BotZ/bot_z/zdaemon.py

# -*- coding: utf-8 -*-

"""Daemon for local execution of commands."""

import errno
import functools
import json
import lockfile
import logging
import logging.handlers
import os
import signal
import typing as T

from bot_z.bot_z import Operator
import daemon
from selenium.webdriver.common.keys import Keys


logging.basicConfig(
    level=os.environ.get("BOTZ_LOGLEVEL", logging.INFO),
    format="%(levelname)s: [%(name)s] -> %(message)s",
)

syslog = logging.handlers.SysLogHandler()

logger = logging.getLogger(__name__)
logger.addHandler(syslog)
logger.debug("Init at debug")


def start_daemon(
    base_uri: str,
    name: str,
    timeout: int = None,
    proxy: T.Optional[T.Tuple[str, int]] = None,
    headless: bool = True,
    debug: bool = False,
) -> Operator:
    """
    Spawns the Operator object.
    """
    optional_args = {}  # type: T.Dict[str, T.Any]
    if timeout is not None:
        optional_args["timeout"] = timeout
    if proxy is not None:
        optional_args["proxy"] = proxy
    optional_args["headless"] = headless
    optional_args["debug"] = debug
    logger.info("Started Operator.")
    logger.debug(
        "Operator parameters: "
        "{base_uri: %s, name: %s, timeout: %s, proxy: %s, headless: %s, debug: %s}",
        base_uri,
        name,
        timeout,
        proxy,
        headless,
        debug,
    )
    return Operator(base_uri=base_uri, name=name, **optional_args)


def drop_operator(op: Operator) -> None:
    """
    Stops the Operator.
    """
    logger.debug("Stopping Operator...")
    logger.debug("Operator id: %s", id(op))
    op.quit()
    logger.info("Stopped Operator.")


def reload_operator(op: Operator) -> None:
    """
    Reload the Operator using the same object.
    """
    op_focus = op.switch_to.active_element
    op_focus.send_keys(Keys.CONTROL + "Escape")
    op.delete_all_cookies()
    logger.info("Operator session cleaned.")


def operator_status(op: Operator, debug: bool = False) -> T.Dict[str, str]:
    """
    Get the current operator status.
    """
    status = {}  # type: T.Dict[str, str]
    status["is_logged_in"] = str(op.logged_in)
    status["is_checked_in"] = str(op.checked_in)
    if debug:
        status["interal_state"] = str(dir(op))
    logger.info("Status: %s", status)

    return status


def daemon_process(
    fifo_path: str,
    working_dir: str,
    umask: int,
    pidfile: lockfile.FileLock,
    base_uri: str,
    name: str,
    timeout: int = None,
    proxy: T.Optional[T.Tuple[str, int]] = None,
    headless: bool = True,
    debug: bool = False,
    foreground: bool = False,
) -> None:
    """
    The daemon function.
    """
    op = start_daemon(base_uri, name, timeout, proxy, headless, debug)
    logger.debug("Started operator id: %s", id(op))
    context = daemon.DaemonContext(
        working_directory=working_dir, umask=umask, pidfile=pidfile
    )
    _stop = functools.partial(drop_operator, op)
    _reload = functools.partial(reload_operator, op)
    _status = functools.partial(operator_status, op)
    context.signal_map = {
        signal.SIGTERM: _stop,
        signal.SIGHUP: "terminate",
        signal.SIGUSR1: _reload,
        signal.SIGUSR2: _status,
    }
    cmd_map = {"stop": _stop, "reload": _reload, "status": _status}

    if foreground:
        listen_commands(fifo_path, cmd_map)
        return
    with context:
        listen_commands(fifo_path, cmd_map)


class Fifo(object):
    """
    Iterator to continuously read the command fifo.
    """

    def __init__(self, fifopath: str, mode: str = "r") -> None:
        try:
            os.mkfifo(fifopath)
            logger.info("Control pipe opened at: %s", fifopath)
        except OSError as err:
            if err.errno != errno.EEXIST:
                logger.critical("Could not open control pipe at: %s", fifopath)
                raise
        self.fh = open(fifopath, mode)

    def __iter__(self):  # pragma: noqa
        return self

    def __next__(self) -> str:
        data = self.fh.read()
        # This is a never ending iterator. We should exit the
        # loop independently.
        return data

    def __del__(self) -> None:
        self.fh.close()

    def __enter__(self) -> T.TextIO:
        return self.fh

    def __exit__(self, *args) -> None:
        self.fh.close()

    def write(self, data) -> None:
        self.fh.write(data)
        self.fh.flush()


def listen_commands(fifopath: str, cmd_map: T.Dict[str, T.Callable]) -> None:
    """
    The main loop to listen incoming commands.
    """
    while True:
        fifo = Fifo(fifopath, "r")
        for command in fifo:
            if command == "stop":
                logger.debug("Received command: %s", "stop")
                cmd_map["stop"]()
                return
            elif command == "reload":
                logger.debug("Received command: %s", "reload")
                cmd_map["reload"]()
            elif command.startswith("status"):
                logger.debug("Received command: %s", "status")
                status = cmd_map["status"]()
                logger.debug("Status: %s", status)
                jenc = json.JSONEncoder()
                with Fifo(command.split("|")[-1], "w") as rfifo:
                    rfifo.write(jenc.encode(status))