/// <summary>
/// Try to process the request using the server. Returns a null-containing Task if a response
/// from the server cannot be retrieved.
/// </summary>
private static async Task <ServerResponse> TryProcessRequest(
Client client,
ServerRequest request,
CancellationToken cancellationToken)
{
ServerResponse response;
using (client)
{
// Write the request
try
{
ServerLogger.Log("Begin writing request");
await request.WriteAsync(client.Stream, cancellationToken).ConfigureAwait(false);
ServerLogger.Log("End writing request");
}
catch (Exception e)
{
ServerLogger.LogException(e, "Error writing build request.");
return(new RejectedServerResponse());
}
// Wait for the compilation and a monitor to detect if the server disconnects
var serverCts = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
ServerLogger.Log("Begin reading response");
var responseTask = ServerResponse.ReadAsync(client.Stream, serverCts.Token);
var monitorTask = client.WaitForDisconnectAsync(serverCts.Token);
await Task.WhenAny(new[] { responseTask, monitorTask }).ConfigureAwait(false);
ServerLogger.Log("End reading response");
if (responseTask.IsCompleted)
{
// await the task to log any exceptions
try
{
response = await responseTask.ConfigureAwait(false);
}
catch (Exception e)
{
ServerLogger.LogException(e, "Error reading response");
response = new RejectedServerResponse();
}
}
else
{
ServerLogger.Log("Server disconnect");
response = new RejectedServerResponse();
}
// Cancel whatever task is still around
serverCts.Cancel();
Debug.Assert(response != null);
return(response);
}
}
internal async Task <ConnectionResult> AcceptConnection(Task <Connection> task, bool accept, CancellationToken cancellationToken)
{
Connection connection;
try
{
connection = await task;
}
catch (Exception ex)
{
// Unable to establish a connection with the client. The client is responsible for
// handling this case. Nothing else for us to do here.
ServerLogger.LogException(ex, "Error creating client named pipe");
return(new ConnectionResult(ConnectionResult.Reason.CompilationNotStarted));
}
try
{
using (connection)
{
ServerRequest request;
try
{
ServerLogger.Log("Begin reading request.");
request = await ServerRequest.ReadAsync(connection.Stream, cancellationToken).ConfigureAwait(false);
ServerLogger.Log("End reading request.");
}
catch (Exception e)
{
ServerLogger.LogException(e, "Error reading build request.");
return(new ConnectionResult(ConnectionResult.Reason.CompilationNotStarted));
}
if (request.IsShutdownRequest())
{
// Reply with the PID of this process so that the client can wait for it to exit.
var response = new ShutdownServerResponse(Environment.ProcessId);
await response.WriteAsync(connection.Stream, cancellationToken);
// We can safely disconnect the client, then when this connection gets cleaned up by the event loop
// the server will go to a shutdown state.
return(new ConnectionResult(ConnectionResult.Reason.ClientShutdownRequest));
}
else if (!accept)
{
// We're already in shutdown mode, respond gracefully so the client can run in-process.
var response = new RejectedServerResponse();
await response.WriteAsync(connection.Stream, cancellationToken).ConfigureAwait(false);
return(new ConnectionResult(ConnectionResult.Reason.CompilationNotStarted));
}
else
{
// If we get here then this is a real request that we will accept and process.
//
// Kick off both the compilation and a task to monitor the pipe for closing.
var buildCancelled = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
var watcher = connection.WaitForDisconnectAsync(buildCancelled.Token);
var worker = ExecuteRequestAsync(request, buildCancelled.Token);
// await will end when either the work is complete or the connection is closed.
await Task.WhenAny(worker, watcher);
// Do an 'await' on the completed task, preference being compilation, to force
// any exceptions to be realized in this method for logging.
ConnectionResult.Reason reason;
if (worker.IsCompleted)
{
var response = await worker;
try
{
ServerLogger.Log("Begin writing response.");
await response.WriteAsync(connection.Stream, cancellationToken);
ServerLogger.Log("End writing response.");
reason = ConnectionResult.Reason.CompilationCompleted;
_eventBus.CompilationCompleted();
}
catch
{
reason = ConnectionResult.Reason.ClientDisconnect;
}
}
else
{
await watcher;
reason = ConnectionResult.Reason.ClientDisconnect;
}
// Begin the tear down of the Task which didn't complete.
buildCancelled.Cancel();
return(new ConnectionResult(reason, request.KeepAlive));
}
}
}
catch (Exception ex)
{
ServerLogger.LogException(ex, "Error handling connection");
return(new ConnectionResult(ConnectionResult.Reason.ClientException));
}
}