Add simple description and getting started instructions to README

Author: christianhelle

README.md

@@ -3,7 +3,155 @@
 
 # ATC Azure Messaging
 
-A component library for publishing messages on Azure Event Hubs and Service Bus.
+A .NET component library for publishing messages on Azure Event Hubs and Service Bus. This targets .NET Standard 2.1 and depends on [ATC Azure Options](https://github.com/atc-net/atc-azure-options).
+
+# Getting Started
+
+The first thing you need to do to make sure that your configuration is setup correctly. For the sake of simplicity, let's use the `appsettings.json` file created with every .NET project
+
+The following is an example of how your would configure your EventHub or ServiceBus for [ATC Azure Options](https://github.com/atc-net/atc-azure-options)
+
+```json
+{  
+  "EventHubOptions": {
+    "ConnectionString": "Endpoint=sb://[your eventhub namespace].servicebus.windows.net/;SharedAccessKeyName=[eventhub name];SharedAccessKey=[sas key]"    
+  },
+  "ServiceBusOptions": {
+    "ConnectionString": "Endpoint=sb://[your servicebus namespace].servicebus.windows.net/;SharedAccessKeyName=[topic|queue name];SharedAccessKey=[sas key]"
+  }
+}
+```
+
+When binding to KeyVault this should of course be `EventHubOptions--ConnectionString` for EventHub or `ServiceBusOptions--ConnectionString` for ServiceBus
+
+The next step is to register the dependencies required to use this component library. For this you can use the `IServiceCollection` extension method `ConfigureMessagingServices(IConfiguration)`. This piggy backs over the `Microsoft.Extensions.DependencyInjection` namespace so that you don't need to include anything extra using statements
+
+Here's an example of how to do this using a Minimal API setup
+
+```csharp
+var builder = WebApplication.CreateBuilder(args);
+builder.Services.AddEndpointsApiExplorer();
+builder.Services.AddSwaggerGen();
+
+// Register Atc.Azure.Messaging dependencies
+builder.Services.ConfigureMessagingServices(builder.Configuration);
+```
+
+## Publishing to EventHub
+
+To publish events to an EventHub you need an instance of `IEventHubPublisher`, this can be constructed via the `IEventHubPublisherFactory` which exposes the `Create(string eventHubName)` method
+
+```csharp
+internal class FooPublisher 
+{
+    private readonly IEventHubPublisher publisher;
+
+    public FooPublisher(IEventHubPublisherFactory factory)
+    {
+        publisher = factory.Create([existing eventhub name]);
+    }
+
+    public Task Publish(object message)
+        => publisher
+            .PublishAsync(
+                bar,
+                new Dictionary<string, string> 
+                {
+                    {"messageType", nameof(message)}
+                }
+            )
+}
+```
+
+## Publishing to ServiceBus
+
+To publish events to a ServiceBus topic or queue you need an instance of `IServiceBusPublisher`
+
+```csharp
+internal class BarPublisher 
+{
+    private readonly IServiceBusPublisher publisher;
+
+    public BarPublisher(IServiceBusPublisher publisher)
+    {
+        this.publisher = publisher;
+    }
+
+    public Task Publish(object message)
+        => publisher
+            .PublishAsync(
+                "[existing servicebus topic]",
+                "[session id or nothing]",
+                JsonSerializer.Serialize(message));
+}
+```
+
+Here's a full example of how to use the publishers above using a Minimal API setup (SwaggerUI enabled) with a single endpoint called `POST /data` that accepts a simple request body `{ "a": "string", "b": "string", "c": "string" }` which publishes the request to an EventHub and a ServiceBus topic
+
+```csharp
+var builder = WebApplication.CreateBuilder(args);
+builder.Services.AddEndpointsApiExplorer();
+builder.Services.AddSwaggerGen();
+builder.Services.AddSingleton<SendDataHandler>();
+
+// Register Atc.Azure.Messaging dependencies
+builder.Services.ConfigureMessagingServices(builder.Configuration);
+
+var app = builder.Build();
+app.UseHttpsRedirection();
+if (app.Environment.IsDevelopment())
+{
+    app.UseSwagger();
+    app.UseSwaggerUI();
+}
+
+app.MapPost(
+    "/data",
+    (Request request, SendDataHandler handler) => handler.Post(request));
+
+app.Run();
+
+internal class SendDataHandler
+{
+    private readonly IEventHubPublisher eventHubPublisher;
+    private readonly IServiceBusPublisher serviceBusPublisher;
+
+    public SendDataHandler(
+        IEventHubPublisherFactory eventHubFactory,
+        IServiceBusPublisher serviceBusPublisher)
+    {
+        eventHubPublisher = eventHubFactory.Create("[existing eventhub]");
+        this.serviceBusPublisher = serviceBusPublisher;
+    }
+
+    public async Task<Response> Post(Request request)
+    {
+        await eventHubPublisher
+            .PublishAsync(
+                request,
+                new Dictionary<string, string>(StringComparer.Ordinal)
+                {
+                    { "MessageType", "example" },
+                });
+
+        await serviceBusPublisher
+            .PublishAsync(
+                "[existing topic|queue",
+                "[session id or nothing]",
+                System.Text.Json.JsonSerializer.Serialize(request));
+
+        return new Response(
+            Guid.NewGuid().ToString("N"),
+            request.A,
+            request.B,
+            request.C);
+    }
+}
+
+internal record Request(string A, string B, string C);
+
+internal record Response(string Id, string A, string B, string C);
+```
 
 
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