private bool ChangeState([NotNull] ClientHolderState currentState, [NotNull] ClientHolderState newState)
{
if (Interlocked.CompareExchange(ref state, newState, currentState) != currentState)
{
return(false);
}
SendOnConnectionStateChanged();
currentState.NextState.TrySetResult(newState);
log.Info("Connection state changed. Old: '{OldState}'. New: '{NewState}'.", currentState, newState);
if (newState.ConnectionState == ConnectionState.Expired)
{
ResetClient(newState);
}
else if (!newState.IsConnected)
{
Task.Run(() => WaitAndResetClient(newState));
}
else
{
suspendedManager.ResetDelay();
}
return(true);
}
private void ProcessEvent(ConnectionEvent connectionEvent)
{
log.Debug("Processing connection state event '{ConnectionEvent}'.", connectionEvent);
var currentState = state;
if (currentState == null || !ReferenceEquals(connectionEvent.EventFrom, currentState.ConnectionWatcher))
{
return;
}
var newState = new ClientHolderState(
currentState.LazyClient,
currentState.ConnectionWatcher,
connectionEvent.NewConnectionState,
currentState.ConnectionString);
if (!ChangeState(currentState, newState))
{
return;
}
if (newState.ConnectionState == ConnectionState.Expired)
{
ResetClient(newState);
}
}
private bool ResetClientIfNeeded([CanBeNull] ClientHolderState currentState)
{
if (currentState != null && NeedToResetClient(currentState))
{
return(ResetClient(currentState));
}
return(true);
}
public ClientHolder(ZooKeeperClientSettings settings, ILog log)
{
this.log = log;
this.settings = settings;
state = new ClientHolderState(null, null, ConnectionState.Disconnected, null);
ZooKeeperLogInjector.Register(this, this.log);
}
public ClientHolder(ZooKeeperClientSettings settings, ILog log)
{
this.log = log;
this.settings = settings;
state = ClientHolderState.CreateActive(null, null, ConnectionState.Disconnected, null, settings);
suspendedManager = new SuspendedManager(settings.Timeout, settings.Timeout.Multiply(settings.MaximumConnectPeriodMultiplier), -3);
ZooKeeperLogInjector.Register(this, this.log);
}
private async Task WaitAndResetClient([NotNull] ClientHolderState currentState)
{
try
{
await Task.Delay(currentState.TimeBeforeReset.Remaining).ConfigureAwait(false);
if (ReferenceEquals(state, currentState))
{
ResetClient(currentState);
}
}
catch (Exception e)
{
log.Error(e, "Failed to reset client.");
}
}
private bool ResetClient([NotNull] ClientHolderState currentState)
{
log.Info("Resetting client. Current state: '{CurrentState}'.", currentState);
var newConnectionString = settings.ConnectionStringProvider();
if (string.IsNullOrEmpty(newConnectionString))
{
log.Error("Failed to resolve any ZooKeeper replicas.");
return(false);
}
var newConnectionWatcher = new ConnectionWatcher(ProcessEvent);
var newClient = new Lazy <ZooKeeperNetExClient>(
() =>
{
using (ExecutionContext.SuppressFlow())
{
return(new ZooKeeperNetExClient(
newConnectionString,
settings.ToInnerConnectionTimeout(),
newConnectionWatcher,
settings.CanBeReadOnly));
}
},
LazyThreadSafetyMode.ExecutionAndPublication);
var suspendedFor = suspendedManager.GetNextDelay();
var newState = suspendedFor != null && !currentState.IsSuspended
? ClientHolderState.CreateSuspended(suspendedFor)
: ClientHolderState.CreateActive(newClient, newConnectionWatcher, ConnectionState.Disconnected, newConnectionString, settings);
if (ChangeState(currentState, newState))
{
newState.Client?.Touch();
// Note(kungurtsev): increase delay for each active (not suspended) client creation.
if (!currentState.IsSuspended)
{
suspendedManager.IncreaseDelay();
}
currentState.Dispose();
}
return(true);
}
private bool ChangeState([NotNull] ClientHolderState currentState, [NotNull] ClientHolderState newState)
{
if (Interlocked.CompareExchange(ref state, newState, currentState) != currentState)
{
return(false);
}
SendOnConnectionStateChanged();
currentState.NextState.TrySetResult(newState);
if (currentState.ConnectionState != newState.ConnectionState)
{
log.Info("Connection state changed. Old: '{OldState}'. New: '{NewState}'.", currentState, newState);
}
return(true);
}
private bool NeedToResetClient([NotNull] ClientHolderState currentState)
{
if (currentState.IsSuspended)
{
return(currentState.TimeBeforeReset.HasExpired);
}
if (currentState.ConnectionString != settings.ConnectionStringProvider())
{
return(true);
}
if (!currentState.IsConnected)
{
return(currentState.TimeBeforeReset.HasExpired);
}
return(false);
}
private bool ResetClient([NotNull] ClientHolderState currentState)
{
log.Info("Resetting client. Current state: '{CurrentState}'.", currentState);
var newConnectionString = settings.ConnectionStringProvider();
if (string.IsNullOrEmpty(newConnectionString))
{
log.Error("Failed to resolve any ZooKeeper replicas.");
return(false);
}
var newConnectionWatcher = new ConnectionWatcher(ProcessEvent);
var newClient = new Lazy <ZooKeeperNetExClient>(
() =>
{
using (ExecutionContext.SuppressFlow())
{
return(new ZooKeeperNetExClient(
newConnectionString,
settings.ToInnerConnectionTimeout(),
newConnectionWatcher,
settings.CanBeReadOnly));
}
},
LazyThreadSafetyMode.ExecutionAndPublication);
var newState = new ClientHolderState(newClient, newConnectionWatcher, ConnectionState.Disconnected, newConnectionString);
if (ChangeState(currentState, newState))
{
newState.Client?.Touch();
currentState.Dispose();
}
return(true);
}