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ajaycjAjay Chinthalapalli Jayakumar
ajaycj
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Ajay Chinthalapalli Jayakumar
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Custom Event Hooks Event Emission (#164)
* custom hook impl Signed-off-by: Ajay Chinthalapalli Jayakumar <[email protected]> * refactor and unit tests Signed-off-by: Ajay Chinthalapalli Jayakumar <[email protected]> * readme and change log Signed-off-by: Ajay Chinthalapalli Jayakumar <[email protected]> * handling both hook and new relic Signed-off-by: Ajay Chinthalapalli Jayakumar <[email protected]> * more tests to increase coverage + static/format fixes Signed-off-by: Ajay Chinthalapalli Jayakumar <[email protected]> * remove unused imports Signed-off-by: Ajay Chinthalapalli Jayakumar <[email protected]> * remove noisy logs + more tests Signed-off-by: Ajay Chinthalapalli Jayakumar <[email protected]> * fixes and implement review suggestions Signed-off-by: Ajay Chinthalapalli Jayakumar <[email protected]> * stic-fx and make format Signed-off-by: Ajay Chinthalapalli Jayakumar <[email protected]> --------- Signed-off-by: Ajay Chinthalapalli Jayakumar <[email protected]> Co-authored-by: Ajay Chinthalapalli Jayakumar <[email protected]>
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‎.gitignore

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@@ -128,6 +128,9 @@ ENV/
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# IntelliJ
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/out/
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# Visual Studio Code
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.vscode/
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# mpeltonen/sbt-idea plugin
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.idea_modules/
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‎CHANGELOG.md

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@@ -7,6 +7,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
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# [Unreleased]
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- [PR 156](https://github.com/salesforce/django-declarative-apis/pull/156) Update GitHub action versions
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- [PR 162](https://github.com/salesforce/django-declarative-apis/pull/162) Fix Makefile install target
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- [PR 164](https://github.com/salesforce/django-declarative-apis/pull/164) Custom Event Hooks Event Emission
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# [0.31.7]
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- [PR 148](https://github.com/salesforce/django-declarative-apis/pull/148) chore: upgrade django 4.2 LTS

‎README.md

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@@ -95,3 +95,10 @@ class PingDefinition(machinery.BaseEndpointDefinition):
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def resource(self):
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return {'ping': 'pong'}
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```
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Optional: Implement Custom Event Hooks for Event Emission
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-----
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```bash
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# settings.py
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DDA_EVENT_HOOK = "my_app.hooks.custom_event_handler"
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```

‎django_declarative_apis/events.py

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#
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# Copyright (c) 2025, salesforce.com, inc.
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# All rights reserved.
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# SPDX-License-Identifier: BSD-3-Clause
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# For full license text, see the LICENSE file in the repo root or https://opensource.org/licenses/BSD-3-Clause
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#
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import importlib
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from enum import Enum
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import logging
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from django.conf import settings
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logger = logging.getLogger(__name__)
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HOOK = getattr(settings, "DDA_EVENT_HOOK", None)
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# Enum for event types
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class EventType(Enum):
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QUEUE_SNAPSHOT = "queue_snapshot"
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TASK_RETRY_ATTEMPT = "task_retry"
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def _import_hook(hook_path):
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"""
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Import and return a hook function from a string path.
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This function dynamically imports a hook function specified by a dotted string path.
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It ensures that the imported object is callable and raises an error if it is not.
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Args:
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hook_path (str): The dotted string path to the hook function.
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For example, 'module.submodule.function'.
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Returns:
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Callable: The imported hook function.
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Raises:
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TypeError: If the imported object is not callable.
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"""
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module_path, function_name = hook_path.rsplit(".", 1)
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module = importlib.import_module(module_path)
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function = getattr(module, function_name)
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if not callable(function):
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raise TypeError(f"Consumer getter ({hook_path}) must be callable")
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return function
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def emit_events(event_type, payload):
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"""
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Emit a metric event using the configured hook.
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This function sends an event to a custom hook, if configured, with the specified
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event type and payload. The hook is dynamically imported and executed. Logs any errors
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encountered during the hook execution.
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Args:
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event_type (EventType): The type of the event, as defined in the EventType enum.
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payload (dict): A dictionary containing the data associated with the event.
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This data is passed to the custom hook for processing.
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Raises:
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Exception: Logs an error if the custom hook encounters an issue during execution.
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"""
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if HOOK:
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try:
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hook_callable = _import_hook(HOOK)
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hook_callable(event_type, payload)
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logger.info(f"Event emitted via custom hook: {event_type}")
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except Exception as e:
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logger.error(f"Error in custom hook for events: {e}", exc_info=True)

‎django_declarative_apis/machinery/tasks.py

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@@ -16,11 +16,7 @@
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from django.conf import settings
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from django.core.cache import cache
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import django.db.models
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try:
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from newrelic import agent as newrelic_agent
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except ImportError:
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newrelic_agent = None
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from django_declarative_apis.events import emit_events, EventType
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try:
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import cid.locals
@@ -73,19 +69,18 @@ def _log_task_stats(
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cache.set(QUEUE_LENGTH_CACHE_KEY, queue_length)
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if newrelic_agent:
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newrelic_agent.record_custom_event(
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"task_runner:queue_length",
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{
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"queue_length": queue_length,
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"queue": queue,
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"routing_key": routing_key,
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"wait_time_seconds": wait_time,
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"queue_delay_seconds": queue_delay,
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"process_task_count": process_task_count,
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"correlation_id": correlation_id,
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},
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)
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emit_events(
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EventType.QUEUE_SNAPSHOT,
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{
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"queue_length": queue_length,
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"queue": queue,
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"routing_key": routing_key,
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"wait_time_seconds": wait_time,
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"queue_delay_seconds": queue_delay,
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"process_task_count": process_task_count,
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"correlation_id": correlation_id,
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},
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)
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logger.info(
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"method=%s, resource_id=%s, queue_length=%s, queue=%s, routing_key=%s, task_wait_time=%s, "
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def _log_retry_stats(method_name, resource_instance_id, correlation_id):
113-
if newrelic_agent:
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newrelic_agent.record_custom_event(
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"task_runner:retry",
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{"method_name": method_name, "resource_instance_id": resource_instance_id},
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)
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logger.warning(
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"will retry task: method=%s, resource_id=%s, correlation_id=%s",
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method_name,
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resource_instance_id,
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correlation_id,
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)
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emit_events(
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EventType.TASK_RETRY_ATTEMPT,
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{"method_name": method_name, "resource_instance_id": resource_instance_id},
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)
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logger.warning(
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"will retry task: method=%s, resource_id=%s, correlation_id=%s",
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method_name,
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resource_instance_id,
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correlation_id,
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)
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class RetryParams(NamedTuple):

‎tests/test_events.py

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#
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# Copyright (c) 2025, salesforce.com, inc.
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# All rights reserved.
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# SPDX-License-Identifier: BSD-3-Clause
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# For full license text, see the LICENSE file in the repo root or https://opensource.org/licenses/BSD-3-Clause
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#
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import unittest
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from unittest.mock import patch, Mock
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from django_declarative_apis.events import _import_hook, emit_events
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from django.test import override_settings
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def test_function():
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pass
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class EmitEventsTest(unittest.TestCase):
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@override_settings(DDA_EVENT_HOOK="tests.test_events.test_function")
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def test_import_hook(self):
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hook_path = "tests.test_events.test_function"
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hook_function = _import_hook(hook_path)
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self.assertTrue(callable(hook_function))
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self.assertEqual(hook_function.__name__, "test_function")
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def test_invalid_hook_path(self):
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with self.assertRaises(ValueError) as context:
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_import_hook("invalid_path")
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self.assertEqual(
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str(context.exception),
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"not enough values to unpack (expected 2, got 1)",
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)
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def test_nonexistent_function(self):
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with self.assertRaises(AttributeError) as context:
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_import_hook("tests.test_events.no_function")
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self.assertIn(
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"module 'tests.test_events' has no attribute 'no_function'",
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str(context.exception),
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)
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@patch("django_declarative_apis.events._import_hook")
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@patch("django_declarative_apis.events.logger")
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def test_emit_events_with_hook(self, mock_logger, mock_import_hook):
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event_type, payload = "test_event", {"key": "value"}
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mock_hook_function = Mock()
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mock_import_hook.return_value = mock_hook_function
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with patch(
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"django_declarative_apis.events.HOOK", "tests.test_events.test_function"
50+
):
51+
emit_events(event_type, payload)
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mock_import_hook.assert_called_once_with("tests.test_events.test_function")
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mock_hook_function.assert_called_once_with(event_type, payload)
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mock_logger.info.assert_called_once_with(
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"Event emitted via custom hook: test_event"
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)
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58+
@patch("django_declarative_apis.events._import_hook")
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@patch("django_declarative_apis.events.logger")
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@override_settings(DDA_EVENT_HOOK="tests.test_events.test_function")
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def test_emit_events_with_exception_calling_hook(
62+
self, mock_logger, mock_import_hook
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):
64+
event_type, payload = "test_event", {"key": "value"}
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mock_import_hook.return_value.side_effect = Exception("Simulated Exception")
66+
with patch(
67+
"django_declarative_apis.events.HOOK", "tests.test_events.test_function"
68+
):
69+
emit_events(event_type, payload)
70+
mock_logger.error.assert_called_once_with(
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"Error in custom hook for events: Simulated Exception", exc_info=True
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)

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