HOTFIX: Avoid mutable default arguments in system test services

Author: Jason Gustafson <jason@confluent.io>

Reviewers: Apurva Mehta <apurva.1618@gmail.com>, Ewen Cheslack-Postava <ewen@confluent.io>

Closes #1947 from hachikuji/hotfix-producer-perf-service

tests/kafkatest/services/console_consumer.py

@@ -89,7 +89,7 @@ class ConsoleConsumer(KafkaPathResolverMixin, JmxMixin, BackgroundThreadService)
 
     def __init__(self, context, num_nodes, kafka, topic, group_id="test-consumer-group", new_consumer=False,
                  message_validator=None, from_beginning=True, consumer_timeout_ms=None, version=TRUNK,
-                 client_id="console-consumer", print_key=False, jmx_object_names=None, jmx_attributes=[],
+                 client_id="console-consumer", print_key=False, jmx_object_names=None, jmx_attributes=None,
                  enable_systest_events=False, stop_timeout_sec=15):
         """
         Args:
@@ -110,7 +110,7 @@ class ConsoleConsumer(KafkaPathResolverMixin, JmxMixin, BackgroundThreadService)
             stop_timeout_sec            After stopping a node, wait up to stop_timeout_sec for the node to stop,
                                         and the corresponding background thread to finish successfully.
         """
-        JmxMixin.__init__(self, num_nodes, jmx_object_names, jmx_attributes)
+        JmxMixin.__init__(self, num_nodes, jmx_object_names, jmx_attributes or [])
         BackgroundThreadService.__init__(self, context, num_nodes)
         self.kafka = kafka
         self.new_consumer = new_consumer

tests/kafkatest/services/kafka/kafka.py

@@ -68,14 +68,14 @@ class KafkaService(KafkaPathResolverMixin, JmxMixin, Service):
     def __init__(self, context, num_nodes, zk, security_protocol=SecurityConfig.PLAINTEXT, interbroker_security_protocol=SecurityConfig.PLAINTEXT,
                  client_sasl_mechanism=SecurityConfig.SASL_MECHANISM_GSSAPI, interbroker_sasl_mechanism=SecurityConfig.SASL_MECHANISM_GSSAPI,
                  authorizer_class_name=None, topics=None, version=TRUNK, jmx_object_names=None,
-                 jmx_attributes=[], zk_connect_timeout=5000, zk_session_timeout=6000):
+                 jmx_attributes=None, zk_connect_timeout=5000, zk_session_timeout=6000):
         """
         :type context
         :type zk: ZookeeperService
         :type topics: dict
         """
         Service.__init__(self, context, num_nodes)
-        JmxMixin.__init__(self, num_nodes, jmx_object_names, jmx_attributes)
+        JmxMixin.__init__(self, num_nodes, jmx_object_names, jmx_attributes or [])
 
         self.zk = zk
 

tests/kafkatest/services/monitor/jmx.py

@@ -21,9 +21,9 @@ class JmxMixin(object):
     - this is not a service in its own right.
     - we assume the service using JmxMixin also uses KafkaPathResolverMixin
     """
-    def __init__(self, num_nodes, jmx_object_names=None, jmx_attributes=[]):
+    def __init__(self, num_nodes, jmx_object_names=None, jmx_attributes=None):
         self.jmx_object_names = jmx_object_names
-        self.jmx_attributes = jmx_attributes
+        self.jmx_attributes = jmx_attributes or []
         self.jmx_port = 9192
 
         self.started = [False] * num_nodes
@@ -88,4 +88,4 @@ class JmxMixin(object):
 
     def read_jmx_output_all_nodes(self):
         for node in self.nodes:
-            self.read_jmx_output(self.idx(node), node)
+            self.read_jmx_output(self.idx(node), node)

tests/kafkatest/services/performance/producer_performance.py

@@ -34,10 +34,10 @@ class ProducerPerformanceService(JmxMixin, PerformanceService):
     LOG_FILE = os.path.join(LOG_DIR, "producer_performance.log")
     LOG4J_CONFIG = os.path.join(PERSISTENT_ROOT, "tools-log4j.properties")
 
-    def __init__(self, context, num_nodes, kafka, topic, num_records, record_size, throughput, version=TRUNK, settings={},
-                 intermediate_stats=False, client_id="producer-performance", jmx_object_names=None, jmx_attributes=[]):
+    def __init__(self, context, num_nodes, kafka, topic, num_records, record_size, throughput, version=TRUNK, settings=None,
+                 intermediate_stats=False, client_id="producer-performance", jmx_object_names=None, jmx_attributes=None):
 
-        JmxMixin.__init__(self, num_nodes, jmx_object_names, jmx_attributes)
+        JmxMixin.__init__(self, num_nodes, jmx_object_names, jmx_attributes or [])
         PerformanceService.__init__(self, context, num_nodes)
 
         self.logs = {
@@ -71,7 +71,7 @@ class ProducerPerformanceService(JmxMixin, PerformanceService):
             'record_size': record_size,
             'throughput': throughput
         }
-        self.settings = settings
+        self.settings = settings or {}
         self.intermediate_stats = intermediate_stats
         self.client_id = client_id