启动 appium

appium -a 127.0.0.1 -p 4725 -bp 4726 -U d3f9cc74 --no-reset at Fri Dec 13 15:51:50 2019
appium -a 127.0.0.1 -p 4723 -bp 4724 -U 399f7063 --no-reset at Fri Dec 13 15:51:50 2019

desired_caps

{'platformName': 'android', 'noReset': True, 'appPackage': 'com.tencent.mm', 'appActivity': '.ui.LauncherUI', 'automationName': 'UIAutomator2', 'chromedriverExecutableDir': '/Users/xxx/dev/chromedriver/2.39', 'chromeOptions': {'androidProcess': 'com.tencent.mm:appbrand0'}, 'deviceName': '399f7063', 'udid': '399f7063', 'workDir': '399f7063', 'unicodeKeyboard': False, 'resetKeyboard': False, 'port': 4723, 'systemPort': 8200}
{'platformName': 'android', 'noReset': True, 'appPackage': 'com.tencent.mm', 'appActivity': '.ui.LauncherUI', 'automationName': 'UIAutomator2', 'chromedriverExecutableDir': '/Users/xxx/dev/chromedriver/2.39', 'chromeOptions': {'androidProcess': 'com.tencent.mm:appbrand0'}, 'deviceName': 'd3f9cc74', 'udid': 'd3f9cc74', 'workDir': 'd3f9cc74', 'unicodeKeyboard': False, 'resetKeyboard': False, 'port': 4725, 'systemPort': 8201}

上面是我的启动过程，由于在微信小程序里面需要切换到不同的页面，我的处理方式是

handles = self._driver.window_handles
for window in handles:
    self._driver.switch_to.window(window)
    title = self._driver.title
    if ':VISIBLE' in title:
        logger.info(f"切换到窗口：{title}")
        return True
return False

这种方式在单台设备运行的时候都没有问题，但是在多台设备同时运行的时候，运行一段时间之后再获取页面标题的时候就直接报错，报错日志如下：

self._driver.switch_to_active_wxapp_window()
common/base_driver.py:421: in switch_to_active_wxapp_window
    title = self._driver.title
../../../.virtualenvs/auto-test/lib/python3.7/site-packages/selenium/webdriver/remote/webdriver.py:342: in title
    resp = self.execute(Command.GET_TITLE)
../../../.virtualenvs/auto-test/lib/python3.7/site-packages/selenium/webdriver/remote/webdriver.py:321: in execute
    self.error_handler.check_response(response)
../../../.virtualenvs/auto-test/lib/python3.7/site-packages/appium/webdriver/errorhandler.py:29: in check_response
    raise wde
../../../.virtualenvs/auto-test/lib/python3.7/site-packages/appium/webdriver/errorhandler.py:24: in check_response
    super(MobileErrorHandler, self).check_response(response)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <appium.webdriver.errorhandler.MobileErrorHandler object at 0x106954d30>
response = {'status': 500, 'value': '{"value":{"error":"unknown error","message":"An unknown server-side error occurred while pro...ocal/lib/node_modules/appium/node_modules/appium-base-driver/lib/protocol/protocol.js:443:25)\\n    at <anonymous>"}}'}

    def check_response(self, response):
        """
        Checks that a JSON response from the WebDriver does not have an error.

        :Args:
         - response - The JSON response from the WebDriver server as a dictionary
           object.

        :Raises: If the response contains an error message.
        """
        status = response.get('status', None)
        if status is None or status == ErrorCode.SUCCESS:
            return
        value = None
        message = response.get("message", "")
        screen = response.get("screen", "")
        stacktrace = None
        if isinstance(status, int):
            value_json = response.get('value', None)
            if value_json and isinstance(value_json, basestring):
                import json
                try:
                    value = json.loads(value_json)
                    if len(value.keys()) == 1:
                        value = value['value']
                    status = value.get('error', None)
                    if status is None:
                        status = value["status"]
                        message = value["value"]
                        if not isinstance(message, basestring):
                            value = message
                            message = message.get('message')
                    else:
                        message = value.get('message', None)
                except ValueError:
                    pass

        exception_class = ErrorInResponseException
        if status in ErrorCode.NO_SUCH_ELEMENT:
            exception_class = NoSuchElementException
        elif status in ErrorCode.NO_SUCH_FRAME:
            exception_class = NoSuchFrameException
        elif status in ErrorCode.NO_SUCH_WINDOW:
            exception_class = NoSuchWindowException
        elif status in ErrorCode.STALE_ELEMENT_REFERENCE:
            exception_class = StaleElementReferenceException
        elif status in ErrorCode.ELEMENT_NOT_VISIBLE:
            exception_class = ElementNotVisibleException
        elif status in ErrorCode.INVALID_ELEMENT_STATE:
            exception_class = InvalidElementStateException
        elif status in ErrorCode.INVALID_SELECTOR \
                or status in ErrorCode.INVALID_XPATH_SELECTOR \
                or status in ErrorCode.INVALID_XPATH_SELECTOR_RETURN_TYPER:
            exception_class = InvalidSelectorException
        elif status in ErrorCode.ELEMENT_IS_NOT_SELECTABLE:
            exception_class = ElementNotSelectableException
        elif status in ErrorCode.ELEMENT_NOT_INTERACTABLE:
            exception_class = ElementNotInteractableException
        elif status in ErrorCode.INVALID_COOKIE_DOMAIN:
            exception_class = InvalidCookieDomainException
        elif status in ErrorCode.UNABLE_TO_SET_COOKIE:
            exception_class = UnableToSetCookieException
        elif status in ErrorCode.TIMEOUT:
            exception_class = TimeoutException
        elif status in ErrorCode.SCRIPT_TIMEOUT:
            exception_class = TimeoutException
        elif status in ErrorCode.UNKNOWN_ERROR:
            exception_class = WebDriverException
        elif status in ErrorCode.UNEXPECTED_ALERT_OPEN:
            exception_class = UnexpectedAlertPresentException
        elif status in ErrorCode.NO_ALERT_OPEN:
            exception_class = NoAlertPresentException
        elif status in ErrorCode.IME_NOT_AVAILABLE:
            exception_class = ImeNotAvailableException
        elif status in ErrorCode.IME_ENGINE_ACTIVATION_FAILED:
            exception_class = ImeActivationFailedException
        elif status in ErrorCode.MOVE_TARGET_OUT_OF_BOUNDS:
            exception_class = MoveTargetOutOfBoundsException
        elif status in ErrorCode.JAVASCRIPT_ERROR:
            exception_class = JavascriptException
        elif status in ErrorCode.SESSION_NOT_CREATED:
            exception_class = SessionNotCreatedException
        elif status in ErrorCode.INVALID_ARGUMENT:
            exception_class = InvalidArgumentException
        elif status in ErrorCode.NO_SUCH_COOKIE:
            exception_class = NoSuchCookieException
        elif status in ErrorCode.UNABLE_TO_CAPTURE_SCREEN:
            exception_class = ScreenshotException
        elif status in ErrorCode.ELEMENT_CLICK_INTERCEPTED:
            exception_class = ElementClickInterceptedException
        elif status in ErrorCode.INSECURE_CERTIFICATE:
            exception_class = InsecureCertificateException
        elif status in ErrorCode.INVALID_COORDINATES:
            exception_class = InvalidCoordinatesException
        elif status in ErrorCode.INVALID_SESSION_ID:
            exception_class = InvalidSessionIdException
        elif status in ErrorCode.UNKNOWN_METHOD:
            exception_class = UnknownMethodException
        else:
            exception_class = WebDriverException
        if value == '' or value is None:
            value = response['value']
        if isinstance(value, basestring):
            if exception_class == ErrorInResponseException:
                raise exception_class(response, value)
            raise exception_class(value)
        if message == "" and 'message' in value:
            message = value['message']

        screen = None
        if 'screen' in value:
            screen = value['screen']

        stacktrace = None
        if 'stackTrace' in value and value['stackTrace']:
            stacktrace = []
            try:
                for frame in value['stackTrace']:
                    line = self._value_or_default(frame, 'lineNumber', '')
                    file = self._value_or_default(frame, 'fileName', '<anonymous>')
                    if line:
                        file = "%s:%s" % (file, line)
                    meth = self._value_or_default(frame, 'methodName', '<anonymous>')
                    if 'className' in frame:
                        meth = "%s.%s" % (frame['className'], meth)
                    msg = "    at %s (%s)"
                    msg = msg % (meth, file)
                    stacktrace.append(msg)
            except TypeError:
                pass
        if exception_class == ErrorInResponseException:
            raise exception_class(response, message)
        elif exception_class == UnexpectedAlertPresentException:
            alert_text = None
            if 'data' in value:
                alert_text = value['data'].get('text')
            elif 'alert' in value:
                alert_text = value['alert'].get('text')
            raise exception_class(message, screen, stacktrace, alert_text)
>       raise exception_class(message, screen, stacktrace)
E       selenium.common.exceptions.WebDriverException: Message: An unknown server-side error occurred while processing the command. Original error: disconnected: unable to connect to renderer
E         (Session info: chrome=66.0.3359.126)
E         (Driver info: chromedriver=2.39.562713 (dd642283e958a93ebf6891600db055f1f1b4f3b2),platform=Mac OS X 10.15.1 x86_64)

../../../.virtualenvs/auto-test/lib/python3.7/site-packages/selenium/webdriver/remote/errorhandler.py:242: WebDriverException

有谁遇到过这种问题吗？求助。