Use bitrate instead of videostreams for load balancing. (#358)

* Use bitrate instead of videostreams for load balancing.

* Fix bridge selector tests.

Author: bgrozev

src/main/java/org/jitsi/jicofo/Bridge.java

@@ -51,6 +51,24 @@ class Bridge
      */
     private static final String STAT_NAME_VIDEO_STREAMS = "videostreams";
 
+    /**
+     * The name of the stat used by jitsi-videobridge to indicate the current
+     * upload bitrate in Kbps.
+     * video streams. This should match
+     * {@code VideobridgeStatistics.BITRATE_UPLOAD}, but is defined separately
+     * to avoid depending on the {@code jitsi-videobridge} maven package.
+     */
+    private static final String STAT_NAME_BITRATE_UP = "bit_rate_upload";
+
+    /**
+     * The name of the stat used by jitsi-videobridge to indicate the current
+     * download bitrate in Kbps.
+     * video streams. This should match
+     * {@code VideobridgeStatistics.BITRATE_DOWNLOAD}, but is defined separately
+     * to avoid depending on the {@code jitsi-videobridge} maven package.
+     */
+    private static final String STAT_NAME_BITRATE_DOWN = "bit_rate_download";
+
     /**
      * The name of the stat used by jitsi-videobridge to indicate its region.
      * This should match {@code VideobridgeStatistics.REGION}, but is defined
@@ -101,6 +119,11 @@ class Bridge
      */
     private int videoStreamCountDiff = 0;
 
+    /**
+     * The last reported bitrate in Kbps.
+     */
+    private int lastReportedBitrateKbps = 0;
+
     /**
      * Holds bridge version (if known - not all bridge version are capable of
      * reporting it).
@@ -154,6 +177,13 @@ void setStats(ColibriStatsExtension stats)
             setVideoStreamCount(videoStreamCount);
         }
 
+        Integer bitrateUpKbps = stats.getValueAsInt(STAT_NAME_BITRATE_UP);
+        Integer bitrateDownKbps = stats.getValueAsInt(STAT_NAME_BITRATE_DOWN);
+        if (bitrateUpKbps != null && bitrateDownKbps != null)
+        {
+            lastReportedBitrateKbps = bitrateDownKbps + bitrateUpKbps;
+        }
+
         setIsOperational(!Boolean.valueOf(stats.getValueAsString(
             JigasiDetector.STAT_NAME_SHUTDOWN_IN_PROGRESS)));
     }
@@ -249,7 +279,8 @@ private void verifyFailureThreshold()
     }
 
     /**
-     * The least value is returned the least the bridge is loaded.
+     * The least value is returned the least the bridge is loaded. Currently
+     * we use the bitrate to estimate load.
      * <p>
      * {@inheritDoc}
      */
@@ -268,8 +299,7 @@ else if (!meOperational && otherOperational)
             return 1;
         }
 
-        return this.getEstimatedVideoStreamCount()
-            - o.getEstimatedVideoStreamCount();
+        return this.lastReportedBitrateKbps - o.lastReportedBitrateKbps;
     }
 
     private int getEstimatedVideoStreamCount()

src/test/java/org/jitsi/jicofo/BridgeSelectorTest.java

@@ -295,13 +295,16 @@ private void testFailureResetThreshold(
             BridgeSelector.DEFAULT_FAILURE_RESET_THRESHOLD);
     }
 
-    ExtensionElement createJvbStats(int videoStreamCount)
+    ExtensionElement createJvbStats(int bitrate)
     {
         ColibriStatsExtension statsExtension = new ColibriStatsExtension();
 
         statsExtension.addStat(
             new ColibriStatsExtension.Stat(
-                VideobridgeStatistics.VIDEOSTREAMS, "" + videoStreamCount));
+                VideobridgeStatistics.BITRATE_DOWNLOAD, bitrate));
+        statsExtension.addStat(
+                new ColibriStatsExtension.Stat(
+                VideobridgeStatistics.BITRATE_UPLOAD, bitrate));
 
         return statsExtension;
     }