[AZ-180] Refactor detection event handling and improve SSE support

- Updated the detection image endpoint to require a channel ID for event streaming.
- Introduced a new endpoint for streaming detection events, allowing clients to receive real-time updates.
- Enhanced the internal buffering mechanism for detection events to manage multiple channels.
- Refactored the inference module to support the new event handling structure.

Made-with: Cursor

e2e/tests/test_streaming_video_upload.py

@@ -10,6 +10,7 @@ Run with:  pytest e2e/tests/test_streaming_video_upload.py -s -v
 import json
 import threading
 import time
+import uuid
 from pathlib import Path
 
 import pytest
@@ -37,21 +38,23 @@ def _chunked_reader(path: str, chunk_size: int = 64 * 1024):
 
 
 def _start_sse_listener(
-    http_client, media_id: str, auth_headers: dict
+    http_client, channel_id: str, auth_headers: dict
 ) -> tuple[list[dict], list[BaseException], threading.Event]:
     events: list[dict] = []
     errors: list[BaseException] = []
     first_event = threading.Event()
+    connected = threading.Event()
 
     def _listen():
         try:
             with http_client.get(
-                f"/detect/{media_id}",
+                f"/detect/events/{channel_id}",
                 stream=True,
                 timeout=_TIMEOUT + 2,
                 headers=auth_headers,
             ) as resp:
                 resp.raise_for_status()
+                connected.set()
                 for event in sseclient.SSEClient(resp).events():
                     if not event.data or not str(event.data).strip():
                         continue
@@ -62,9 +65,12 @@ def _start_sse_listener(
         except BaseException as exc:
             errors.append(exc)
         finally:
+            connected.set()
             first_event.set()
 
-    threading.Thread(target=_listen, daemon=True).start()
+    th = threading.Thread(target=_listen, daemon=True)
+    th.start()
+    connected.wait(timeout=3)
     return events, errors, first_event
 
 
@@ -74,6 +80,8 @@ def test_streaming_video_detections_appear_during_upload(
 ):
     # Arrange
     video_path = _fixture_path("video_test01.mp4")
+    channel_id = str(uuid.uuid4())
+    events, errors, first_event = _start_sse_listener(http_client, channel_id, auth_headers)
 
     # Act
     r = http_client.post(
@@ -81,14 +89,13 @@ def test_streaming_video_detections_appear_during_upload(
         data=_chunked_reader(video_path),
         headers={
             **auth_headers,
+            "X-Channel-Id": channel_id,
             "X-Filename": "video_test01.mp4",
             "Content-Type": "application/octet-stream",
         },
         timeout=8,
     )
-    assert r.status_code == 200
-    media_id = r.json()["mediaId"]
-    events, errors, first_event = _start_sse_listener(http_client, media_id, auth_headers)
+    assert r.status_code == 202
     first_event.wait(timeout=_TIMEOUT)
 
     # Assert
@@ -103,6 +110,8 @@ def test_streaming_video_detections_appear_during_upload(
 def test_non_faststart_video_still_works(warm_engine, http_client, auth_headers):
     # Arrange
     video_path = _fixture_path("video_test01.mp4")
+    channel_id = str(uuid.uuid4())
+    events, errors, first_event = _start_sse_listener(http_client, channel_id, auth_headers)
 
     # Act
     r = http_client.post(
@@ -110,14 +119,13 @@ def test_non_faststart_video_still_works(warm_engine, http_client, auth_headers)
         data=_chunked_reader(video_path),
         headers={
             **auth_headers,
+            "X-Channel-Id": channel_id,
             "X-Filename": "video_test01_plain.mp4",
             "Content-Type": "application/octet-stream",
         },
         timeout=8,
     )
-    assert r.status_code == 200
-    media_id = r.json()["mediaId"]
-    events, errors, first_event = _start_sse_listener(http_client, media_id, auth_headers)
+    assert r.status_code == 202
     first_event.wait(timeout=_TIMEOUT)
 
     # Assert