Adding single retry to Insights jobs that time out. (#21)

* Adding single retry to Insights jobs that time out.

* Changing retry pattern to use backoff.

* fix pylint errors

* Clarifying retry function as per code review

tap_facebook/__init__.py

@@ -193,6 +193,11 @@ def advance_bookmark(state, tap_stream_id, bookmark_key, date):
 class InsightsJobTimeout(Exception):
     pass
 
+def log_insights_retry_attempt(details):
+    _, exception, _ = sys.exc_info()
+    LOGGER.info(exception)
+    LOGGER.info('Retrying Insights job...')
+
 @attr.s
 class AdsInsights(Stream):
     field_class = adsinsights.AdsInsights.Field
@@ -219,11 +224,6 @@ def __attrs_post_init__(self):
         if self.options.get('primary-keys'):
             self.key_properties.extend(self.options['primary-keys'])
 
-    @backoff.on_exception(
-        backoff.expo,
-        (InsightsJobTimeout),
-        max_tries=3,
-        factor=2)
     def job_params(self):
         start_date = pendulum.parse(get_start(self.state, self.name, self.bookmark_key))
 
@@ -252,7 +252,13 @@ def job_params(self):
             }
             buffered_start_date = buffered_start_date.add(days=1)
 
-
+    @backoff.on_exception(
+        backoff.constant,
+        InsightsJobTimeout,
+        max_tries=2,
+        interval=0,
+        on_backoff=log_insights_retry_attempt
+    )
     def run_job(self, params):
         LOGGER.info('Starting adsinsights job with params %s', params)
         job = self.account.get_insights( # pylint: disable=no-member
@@ -279,17 +285,18 @@ def run_job(self, params):
                         job_id, INSIGHTS_MAX_WAIT_TO_START_SECONDS))
             elif duration > INSIGHTS_MAX_WAIT_TO_FINISH_SECONDS and status != "Job Completed":
                 pretty_error_message = ('Insights job {} did not complete after {} minutes. ' +
-                    'This is an intermittent error and may resolve itself on subsequent queries to the Facebook API. ' +
-                    'You should deselect fields from the schema that are not necessary, ' +
-                    'as that may help improve the reliability of the Facebook API.')
-                raise Exception(pretty_error_message.format(job_id, INSIGHTS_MAX_WAIT_TO_FINISH_SECONDS//60))
+                                        'This is an intermittent error and may resolve itself on subsequent queries to the Facebook API. ' +
+                                        'You should deselect fields from the schema that are not necessary, ' +
+                                        'as that may help improve the reliability of the Facebook API.')
+                raise InsightsJobTimeout(pretty_error_message.format(job_id,
+                                                                     INSIGHTS_MAX_WAIT_TO_FINISH_SECONDS//60))
+
             LOGGER.info("sleeping for %d seconds until job is done", sleep_time)
             time.sleep(sleep_time)
             if sleep_time < INSIGHTS_MAX_ASYNC_SLEEP_SECONDS:
                 sleep_time = 2 * sleep_time
         return job
 
-
     def __iter__(self):
         for params in self.job_params():
             with metrics.job_timer('insights'):