How to use _get_standard_streams method in tox

Best Python code snippet using tox_python

action.py

Source:action.py

...59        """this drives an interaction with a subprocess"""60        cwd = py.path.local() if cwd is None else cwd61        cmd_args = [str(x) for x in self._rewrite_args(cwd, args)]62        cmd_args_shell = " ".join(pipes.quote(i) for i in cmd_args)63        stream_getter = self._get_standard_streams(64            capture_err, cmd_args_shell, redirect, returnout, cwd65        )66        exit_code, output = None, None67        with stream_getter as (fin, out_path, stderr, stdout):68            try:69                process = self.via_popen(70                    cmd_args,71                    stdout=stdout,72                    stderr=stderr,73                    cwd=str(cwd),74                    env=os.environ.copy() if env is None else env,75                    universal_newlines=True,76                    shell=False,77                    creationflags=(78                        subprocess.CREATE_NEW_PROCESS_GROUP79                        if sys.platform == "win32"80                        else 081                        # needed for Windows signal send ability (CTRL+C)82                    ),83                )84            except OSError as exception:85                exit_code = exception.errno86            else:87                if callback is not None:88                    callback(process)89                reporter.log_popen(cwd, out_path, cmd_args_shell, process.pid)90                output = self.evaluate_cmd(fin, process, redirect)91                exit_code = process.returncode92            finally:93                if out_path is not None and out_path.exists():94                    lines = out_path.read_text("UTF-8").split("\n")95                    # first three lines are the action, cwd, and cmd - remove it96                    output = "\n".join(lines[3:])97                try:98                    if exit_code and not ignore_ret:99                        if report_fail:100                            msg = "invocation failed (exit code {:d})".format(exit_code)101                            if out_path is not None:102                                msg += ", logfile: {}".format(out_path)103                                if not out_path.exists():104                                    msg += " warning log file missing"105                            reporter.error(msg)106                            if out_path is not None and out_path.exists():107                                reporter.separator("=", "log start", Verbosity.QUIET)108                                reporter.quiet(output)109                                reporter.separator("=", "log end", Verbosity.QUIET)110                        raise InvocationError(cmd_args_shell, exit_code, output)111                finally:112                    self.command_log.add_command(cmd_args, output, exit_code)113        return output114    def evaluate_cmd(self, input_file_handler, process, redirect):115        try:116            if self.generate_tox_log and not redirect:117                if process.stderr is not None:118                    # prevent deadlock119                    raise ValueError("stderr must not be piped here")120                # we read binary from the process and must write using a binary stream121                buf = getattr(sys.stdout, "buffer", sys.stdout)122                last_time = time.time()123                while True:124                    # we have to read one byte at a time, otherwise there125                    # might be no output for a long time with slow tests126                    data = input_file_handler.read(1)127                    if data:128                        buf.write(data)129                        if b"\n" in data or (time.time() - last_time) > 1:130                            # we flush on newlines or after 1 second to131                            # provide quick enough feedback to the user132                            # when printing a dot per test133                            buf.flush()134                            last_time = time.time()135                    elif process.poll() is not None:136                        if process.stdout is not None:137                            process.stdout.close()138                        break139                    else:140                        time.sleep(0.1)141                        # the seek updates internal read buffers142                        input_file_handler.seek(0, 1)143                input_file_handler.close()144            out, _ = process.communicate()  # wait to finish145        except KeyboardInterrupt as exception:146            reporter.error("got KeyboardInterrupt signal")147            main_thread = is_main_thread()148            while True:149                try:150                    if main_thread:151                        # spin up a new thread to disable further interrupt on main thread152                        stopper = Thread(target=self.handle_interrupt, args=(process,))153                        stopper.start()154                        stopper.join()155                    else:156                        self.handle_interrupt(process)157                except KeyboardInterrupt:158                    continue159                break160            raise exception161        return out162    def handle_interrupt(self, process):163        """A three level stop mechanism for children - INT -> TERM -> KILL"""164        msg = "from {} {{}} pid {}".format(os.getpid(), process.pid)165        if process.poll() is None:166            self.info("KeyboardInterrupt", msg.format("SIGINT"))167            process.send_signal(signal.CTRL_C_EVENT if sys.platform == "win32" else signal.SIGINT)168            if self._wait(process, WAIT_INTERRUPT) is None:169                self.info("KeyboardInterrupt", msg.format("SIGTERM"))170                process.terminate()171                if self._wait(process, WAIT_TERMINATE) is None:172                    self.info("KeyboardInterrupt", msg.format("SIGKILL"))173                    process.kill()174                    process.communicate()175    @staticmethod176    def _wait(process, timeout):177        if sys.version_info >= (3, 3):178            # python 3 has timeout feature built-in179            try:180                process.communicate(timeout=WAIT_INTERRUPT)181            except subprocess.TimeoutExpired:182                pass183        else:184            # on Python 2 we need to simulate it185            delay = 0.01186            while process.poll() is None and timeout > 0:187                time.sleep(delay)188                timeout -= delay189        return process.poll()190    @contextmanager191    def _get_standard_streams(self, capture_err, cmd_args_shell, redirect, returnout, cwd):192        stdout = out_path = input_file_handler = None193        stderr = subprocess.STDOUT if capture_err else None194        if self.generate_tox_log or redirect:195            out_path = self.get_log_path(self.name)196            with out_path.open("wt") as stdout, out_path.open("rb") as input_file_handler:197                msg = "action: {}, msg: {}\ncwd: {}\ncmd: {}\n".format(198                    self.name.replace("\n", " "),199                    self.msg.replace("\n", " "),200                    str(cwd).replace("\n", " "),201                    cmd_args_shell.replace("\n", " "),202                )203                stdout.write(msg)204                stdout.flush()205                input_file_handler.read()  # read the header, so it won't be written to stdout...

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