/// <summary> /// Gets all nodes that make up the cluster /// </summary> /// <param name="seed"> The reference. </param> /// <param name="logger"> logger used to log progress </param> /// <param name="token"> The token. </param> /// <returns> </returns> /// <exception cref="CqlException"> /// Could not detect datacenter or rack information from the reference specified in the /// config section! /// </exception> private async Task GetClusterInfoAsync(Node seed, Logger logger, CancellationToken token) { Connection c; using(logger.ThreadBinding()) { //get a connection if(seed != null && seed.IsUp) c = seed.GetOrCreateConnection(); else if(_maintenanceConnection != null && _maintenanceConnection.IsAvailable) { c = _maintenanceConnection; seed = c.Node; } else { c = _connectionStrategy.GetOrCreateConnection(ConnectionScope.Infrastructure, null); seed = c.Node; } } //get local information string partitioner; using(var result = await ExecQuery(c, "select cluster_name, cql_version, release_version, partitioner, data_center, rack, tokens from system.local", logger, token ).AutoConfigureAwait()) { if(! await result.ReadAsyncInternal(token).AutoConfigureAwait()) throw new CqlException("Could not fetch configuration data from seed"); _name = result.GetString(0); _cqlVersion = result.GetString(1); _release = result.GetString(2); partitioner = result.GetString(3); _dataCenter = seed.DataCenter = result.GetString(4); _rack = seed.Rack = result.GetString(5); seed.Tokens = result.GetSet<string>(6) ?? new HashSet<string>(); } logger.LogInfo( "Reconfigured cluster {0}: based on Cassandra Release {1}, supporting CqlVersion {2}, using partitioner '{3}'", _name, _release, _cqlVersion, partitioner); //create list of nodes that make up the cluster, and add the seed var found = new List<Node> {seed}; //get the peers using( var result = await ExecQuery(c, "select peer, rpc_address, data_center, rack, tokens, release_version from system.peers", logger, token).AutoConfigureAwait()) { //iterate over the peers while(await result.ReadAsyncInternal(token).AutoConfigureAwait()) { var newNode = GetNodeFromDataReader(result, logger); //add it if it is in scope if(InDiscoveryScope(seed, newNode, _config.DiscoveryScope)) found.Add(newNode); } } //set the new Ring of nodes _nodes.Update(found, partitioner, logger); //check if all tokens are received if(_nodes.Any(n => n.Tokens.Count == 0)) { //wait and retry the fetch later... Scheduler.RunOnThreadPool(async () => { try { logger.LogInfo("Cluster info incomplete scheduling new retrieval in 1 minute"); await Task.Delay(TimeSpan.FromMinutes(1)).AutoConfigureAwait(); await GetClusterInfoAsync(null, logger, CancellationToken.None).AutoConfigureAwait(); } catch(Exception ex) { logger.LogCritical("Critical error occured while updating cluster info: {0}", ex); } }); } }
/// <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> /// 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)); }