Philip/ussd poler

apps/cic-ussd/cic_ussd/processor/menu.py

@@ -31,7 +31,8 @@ from cic_ussd.cache import cache_data_key, cache_data, get_cached_data
 from cic_ussd.db.models.account import Account
 from cic_ussd.metadata import PersonMetadata
 from cic_ussd.phone_number import Support
-from cic_ussd.processor.util import parse_person_metadata, ussd_menu_list, wait_for_session_data
+from cic_ussd.processor.poller import wait_for_session_data
+from cic_ussd.processor.util import parse_person_metadata, ussd_menu_list
 from cic_ussd.session.ussd_session import save_session_data
 from cic_ussd.state_machine.logic.language import preferred_langauge_from_selection
 from cic_ussd.translation import translation_for

apps/cic-ussd/cic_ussd/processor/poller.py

@@ -0,0 +1,104 @@
+# standard imports
+import logging
+import time
+from queue import Queue
+from typing import Callable, Dict, Optional, Tuple, Union
+
+# external imports
+from cic_types.condiments import MetadataPointer
+
+# local imports
+from cic_ussd.cache import cache_data_key, get_cached_data
+from cic_ussd.error import MaxRetryReached
+
+
+logg = logging.getLogger()
+
+
+# adapted from https://github.com/justiniso/polling/blob/master/polling.py
+# opted not to use the package to reduce dependency
+def poller(args: Optional[Tuple],
+           interval: int,
+           kwargs: Optional[Dict],
+           max_retry: int,
+           target: Callable[..., Union[Dict, str]]):
+    """"""
+    collected_values: list = []
+    expected_value = None
+    tries = 0
+
+    while True:
+        if tries >= max_retry:
+            raise MaxRetryReached(collected_values, expected_value)
+        try:
+            if args:
+                value = target(*args)
+            elif kwargs:
+                value = target(**kwargs)
+            else:
+                value = target()
+            expected_value = value
+        except () as error:
+            expected_value = error
+        else:
+            if bool(value) or value == {}:
+                logg.debug(f'Resource: {expected_value} now available.')
+                break
+        collected_values.append(expected_value)
+        logg.debug(f'Collected values are: {collected_values}')
+        tries += 1
+        time.sleep(interval)
+
+
+def wait_for_cache(identifier: Union[list, bytes],
+                   resource_name: str,
+                   salt: MetadataPointer,
+                   interval: int = 1,
+                   max_retry: int = 5):
+    """
+    :param identifier:
+    :type identifier:
+    :param interval:
+    :type interval:
+    :param resource_name:
+    :type resource_name:
+    :param salt:
+    :type salt:
+    :param max_retry:
+    :type max_retry:
+    :return:
+    :rtype:
+    """
+    key: str = cache_data_key(identifier=identifier, salt=salt)
+    logg.debug(f'Polling for resource: {resource_name} at: {key} every: {interval} second(s) for {max_retry} seconds.')
+    poller(args=(key,), interval=interval, kwargs=None, max_retry=max_retry, target=get_cached_data)
+
+
+def wait_for_session_data(resource_name: str,
+                          session_data_key: str,
+                          ussd_session: dict,
+                          interval: int = 1,
+                          max_retry: int = 5):
+    """
+    :param interval:
+    :type interval:
+    :param resource_name:
+    :type resource_name:
+    :param session_data_key:
+    :type session_data_key:
+    :param ussd_session:
+    :type ussd_session:
+    :param max_retry:
+    :type max_retry:
+    :return:
+    :rtype:
+    """
+    # poll for data element first
+    logg.debug(f'Data poller with max retry at: {max_retry}. Checking for every: {interval} seconds.')
+    poller(args=('data',), interval=interval, kwargs=None, max_retry=max_retry, target=ussd_session.get)
+
+    # poll for session data element
+    get_session_data = ussd_session.get('data').get
+    logg.debug(f'Session data poller for: {resource_name} with max retry at: {max_retry}. Checking for every: {interval} seconds.')
+    poller(args=(session_data_key,), interval=interval, kwargs=None, max_retry=max_retry, target=get_session_data)
+

apps/cic-ussd/cic_ussd/processor/util.py

@@ -102,77 +102,3 @@ def ussd_menu_list(fallback: str, menu_list: list, split: int = 3) -> List[str]:
         except IndexError:
             menu_list_reprs.append(fallback)
     return menu_list_reprs
-
-
-def wait_for_cache(identifier: Union[list, bytes], resource_name: str, salt: MetadataPointer, interval: int = 1, max_retry: int = 5):
-    """
-    :param identifier:
-    :type identifier:
-    :param interval:
-    :type interval:
-    :param resource_name:
-    :type resource_name:
-    :param salt:
-    :type salt:
-    :param max_retry:
-    :type max_retry:
-    :return:
-    :rtype:
-    """
-    key = cache_data_key(identifier=identifier, salt=salt)
-    resource = get_cached_data(key)
-    counter = 0
-    while resource is None:
-        logg.debug(f'Waiting for: {resource_name} at: {key}. Checking after: {interval} ...')
-        time.sleep(interval)
-        counter += 1
-        resource = get_cached_data(key)
-        if resource is not None:
-            logg.debug(f'{resource_name} now available.')
-            break
-        else:
-            if counter == max_retry:
-                logg.debug(f'Could not find: {resource_name} within: {max_retry}')
-                break
-
-
-def wait_for_session_data(resource_name: str, session_data_key: str, ussd_session: dict, interval: int = 1, max_retry: int = 5):
-    """
-    :param interval:
-    :type interval:
-    :param resource_name:
-    :type resource_name:
-    :param session_data_key:
-    :type session_data_key:
-    :param ussd_session:
-    :type ussd_session:
-    :param max_retry:
-    :type max_retry:
-    :return:
-    :rtype:
-    """
-    data = ussd_session.get('data')
-    data_poller = 0
-    while not data:
-        logg.debug(f'Waiting for data object on ussd session: {ussd_session.get("external_session_id")}')
-        logg.debug(f'Data poller at: {data_poller}. Checking again after: {interval} secs...')
-        time.sleep(interval)
-        data_poller += 1
-        if data:
-            logg.debug(f'Data object found, proceeding to poll for: {session_data_key}')
-            break
-    if data:
-        session_data_poller = 0
-        session_data = data.get(session_data_key)
-        while not session_data_key:
-            logg.debug(
-                f'Session data poller at: {data_poller} with max retry at: {max_retry}. Checking again after: {interval} secs...')
-            time.sleep(interval)
-            session_data_poller += 1
-
-            if session_data:
-                logg.debug(f'{resource_name} now available.')
-                break
-
-            elif session_data_poller >= max_retry:
-                logg.debug(f'Could not find data object within: {max_retry}')