def _read_results()

in cstar/remote_paramiko.py [0:0]

• 33 lines of code
• 6 McCabe index (conditional complexity)

    def _read_results(self, stdin, stdout, stderr, timeout=30):

        # get the shared channel for stdout/stderr/stdin
        channel = stdout.channel

        stdin.close()
        # indicate that we're not going to write to that channel anymore
        channel.shutdown_write()

        # read stdout/stderr in order to prevent read block hangs
        stdout_chunks, stderr_chunks = [], []
        stdout_chunks.append(stdout.channel.recv(len(stdout.channel.in_buffer)))
        # chunked read to prevent stalls
        while not channel.closed or channel.recv_ready() or channel.recv_stderr_ready():
            # stop if channel was closed prematurely, and there is no data in the buffers.
            got_chunk = False
            readq, _, _ = select.select([stdout.channel], [], [], timeout)
            for c in readq:
                if c.recv_ready():
                    stdout_chunks.append(stdout.channel.recv(len(c.in_buffer)))
                    got_chunk = True
                if c.recv_stderr_ready():
                    # make sure to read stderr to prevent stall
                    stderr_chunks.append(stderr.channel.recv_stderr(len(c.in_stderr_buffer)))
                    got_chunk = True
            '''
            1) make sure that there are at least 2 cycles with no data in the input buffers in order to not exit too early (i.e. cat on a >200k file).
            2) if no data arrived in the last loop, check if we already received the exit code
            3) check if input buffers are empty
            4) exit the loop
            '''
            if not got_chunk \
                    and stdout.channel.exit_status_ready() \
                    and not stderr.channel.recv_stderr_ready() \
                    and not stdout.channel.recv_ready():
                # indicate that we're not going to read from this channel anymore
                stdout.channel.shutdown_read()
                # close the channel
                stdout.channel.close()
                break    # exit as remote side is finished and our bufferes are empty

        # close all the pseudofiles
        stdout.close()
        stderr.close()

        status = stdout.channel.recv_exit_status()
        return status, stdout_chunks, stderr_chunks