private async ValueTask <Connection> GetConnectionAsync(SiloAddress endpoint)
{
ImmutableArray <Connection> result;
ConnectionEntry entry = default;
var acquiredConnectionLock = false;
try
{
// Lock the entry to ensure it will not be removed while the connectio attempt is occuring.
while (!acquiredConnectionLock)
{
entry = GetOrCreateEntry(endpoint, ref acquiredConnectionLock);
if (entry.Connections.Length >= this.connectionOptions.ConnectionsPerEndpoint)
{
result = entry.Connections;
break;
}
ThrowIfRecentFailure(endpoint, entry);
// Wait a short time before reattempting to acquire the lock
await Task.Delay(10);
}
// Attempt to connect.
Connection connection = default;
var now = DateTime.UtcNow;
try
{
connection = await this.ConnectAsync(endpoint);
entry = OnConnectedInternal(endpoint, connection);
result = entry.Connections;
}
catch (Exception exception)
{
OnConnectionFailed(endpoint, now);
throw new ConnectionFailedException(
$"Unable to connect to endpoint {endpoint}. See {nameof(exception.InnerException)}", exception);
}
}
finally
{
if (acquiredConnectionLock)
{
entry.ReleaseLock();
}
}
nextConnection = (nextConnection + 1) % result.Length;
return(result[nextConnection]);
}
private void OnConnectionFailed(SiloAddress address, DateTime lastFailure)
{
bool acquiredConnectionLock = false;
ConnectionEntry entry = default;
lock (this.collectionLock)
{
try
{
entry = this.GetOrCreateEntry(address, ref acquiredConnectionLock);
if (entry.LastFailure.HasValue)
{
var ticks = Math.Max(lastFailure.Ticks, entry.LastFailure.Value.Ticks);
lastFailure = new DateTime(ticks);
}
// Clean up defunct connections
var connections = entry.Connections;
foreach (var c in connections)
{
if (!c.IsValid)
{
connections = connections.Remove(c);
}
}
this.connections[address] = entry.WithLastFailure(lastFailure).WithConnections(connections);
}
finally
{
if (acquiredConnectionLock)
{
entry.ReleaseLock();
}
}
}
}