Merq.DependencyInjection 2.0.0-rc.2

var builder = WebApplication.CreateBuilder(args);
...
// Automatically add the message bus and all command handlers and 
// event producers in the current project and any dependencies
// The enableAutoMapping parameter enables duck typing for events and commands
// across assemblies
builder.Services.AddMessageBus(enableAutoMapping: false);

The AddMessageBus extension method leverages compile-time code generation to avoid negatively impacting run-time app startup, via the dependency on Devlooped.Extensions.DependencyInjection.Attributed. This also ensures that all proper service interfaces are registered for the various components.

Telemetry and Monitoring

The core implementation of the IMessageBus is instrumented with ActivitySource and Metric, providing out of the box support for Open Telemetry-based monitoring, as well as via dotnet trace and dotnet counters.

To export telemetry using Open Telemetry, for example:

using var tracer = Sdk
    .CreateTracerProviderBuilder()
    .SetResourceBuilder(ResourceBuilder.CreateDefault().AddService("ConsoleApp"))
    .AddSource(source.Name)
    .AddSource("Merq.Core")
    .AddSource("Merq.AutoMapper")
    .AddConsoleExporter()
    .AddZipkinExporter()
    .AddAzureMonitorTraceExporter(o => o.ConnectionString = config["AppInsights"])
    .Build();

Collecting traces via dotnet-trace:

dotnet trace collect --name [PROCESS_NAME] --providers="Microsoft-Diagnostics-DiagnosticSource:::FilterAndPayloadSpecs=[AS]Merq,System.Diagnostics.Metrics:::Metrics=Merq"

Monitoring metrics via dotnet-counters:

dotnet counters monitor --process-id [PROCESS_ID] --counters Merq

Duck Typing Support

Being able to loosely couple both events (and their consumers) and command execution (from their command handler implementations) is a key feature of Merq. To take this decoupling to the extreme, Merq allows a similar capability as allowed by the TypeScript/JavaScript in VSCode: you can just copy/paste an event/command definition as source into your assembly, and perform the regular operations with it (like Observe an event and Execute a command), in a "duck typing" manner.

As long as the types' full name match, the conversion will happen automatically. Since this functionality isn't required in many scenarios, and since there are a myriad ways to implement such an object mapping functionality, the Merq.Core package only provides the hooks to enable this, but does not provide any built-in implementation for it.

The Merq.AutoMapper package provides one such implementation, based on the excelent AutoMapper library.

Dogfooding

We also produce CI packages from branches and pull requests so you can dogfood builds as quickly as they are produced.

The CI feed is https://pkg.kzu.io/index.json.

The versioning scheme for packages is:

• PR builds: 42.42.42-pr[NUMBER]
• Branch builds: 42.42.42-[BRANCH].[COMMITS]

Sponsors

Learn more about GitHub Sponsors

For usage and authoring of commands and events, see Merq readme.

Sponsors

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