Name: Cleipnir.ResilientFunctions.PostgreSQL
Author: Thomas Stidsborg Sylvest

Cleipnir.ResilientFunctions.PostgreSQL v4.0.6 — nugetz

What it is not?
Unlike other saga frameworks Resilient Functions does not require a message-broker to operate. It is a fully self-contained solution - which operates on top of a database of choice or in-memory when testing.

dotnet add package Cleipnir.ResilientFunctions.PostgreSQL

 var store = new PostgreSqlFunctionStore(ConnStr);
 await store.Initialize();
 var functionsRegistry = new FunctionsRegistry(
   store,
   new Settings(
     unhandledExceptionHandler: e => Console.WriteLine($"Unhandled framework exception occured: '{e}'"),
     leaseLength: TimeSpan.FromSeconds(5)
   )
 );

var actionRegistration = functionsRegistry.RegisterAction(
  flowType: "OrderProcessor",
  async (Order order, Workflow workflow) => 
  { 
    var effect = workflow.Effect;  
    var transactionId = effect.Capture("TransactionId", Guid.NewGuid);    
    await _paymentProviderClient.Reserve(order.CustomerId, transactionId, order.TotalPrice);

    await effect.Capture(
      "ShipProducts",
      work: () => _logisticsClient.ShipProducts(order.CustomerId, order.ProductIds),
      ResiliencyLevel.AtMostOnce
    );

    await _paymentProviderClient.Capture(transactionId);
    await _emailClient.SendOrderConfirmation(order.CustomerId, order.ProductIds);
  }
);

var order = new Order(
  OrderId: "MK-4321",
  CustomerId: Guid.NewGuid(),
  ProductIds: new[] { Guid.NewGuid(), Guid.NewGuid() },
  TotalPrice: 123.5M
);

await actionRegistration.Invoke(order.OrderId, order);

 var rAction = functionsRegistry.RegisterAction(
  flowType: "MessageWaitingFunc",
  async (string param, Workflow workflow) => 
  {
    var messages = await workflow.Messages;
    await messages
      .OfTypes<FundsReserved, InventoryLocked>()
      .Take(2)
      .Completion();
  }
);

var store = new InMemoryFunctionStore();
var functions = new FunctionsRegistry(store, unhandledExceptionHandler: Console.WriteLine);

var rFunc = functions.RegisterFunc(
  flowType: "HelloWorld",
  inner: (string param) => param.ToUpper()
).Invoke;

var returned = await rFunc(flowInstance: "", param: "hello world");
Console.WriteLine($"Returned: '{returned}'");

public static async Task RegisterAndInvoke(IDbConnection connection, IFunctionStore store)
{
  var functions = new FunctionsRegistry(store, new Settings(UnhandledExceptionHandler: Console.WriteLine));
  var httpClient = new HttpClient();

  var rAction = functions.RegisterAction(
    flowType: "HttpAndDatabaseSaga",
    inner: async (Guid id) =>
    {
      var response = await httpClient.PostAsync(URL, new StringContent(id.ToString()));
      response.EnsureSuccessStatusCode();
      var content = await response.Content.ReadAsStringAsync();
      await connection.ExecuteAsync(
        "UPDATE Entity SET State=@State WHERE Id=@Id",
        new {State = content, Id = id}
      );
    }).Invoke;

  var id = Guid.NewGuid();
  await rAction(flowInstance: id.ToString(), param: id);
}

public static class EmailSenderSaga
{
  public static async Task Start(MailAndRecipients mailAndRecipients, Workflow workflow)
  {
    var state = workflow.States.CreateOrGet<State>();  
    var (recipients, subject, content) = mailAndRecipients;

    using var client = new SmtpClient();
    await client.ConnectAsync("mail.smtpbucket.com", 8025);
        
    for (var atRecipient = state.AtRecipient; atRecipient < mailAndRecipients.Recipients.Count; atRecipient++)
    {
      var recipient = recipients[atRecipient];
      var message = new MimeMessage();
      message.To.Add(new MailboxAddress(recipient.Name, recipient.Address));
      message.From.Add(new MailboxAddress("The Travel Agency", "offers@thetravelagency.co.uk"));

      message.Subject = subject;
      message.Body = new TextPart(TextFormat.Html) { Text = content };
      await client.SendAsync(message);

      state.AtRecipient = atRecipient;
      await state.Save();
    }
  }

  public class State : FlowState
  {
    public int AtRecipient { get; set; }
  }
}

stidsborg/Cleipnir.ResilientFunctions.PostgreSQLv4.0.6

Get Started

Readme

Cleipnir.Flows

Cleipnir Resilient Functions

Getting Started

Message-based solution:

Show me more code

Hello-World

HTTP-call & database

Sending customer emails