包装子进程的标准输出/标准错误

I can see that it accesses the filenoattribute - so it is doing something with the object. However, the write() method is never invoked. Is my approach completely off or am I just missing something?

class Process(object):
    class StreamWrapper(object):
        def __init__(self, stream):
            self._stream = stream
            self._buffer = []
        def _print(self, msg):
            print repr(self), msg
        def __getattr__(self, name):
            if not name in ['fileno']:
                self._print("# Redirecting: %s" % name)
            return getattr(self._stream, name)
        def write(self, data):
            print "###########"
            self._buffer.append(data)
            self._stream.write(data)
            self._stream.flush()
        def getBuffer(self):
            return self._buffer[:]
    def __init__(self, *args, **kwargs):
        print ">> Running `%s`" % " ".join(args[0])
        self._stdout = self.StreamWrapper(sys.stdout)
        self._stderr = self.StreamWrapper(sys.stderr)
        kwargs.setdefault('stdout', self._stdout)
        kwargs.setdefault('stderr', self._stderr)
        self._process = subprocess.Popen(*args, **kwargs)
        self._process.communicate()

更新:

我也想使用 ANSI 控制字符来移动光标并覆盖以前的输出内容.我不知道这是否是正确的术语，但这里是我的意思的一个例子:我正在尝试自动化一些 GIT 的东西，并且他们有自己更新的进度，而不是每次都写一个新的行.