From f103064d1ab54679dfd784c90e09209e6d66e88f Mon Sep 17 00:00:00 2001
From: Cristhian Garcia <crisgarta8@gmail.com>
Date: Mon, 5 Jun 2023 15:04:05 -0500
Subject: [PATCH] feat: add listener for tracking event emitted signal

---
 event_routing_backends/apps.py            |  1 +
 event_routing_backends/config.py          | 14 +++++++
 event_routing_backends/settings/common.py |  1 +
 event_routing_backends/signals.py         | 50 +++++++++++++++++++++++
 4 files changed, 66 insertions(+)
 create mode 100644 event_routing_backends/config.py
 create mode 100644 event_routing_backends/signals.py

diff --git a/event_routing_backends/apps.py b/event_routing_backends/apps.py
index f8cd99d4..9289460f 100644
--- a/event_routing_backends/apps.py
+++ b/event_routing_backends/apps.py
@@ -35,5 +35,6 @@ def ready(self):
         """
         super().ready()
         # pylint: disable=import-outside-toplevel, unused-import
+        from event_routing_backends import signals  # noqa: F401
         from event_routing_backends.processors.caliper import event_transformers as caliper_event_transformers
         from event_routing_backends.processors.xapi import event_transformers as xapi_event_transformers
diff --git a/event_routing_backends/config.py b/event_routing_backends/config.py
new file mode 100644
index 00000000..fde1d207
--- /dev/null
+++ b/event_routing_backends/config.py
@@ -0,0 +1,14 @@
+"""
+This module contains various configuration settings via
+waffle switches for the Certificates app.
+"""
+
+from edx_toggles.toggles import SettingToggle, WaffleSwitch
+
+# .. toggle_name: SEND_TRACKING_EVENT_EMITTED_SIGNAL
+# .. toggle_implementation: SettingToggle
+# .. toggle_default: False
+# .. toggle_description: When True, the system will publish `TRACKING_EVENT_EMITTED` signals to the event bus. The
+#   `TRACKING_EVENT_EMITTED` signal is emit when a tracking log is emitted.
+# .. toggle_use_cases: publish
+SEND_TRACKING_EVENT_EMITTED_SIGNAL = SettingToggle('SEND_TRACKING_EVENT_EMITTED_SIGNAL', default=False, module_name=__name__)
diff --git a/event_routing_backends/settings/common.py b/event_routing_backends/settings/common.py
index 3be8f012..8caa3e96 100644
--- a/event_routing_backends/settings/common.py
+++ b/event_routing_backends/settings/common.py
@@ -11,6 +11,7 @@ def plugin_settings(settings):
     settings.XAPI_EVENTS_ENABLED = True
     settings.EVENT_ROUTING_BACKEND_MAX_RETRIES = 3
     settings.EVENT_ROUTING_BACKEND_COUNTDOWN = 30
+    settings.EVENT_ROUTING_BATCH_SIZE = 5
 
     # .. setting_name: XAPI_AGENT_IFI_TYPE
     # .. setting_default: 'external_id'
diff --git a/event_routing_backends/signals.py b/event_routing_backends/signals.py
new file mode 100644
index 00000000..842acf84
--- /dev/null
+++ b/event_routing_backends/signals.py
@@ -0,0 +1,50 @@
+import json
+import logging
+
+from django.conf import settings
+from django.dispatch import receiver
+from django_redis import get_redis_connection
+from edx_django_utils.cache.utils import get_cache_key
+from openedx_events.analytics.signals import TRACKING_EVENT_EMITTED
+from openedx_events.event_bus import get_producer
+
+from event_routing_backends.config import SEND_TRACKING_EVENT_EMITTED_SIGNAL
+
+logger = logging.getLogger(__name__)
+
+TRANSFORMED_EVENT_KEY_NAME = "transformed_events"
+
+@receiver(TRACKING_EVENT_EMITTED)
+def listen_for_tracking_event_emitted_event(sender, signal, **kwargs):
+    """
+    Publish `TRACKING_EVENT_EMITTED` events to the event bus.
+    """
+    event = kwargs['tracking_log']
+
+    ## TODO: Should we ignore events that we don't care about here or in the event routing backend config?
+
+    redis = get_redis_connection("default")
+
+    queue_size = redis.llen(TRANSFORMED_EVENT_KEY_NAME)
+    if queue_size >= settings.EVENT_ROUTING_BATCH_SIZE:
+        queued_events = redis.rpop(TRANSFORMED_EVENT_KEY_NAME, settings.EVENT_ROUTING_BATCH_SIZE)
+        queued_events.append(event)
+        ## TODO: Send events to event bus in batch
+        logger.info("Sending events to event bus in batch")
+
+        #if SEND_TRACKING_EVENT_EMITTED_SIGNAL.is_enabled():
+        #    get_producer().send(
+        #        signal=TRACKING_EVENT_EMITTED,
+        #        topic='analytics',
+        #        event_key_field='tracking_log.name',
+        #        event_data={'tracking_log': kwargs['tracking_log']},
+        #        event_metadata=kwargs['metadata']
+        #    )
+    else:
+        redis.lpush(TRANSFORMED_EVENT_KEY_NAME, json.dumps({
+            "name": event.name,
+            "timestamp": event.timestamp,
+            "data": event.data,
+            "context": event.context,
+        }))
+        logger.info("Event pushed to the queue, current size: %s", queue_size + 1)