runutil

Various useful tools for running and pipe-ing stuff outside of Go.

This library makes it very easy to execute complex sequences of executables mixing both go native methods like gzip.NewReader and UNIX commands in the way pipes work on bash/etc.

For example it is possible to run the following:

compressed, err := RunPipe(input, "gzip", "-9")
if err != nil {
	t.Errorf("failed to run test: %s", err)
	return
}

res, err = gzip.NewReader(compressed)
if err != nil {
	t.Errorf("failed to run test: %s", err)
	return
}

Reading from res in that example will return the exact same bytes as input, after having been compressed once (into compressed), then decompressed.

If the command fails, the final Read() call will return the failure code, and allows correctly catching any problem (by default, go os/exec will only return the error when calling Wait(), which may result in errors not being catched).

Help

There are a lot of zombie threads

This means Wait() was not called. If using a method returning a pipe, you need to read the pipe to EOF in order for resources to be cleared. Another option is to call defer pipe.Close() in order to ensure resources are freed.

Close() will return quickly and kill the process, however if you want to wait and give the process some time, defer pipe.CloseWait(ctx) can be used. If the context has a deadline the process will be killed as per the deadline.