Add ability to deserialize single message with message.loads

Signed-off-by: Sebastian Wojciechowski <s.wojciechowski89@gmail.com>
fedora-infra · May 15, 2019 · a783742 · a783742
1 parent be3e885
commit a783742
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Showing 2 changed files with 74 additions and 81 deletions.
diff --git a/fedora_messaging/message.py b/fedora_messaging/message.py
@@ -244,84 +244,81 @@ def dumps(messages):
 
 def loads(serialized_messages):
     """
-    Deserialize messages from a JSON formatted str
+    Deserialize message from a JSON formatted str.
 
     Args:
-        serialized_messages (JSON str):
+        serialized_message (JSON str): JSON string message to deserialize.
 
     Returns:
-        list: Deserialized message objects.
+        Message: Deserialized message object.
 
     Raises:
         ValidationError: If deserialized message validation failed.
-        KeyError: If serialized_messages aren't properly serialized.
-        ValueError: If serialized_messages is not valid JSON
+        KeyError: If serialized_message aren't properly serialized.
+        ValueError: If serialized_message is not valid JSON
     """
     try:
-        messages_dicts = json.loads(serialized_messages)
+        message_dict = json.loads(serialized_messages)
     except ValueError:
         _log.error("Loading serialized messages failed.")
         raise
 
-    messages = []
-    for message_dict in messages_dicts:
-        try:
-            headers = message_dict["headers"]
-        except KeyError:
-            _log.error("Message saved without headers.")
-            raise
+    try:
+        headers = message_dict["headers"]
+    except KeyError:
+        _log.error("Message saved without headers.")
+        raise
 
-        try:
-            MessageClass = get_class(headers["fedora_messaging_schema"])
-        except KeyError:
-            _log.error("Message (headers=%r) saved without a schema header.", headers)
-            raise
+    try:
+        MessageClass = get_class(headers["fedora_messaging_schema"])
+    except KeyError:
+        _log.error("Message (headers=%r) saved without a schema header.", headers)
+        raise
 
-        try:
-            body = message_dict["body"]
-        except KeyError:
-            _log.error("Message saved without body.")
-            raise
+    try:
+        body = message_dict["body"]
+    except KeyError:
+        _log.error("Message saved without body.")
+        raise
 
-        try:
-            id = message_dict["id"]
-        except KeyError:
-            _log.error("Message saved without id.")
-            raise
+    try:
+        id = message_dict["id"]
+    except KeyError:
+        _log.error("Message saved without id.")
+        raise
 
-        try:
-            queue = message_dict["queue"]
-        except KeyError:
-            _log.warning("Message saved without queue.")
-            queue = None
+    try:
+        queue = message_dict["queue"]
+    except KeyError:
+        _log.warning("Message saved without queue.")
+        queue = None
 
-        try:
-            topic = message_dict["topic"]
-        except KeyError:
-            _log.error("Message saved without topic.")
-            raise
+    try:
+        topic = message_dict["topic"]
+    except KeyError:
+        _log.error("Message saved without topic.")
+        raise
 
-        try:
-            severity = headers["fedora_messaging_severity"]
-        except KeyError:
-            _log.error("Message saved without a severity.")
-            raise
+    try:
+        severity = headers["fedora_messaging_severity"]
+    except KeyError:
+        _log.error("Message saved without a severity.")
+        raise
 
-        message = MessageClass(
-            body=body, topic=topic, headers=headers, severity=severity
-        )
-        try:
-            message.validate()
-            _log.debug("Successfully validated message %r", message)
-        except jsonschema.exceptions.ValidationError as e:
-            _log.error("Message validation of %r failed: %r", message, e)
-            raise ValidationError(e)
+    message = MessageClass(
+        body=body, topic=topic, headers=headers, severity=severity
+    )
+    try:
+        message.validate()
+        _log.debug("Successfully validated message %r", message)
+    except jsonschema.exceptions.ValidationError as e:
+        _log.error("Message validation of %r failed: %r", message, e)
+        raise ValidationError(e)
 
-        message.queue = queue
-        message.id = id
-        messages.append(message)
+    message.queue = queue
+    message.id = id
 
-    return messages
+    return message
 
 
 class Message(object):

diff --git a/fedora_messaging/tests/unit/test_message.py b/fedora_messaging/tests/unit/test_message.py
@@ -102,16 +102,14 @@ def test_improper_messages(self):
 class MessageLoadsTests(unittest.TestCase):
     """Tests for the :func:`fedora_messaging.message.loads` function."""
 
-    def test_proper_json(self):
+    def test_proper_json_with_dict(self):
         """Assert loading message from json work."""
         message_json = (
-            '[{"topic": "test topic", "headers": {"fedora_messaging_schema": "base.message", '
+            '{"topic": "test topic", "headers": {"fedora_messaging_schema": "base.message", '
             '"fedora_messaging_severity": 30}, "id": "test id", "body": '
-            '{"test_key": "test_value"}, "queue": "test queue"}]'
+            '{"test_key": "test_value"}, "queue": "test queue"}'
         )
-        messages = message.loads(message_json)
-        test_message = messages[0]
-        self.assertEqual(len(messages), 1)
+        test_message = message.loads(message_json)
         self.assertIsInstance(test_message, message.Message)
         self.assertEqual("test topic", test_message.topic)
         self.assertEqual("test id", test_message.id)
@@ -134,8 +132,8 @@ def test_improper_json(self):
     def test_missing_headers(self):
         """Assert proper exception is raised when headers are missing."""
         message_json = (
-            '[{"topic": "test topic", "id": "test id",'
-            '"body": {"test_key": "test_value"}, "queue": "test queue"}]'
+            '{"topic": "test topic", "id": "test id",'
+            '"body": {"test_key": "test_value"}, "queue": "test queue"}'
         )
         with mock.patch("fedora_messaging.message._log") as mock_log:
             self.assertRaises(KeyError, message.loads, message_json)
@@ -144,8 +142,8 @@ def test_missing_headers(self):
     def test_missing_messaging_schema(self):
         """Assert proper exception is raised when messaging schema missing."""
         message_json = (
-            '[{"topic": "test topic", "headers": {"fedora_messaging_severity": 30}, '
-            '"id": "test id", "body": {"test_key": "test_value"}, "queue": "test queue"}]'
+            '{"topic": "test topic", "headers": {"fedora_messaging_severity": 30}, '
+            '"id": "test id", "body": {"test_key": "test_value"}, "queue": "test queue"}'
         )
         with mock.patch("fedora_messaging.message._log") as mock_log:
             self.assertRaises(KeyError, message.loads, message_json)
@@ -157,9 +155,9 @@ def test_missing_messaging_schema(self):
     def test_missing_body(self):
         """Assert proper exception is raised when body is missing."""
         message_json = (
-            '[{"topic": "test topic", "headers": {"fedora_messaging_schema": '
+            '{"topic": "test topic", "headers": {"fedora_messaging_schema": '
             '"base.message", "fedora_messaging_severity": 30}, "id": "test id", '
-            '"queue": "test queue"}]'
+            '"queue": "test queue"}'
         )
         with mock.patch("fedora_messaging.message._log") as mock_log:
             self.assertRaises(KeyError, message.loads, message_json)
@@ -168,9 +166,9 @@ def test_missing_body(self):
     def test_missing_id(self):
         """Assert proper exception is raised when id is missing."""
         message_json = (
-            '[{"topic": "test topic", "headers": {"fedora_messaging_schema": '
+            '{"topic": "test topic", "headers": {"fedora_messaging_schema": '
             '"base.message", "fedora_messaging_severity": 30}, '
-            '"body": {"test_key": "test_value"}, "queue": "test queue"}]'
+            '"body": {"test_key": "test_value"}, "queue": "test queue"}'
         )
         with mock.patch("fedora_messaging.message._log") as mock_log:
             self.assertRaises(KeyError, message.loads, message_json)
@@ -179,15 +177,13 @@ def test_missing_id(self):
     def test_missing_queue(self):
         """Assert message without queue is returned and warning is printed."""
         message_json = (
-            '[{"topic": "test topic", "headers": {"fedora_messaging_schema": '
+            '{"topic": "test topic", "headers": {"fedora_messaging_schema": '
             '"base.message", "fedora_messaging_severity": 30}, "id": "test id", '
-            '"body": {"test_key": "test_value"}}]'
+            '"body": {"test_key": "test_value"}}'
         )
         with mock.patch("fedora_messaging.message._log") as mock_log:
-            messages = message.loads(message_json)
+            test_message = message.loads(message_json)
         mock_log.warning.assert_called_once_with("Message saved without queue.")
-        test_message = messages[0]
-        self.assertEqual(len(messages), 1)
         self.assertEqual("test topic", test_message.topic)
         self.assertEqual("test id", test_message.id)
         self.assertEqual({"test_key": "test_value"}, test_message.body)
@@ -202,9 +198,9 @@ def test_missing_queue(self):
     def test_missing_topic(self):
         """Assert proper exception is raised when topic is missing."""
         message_json = (
-            '[{"headers": {"fedora_messaging_schema": "base.message", '
+            '{"headers": {"fedora_messaging_schema": "base.message", '
             '"fedora_messaging_severity": 30}, "id": "test id", '
-            '"body": {"test_key": "test_value"}, "queue": "test queue"}]'
+            '"body": {"test_key": "test_value"}, "queue": "test queue"}'
         )
         with mock.patch("fedora_messaging.message._log") as mock_log:
             self.assertRaises(KeyError, message.loads, message_json)
@@ -213,9 +209,9 @@ def test_missing_topic(self):
     def test_missing_severity(self):
         """Assert proper exception is raised when topic severity missing."""
         message_json = (
-            '[{"topic": "test topic", "headers": {"fedora_messaging_schema": '
+            '{"topic": "test topic", "headers": {"fedora_messaging_schema": '
             '"base.message"}, "id": "test id", "body": {"test_key": "test_value"},'
-            '"queue": "test queue"}]'
+            '"queue": "test queue"}'
         )
         with mock.patch("fedora_messaging.message._log") as mock_log:
             self.assertRaises(KeyError, message.loads, message_json)
@@ -224,9 +220,9 @@ def test_missing_severity(self):
     def test_validation_failure(self):
         """Assert proper exception is raised when message validation failed."""
         message_json = (
-            '[{"topic": "test topic", "headers": {"fedora_messaging_schema": "base.message", '
+            '{"topic": "test topic", "headers": {"fedora_messaging_schema": "base.message", '
             '"fedora_messaging_severity": 41}, "id": "test id", '
-            '"body": {"test_key": "test_value"}, "queue": "test queue"}]'
+            '"body": {"test_key": "test_value"}, "queue": "test queue"}'
         )
         with mock.patch("fedora_messaging.message._log") as mock_log:
             self.assertRaises(exceptions.ValidationError, message.loads, message_json)