Send termination request

[OskarKlintrot]

I couldn't figure out a way to gracefully shutdown a dotnet app I'm testing. I wish I could send a termination request to let the process know that I want it to try to shut down and still be able to read the output from it. Something like this:

var cancellationTokenSource = new CancellationTokenSource(TimeSpan.FromMinutes(2));
var terminationTokenSource = new CancellationTokenSource(); // Maybe not a cts but something 
                                                            // similar that better indicates
                                                            // that it's the process that should 
                                                            // shut down and not the task 
                                                            // that should be cancelled

var webApiTask = ReadAsync(
    "dotnet",
    "run",
    workingDirectory: "path-to-my-api",
    terminationRequest: terminationTokenSource.Token,
    cancellationToken: cancellationTokenSource.Token);

// Ping webapi

terminationTokenSource.Cancel();

var (output, error) = await webApiTask; // Not cancelled unless it has passed more than 2 minutes

// Assert output and error

I can use the cancellationToken to at least kill the process and move on but I wish there were a way to still capture the output.

[adamralph]

Regarding determining whether the process was cancelled or whether it timed out, this is the way to do it:

var timeoutTokenSource = new CancellationTokenSource(TimeSpan.FromMinutes(2));
var terminationTokenSource = new CancellationTokenSource();

var combinedTokenSource =
    CancellationTokenSource.CreateLinkedTokenSource(timeoutTokenSource.Token, terminationTokenSource.Token);

var webApiTask = ReadAsync(
    "dotnet",
    "run",
    workingDirectory: "path-to-my-api",
    cancellationToken: combinedTokenSource.Token);

// Ping webapi

terminationTokenSource.Cancel();

try
{
    var (output, error) = await webApiTask; // Not cancelled unless it has passed more than 2 minutes
}
catch (OperationCanceledException ex)) when (terminationTokenSource.IsCancellationRequested)
{
    // the process was terminated
}

However, this won't let you capture the output or error streams. While we could try and throw a custom exception, inheriting from OperationCancelledException, with Output and Error properties, I'm not sure it will work, given the simple approach taken by SimpleExec to reading those streams.

Taking a step back for a moment, I think your use case may be a bit further advanced than the simple use cases SimpleExec is designed for. Perhaps you should look into using a more advanced package such as CliWrap.

[OskarKlintrot]

I have another implementation I've used before that reads via events instead and that pipes the event back out to the user; https://gist.github.com/OskarKlintrot/3947da8d31c4fa275525e4afc4138e28#file-processrunner-cs-L17-L18. That way I have the output when the process is cancelled. Not that much more complicated ;)

Yeah, I might have to change to CliWrap even though I found your API much nicer to work with!