Chunked transfer fixes

camtiler.py

@@ -38,6 +38,9 @@ counter_rx_bytes = Counter(
 counter_tx_bytes = Counter(
     "camtiler_client_tx_bytes",
     "Bytes transmitted over HTTP streams")
+counter_rx_chunks = Counter(
+    "camtiler_client_rx_chunks",
+    "HTTP chunks received")
 counter_rx_frames = Counter(
     "camtiler_client_rx_frames",
     "Frames received")
@@ -47,9 +50,6 @@ counter_tx_frames = Counter(
 counter_tx_events = Counter(
     "camtiler_client_tx_events",
     "Events emitted")
-counter_eos = Counter(
-    "camtiler_client_eos",
-    "Count of End of Stream occurrences")
 counter_timeout_errors =  Counter(
     "camtiler_client_timeout_errors",
     "Upstream connection timeout errors")
@@ -106,18 +106,18 @@ async def client_connect(name, resp):
     buf = b""
     print("Upstream connection opened with status:", resp.status)
     async for data, end_of_http_chunk in resp.content.iter_chunks():
-        counter_rx_bytes.inc(len(data))
         if end_of_http_chunk:
-            counter_eos.inc()
-            break
+            counter_rx_chunks.inc()
 
         if buf:
-            # seek end
+            # If we already have something in buffer, seek end in new data
             marker = data.find(b'\xff\xd9')
             if marker < 0:
+                # If no end marker was found add it to buffer
                 buf += data
                 continue
             else:
+                # If end marker was found, decode JPEG frame
                 blob = np.frombuffer(buf + data[:marker+2], dtype=np.uint8)
                 img = cv2.imdecode(blob, cv2.IMREAD_UNCHANGED)
                 app.ctx.frames[name] = img
@@ -125,17 +125,19 @@ async def client_connect(name, resp):
                 buf = b""
                 counter_rx_frames.inc()
 
-        # seek begin
+        # Seek begin in newly received data
         marker = data.find(b'\xff\xd8')
         if marker >= 0:
-            buf = data[marker:]
-        else:
-            counter_dropped_bytes.inc(len(data))
+            data, buf = data[:marker], data[marker:]
+
+        # Remaining data is effectively dropped
+        counter_dropped_bytes.inc(len(data))
 
 
 async def client(name, url):
     print("Opening upstream connection to %s" % url)
-    async with aiohttp.ClientSession() as session:
+    while True:
+      async with aiohttp.ClientSession() as session:
         async with session.get(url) as resp:
             try:
                 await client_connect(name, resp)