Update linting

tools/slo-generator/.pylintrc

@@ -140,7 +140,8 @@ disable=print-statement,
         deprecated-sys-function,
         exception-escape,
         comprehension-escape,
-        arguments-differ
+        arguments-differ,
+        dangerous-default-value
 
 # Enable the message, report, category or checker with the given id(s). You can
 # either give multiple identifier separated by comma (,) or put this option
@@ -553,7 +554,7 @@ max-locals=30
 max-parents=7
 
 # Maximum number of public methods for a class (see R0904).
-max-public-methods=20
+max-public-methods=30
 
 # Maximum number of return / yield for function / method body.
 max-returns=6

tools/slo-generator/slo_generator/backends/elasticsearch.py

@@ -20,14 +20,11 @@
 
 from elasticsearch import Elasticsearch
 
-from slo_generator.backends.base import MetricBackend
-
 LOGGER = logging.getLogger(__name__)
 
 
-class ElasticsearchBackend(MetricBackend):
+class ElasticsearchBackend:
     """Backend for querying metrics from ElasticSearch."""
-
     def __init__(self, **kwargs):
         self.client = kwargs.get('client')
         if self.client is None:

tools/slo-generator/slo_generator/backends/prometheus.py

@@ -22,14 +22,11 @@
 import pprint
 from prometheus_http_client import Prometheus
 
-from slo_generator.backends.base import MetricBackend
-
 LOGGER = logging.getLogger(__name__)
 
 
-class PrometheusBackend(MetricBackend):
+class PrometheusBackend:
     """Backend for querying metrics from Prometheus."""
-
     def __init__(self, **kwargs):
         self.client = kwargs.pop('client')
         if not self.client:

tools/slo-generator/slo_generator/backends/stackdriver.py

@@ -21,19 +21,17 @@
 import warnings
 
 from google.cloud import monitoring_v3
-from slo_generator.backends.base import MetricBackend
 
 LOGGER = logging.getLogger(__name__)
 
 
-class StackdriverBackend(MetricBackend):
+class StackdriverBackend:
     """Backend for querying metrics from Stackdriver Monitoring.
 
     Args:
         obj:`monitoring_v3.MetricServiceClient` (optional): A Stackdriver
             Monitoring client. Initialize a new client if omitted.
     """
-
     def __init__(self, client=None, **kwargs):  # pylint: disable=W0613
         self.client = client
         if client is None:
@@ -87,7 +85,8 @@ def good_bad_ratio(self, timestamp, window, **slo_config):
             bad_event_count = \
                 StackdriverBackend.count(valid_ts) - good_event_count
         else:
-            raise Exception("Oneof `filter_bad` or `filter_valid` is required.")
+            raise Exception(
+                "Oneof `filter_bad` or `filter_valid` is required.")
 
         LOGGER.debug(f'Good events: {good_event_count} | '
                      f'Bad events: {bad_event_count}')