Updates to docs for multiple stream aggregate handler workflow

docs/guide/durability/dead-letter-storage.md

@@ -82,7 +82,7 @@ app.MapDeadLettersEndpoints()
 
     ;
 ```
-<sup><a href='https://github.com/JasperFx/wolverine/blob/main/src/Http/WolverineWebApi/Program.cs#L203-L213' title='Snippet source file'>snippet source</a> | <a href='#snippet-sample_register_dead_letter_endpoints' title='Start of snippet'>anchor</a></sup>
+<sup><a href='https://github.com/JasperFx/wolverine/blob/main/src/Http/WolverineWebApi/Program.cs#L204-L214' title='Snippet source file'>snippet source</a> | <a href='#snippet-sample_register_dead_letter_endpoints' title='Start of snippet'>anchor</a></sup>
 <!-- endSnippet -->
 
 ### Using the Dead Letters REST API

docs/guide/durability/efcore/multi-tenancy.md

@@ -184,11 +184,11 @@ public class MyMessageHandler
         _factory = factory;
     }
 
-    public async Task HandleAsync(CreateItem command, string tenantId, CancellationToken cancellationToken)
+    public async Task HandleAsync(CreateItem command, TenantId tenantId, CancellationToken cancellationToken)
     {
         // Get an EF Core DbContext wrapped in a Wolverine IDbContextOutbox<ItemsDbContext>
         // for message sending wrapped in a transaction spanning the DbContext and Wolverine
-        var outbox = await _factory.CreateForTenantAsync<ItemsDbContext>(tenantId, cancellationToken);
+        var outbox = await _factory.CreateForTenantAsync<ItemsDbContext>(tenantId.Value, cancellationToken);
         var item = new Item { Name = command.Name, Id = CombGuidIdGeneration.NewGuid() };
 
         outbox.DbContext.Items.Add(item);

docs/guide/durability/marten/event-sourcing.md

@@ -529,7 +529,7 @@ public class MarkItemReady
 ```
 <sup><a href='https://github.com/JasperFx/wolverine/blob/main/src/Persistence/OrderEventSourcingSample/Alternatives/Signatures.cs#L9-L20' title='Snippet source file'>snippet source</a> | <a href='#snippet-sample_markitemready_with_explicit_identity' title='Start of snippet'>anchor</a></sup>
 <!-- endSnippet -->
-~~~~
+
 ## Validation <Badge type="tip" text="4.8" />
 
 Every possible attribute for triggering the "aggregate handler workflow" includes support for data requirements as
@@ -553,7 +553,7 @@ public static string GetLetter2([ReadAggregate(Required = false)] LetterAggregat
 [WolverineGet("/letters3/{id}")]
 public static LetterAggregate GetLetter3([ReadAggregate(OnMissing = OnMissing.ProblemDetailsWith404)] LetterAggregate letters) => letters;
 ```
-<sup><a href='https://github.com/JasperFx/wolverine/blob/main/src/Http/Wolverine.Http.Tests/Marten/reacting_to_read_aggregate.cs#L116-L135' title='Snippet source file'>snippet source</a> | <a href='#snippet-sample_read_aggregate_fine_grained_validation_control' title='Start of snippet'>anchor</a></sup>
+<sup><a href='https://github.com/JasperFx/wolverine/blob/main/src/Http/Wolverine.Http.Tests/Marten/reacting_to_read_aggregate.cs#L144-L163' title='Snippet source file'>snippet source</a> | <a href='#snippet-sample_read_aggregate_fine_grained_validation_control' title='Start of snippet'>anchor</a></sup>
 <!-- endSnippet -->
 
 ## Forwarding Events
@@ -720,6 +720,7 @@ public static class FindLettersHandler
         return new LetterAggregateEnvelope(aggregate);
     }
 
+    /* ALTERNATIVE VERSION
     [WolverineHandler]
     public static LetterAggregateEnvelope Handle2(
         FindAggregate command, 
@@ -729,9 +730,10 @@ public static class FindLettersHandler
     {
         return aggregate == null ? null : new LetterAggregateEnvelope(aggregate);
     }
+    */
 }
 ```
-<sup><a href='https://github.com/JasperFx/wolverine/blob/main/src/Persistence/MartenTests/read_aggregate_attribute_usage.cs#L81-L104' title='Snippet source file'>snippet source</a> | <a href='#snippet-sample_using_readaggregate_in_messsage_handlers' title='Start of snippet'>anchor</a></sup>
+<sup><a href='https://github.com/JasperFx/wolverine/blob/main/src/Persistence/MartenTests/read_aggregate_attribute_usage.cs#L81-L106' title='Snippet source file'>snippet source</a> | <a href='#snippet-sample_using_readaggregate_in_messsage_handlers' title='Start of snippet'>anchor</a></sup>
 <!-- endSnippet -->
 
 If the aggregate doesn't exist, the HTTP request will stop with a 404 status code.
@@ -762,9 +764,128 @@ public static string GetLetter2([ReadAggregate(Required = false)] LetterAggregat
 [WolverineGet("/letters3/{id}")]
 public static LetterAggregate GetLetter3([ReadAggregate(OnMissing = OnMissing.ProblemDetailsWith404)] LetterAggregate letters) => letters;
 ```
-<sup><a href='https://github.com/JasperFx/wolverine/blob/main/src/Http/Wolverine.Http.Tests/Marten/reacting_to_read_aggregate.cs#L116-L135' title='Snippet source file'>snippet source</a> | <a href='#snippet-sample_read_aggregate_fine_grained_validation_control' title='Start of snippet'>anchor</a></sup>
+<sup><a href='https://github.com/JasperFx/wolverine/blob/main/src/Http/Wolverine.Http.Tests/Marten/reacting_to_read_aggregate.cs#L144-L163' title='Snippet source file'>snippet source</a> | <a href='#snippet-sample_read_aggregate_fine_grained_validation_control' title='Start of snippet'>anchor</a></sup>
 <!-- endSnippet -->
 
 There is also an option with `OnMissing` to throw a `RequiredDataMissingException` exception if a required data element
 is missing. This option is probably most useful with message handlers where you may want to key off the exception with custom
 error handling rules.
+
+## Targeting Multiple Streams at Once <Badge type="tip" text="4.9.0" />
+
+It's now possible to use the "aggregate handler workflow" while needing to append events to more
+than one event stream at a time.
+
+::: tip
+You can use read only views of event streams through `[ReadAggregate]` at will, and that will use
+Marten's `FetchLatest()` API underneath. For appending to multiple streams though, for now you will 
+have to directly target `IEventStream<T>` to help Marten know which stream you're appending events to.
+:::
+
+Using the canonical example of a use case where you move money from one account to another account and need both
+changes to be persisted in one atomic transaction. Let’s start with a simplified domain model of
+events and a “self-aggregating” Account type like this:
+
+<!-- snippet: sample_account_domain_code -->
+<a id='snippet-sample_account_domain_code'></a>
+```cs
+public record AccountCreated(double InitialAmount);
+public record Debited(double Amount);
+public record Withdrawn(double Amount);
+
+public class Account
+{
+    public Guid Id { get; set; }
+    public double Amount { get; set; }
+
+    public static Account Create(IEvent<AccountCreated> e)
+        => new Account { Id = e.StreamId, Amount = e.Data.InitialAmount};
+
+    public void Apply(Debited e) => Amount += e.Amount;
+    public void Apply(Withdrawn e) => Amount -= e.Amount;
+}
+```
+<sup><a href='https://github.com/JasperFx/wolverine/blob/main/src/Http/WolverineWebApi/Accounts/AccountCode.cs#L9-L27' title='Snippet source file'>snippet source</a> | <a href='#snippet-sample_account_domain_code' title='Start of snippet'>anchor</a></sup>
+<!-- endSnippet -->
+
+And you need to handle a command like this:
+
+<!-- snippet: sample_TransferMoney_command -->
+<a id='snippet-sample_transfermoney_command'></a>
+```cs
+public record TransferMoney(Guid FromId, Guid ToId, double Amount);
+```
+<sup><a href='https://github.com/JasperFx/wolverine/blob/main/src/Http/WolverineWebApi/Accounts/AccountCode.cs#L29-L33' title='Snippet source file'>snippet source</a> | <a href='#snippet-sample_transfermoney_command' title='Start of snippet'>anchor</a></sup>
+<!-- endSnippet -->
+
+Using the `[WriteAggregate]` attribute to denote the event streams we need to work with,
+we could write this message handler + HTTP endpoint:
+
+<!-- snippet: sample_TransferMoneyEndpoint -->
+<a id='snippet-sample_transfermoneyendpoint'></a>
+```cs
+public static class TransferMoneyHandler    
+{
+    [WolverinePost("/accounts/transfer")]
+    public static void Handle(
+        TransferMoney command,
+
+        [WriteAggregate(nameof(TransferMoney.FromId))] IEventStream<Account> fromAccount,
+
+        [WriteAggregate(nameof(TransferMoney.ToId))] IEventStream<Account> toAccount)
+    {
+        // Would already 404 if either referenced account does not exist
+        if (fromAccount.Aggregate.Amount >= command.Amount)
+        {
+            fromAccount.AppendOne(new Withdrawn(command.Amount));
+            toAccount.AppendOne(new Debited(command.Amount));
+        }
+    }
+}
+```
+<sup><a href='https://github.com/JasperFx/wolverine/blob/main/src/Http/WolverineWebApi/Accounts/AccountCode.cs#L35-L56' title='Snippet source file'>snippet source</a> | <a href='#snippet-sample_transfermoneyendpoint' title='Start of snippet'>anchor</a></sup>
+<!-- endSnippet -->
+
+The `IEventStream<T>` abstraction comes from Marten’s `FetchForWriting()` API that is our
+recommended way to interact with Marten streams in typical command handlers. This
+API is used underneath Wolverine’s “aggregate handler workflow”, but normally hidden
+from user written code if you’re only working with one stream at a time. In this case
+though, we’ll need to work with the raw `IEventStream<T>` objects that both wrap the
+projected aggregation of each Account as well as providing a point where we can explicitly
+append events separately to each event stream. `FetchForWriting()` guarantees that you get
+the most up to date information for the Account view of each event stream regardless of
+how you have configured Marten’s `ProjectionLifecycle` for `Account` (kind of an important
+detail here!).
+
+The typical Marten transactional middleware within Wolverine is calling `SaveChangesAsync()`
+for us on the Marten unit of work IDocumentSession for the command. If there’s enough funds in
+the “From” account, this command will append a `Withdrawn` event to the “From” account and
+a `Debited` event to the “To” account. If either account has been written to between
+fetching the original information, Marten will reject the changes and throw its
+`ConcurrencyException` as an optimistic concurrency check.
+
+In unit testing, we could write a unit test for the “happy path” where you have enough funds to cover the transfer like this:
+
+<!-- snippet: sample_when_transfering_money -->
+<a id='snippet-sample_when_transfering_money'></a>
+```cs
+public class when_transfering_money
+{
+    [Fact]
+    public void happy_path_have_enough_funds()
+    {
+        // StubEventStream<T> is a type that was recently added to Marten
+        // specifically to facilitate testing logic like this
+        var fromAccount = new StubEventStream<Account>(new Account { Amount = 1000 }){Id = Guid.NewGuid()};
+        var toAccount = new StubEventStream<Account>(new Account { Amount = 100}){Id = Guid.NewGuid()});
+
+        TransferMoneyHandler.Handle(new TransferMoney(fromAccount.Id, toAccount.Id, 100), fromAccount, toAccount);
+
+        // Now check the events we expected to be appended
+        fromAccount.Events.Single().ShouldBeOfType<Withdrawn>().Amount.ShouldBe(100);
+        toAccount.Events.Single().ShouldBeOfType<Debited>().Amount.ShouldBe(100);
+    }
+}
+```
+<sup><a href='https://github.com/JasperFx/wolverine/blob/main/src/Http/Wolverine.Http.Tests/Marten/working_against_multiple_streams.cs#L89-L109' title='Snippet source file'>snippet source</a> | <a href='#snippet-sample_when_transfering_money' title='Start of snippet'>anchor</a></sup>
+<!-- endSnippet -->

docs/guide/durability/postgresql.md

@@ -195,8 +195,8 @@ public class OurFancyPostgreSQLMultiTenancy : IWolverineExtension
             .RegisterStaticTenantsByDataSource(tenants =>
             {
                 tenants.Register("tenant1", _provider.GetRequiredKeyedService<NpgsqlDataSource>("tenant1"));
-                tenants.Register("tenant1", _provider.GetRequiredKeyedService<NpgsqlDataSource>("tenant2"));
-                tenants.Register("tenant1", _provider.GetRequiredKeyedService<NpgsqlDataSource>("tenant3"));
+                tenants.Register("tenant2", _provider.GetRequiredKeyedService<NpgsqlDataSource>("tenant2"));
+                tenants.Register("tenant3", _provider.GetRequiredKeyedService<NpgsqlDataSource>("tenant3"));
             });
     }
 }

docs/guide/extensions.md

@@ -242,7 +242,7 @@ var app = builder.Build();
 // you will need to explicitly call this *before* MapWolverineEndpoints()
 await app.Services.ApplyAsyncWolverineExtensions();
 ```
-<sup><a href='https://github.com/JasperFx/wolverine/blob/main/src/Http/WolverineWebApi/Program.cs#L165-L173' title='Snippet source file'>snippet source</a> | <a href='#snippet-sample_calling_applyasyncwolverineextensions' title='Start of snippet'>anchor</a></sup>
+<sup><a href='https://github.com/JasperFx/wolverine/blob/main/src/Http/WolverineWebApi/Program.cs#L166-L174' title='Snippet source file'>snippet source</a> | <a href='#snippet-sample_calling_applyasyncwolverineextensions' title='Start of snippet'>anchor</a></sup>
 <!-- endSnippet -->
 
 ## Wolverine Plugin Modules

docs/guide/handlers/index.md

@@ -416,6 +416,13 @@ public static class ShipOrderHandler
 <sup><a href='https://github.com/JasperFx/wolverine/blob/main/src/Samples/DocumentationSamples/CompoundHandlerSamples.cs#L28-L58' title='Snippet source file'>snippet source</a> | <a href='#snippet-sample_shiporderhandler' title='Start of snippet'>anchor</a></sup>
 <!-- endSnippet -->
 
+::: warning
+You may need to use separate handlers for separate messages if you are wanting to use `Before/After/Validate/Load` methods that
+target a specific message type. Wolverine is not (yet) smart enough to filter out the application of the implied middleware by
+message type and may throw exceptions on code compilation in some cases. Again, the easy work around is to just use separate message
+handler types for different message types in this case.
+:::
+
 The naming conventions for what Wolverine will consider to be either a "before" or "after" method is shown below:
 
 Here's the conventions:

docs/guide/http/endpoints.md

@@ -145,7 +145,7 @@ public static class TodoCreationEndpoint
     }
 }
 ```
-<sup><a href='https://github.com/JasperFx/wolverine/blob/main/src/Http/WolverineWebApi/Samples/TodoController.cs#L80-L112' title='Snippet source file'>snippet source</a> | <a href='#snippet-sample_using_wolverine_endpoint_for_create_todo' title='Start of snippet'>anchor</a></sup>
+<sup><a href='https://github.com/JasperFx/wolverine/blob/main/src/Http/WolverineWebApi/Samples/TodoController.cs#L83-L115' title='Snippet source file'>snippet source</a> | <a href='#snippet-sample_using_wolverine_endpoint_for_create_todo' title='Start of snippet'>anchor</a></sup>
 <!-- endSnippet -->
 
 In the case above, `TodoCreationResponse` is the first item in the tuple, so Wolverine treats that as 
@@ -319,7 +319,7 @@ and register that strategy within our `MapWolverineEndpoints()` set up like so:
 // Customizing parameter handling
 opts.AddParameterHandlingStrategy<NowParameterStrategy>();
 ```
-<sup><a href='https://github.com/JasperFx/wolverine/blob/main/src/Http/WolverineWebApi/Program.cs#L265-L270' title='Snippet source file'>snippet source</a> | <a href='#snippet-sample_adding_custom_parameter_handling' title='Start of snippet'>anchor</a></sup>
+<sup><a href='https://github.com/JasperFx/wolverine/blob/main/src/Http/WolverineWebApi/Program.cs#L270-L275' title='Snippet source file'>snippet source</a> | <a href='#snippet-sample_adding_custom_parameter_handling' title='Start of snippet'>anchor</a></sup>
 <!-- endSnippet -->
 
 And lastly, here's the application within an HTTP endpoint for extra context:
@@ -352,7 +352,59 @@ To make a single class and method be both a message handler and HTTP endpoint, j
 with the route directly on your message handler. As long as that method follows Wolverine's normal naming rules for message
 discovery, Wolverine will treat it as both a message handler and as an HTTP endpoint. Here's an example from our tests:
 
-snippet: sample_using_problem_details_in_message_handler
+<!-- snippet: sample_using_problem_details_in_message_handler -->
+<a id='snippet-sample_using_problem_details_in_message_handler'></a>
+```cs
+public static class NumberMessageHandler
+{
+    public static ProblemDetails Validate(NumberMessage message)
+    {
+        if (message.Number > 5)
+        {
+            return new ProblemDetails
+            {
+                Detail = "Number is bigger than 5",
+                Status = 400
+            };
+        }
+
+        // All good, keep on going!
+        return WolverineContinue.NoProblems;
+    }
+
+    // This "Before" method would only be utilized as
+    // an HTTP endpoint
+    [WolverineBefore(MiddlewareScoping.HttpEndpoints)]
+    public static void BeforeButOnlyOnHttp(HttpContext context)
+    {
+        Debug.WriteLine("Got an HTTP request for " + context.TraceIdentifier);
+        CalledBeforeOnlyOnHttpEndpoints = true;
+    }
+
+    // This "Before" method would only be utilized as
+    // a message handler
+    [WolverineBefore(MiddlewareScoping.MessageHandlers)]
+    public static void BeforeButOnlyOnMessageHandlers()
+    {
+        CalledBeforeOnlyOnMessageHandlers = true;
+    }
+
+    // Look at this! You can use this as an HTTP endpoint too!
+    [WolverinePost("/problems2")]
+    public static void Handle(NumberMessage message)
+    {
+        Debug.WriteLine("Handled " + message);
+        Handled = true;
+    }
+
+    // These properties are just a cheap trick in Wolverine internal tests
+    public static bool Handled { get; set; }
+    public static bool CalledBeforeOnlyOnMessageHandlers { get; set; }
+    public static bool CalledBeforeOnlyOnHttpEndpoints { get; set; }
+}
+```
+<sup><a href='https://github.com/JasperFx/wolverine/blob/main/src/Http/WolverineWebApi/ProblemDetailsUsage.cs#L38-L88' title='Snippet source file'>snippet source</a> | <a href='#snippet-sample_using_problem_details_in_message_handler' title='Start of snippet'>anchor</a></sup>
+<!-- endSnippet -->
 
 If you are using Wolverine.HTTP in your application, Wolverine is able to treat `ProblemDetails` similar to the built in
 `HandlerContinuation` when running inside of message handlers.

docs/guide/http/fluentvalidation.md

@@ -44,5 +44,5 @@ app.MapWolverineEndpoints(opts =>
     // Wolverine.Http.FluentValidation
     opts.UseFluentValidationProblemDetailMiddleware();
 ```
-<sup><a href='https://github.com/JasperFx/wolverine/blob/main/src/Http/WolverineWebApi/Program.cs#L215-L236' title='Snippet source file'>snippet source</a> | <a href='#snippet-sample_using_configure_endpoints' title='Start of snippet'>anchor</a></sup>
+<sup><a href='https://github.com/JasperFx/wolverine/blob/main/src/Http/WolverineWebApi/Program.cs#L216-L237' title='Snippet source file'>snippet source</a> | <a href='#snippet-sample_using_configure_endpoints' title='Start of snippet'>anchor</a></sup>
 <!-- endSnippet -->