add metric for data download rate

Author: edwaddle

modules/cache.py

@@ -4,6 +4,7 @@
 import os
 import uuid
 import json
+import time
 
 from pytubefix import YouTube
 
@@ -58,8 +59,10 @@ def add(self, url: str):
             MetricsHandler.cache_size.set(len(self.video_id_to_path))
             MetricsHandler.cache_size_bytes.set(self.current_size_bytes)
         video_file_name = video.default_filename
+        start_time = time.time()
         with MetricsHandler.download_time.time():
             video.download(self.file_path)
+        end_time = time.time()
         MetricsHandler.data_downloaded.inc(video.filesize)
         MetricsHandler.video_download_count.inc()
         video_id = self.get_video_id(url)
@@ -80,6 +83,9 @@ def add(self, url: str):
         self.current_size_bytes += video_info.size_bytes
         MetricsHandler.cache_size.set(len(self.video_id_to_path))
         MetricsHandler.cache_size_bytes.set(self.current_size_bytes)
+        #download rate are currently listed in bytes / second
+        download_rate = (video.filesize /  (end_time-start_time)) 
+        MetricsHandler.download_rate.set(download_rate)
 
     def find(self, video_id: str):
         if video_id in self.video_id_to_path:
@@ -158,4 +164,4 @@ def write_cache(self):
     def get_video_id(url) -> str:
         parsed_url = urlparse(url)
         video_id = parse_qs(parsed_url.query)["v"][0]
-        return video_id
+        return video_id

modules/metrics.py

@@ -30,6 +30,12 @@ class Metrics(enum.Enum):
         prometheus_client.Summary,
     )
 
+    DOWNLOAD_RATE = (
+        "download_rate",
+        "The rate of downloading videos in bytes per seconds",
+        prometheus_client.Gauge,
+    )
+
     DATA_DOWNLOADED = (
         "data_downloaded",
         "Total video data downloaded in bytes",
@@ -100,4 +106,4 @@ def init(self) -> None:
                 metric.prometheus_type(
                     metric.title, metric.description, labelnames=metric.labels
                 ),
-            )
+            )