustomerState.
Our concrete class CustomerGrain that implements that new ICustomerGrain.
Lastly I created a CustomerStateService which just contains some static methods that create and retrieve our POCO.
Usage
As per my previous post, I’m using ASP.NET Core with Botwin Middleware for a route endpoint. From here I can use theCustomerStateService to create and fetch out our data.