/// <summary>
/// Runs the broker process.
/// </summary>
/// <param name="node">This nodes information</param>
/// <param name="maxconnections">The maximum number of connections to allow</param>
/// <returns>An awaitable task.</returns>
public static Task RunAsync(PeerInfo node, int maxconnections = 50)
{
// The primary table for finding peers
var peers = new Dictionary <EndPoint, Tuple <Task, IWriteChannel <ConnectionRequest> > >();
// The peers listed by key
var peersbykey = new Dictionary <Key, EndPoint>();
// The MRU cache of peers
var mrucache = new MRUCache <EndPoint, Key>(maxconnections, TimeSpan.FromDays(10));
return(AutomationExtensions.RunTask(
new
{
Request = Channels.ConnectionBrokerRequests.ForRead,
Registrations = Channels.ConnectionBrokerRegistrations.ForRead,
Stats = Channels.ConnectionBrokerStats.ForRead,
SelfHandler = Channels.RemoteRequests.ForWrite,
Routing = Channels.RoutingTableRequests.ForWrite
},
async self =>
{
log.Debug($"Broker is now running");
while (true)
{
log.Debug($"Broker is waiting for requests ...");
var mreq = await MultiChannelAccess.ReadFromAnyAsync(
self.Stats.RequestRead(),
self.Registrations.RequestRead(),
self.Request.RequestRead()
);
if (mreq.Channel == self.Stats)
{
log.Debug($"Broker got stat request");
var req = (IWriteChannel <ConnectionStatsResponse>)mreq.Value;
await req.WriteAsync(new ConnectionStatsResponse()
{
EndPoints = peers.Count,
Keys = peersbykey.Count,
Stats = (Channels.ConnectionBrokerRequests.Get() as ProfilingChannel <ConnectionRequest>)?.ReportStats()
});
}
else if (mreq.Channel == self.Registrations)
{
var req = (ConnectionRegistrationRequest)mreq.Value;
log.Debug($"Broker got {(req.IsTerminate ? "termination" : "registration")} request");
if (req.IsTerminate)
{
// Make sure we do not have stale stuff in the MRU cache
if (req.Peer != null && req.Peer.Address != null)
{
mrucache.Remove(req.Peer.Address);
}
if (req.Peer.Address != null && peers.TryGetValue(req.Peer.Address, out var c) && c.Item2 == req.Channel)
{
peers.Remove(req.Peer.Address);
if (req.Peer.Key != null)
{
peersbykey.Remove(req.Peer.Key);
}
}
if (req.UpdateRouting)
{
log.Debug($"Removing peer in routing table due to termination of connection {req.Peer.Key} - {req.Peer.Address}");
await self.Routing.RemovePeerAsync(req.Peer.Key);
}
}
else
{
if (req.Peer.Address != null && peers.TryGetValue(req.Peer.Address, out var c) && (c.Item2 == req.Channel || c == null))
{
if (c == null)
{
peers[req.Peer.Address] = new Tuple <Task, IWriteChannel <ConnectionRequest> >(null, req.Channel);
}
if (!peersbykey.ContainsKey(req.Peer.Key))
{
peersbykey[req.Peer.Key] = req.Peer.Address;
}
}
if (req.UpdateRouting)
{
log.Debug($"Adding new peer to routing table {req.Peer.Key} - {req.Peer.Address}");
await self.Routing.AddPeerAsync(req.Peer.Key, req.Peer);
}
}
}
else
{
var req = (ConnectionRequest)mreq.Value;
log.Debug($"Broker got connection request for {req.EndPoint}");
// Check if we request ourselves
if (node.Key.Equals(req.Key) || node.Address.Equals(req.EndPoint))
{
log.Debug($"Broker got self-request, forwarding to owner");
await self.SelfHandler.WriteAsync(req);
continue;
}
Tuple <Task, IWriteChannel <ConnectionRequest> > peer = null;
try
{
// Existing connection, update MRU
var overflow = mrucache.Add(req.EndPoint, req.Key);
// If we have too many connections, kill one now
if (overflow != null)
{
// We could make this also take the closest k peers into account
log.Debug($"Broker has too many connections, closing {req.EndPoint}");
await peers[overflow].Item2.RetireAsync();
}
if (!peers.TryGetValue(req.EndPoint, out peer))
{
log.Debug($"Broker is starting a connection to {req.EndPoint}");
mrucache.Add(req.EndPoint, req.Key);
peer = peers[req.EndPoint] =
PeerConnection.CreatePeer(
node,
new PeerInfo(req.Key, req.EndPoint),
() => ConnectToPeerAsync(req.EndPoint),
REQ_BUFFER_SIZE
);
if (req.Key != null)
{
peersbykey[req.Key] = req.EndPoint;
}
}
await peer.Item2.WriteAsync(req);
}
catch (Exception ex)
{
log.Warn("Failed to send request to peer", ex);
try { await req.Response.WriteAsync(new ConnectionResponse()
{
Exception = ex
}); }
catch (Exception ex2) { log.Warn("Failed to write failure response", ex2); }
if (peer != null)
{
try { peer.Item2.AsWriteOnly().Dispose(); }
catch (Exception ex2) { log.Warn("Failed to terminate write channel", ex2); }
try { await peer.Item1; }
catch (Exception ex2) { log.Warn("Peer connection stopped with error", ex2); }
}
peers.Remove(req.EndPoint);
}
}
}
}
));
}
/// <summary>
/// Runs the MRU cache
/// </summary>
/// <returns>An awaitable task.</returns>
/// <param name="selfinfo">This peer's information</param>
/// <param name="storesize">The size of the MRU store</param>
/// <param name="maxage">The maximum amount of time items are stored</param>
/// <param name="buffersize">The size of the parallel processing buffer</param>
private static Task RunMRUAsync(PeerInfo selfinfo, int storesize, TimeSpan maxage, int buffersize)
{
var storechan = Channel.Create <MRUInternalStore>();
return(AutomationExtensions.RunTask(new
{
Request = Channels.MRURequests.ForRead,
Routing = Channels.RoutingTableRequests.ForWrite,
Stats = Channels.MRUStats.ForRead,
Store = storechan.AsRead()
},
async self =>
{
var cache = new MRUCache <Key, byte[]>(storesize, maxage);
var store = new MRUCache <Key, byte[]>(int.MaxValue, maxage);
log.Debug($"Store is now running");
// Set up a shared error handler for logging and reporting errors
Func <MRURequest, Exception, Task> errorHandler = async(req, ex) =>
{
log.Warn("Failed to process request, sending error", ex);
try { await req.SendResponseAsync(ex); }
catch (Exception ex2) { log.Warn("Failed to forward error report", ex2); }
};
using (var tp = new TaskPool <MRURequest>(buffersize, errorHandler))
while (true)
{
log.Debug($"Store is waiting for requests ...");
var mreq = await MultiChannelAccess.ReadFromAnyAsync(
self.Stats.RequestRead(),
self.Store.RequestRead(),
self.Request.RequestRead()
);
if (mreq.Channel == self.Stats)
{
log.Debug($"Store got stat request");
var r = (IWriteChannel <MRUStatResponse>)mreq.Value;
await r.WriteAsync(new MRUStatResponse()
{
Items = cache.Count + store.Count,
Oldest = new DateTime(Math.Min(cache.OldestItem.Ticks, store.OldestItem.Ticks)),
Size = cache.Select(x => x.Value.Length).Sum() + store.Select(x => x.Value.Length).Sum(),
Stats = (Channels.MRURequests.Get() as ProfilingChannel <MRURequest>)?.ReportStats()
});
continue;
}
if (mreq.Channel == self.Store)
{
var sreq = (MRUInternalStore)mreq.Value;
log.Debug($"Store got internal store request");
var shouldBroadCast = sreq.Peers != null && !store.TryGetValue(sreq.Key, out _);
store.Add(sreq.Key, sreq.Data);
// We currently rely on the injector to broadcast,
// If we enable this, we need some logic to figure out
// the source of the Add, to both allow re-insertion
// and avoid repeated broadcasts if two peers determine
// they are *the* handling peer
//if (shouldBroadCast)
//await tp.Run(new MRURequest() { }, () => BroadcastValueAsync(selfinfo, sreq));
continue;
}
var req = (MRURequest)mreq.Value;
log.Debug($"Store got request {req.Operation}");
try
{
switch (req.Operation)
{
case MRUOperation.Add:
{
// Always store it in our cache
cache.Add(req.Key, req.Data);
// Process long-term if needed
await tp.Run(req, () => StoreLongTermAsync(selfinfo, self.Routing, storechan.AsWrite(), req.Key, req.Data));
// Respond that we completed
await tp.Run(req, () => req.SendResponseAsync(req.Key, null));
break;
}
case MRUOperation.Get:
{
var res = cache.TryGetValue(req.Key, out var data);
if (!res)
{
res = store.TryGetValue(req.Key, out data);
}
await tp.Run(req, () => req.SendResponseAsync(req.Key, data, res));
break;
}
case MRUOperation.Expire:
cache.ExpireOldItems();
store.ExpireOldItems();
await tp.Run(req, () => req.SendResponseAsync(null, null));
break;
default:
throw new Exception($"Unable to handle request with type {req.Operation}");
}
log.Debug($"Store completed request {req.Operation}");
}
catch (Exception ex)
{
await errorHandler(req, ex);
}
}
}));
}
