/// <summary> /// Opens the cluster for queries. Contains actual implementation and will be called only once per cluster /// </summary> /// <returns></returns> /// <exception cref="CqlException">Cannot construct ring from provided seeds!</exception> private async Task OpenAsyncInternal(Logger logger) { logger.LogInfo("Opening Cluster with parameters: {0}", _config.ToString()); //try to connect to the seeds in turn foreach (IPAddress seedAddress in _config.NodeAddresses) { try { var seed = new Node(seedAddress, this); _nodes = await DiscoverNodesAsync(seed, logger).ConfigureAwait(false); } catch (Exception ex) { //seed not reachable, try next logger.LogWarning("Could not discover nodes via seed {0}: {1}", seedAddress, ex); } } if (_nodes == null) { var ex = new CqlException("Cannot construct ring from provided seeds!"); logger.LogCritical("Unable to setup Cluster based on given configuration: {0}", ex); throw ex; } logger.LogInfo("Nodes detected: " + string.Join(", ", _nodes.Select(n => n.Address))); //setup cluster connection strategy switch (_config.ConnectionStrategy) { case ConnectionStrategy.Balanced: _connectionSelector = new BalancedConnectionStrategy(_nodes, _config); break; case ConnectionStrategy.Random: _connectionSelector = new RandomConnectionStrategy(_nodes, _config); break; case ConnectionStrategy.Exclusive: _connectionSelector = new ExclusiveConnectionStrategy(_nodes, _config); break; case ConnectionStrategy.PartitionAware: _connectionSelector = new PartitionAwareConnectionStrategy(_nodes, _config); if (_config.DiscoveryScope != DiscoveryScope.Cluster || _config.DiscoveryScope != DiscoveryScope.DataCenter) logger.LogWarning("PartitionAware connection strategy performs best if DiscoveryScope is set to cluster or datacenter"); break; } //setup throttle int concurrent = _config.MaxConcurrentQueries <= 0 ? _nodes.Count * _config.MaxConnectionsPerNode * 256 : _config.MaxConcurrentQueries; logger.LogInfo("Cluster is configured to allow {0} parallel queries", concurrent); _throttle = new SemaphoreSlim(concurrent, concurrent); //setup prepared query cache _prepareResultCache = new ConcurrentDictionary<string, ConcurrentDictionary<IPAddress, ResultFrame>>(); //setup maintenance connection SetupMaintenanceConnection(logger); }
/// <summary> /// Setups the maintenance channel. /// </summary> private async void SetupMaintenanceConnection(Logger logger) { //skip if disposed if(_disposed) return; try { if(_maintenanceConnection == null || !_maintenanceConnection.IsAvailable) { //setup maintenance connection logger.LogVerbose("Creating new maintenance connection"); //get or create a connection Connection connection; using(logger.ThreadBinding()) { connection = _connectionStrategy.GetOrCreateConnection(ConnectionScope.Infrastructure, null); } //check if we really got a connection if(connection == null) throw new CqlException("Can not obtain connection for maintenance channel"); //register for events await connection.RegisterForClusterChangesAsync(logger).AutoConfigureAwait(); //setup event handlers connection.OnConnectionChange += (src, ev) => Scheduler.RunOnThreadPool(() => SetupMaintenanceConnection(logger)); connection.OnClusterChange += OnClusterChange; //store the new connection _maintenanceConnection = connection; logger.LogInfo("Registered for cluster changes using {0}", connection); } //all seems right, we're done return; } catch(Exception ex) { logger.LogWarning("Failed to setup maintenance connection: {0}", ex); //temporary disconnect or registration failed, reset maintenance connection _maintenanceConnection = null; } //don't retry if disposed if(_disposed) return; //wait a moment, try again logger.LogVerbose("Waiting 5secs before retrying setup maintenance connection"); await Task.Delay(5000).AutoConfigureAwait(); SetupMaintenanceConnection(logger); }
/// <summary> /// Setups the maintenance channel. /// </summary> private async void SetupMaintenanceConnection(Logger logger) { try { if (_maintenanceConnection == null || !_maintenanceConnection.IsConnected) { //setup maintenance connection logger.LogVerbose("Creating new maintenance connection"); //pick a random node from the list var strategy = new RandomConnectionStrategy(_nodes, _config); //get or create a connection var connection = strategy.GetOrCreateConnection(null); //allow this connection to be used by others as well _connectionSelector.ReturnConnection(connection); //setup event handlers connection.OnConnectionChange += (src, ev) => SetupMaintenanceConnection(logger); connection.OnClusterChange += OnClusterChange; //store the new connection _maintenanceConnection = connection; //register for events await connection.RegisterForClusterChangesAsync(logger).ConfigureAwait(false); logger.LogInfo("Registered for cluster changes using {0}", connection); } //all seems right, we're done return; } catch (Exception ex) { logger.LogWarning("Failed to setup maintenance connection: {0}", ex); //temporary disconnect or registration failed, reset maintenance connection _maintenanceConnection = null; } //wait a moment, try again logger.LogVerbose("Waiting 2secs before retrying setup maintenance connection"); await Task.Delay(2000).ConfigureAwait(false); SetupMaintenanceConnection(logger); }
/// <summary> /// Opens the cluster for queries. Contains actual implementation and will be called only once per cluster /// </summary> /// <returns> </returns> /// <exception cref="CqlException">Cannot construct ring from provided seeds!</exception> private async Task OpenAsyncInternal(Logger logger, CancellationToken token) { logger.LogInfo("Opening Cluster with parameters: {0}", _config.ToString()); //initialize the ring _nodes = new Ring(); //retry a few times to deal with bad network conditions for(int attempt = 0; attempt <= _config.MaxQueryRetries && _nodes.Count == 0; attempt++) { //try to connect to the seeds in turn foreach(IPAddress seedAddress in _config.ServerAddresses) { try { var seed = new Node(seedAddress, this); await GetClusterInfoAsync(seed, logger, token).AutoConfigureAwait(); //break from the loop as it seems we are done if(_nodes.Count > 0) break; } catch(OperationCanceledException) { logger.LogWarning("Opening connection to cluster was cancelled"); throw; } catch(ProtocolException pex) { logger.LogWarning("Could not open cluster via {0}: {1}", seedAddress, pex.Message); //node is not available, or starting up, try next, otherwise throw error if(pex.Code != ErrorCode.Overloaded && pex.Code != ErrorCode.IsBootstrapping) throw; } catch(SocketException ex) { //seed not reachable, try next logger.LogWarning("Could not open TCP connection to seed {0}: {1}", seedAddress, ex.Message); } catch(IOException ex) { //seed not reachable, try next logger.LogWarning("Could not discover nodes via seed {0}: {1}", seedAddress, ex); } } } //check if not disposed while opening if(_disposed) { foreach(var node in _nodes) node.Dispose(); throw new ObjectDisposedException("Cluster", "Cluster was disposed while opening"); } //check if we found any nodes if(_nodes.Count == 0) { var ex = new CqlException("Unable to connect to the cluster as none of the provided seeds is reachable."); logger.LogCritical("Unable to setup Cluster based on given configuration: {0}", ex); throw ex; } //setup cluster connection strategy switch(_config.ConnectionStrategy) { case CqlSharp.ConnectionStrategy.Balanced: _connectionStrategy = new BalancedConnectionStrategy(_nodes, _config); break; case CqlSharp.ConnectionStrategy.Random: _connectionStrategy = new RandomConnectionStrategy(_nodes, _config); break; case CqlSharp.ConnectionStrategy.Exclusive: _connectionStrategy = new ExclusiveConnectionStrategy(_nodes, _config); break; case CqlSharp.ConnectionStrategy.PartitionAware: _connectionStrategy = new PartitionAwareConnectionStrategy(_nodes, _config); if(_config.DiscoveryScope != DiscoveryScope.Cluster && _config.DiscoveryScope != DiscoveryScope.DataCenter) { logger.LogWarning( "PartitionAware connection strategy performs best if DiscoveryScope is set to cluster or datacenter"); } break; } //setup prepared query cache PreparedQueryCache = new ConcurrentDictionary<string, ResultFrame>(); //setup maintenance connection Scheduler.RunOnThreadPool(() => SetupMaintenanceConnection(logger)); }