Microsoft Orleans Grain Persistence using PostgreSQL

I didn’t found the documentation really clear on the steps involved when using Grain Persistence in combination with PostgreSQL.

So here is my attempt to describe the process:

• Add a reference to the following NuGet packages:
• Microsoft.Orleans.OrleansSQLUtils
• Microsoft.Orleans.Persistence.AdoNet
• Npgsql
• Update the cluster configuration to add the storage:

	.AddAdoNetGrainStorage("OrleansStorage", options =>
	{
	options.Invariant = "Npgsql";
	options.ConnectionString = "host=192.168.0.1;database=orleans;password=orleans;username=orleanssample";
	options.UseJsonFormat = true;
	})

view raw StorageConfig.cs hosted with ❤ by GitHub

• Invariant should be set to ‘npgsql’
• ConnectionString should be set to the connection to the PostgreSQL instance you want to use
• UseJsonFormat should be set to true as PostgreSQL has good Json support.
• Let your grain inherit from Grain<> and specify a state object:

	public class GrainState
	{
	public GrainState()
	{
	this.Greetings = new List<string>();
	}
	public List<string> Greetings { get; set; }
	}

view raw GrainState.cs hosted with ❤ by GitHub

	public class HelloGrain : Grain<GrainState>, IHello
	{
	public async Task<string> SayHello(string greeting)
	{
	this.State.Greetings.Add(greeting);
	await this.WriteStateAsync();
	return greeting;
	}
	}

view raw HelloGrain.cs hosted with ❤ by GitHub

• Add a StorageProvider attribute on top of your Grain and set the name to the storage name you used inside the cluster config
• In our example we had set this to ‘OrleansStorage’:

	[StorageProvider(ProviderName = "OrleansStorage")]
	public class HelloGrain : Grain<GrainState>, IHello
	{
	}

view raw StorageAttribute.cs hosted with ❤ by GitHub

• Execute the PostgreSQL-Main.sql and PostgreSQL-Persistence.sql scripts inside the OrleansAdoNetContent/PostgreSQL folder to create the necessary database objects
• Now you are good to go!