Mini Shell

"""
    :codeauthor: Pedro Algarvio (pedro@algarvio.me)


    salt.utils.nb_popen
    ~~~~~~~~~~~~~~~~~~~

    Non blocking subprocess Popen.

    This functionality has been adapted to work on windows following the recipe
    found on:

        http://code.activestate.com/recipes/440554/
"""

import errno
import logging
import os
import select
import subprocess
import sys
import tempfile
import time

mswindows = sys.platform == "win32"

if mswindows:
    import msvcrt

    import pywintypes
    from win32file import ReadFile, WriteFile
    from win32pipe import PeekNamedPipe

log = logging.getLogger(__name__)


class NonBlockingPopen(subprocess.Popen):

    # _stdin_logger_name_ = 'salt.utils.nb_popen.STDIN.PID-{pid}'
    _stdout_logger_name_ = "salt.utils.nb_popen.STDOUT.PID-{pid}"
    _stderr_logger_name_ = "salt.utils.nb_popen.STDERR.PID-{pid}"

    def __init__(self, *args, **kwargs):
        self.stream_stds = kwargs.pop("stream_stds", False)

        # Half a megabyte in memory is more than enough to start writing to
        # a temporary file.
        self.max_size_in_mem = kwargs.pop("max_size_in_mem", 512000)

        # Let's configure the std{in, out,err} logging handler names
        # self._stdin_logger_name_ = kwargs.pop(
        #    'stdin_logger_name', self._stdin_logger_name_
        # )
        self._stdout_logger_name_ = kwargs.pop(
            "stdout_logger_name", self._stdout_logger_name_
        )
        self._stderr_logger_name_ = kwargs.pop(
            "stderr_logger_name", self._stderr_logger_name_
        )

        logging_command = kwargs.pop("logging_command", None)
        stderr = kwargs.get("stderr", None)

        super().__init__(*args, **kwargs)

        # self._stdin_logger = logging.getLogger(
        #    self._stdin_logger_name_.format(pid=self.pid)
        # )

        self.stdout_buff = tempfile.SpooledTemporaryFile(self.max_size_in_mem)
        self._stdout_logger = logging.getLogger(
            self._stdout_logger_name_.format(pid=self.pid)
        )

        if stderr is subprocess.STDOUT:
            self.stderr_buff = self.stdout_buff
            self._stderr_logger = self._stdout_logger
        else:
            self.stderr_buff = tempfile.SpooledTemporaryFile(self.max_size_in_mem)
            self._stderr_logger = logging.getLogger(
                self._stderr_logger_name_.format(pid=self.pid)
            )

        log.info(
            "Running command under pid %s: '%s'",
            self.pid,
            args if logging_command is None else logging_command,
        )

    def recv(self, maxsize=None):
        return self._recv("stdout", maxsize)

    def recv_err(self, maxsize=None):
        return self._recv("stderr", maxsize)

    def send_recv(self, input="", maxsize=None):
        return self.send(input), self.recv(maxsize), self.recv_err(maxsize)

    def get_conn_maxsize(self, which, maxsize):
        if maxsize is None:
            maxsize = 1024
        elif maxsize < 1:
            maxsize = 1
        return getattr(self, which), maxsize

    def _close(self, which):
        getattr(self, which).close()
        setattr(self, which, None)

    if mswindows:

        def send(self, input):
            if not self.stdin:
                return None

            try:
                x = msvcrt.get_osfhandle(self.stdin.fileno())
                (errCode, written) = WriteFile(x, input)
                # self._stdin_logger.debug(input.rstrip())
            except ValueError:
                return self._close("stdin")
            except (pywintypes.error, Exception) as why:
                if why.args[0] in (109, errno.ESHUTDOWN):
                    return self._close("stdin")
                raise

            return written

        def _recv(self, which, maxsize):
            conn, maxsize = self.get_conn_maxsize(which, maxsize)
            if conn is None:
                return None

            try:
                x = msvcrt.get_osfhandle(conn.fileno())
                (read, nAvail, nMessage) = PeekNamedPipe(x, 0)
                if maxsize < nAvail:
                    nAvail = maxsize
                if nAvail > 0:
                    (errCode, read) = ReadFile(x, nAvail, None)
            except ValueError:
                return self._close(which)
            except (pywintypes.error, Exception) as why:
                if why.args[0] in (109, errno.ESHUTDOWN):
                    return self._close(which)
                raise

            getattr(self, f"{which}_buff").write(read)
            getattr(self, f"_{which}_logger").debug(read.rstrip())
            if self.stream_stds:
                getattr(sys, which).write(read)

            if self.universal_newlines:
                read = self._translate_newlines(read)
            return read

    else:

        def send(self, input):
            if not self.stdin:
                return None

            if not select.select([], [self.stdin], [], 0)[1]:
                return 0

            try:
                written = os.write(self.stdin.fileno(), input)
                # self._stdin_logger.debug(input.rstrip())
            except OSError as why:
                if why.args[0] == errno.EPIPE:  # broken pipe
                    return self._close("stdin")
                raise

            return written

        def _recv(self, which, maxsize):
            conn, maxsize = self.get_conn_maxsize(which, maxsize)
            if conn is None:
                return None

            import fcntl

            flags = fcntl.fcntl(conn, fcntl.F_GETFL)
            if not conn.closed:
                fcntl.fcntl(conn, fcntl.F_SETFL, flags | os.O_NONBLOCK)

            try:
                if not select.select([conn], [], [], 0)[0]:
                    return ""

                buff = conn.read(maxsize)
                if not buff:
                    return self._close(which)

                if self.universal_newlines:
                    buff = self._translate_newlines(buff)

                getattr(self, f"{which}_buff").write(buff)
                getattr(self, f"_{which}_logger").debug(buff.rstrip())
                if self.stream_stds:
                    getattr(sys, which).write(buff)

                return buff
            finally:
                if not conn.closed:
                    fcntl.fcntl(conn, fcntl.F_SETFL, flags)

    def poll_and_read_until_finish(self, interval=0.01):
        silent_iterations = 0
        while self.poll() is None:
            if self.stdout is not None:
                silent_iterations = 0
                self.recv()

            if self.stderr is not None:
                silent_iterations = 0
                self.recv_err()

            silent_iterations += 1

            if silent_iterations > 100:
                silent_iterations = 0
                (stdoutdata, stderrdata) = self.communicate()
                if stdoutdata:
                    log.debug(stdoutdata)
                if stderrdata:
                    log.error(stderrdata)
            time.sleep(interval)

    def communicate(self, input=None):  # pylint: disable=arguments-differ
        super().communicate(input)
        self.stdout_buff.flush()
        self.stdout_buff.seek(0)
        self.stderr_buff.flush()
        self.stderr_buff.seek(0)
        return self.stdout_buff.read(), self.stderr_buff.read()