/// <summary>
/// Initializes a new instance of <see cref="KafkaBusHost{TContext}"/>
/// </summary>
/// <param name="subscriber">The KafkaBus Subscriber</param>
/// <param name="application">The HttpApplication</param>
internal KafkaBusHost(IKafkaBusSubscriber subscriber, IHttpApplication <TContext> application, IApplicationLifetime applicationLifetime, ILoggerFactory logFactory)
{
this.subscriber = subscriber;
this.application = application;
this.applicationLifetime = applicationLifetime;
this.logger = logFactory.CreateLogger <KafkaBusHost <TContext> >();
}
/// <summary>
/// Starts running a new KafkaBus host.
/// </summary>
/// <param name="app">The Application builder</param>
/// <param name="subscriber">The KafkaBus subscriber</param>
/// <param name="skipKafkaBusServerCheck">Set to true to run the host even if the application server is the KafkaBus.AspNet server</param>
public static void RunKafkaBusHost(this IApplicationBuilder app, IKafkaBusSubscriber subscriber, bool skipKafkaBusServerCheck)
{
if (app == null)
{
throw new ArgumentNullException("app");
}
if (subscriber == null)
{
throw new ArgumentNullException("subscriber");
}
if (!skipKafkaBusServerCheck && Server.InstanceCount > 0)
{
//The application is running KafkaBusServer, so exit
return;
}
var appFunc = app.Build();
var _loggerFactory = app.ApplicationServices.GetRequiredService <ILoggerFactory>();
var diagnosticSource = app.ApplicationServices.GetRequiredService <DiagnosticSource>();
var httpContextFactory = app.ApplicationServices.GetRequiredService <IHttpContextFactory>();
//TODO: Work on counting instances (all hosts + server) and adding the count to the logger name e.g KafkaBus.AspNet (2), consider including the typename as well.
var application = new HostingApplication(appFunc, _loggerFactory.CreateLogger(typeof(Server).FullName), diagnosticSource, httpContextFactory);
var server = app.ApplicationServices.GetRequiredService <Server>();
server.Start(application, subscriber);
}
/// <summary>
/// Configures the KafkaBus server to use a specified subscriber
/// </summary>
/// <param name="app">The Application builder</param>
/// <param name="subscriber">The KafkaBus subscriber</param>
public static void ConfigureKafkaBusServer(this IApplicationBuilder app, IKafkaBusSubscriber subscriber)
{
if (app == null)
{
throw new ArgumentNullException("app");
}
if (subscriber == null)
{
throw new ArgumentNullException("subscriber");
}
var feature = app.ServerFeatures.Get <IServerInformation>();
if (feature == null)
{
return; //Application isn't running KafkaBus server so return
}
var serverInfo = feature as ServerInformation;
if (serverInfo != null)
{
serverInfo.Subscriber = subscriber;
}
}
//TODO: See if it's possible to prevent middleware from being added after RunKafkaBusHost() is called, subsequent calls to RunKafkaBusHost must succeed.
/// <summary>
/// Starts running a new KafkaBus host.
/// </summary>
/// <param name="app">The Application builder</param>
/// <param name="subscriber">The KafkaBus subscriber</param>
/// <remarks>The KafkaBus host will not be started if the application is running a KafkaBus server.</remarks>
public static void RunKafkaBusHost(this IApplicationBuilder app, IKafkaBusSubscriber subscriber)
{
RunKafkaBusHost(app, subscriber, false);
}
public void Start <TContext>(IHttpApplication <TContext> application, IKafkaBusSubscriber subscriber)
{
//TODO: Code a better way to prevent same server from starting twice.
if (_disposables != null)
{
// The server has already started and/or has not been cleaned up yet
throw new InvalidOperationException("Server has already started.");
}
_disposables = new Stack <IDisposable>();
try {
var information = this.Features.Get <IServerInformation>();
if (information?.Subscriber == null)
{
if (subscriber != null)
{
information = new ServerInformation()
{
Subscriber = subscriber
};
//information.Subscriber = subscriber;
}
else
{
throw new InvalidOperationException($"KafkaBus subscriber could not be found. To use the KafkaBus server, call app.{nameof(ServerExtensions.ConfigureKafkaBusServer)} in Startup.Configure method and specify a subscriber to use.");
}
}
else
{
subscriber = information.Subscriber;
}
//TODO: Add _logger properly
this._logger.LogInformation($"{nameof(Server)} is starting the KafkaBus host.");
var host = new KafkaBusHost <TContext>(subscriber, application, this._applicationLifetime, this._logFactory);
//Register host for disposal
//TODO: Make IApplicationLifeTime.Stopping to stop polling the queue.
this._applicationLifetime.ApplicationStopping.Register(() => {
//TODO: Make ApplicationStopping event stop dequeueing items (StopPollingQueue)
host.Dispose();
});
this._applicationLifetime.ApplicationStopped.Register(() => host.Dispose());
_disposables.Push(host);
host.Start();
foreach (var name in subscriber.ConnectionNames)
{
information.AddAddress(name);
}
}
catch (Exception ex) {
this._logger.LogError(ex.Message + Environment.NewLine + ex.StackTrace);
Dispose();
throw;
}
}