/// <summary>
/// Processes NeighbourhoodChangedNotificationRequest message from LOC server.
/// <para>Adds, changes, or deletes neighbor and possibly adds new neighborhood action to the database.</para>
/// </summary>
/// <param name="Client">TCP client who received the message.</param>
/// <param name="RequestMessage">Full request message.</param>
/// <returns>Response message to be sent to the client.</returns>
public async Task <LocProtocolMessage> ProcessMessageNeighbourhoodChangedNotificationRequestAsync(LocClient Client, LocProtocolMessage RequestMessage)
{
log.Trace("()");
LocProtocolMessage res = Client.MessageBuilder.CreateErrorInternalResponse(RequestMessage);
bool signalActionProcessor = false;
NeighbourhoodChangedNotificationRequest neighbourhoodChangedNotificationRequest = RequestMessage.Request.LocalService.NeighbourhoodChanged;
using (UnitOfWork unitOfWork = new UnitOfWork())
{
DatabaseLock[] lockObjects = new DatabaseLock[] { UnitOfWork.NeighborLock, UnitOfWork.NeighborhoodActionLock };
using (IDbContextTransaction transaction = await unitOfWork.BeginTransactionWithLockAsync(lockObjects))
{
bool success = false;
bool saveDb = false;
try
{
int neighborhoodSize = await unitOfWork.NeighborRepository.CountAsync();
foreach (NeighbourhoodChange change in neighbourhoodChangedNotificationRequest.Changes)
{
// We do ignore errors here for each individual change and just continue processing the next item from the list.
log.Trace("Neighborhood change type is {0}.", change.ChangeTypeCase);
switch (change.ChangeTypeCase)
{
case NeighbourhoodChange.ChangeTypeOneofCase.AddedNodeInfo:
case NeighbourhoodChange.ChangeTypeOneofCase.UpdatedNodeInfo:
{
bool isAdd = change.ChangeTypeCase == NeighbourhoodChange.ChangeTypeOneofCase.AddedNodeInfo;
NodeInfo nodeInfo = isAdd ? change.AddedNodeInfo : change.UpdatedNodeInfo;
// Check whether a proximity server is running on this node.
// If not, it is not interesting for us at all, skip it.
int proximityServerPort;
byte[] proximityServerId;
if (!HasProximityServerService(nodeInfo, out proximityServerPort, out proximityServerId))
{
break;
}
NodeContact contact = nodeInfo.Contact;
IPAddress ipAddress = new IPAddress(contact.IpAddress.ToByteArray());
Iop.Locnet.GpsLocation location = nodeInfo.Location;
int latitude = location.Latitude;
int longitude = location.Longitude;
AddOrChangeNeighborResult addChangeRes = await AddOrChangeNeighborAsync(unitOfWork, proximityServerId, ipAddress, proximityServerPort, latitude, longitude, neighborhoodSize);
neighborhoodSize = addChangeRes.NeighborhoodSize;
if (addChangeRes.SaveDb)
{
saveDb = true;
}
if (addChangeRes.SignalActionProcessor)
{
signalActionProcessor = true;
}
break;
}
case NeighbourhoodChange.ChangeTypeOneofCase.RemovedNodeId:
{
byte[] serverId = change.RemovedNodeId.ToByteArray();
bool serverIdValid = serverId.Length == ProtocolHelper.NetworkIdentifierLength;
if (!serverIdValid)
{
log.Error("Received invalid neighbor server ID '{0}' from LOC server.", serverId.ToHex());
break;
}
// Data processing.
Neighbor existingNeighbor = (await unitOfWork.NeighborRepository.GetAsync(n => n.NetworkId == serverId)).FirstOrDefault();
if (existingNeighbor != null)
{
log.Trace("Creating neighborhood action to deleting neighbor ID '{0}' from the database.", serverId.ToHex());
string neighborInfo = JsonConvert.SerializeObject(existingNeighbor);
// Delete neighbor completely.
// This will cause our proximity server to erase all activities of the neighbor that has been removed.
bool deleted = await unitOfWork.NeighborRepository.DeleteNeighborAsync(serverId, -1, true);
if (deleted)
{
// Add action that will contact the neighbor and ask it to stop sending updates.
// Note that the neighbor information will be deleted by the time this action
// is executed and this is why we have to fill in AdditionalData.
NeighborhoodAction stopUpdatesAction = new NeighborhoodAction()
{
ServerId = serverId,
Timestamp = DateTime.UtcNow,
Type = NeighborhoodActionType.StopNeighborhoodUpdates,
TargetActivityId = 0,
TargetActivityOwnerId = null,
ExecuteAfter = DateTime.UtcNow,
AdditionalData = neighborInfo
};
await unitOfWork.NeighborhoodActionRepository.InsertAsync(stopUpdatesAction);
signalActionProcessor = true;
saveDb = true;
}
else
{
log.Error("Failed to remove neighbor ID '{0}' from the database.", serverId.ToHex());
// This is actually bad, we failed to remove a record from the database, which should never happen.
// We try to insert action to remove this neighbor later, but adding the action might fail as well.
NeighborhoodAction action = new NeighborhoodAction()
{
ServerId = serverId,
Timestamp = DateTime.UtcNow,
Type = NeighborhoodActionType.RemoveNeighbor,
TargetActivityId = 0,
TargetActivityOwnerId = null,
AdditionalData = null
};
await unitOfWork.NeighborhoodActionRepository.InsertAsync(action);
signalActionProcessor = true;
saveDb = true;
}
}
else
{
log.Debug("Neighbor ID '{0}' not found, can not be removed.", serverId.ToHex());
// It can be the case that this node has not an associated proximity server, so in that case we should ignore it.
// If the node has an associated proximity server, then nothing bad really happens here if we have activities
// of such a neighbor in NeighborActivity table. Those entries will expire and will be deleted.
}
break;
}
default:
log.Error("Invalid neighborhood change type '{0}'.", change.ChangeTypeCase);
break;
}
}
if (saveDb)
{
await unitOfWork.SaveThrowAsync();
transaction.Commit();
}
success = true;
res = Client.MessageBuilder.CreateNeighbourhoodChangedNotificationResponse(RequestMessage);
}
catch (Exception e)
{
log.Error("Exception occurred: {0}", e.ToString());
}
if (!success)
{
log.Warn("Rolling back transaction.");
unitOfWork.SafeTransactionRollback(transaction);
}
unitOfWork.ReleaseLock(lockObjects);
}
}
if (signalActionProcessor)
{
NeighborhoodActionProcessor neighborhoodActionProcessor = (NeighborhoodActionProcessor)Base.ComponentDictionary[NeighborhoodActionProcessor.ComponentName];
neighborhoodActionProcessor.Signal();
}
log.Trace("(-):*.Response.Status={0}", res.Response.Status);
return(res);
}
/// <summary>
/// Obtains IP address and neighbor port from the server's network identifier.
/// </summary>
/// <param name="NetworkId">Network identifer of the server.</param>
/// <param name="NotFound">If the function fails, this is set to true if the reason for failure was that the remote server was not found.</param>
/// <param name="IgnoreDbPortValue">If set to true, the function will ignore NeighborPort value of the server even if it is set in the database
/// and will contact the server on its primary port and then update NeighborPort in the database, if it successfully gets its value.</param>
/// <returns>End point description or null if the function fails.</returns>
public async Task <IPEndPoint> GetServerContactAsync(byte[] NetworkId, StrongBox <bool> NotFound, bool IgnoreDbPortValue = false)
{
log.Trace("(NetworkId:'{0}',IgnoreDbPortValue:{1})", NetworkId.ToHex(), IgnoreDbPortValue);
IPEndPoint res = null;
DatabaseLock lockObject = null;
bool unlock = false;
try
{
T remoteServer = (await GetAsync(n => n.NetworkId == NetworkId)).FirstOrDefault();
if (remoteServer != null)
{
log.Trace("{0} server found in the database.", remoteServer is Neighbor ? "Neighbor" : "Follower");
IPAddress addr = new IPAddress(remoteServer.IpAddress);
if (!IgnoreDbPortValue && (remoteServer.NeighborPort != null))
{
res = new IPEndPoint(addr, remoteServer.NeighborPort.Value);
}
else
{
NeighborhoodActionProcessor neighborhoodActionProcessor = (NeighborhoodActionProcessor)Base.ComponentDictionary[NeighborhoodActionProcessor.ComponentName];
// We do not know neighbor port of this server yet (or we ignore it), we have to connect to its primary port and get that information.
int neighborPort = await neighborhoodActionProcessor.GetServerRolePortFromPrimaryPort(addr, remoteServer.PrimaryPort, ServerRoleType.Neighbor);
if (neighborPort != 0)
{
lockObject = GetTableLock();
await unitOfWork.AcquireLockAsync(lockObject);
unlock = true;
remoteServer.NeighborPort = neighborPort;
Update(remoteServer);
if (!await unitOfWork.SaveAsync())
{
log.Error("Unable to save new neighbor port information {0} of {1} ID '{2}' to the database.", neighborPort, remoteServer is Neighbor ? "neighbor" : "follower", NetworkId.ToHex());
}
res = new IPEndPoint(addr, neighborPort);
}
else
{
log.Debug("Unable to obtain srNeighbor port from primary port of {0} ID '{1}'.", remoteServer is Neighbor ? "neighbor" : "follower", NetworkId.ToHex());
}
}
}
else
{
log.Error("Unable to find {0} ID '{1}' in the database.", remoteServer is Neighbor ? "neighbor" : "follower", NetworkId.ToHex());
NotFound.Value = true;
}
}
catch (Exception e)
{
log.Error("Exception occurred: {0}", e.ToString());
}
if (unlock)
{
unitOfWork.ReleaseLock(lockObject);
}
log.Trace("(-):{0}", res != null ? res.ToString() : "null");
return(res);
}
/// <summary>
/// Processes GetNeighbourNodesByDistanceResponse message received from LOC server.
/// <para>This message contains information about proximity server's neighbors, with which it should share its activity database.</para>
/// </summary>
/// <param name="ResponseMessage">Full response message.</param>
/// <param name="IsInitialization">true if the response was received to the request during the LOC initialization, false if it was received to the refresh request after the initialization.</param>
/// <returns>true if the connection to the LOC server should remain open, false if it should be closed.</returns>
public async Task <bool> ProcessMessageGetNeighbourNodesByDistanceResponseAsync(LocProtocolMessage ResponseMessage, bool IsInitialization)
{
log.Trace("(IsInitialization:{0})", IsInitialization);
bool res = false;
bool signalActionProcessor = false;
GetNeighbourNodesByDistanceResponse getNeighbourNodesByDistanceResponse = ResponseMessage.Response.LocalService.GetNeighbourNodes;
if (getNeighbourNodesByDistanceResponse.Nodes.Count > 0)
{
using (UnitOfWork unitOfWork = new UnitOfWork())
{
DatabaseLock[] lockObjects = new DatabaseLock[] { UnitOfWork.NeighborLock, UnitOfWork.NeighborhoodActionLock };
using (IDbContextTransaction transaction = await unitOfWork.BeginTransactionWithLockAsync(lockObjects))
{
bool success = false;
bool saveDb = false;
try
{
int neighborhoodSize = await unitOfWork.NeighborRepository.CountAsync();
foreach (NodeInfo nodeInfo in getNeighbourNodesByDistanceResponse.Nodes)
{
// Check whether a proximity server is running on this node.
// If not, it is not interesting for us at all, skip it.
int proximityServerPort;
byte[] proximityServerId;
if (!HasProximityServerService(nodeInfo, out proximityServerPort, out proximityServerId))
{
continue;
}
NodeContact contact = nodeInfo.Contact;
byte[] ipBytes = contact.IpAddress.ToByteArray();
IPAddress ipAddress = new IPAddress(ipBytes);
int latitude = nodeInfo.Location.Latitude;
int longitude = nodeInfo.Location.Longitude;
AddOrChangeNeighborResult addChangeRes = await AddOrChangeNeighborAsync(unitOfWork, proximityServerId, ipAddress, proximityServerPort, latitude, longitude, neighborhoodSize);
neighborhoodSize = addChangeRes.NeighborhoodSize;
if (addChangeRes.SaveDb)
{
saveDb = true;
}
if (addChangeRes.SignalActionProcessor)
{
signalActionProcessor = true;
}
// We do ignore errors here and just continue processing another item from the list.
}
if (saveDb)
{
await unitOfWork.SaveThrowAsync();
transaction.Commit();
}
success = true;
res = true;
}
catch (Exception e)
{
log.Error("Exception occurred: {0}", e.ToString());
}
if (!success)
{
log.Warn("Rolling back transaction.");
unitOfWork.SafeTransactionRollback(transaction);
}
unitOfWork.ReleaseLock(lockObjects);
}
}
}
else
{
log.Debug("No neighbors announced by LOC server.");
res = true;
}
if (signalActionProcessor)
{
NeighborhoodActionProcessor neighborhoodActionProcessor = (NeighborhoodActionProcessor)Base.ComponentDictionary[NeighborhoodActionProcessor.ComponentName];
neighborhoodActionProcessor.Signal();
}
if (res && IsInitialization)
{
log.Debug("LOC component is now considered in sync with LOC server.");
serverComponent.SetLocServerInitialized(true);
}
log.Trace("(-):{0}", res);
return(res);
}
