Merge pull request #20 from EventStore/subsystems

Add ISubsystemsPlugin as a way to plugably create subsystems

src/EventStore.Plugins/Subsystems/ISubsystem.cs

@@ -0,0 +1,13 @@
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace EventStore.Plugins.Subsystems;
+
+public interface ISubsystem {
+	IApplicationBuilder Configure(IApplicationBuilder builder);
+	IServiceCollection ConfigureServices(IServiceCollection services);
+	IEnumerable<Task> Start();
+	void Stop();
+}

src/EventStore.Plugins/Subsystems/ISubsystemFactory.cs

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+namespace EventStore.Plugins.Subsystems;
+
+public interface ISubsystemFactory<TArg> {
+	ISubsystem Create(TArg arg);
+}

src/EventStore.Plugins/Subsystems/ISubsystemsPlugin.cs

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+using System.Collections.Generic;
+
+namespace EventStore.Plugins.Subsystems;
+
+// A plugin that can create multiple subsystems.
+// A TArg is required to produce each subsystem from its respective factory.
+public interface ISubsystemsPlugin<TArg> {
+	string Name { get; }
+	string Version { get; }
+	string CommandLineName { get; }
+	IEnumerable<ISubsystemFactory<TArg>> GetSubsystemFactories(string configPath);
+}