Merge branch 'avoid_new_broker_instances' into 'master'

Don't create new broker and producer instances

See merge request !14

src/AsapoWorker/application.py

@@ -110,24 +110,33 @@ class Application:
         logging.basicConfig(level=log_level, format=format)
         logging.info("Log level set to %s", log_level)
 
-    # TODO: resuse the same broker and sender objects for all threads
+    # TODO: resusing the same broker and sender objects for all threads relies
+    # on an implementation detail of create_instance_from_configurable
     def _create_streamer(self, substream=None):
-        consumer = create_instance_from_configurable(
-            self.consumer_class, self.options["receiver"])
-
         if self.receiver_broker:
-            consumer.broker = self.receiver_broker
+            kwargs = {"broker": self.receiver_broker}
         else:
+            kwargs = {}
+
+        consumer = create_instance_from_configurable(
+            self.consumer_class, self.options["receiver"], kwargs=kwargs)
+
+        if not self.receiver_broker:
             self.receiver_broker = consumer.broker
 
         if self.producer_class:
-            sender = create_instance_from_configurable(
-                self.producer_class, self.options["sender"])
             if self.sender_broker:
                 assert self.sender_producer is not None
-                sender.broker = self.sender_broker
-                sender.producer = self.sender_producer
+                kwargs = {
+                    "broker": self.sender_broker,
+                    "producer": self.sender_producer}
             else:
+                kwargs = {}
+
+            sender = create_instance_from_configurable(
+                self.producer_class, self.options["sender"], kwargs=kwargs)
+
+            if not self.sender_broker:
                 self.sender_broker = sender.broker
                 self.sender_producer = sender.producer
         else:

src/AsapoWorker/configuration.py

@@ -165,7 +165,8 @@ def create_instance_from_configurable(
 
 
 def create_instance_from_attribute(attribute, options, kwargs):
-    assert(attribute.name not in kwargs)
+    if attribute.name in kwargs:
+        return
     config_entry = attribute.metadata[CONFIGURABLE_CONFIG_ENTRY]
     if not config_entry.flatten:
         options = options.get(attribute.name, {})

tests/test_configuration.py

@@ -418,7 +418,7 @@ def test_merge_flattened_config_from_builder_in_parent_cli(capsys):
     """
     Flattened config options from builder function are merged with identical
     config options of a parent class.
-    
+
     This test fails with attrs version 20.1.0 due to a regression in attrs.
     The regression is fixed in attrs version 20.2.0.
     """
@@ -454,3 +454,22 @@ def test_merge_flattened_config_from_builder_in_parent_cli(capsys):
     captured_flat = capsys.readouterr()
 
     assert captured_flattened == captured_flat
+
+
+def test_create_instance_overwrite_options_via_kwargs():
+    options = {
+        "simple_attribute": 10,
+        "configurable_attribute": {
+            "untyped": "whatever"}}
+    simple_attribute = 11
+    configurable_attribute = ConfigurableClass("whatever else")
+    extern_attribute = ExternClass(2, 2.34)
+    kwargs = {
+        "simple_attribute": simple_attribute,
+        "configurable_attribute": configurable_attribute,
+        "extern_attribute": extern_attribute}
+    instance = create_instance_from_configurable(
+        TopLevel, options, kwargs=kwargs)
+    assert instance.simple_attribute is simple_attribute
+    assert instance.configurable_attribute is configurable_attribute
+    assert instance.extern_attribute is extern_attribute