Centralise the child-process-terminating logic in NodeServicesImpl - don't also do it in OutOfProcessNodeInstance. This works towards connection draining.

This commit is contained in:
SteveSandersonMS
2016-07-07 12:52:15 +01:00
parent 26e8bd823c
commit be13f0b7bf

View File

@@ -23,6 +23,7 @@ namespace Microsoft.AspNetCore.NodeServices.HostingModels
private bool _disposed;
private readonly StringAsTempFile _entryPointScript;
private readonly Process _nodeProcess;
private bool _nodeProcessNeedsRestart;
public OutOfProcessNodeInstance(string entryPointScript, string projectPath, string commandLineArguments = null)
{
@@ -33,16 +34,19 @@ namespace Microsoft.AspNetCore.NodeServices.HostingModels
public async Task<T> InvokeExportAsync<T>(string moduleName, string exportNameOrNull, params object[] args)
{
// Wait until the connection is established. This will throw if the connection fails to initialize.
await _connectionIsReadySource.Task;
if (_nodeProcess.HasExited)
if (_nodeProcess.HasExited || _nodeProcessNeedsRestart)
{
// This special kind of exception triggers a transparent retry - NodeServicesImpl will launch
// a new Node instance and pass the invocation to that one instead.
throw new NodeInvocationException("The Node process has exited", null, nodeInstanceUnavailable: true);
var message = _nodeProcess.HasExited
? "The Node process has exited"
: "The Node process needs to restart";
throw new NodeInvocationException(message, null, nodeInstanceUnavailable: true);
}
// Wait until the connection is established. This will throw if the connection fails to initialize.
await _connectionIsReadySource.Task;
return await InvokeExportAsync<T>(new NodeInvocationInfo
{
ModuleName = moduleName,
@@ -115,7 +119,17 @@ namespace Microsoft.AspNetCore.NodeServices.HostingModels
startInfo.Environment["NODE_PATH"] = nodePathValue;
#endif
return Process.Start(startInfo);
var process = Process.Start(startInfo);
// On Mac at least, a killed child process is left open as a zombie until the parent
// captures its exit code. We don't need the exit code for this process, and don't want
// to use process.WaitForExit() explicitly (we'd have to block the thread until it really
// has exited), but we don't want to leave zombies lying around either. It's sufficient
// to use process.EnableRaisingEvents so that .NET will grab the exit code and let the
// zombie be cleaned away without having to block our thread.
process.EnableRaisingEvents = true;
return process;
}
private void ConnectToInputOutputStreams()
@@ -134,7 +148,7 @@ namespace Microsoft.AspNetCore.NodeServices.HostingModels
// Temporarily, the file-watching logic is in Node, so look out for the
// signal that we need to restart. This can be removed once the file-watching
// logic is moved over to the .NET side.
Dispose();
_nodeProcessNeedsRestart = true;
}
else if (evt.Data != null)
{