commands.py 文件源码

def follow(self, lines=20):
        if not self.exists:
            yield "Instance does not exist."
            return

        process = popen("tail", "-n", str(lines), "-f", self.logpath)
        streams = set([process.stdout, process.stderr])

        try:
            while self.is_running and streams:
                readable, _, errors = select.select(streams, (), (), 0.5)
                for stream in readable:
                    line = stream.readline()
                    if not line:
                        streams.discard(stream)
                        continue

                    yield line.rstrip("\n").rstrip("\r")
        finally:
            send_signal(process.pid, signal.SIGKILL)