/// <summary>
/// Associates the service handler with a message router by registering
/// the necessary application message handlers.
/// </summary>
/// <param name="router">The message router.</param>
/// <param name="keyPrefix">The configuration key prefix or (null to use <b>LillTek.Datacenter.AppStore</b>).</param>
/// <param name="perfCounters">The application's performance counter set (or <c>null</c>).</param>
/// <param name="perfPrefix">The string to prefix any performance counter names (or <c>null</c>).</param>
/// <remarks>
/// <para>
/// Applications that expose performance counters will pass a non-<c>null</c> <b>perfCounters</b>
/// instance. The service handler should add any counters it implements to this set.
/// If <paramref name="perfPrefix" /> is not <c>null</c> then any counters added should prefix their
/// names with this parameter.
/// </para>
/// </remarks>
public void Start(MsgRouter router, string keyPrefix, PerfCounterSet perfCounters, string perfPrefix)
{
var config = new Config(keyPrefix != null ? keyPrefix : ConfigPrefix);
// Make sure the syncLock is set early.
this.syncLock = router.SyncRoot;
// Make sure that the LillTek.Datacenter message types have been
// registered with the LillTek.Messaging subsystem.
LillTek.Datacenter.Global.RegisterMsgTypes();
// Verify the router parameter
if (router == null)
{
throw new ArgumentNullException("router", "Router cannot be null.");
}
if (this.router != null)
{
throw new InvalidOperationException("This handler has already been started.");
}
// General initialization
mode = config.Get <AppStoreMode>("Mode", AppStoreMode.Primary);
primaryBroadcast = config.Get("PrimaryBroadcast", true);
packageScanInterval = config.Get("PackageScanInterval", TimeSpan.FromMinutes(5));
primaryPollInterval = config.Get("PrimaryPollInterval", TimeSpan.FromMinutes(15));
primaryPollTime = SysTime.Now;
onTransfer = new AsyncCallback(OnTransfer);
downloads = new Dictionary <AppRef, PendingDownload>();
forceSync = false;
cDownloads = 0;
netFail = false;
// Initialize the package folder
packageFolder = new AppPackageFolder(syncLock, config.Get("PackageFolder", "Packages"));
packageFolder.ChangeEvent += new MethodArg1Invoker(OnPackageFolderChange);
packageScanTime = SysTime.Now;
// Initialize the performance counters
startTime = DateTime.UtcNow;
perf = new Perf(perfCounters, perfPrefix);
// Crank up the background task timer.
bkTimer = new GatedTimer(new TimerCallback(OnBkTimer), null, config.Get("BkTaskInterval", TimeSpan.FromSeconds(1)));
try
{
// Initialize the router
this.router = router;
// Join the cluster, initializing this instance's state.
cluster = new ClusterMember(router, ClusterMemberSettings.LoadConfig(config.KeyPrefix + "Cluster"));
cluster["Mode"] = this.mode.ToString();
cluster.ClusterStatusUpdate += new ClusterMemberEventHandler(OnClusterStatusUpdate);
cluster.Start();
// Rather than calling cluster.JoinWait() which could take a really long
// time, I'm going to sleep for two seconds. There are three scenarios:
//
// 1. This is the first Application Store instance.
//
// 2. Other instances are running but they haven't
// organized into a cluster.
//
// 3. A cluster is already running.
//
// If #1 is the current situation, then it will take a very long time
// for JoinWait() to return because we have to go through the entire
// missed master broadcast and election periods. Since we're the only
// instance, we could have started serving content well before this.
//
// #2 won't be very common but if it is the case, the worst thing
// that will happen is that it will take a while to discover the
// primary store.
//
// If #3 is the case, then two seconds should be long enough for the
// master to send the instance a cluster update.
Thread.Sleep(2000);
// Register the message handlers via the cluster member
// so that the endpoint used will be the member's instanceEP.
cluster.AddTarget(this, AppStoreHandler.DynamicScope);
}
catch
{
if (packageFolder != null)
{
packageFolder.Dispose();
packageFolder = null;
}
if (bkTimer != null)
{
bkTimer.Dispose();
bkTimer = null;
}
router.Dispatcher.RemoveTarget(this);
if (cluster != null)
{
cluster.Stop();
cluster = null;
}
throw;
}
}