/// <summary>
/// Attempts the connection.
/// </summary>
/// <param name="endpoint">The endpoint.</param>
/// <param name="workCategoryId">The work category identifier.</param>
/// <param name="cancellationToken">The cancellation token.</param>
/// <returns>
/// An awaitable task, the result is the connection result.
/// </returns>
protected static async Task <ConnectionResult> AttemptConnection(
IPEndPoint endpoint,
int workCategoryId,
CancellationToken cancellationToken)
{
StreamWorkerConnection connection = null;
try
{
var tcpClient = new TcpClient();
await tcpClient.ConnectAsync(endpoint.Address, endpoint.Port).ConfigureAwait(false);
connection = new StreamWorkerConnection(tcpClient.GetStream());
await connection.SendIntAsync(workCategoryId, cancellationToken).ConfigureAwait(false);
var benchmark = await connection.ReceiveIntAsync(cancellationToken).ConfigureAwait(false);
// If we've been cancelled, trigger a clean up
cancellationToken.ThrowIfCancellationRequested();
return(new ConnectionResult(connection, benchmark));
}
catch (Exception ex)
{
if (connection != null)
{
connection.Dispose();
}
return(new ConnectionResult(ex));
}
}
/// <summary>
/// Processes the client's connection and associated work item asynchronously.
/// </summary>
/// <param name="client">The client.</param>
/// <param name="cancellationToken">The cancellation token.</param>
/// <returns>An awaitable task.</returns>
private async Task ProcessClientAsync(TcpClient client, CancellationToken cancellationToken)
{
IPEndPoint endpoint = null;
dynamic workItem = null;
try
{
using (var connection = new StreamWorkerConnection(client.GetStream()))
{
endpoint = (IPEndPoint)client.Client.RemoteEndPoint;
// Get our benchmark for the provided work category
var workCategoryId = await connection.ReceiveIntAsync(cancellationToken).ConfigureAwait(false);
var benchmark = await _workloadBenchmark.GetScoreAsync(workCategoryId).ConfigureAwait(false);
// Send the client our benchmark, they'll use this to determine whether to use us for the work
await connection.SendIntAsync(benchmark, cancellationToken).ConfigureAwait(false);
// Try to receive work from the client, if they close the connection then we'll catch the exception
workItem = await connection.ReceiveObjectAsync(cancellationToken).ConfigureAwait(false);
// do the work, capturing any exceptions that may occur
object result = null;
Exception exception = null;
try
{
result = await workItem.DoWorkAsync(cancellationToken).ConfigureAwait(false);
}
catch (Exception ex)
{
exception = ex;
}
// Send the client the result of the work item, if an exception occurred, send that instead
await connection.SendObjectAsync(exception ?? result, cancellationToken).ConfigureAwait(false);
// If an exception occurred while processing work, throw it again to trigger the handling
if (exception != null)
{
throw exception;
}
}
}
catch (Exception ex)
{
var message = string.Format(
"An exception occurred when processing TCP client {0}:{1}.",
endpoint != null ? endpoint.Address.ToString() : "????",
endpoint != null ? endpoint.Port.ToString(CultureInfo.InvariantCulture) : "????");
OnWorkException(new WorkException(message, workItem, ex));
}
}
/// <summary>
/// Initializes a new instance of the <see cref="ConnectionResult"/> struct.
/// </summary>
/// <param name="connection">The connection.</param>
/// <param name="benchmarkScore">The benchmark score.</param>
public ConnectionResult(StreamWorkerConnection connection, int benchmarkScore)
: this()
{
WorkerConnection = connection;
CurrentWorkloadBenchmarkScore = benchmarkScore;
}