Added error handling and exit statements

blocklenium/blocklenium.py

@@ -14,19 +14,29 @@
 class Blocklenium(object):
     def __init__(self, config):
 
-        self.plc_start_flag = config['PLC_START_FLAG']
+        self.config = config
+        self.plc_start_flag = self.config['PLC_START_FLAG']
 
-        self.queue = queue.Queue()
+        self.is_error = False
+
+        try:
+            self._plc = pyads.Connection(config['PLC_ID'], 851)
+        except pyads.ADSError as e:
+            logger.exception(e)
+            self.is_error = True
+            exit(1)
 
-        self._t = SeleniumWorker(self.queue, config)
+        self.queue = queue.Queue()
 
-        self._plc = pyads.Connection(config['PLC_ID'], 851)
+        try:
+            self._t = SeleniumWorker(self.queue, config)
+        except ValueError as e:
+            self.handle_error('Error during setup. Check the logs.', e)
+            exit(1)
 
         self.callback = self._plc.notification(pyads.
                                                PLCTYPE_BOOL)(
-                                                    self._callback)
-
-        self.config = config
+                                               self._callback)
 
     def _callback(self, handle, name, timestamp, value):
         if value:
@@ -37,6 +47,23 @@ def _callback(self, handle, name, timestamp, value):
              'handle: {0} | name: {1} | timestamp: {2} | value: {3}'.format(
                 handle, name, timestamp, value))
 
+    def handle_error(self, message, error=None):
+        self.is_error = True
+
+        self.queue.put(False)
+        self._t.join()
+
+        self._plc.write_by_name(self.config['PLC_ERROR_FLAG'], True,
+                                pyads.PLCTYPE_BOOL)
+        self._plc.write_by_name(self.config['PLC_ERROR_MSG'], message,
+                                pyads.PLCTYPE_STRING)
+
+        logging.error(message)
+        if error is not None:
+            logging.error(error, exc_info=True)
+
+        exit(1)
+
     def start(self):
         logger.info('Starting blocklenium...')
 
@@ -58,17 +85,17 @@ def start(self):
                     self._t.desk_username = user
                     self._t.desk_password = pwd
                 except pyads.ADSError as e:
-                    logging.error('''{0} or {1} not defined on PLC with 
+                    self.handle_error('''{0} or {1} not defined on PLC with 
                                   --login-required flag set.'''.format(
                         self.config['PLC_DESK_USER'],
-                        self.config['PLC_DESK_PW']))
+                        self.config['PLC_DESK_PW']), e)
                     return
 
             self._plc.add_device_notification(
                 self.plc_start_flag, attr,
                 self.callback)
 
-            while True:
+            while not self.is_error:
                 sleep(10)
 
                 try:
@@ -81,3 +108,4 @@ def start(self):
 
         self._t.join()
         logger.debug('Blocklenium terminated.')
+        exit(0)

blocklenium/main.py

@@ -9,27 +9,42 @@
 logger = logging.getLogger('blocklenium.main')
 
 
+if __name__ == '__main__':
+    print('Please use the click entry-point.')
+    pass
+
+
+
+
+
 @click.command()
 @click.option('--plc_id', default=settings.PLC_ID, show_default=True,
               help='ADS Id of PLC')
 @click.option('--plc_flag', 'plc_start_flag',
               default=settings.PLC_START_FLAG, show_default=True,
               help='PLC variable name of flag to start browser (BOOL)')
+@click.option('--plc_errorflag', 'plc_error_flag',
+              default=settings.PLC_ERROR_FLAG, show_default=True,
+              help='PLC variable name of flag set TRUE if an error occurs.'
+              )
+@click.option('--plc_errormsg', 'plc_error_msg',
+              default=settings.PLC_ERROR_MSG, show_default=True,
+              help='PLC variable name to hold error messages')
 @click.option('--webdriver', 'chromedriver_path',
               default=settings.CHROMEDRIVER_PATH, show_default=True,
               type=click.Path(exists=True, file_okay=True, dir_okay=False),
               help='Path to selenium webdriver for chrome')
-@click.option('--insecure-con', 'chromedriver_insecure', is_flag=True,
+@click.option('--insecure-con', 'browser_insecure_certs', is_flag=True,
               help='Suppress warning for insecure site certificates')
-@click.option('--login-required', 'chromedriver_login', is_flag=True,
+@click.option('--login-required', 'desk_login_required', is_flag=True,
               help='''Target URL requires a login. Requires the login 
                    credentials to be set to the appropriate variables in 
                    the PLC (see below for default values)''')
-@click.option('--plc-desk-user', 'plc_desk_username', show_default=True,
+@click.option('--plc-desk-user', 'plc_desk_user', show_default=True,
               default=settings.PLC_DESK_USER,
               help='''Change the PLC variable which stores the username for
                    the target URL''')
-@click.option('--plc-desk-password', 'plc_desk_password',
+@click.option('--plc-desk-password', 'plc_desk_pw',
               show_default=True,
               default=settings.PLC_DESK_PW,
               help='''Change the PLC variable which stores the password for
@@ -43,27 +58,21 @@
               help='URL to run bookmarklet on')
 def main(plc_id,
          plc_start_flag,
+         plc_error_flag,
+         plc_error_msg,
          chromedriver_path,
-         chromedriver_insecure,
-         chromedriver_login,
-         plc_desk_username,
-         plc_desk_password,
+         browser_insecure_certs,
+         desk_login_required,
+         plc_desk_user,
+         plc_desk_pw,
          bookmarklet_path,
          desk_url):
     logging.basicConfig(level=logging.INFO, stream=sys.stdout)
 
-    logger.debug('Initializing...')
+    logger.info('Initializing blocklenium...')
 
-    config = dict()
-    config['PLC_ID'] = plc_id
-    config['PLC_START_FLAG'] = plc_start_flag
-    config['PLC_DESK_USER'] = plc_desk_username
-    config['PLC_DESK_PW'] = plc_desk_password
-    config['CHROMEDRIVER_PATH'] = chromedriver_path
-    config['BROWSER_INSECURE_CERTS'] = chromedriver_insecure
-    config['BOOKMARKLET_PATH'] = bookmarklet_path
-    config['DESK_LOGIN_REQUIRED'] = chromedriver_login
-    config['DESK_URL'] = desk_url
+    # Build config dictionary from passed arguments
+    config = {key.upper(): value for key, value in locals().items()}
 
     if logger.level == logging.DEBUG:
         for k in config.keys():
@@ -72,8 +81,3 @@ def main(plc_id,
     blknm = Blocklenium(config)
 
     blknm.start()
-
-
-if __name__ == '__main__':
-    print('Please use the click entry-point.')
-    pass

blocklenium/selenium_worker.py

@@ -40,7 +40,6 @@ def __init__(self, queue, config):
             else:
                 raise ValueError('Bookmarklet file must be a web link!')
         else:
-            # TODO error handling
             with open(bookmarklet_path, "r") as f:
                 self.js = f.read()
 
@@ -68,7 +67,6 @@ def run(self):
                 if self.login_required:
                     self.desk_login()
 
-
                 # Execute JavaScript
                 if self.js is not None:
                     logger.info('Executing JavaScript...')
@@ -91,7 +89,7 @@ def desk_login(self):
         pwdfields = self.chromedriver.find_elements_by_css_selector(
             "input[id*='Password']")
 
-        try:
+        if (len(userfields) > 0) and (len(pwdfields > 0)):
             userfields[0].send_keys(self.desk_username)
             pwdfields[0].send_keys(self.desk_password)
 
@@ -104,5 +102,6 @@ def desk_login(self):
                 EC.presence_of_element_located((By.CLASS_NAME,
                                                 "timeline-header"))
             )
-        except Exception as e:
-            logger.info("Attempting to login caused {0}.".format(e))
+        else:
+            logger.info(
+                'Expected Login page but found no login fields. Ignored')

blocklenium/settings.py

@@ -1,17 +1,29 @@
+# The path to the Webdriver (for Chrome/Chromium)
 CHROMEDRIVER_PATH = 'C:\\WebDriver\\bin\\chromedriver.exe'
 
-BOOKMARKLET_PATH = 'C:\\Users\\Administrator\\Desktop\\test-bookmarklet.js'
-
+# Tell the browser to ignore invalid/insecure https connections
 BROWSER_INSECURE_CERTS = True
 
-DESK_LOGIN_REQUIRED = True
-
+# The URL pointing to the Franka Control Webinterface (Desk)
 DESK_URL = 'robot.franka.de'
 
+# Expect a login page when calling Desk
+DESK_LOGIN_REQUIRED = True
+
+# The ADS Id of the PLC (defaults to localhost)
 PLC_ID = '127.0.0.1.1.1'
 
+# Boolean flag on the PLC, set TRUE to start the web browser
 PLC_START_FLAG = 'GVL.bStartBlockly'
 
+# Blocklenium sets this flag TRUE if it terminates due to an exception
+PLC_ERROR_FLAG = 'GVL.bBlockleniumError'
+
+# Blocklenium sets this to it's terminating error message
+PLC_ERROR_MSG = 'GVL.sBlockleniumErrorMsg'
+
+# Set the Username for Desk on the PLC
 PLC_DESK_USER = 'GVL.sDeskUsername'
 
+# Set the Password for Desk on the PLC
 PLC_DESK_PW = 'GVL.sDeskPassword'