feat: Export JVM metrics to prometheus.

jvb/src/main/kotlin/org/jitsi/videobridge/metrics/JvmMetrics.kt

@@ -0,0 +1,101 @@
+/*
+ * Copyright @ 2024 - present 8x8, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jitsi.videobridge.metrics
+
+import com.sun.management.UnixOperatingSystemMXBean
+import org.jitsi.config.JitsiConfig
+import org.jitsi.metaconfig.config
+import org.jitsi.utils.logging2.createLogger
+import java.lang.management.ManagementFactory
+import org.jitsi.videobridge.metrics.VideobridgeMetricsContainer.Companion.instance as metricsContainer
+
+class JvmMetrics private constructor() {
+    val logger = createLogger()
+
+    fun update() {
+        threadCount.set(ManagementFactory.getThreadMXBean().threadCount.toLong())
+        ManagementFactory.getGarbageCollectorMXBeans().forEach { gc ->
+            if (gc.name.lowercase().contains("g1 young")) {
+                g1YoungTime.set(gc.collectionTime)
+                g1YoungCount.set(gc.collectionCount)
+            } else if (gc.name.lowercase().contains("g1 old")) {
+                g1OldTime.set(gc.collectionTime)
+                g1OldCount.set(gc.collectionCount)
+            }
+            ManagementFactory.getMemoryPoolMXBeans().toSet().forEach { b ->
+                if (b.name.lowercase().contains("g1 old")) {
+                    logger.info("${b.name} ${b.memoryManagerNames.joinToString { "," }}....${b.usage}")
+                    g1OldUsage.set(b.usage.used)
+                    g1OldCapacity.set(b.usage.max)
+                }
+            }
+        }
+        (ManagementFactory.getOperatingSystemMXBean() as? UnixOperatingSystemMXBean)?.let {
+            openFdCount.set(it.openFileDescriptorCount)
+        }
+    }
+
+    val threadCount = metricsContainer.registerLongGauge(
+        "thread_count",
+        "Current number of JVM threads."
+    )
+
+    private val g1YoungCount = metricsContainer.registerLongGauge(
+        "jvm_g1_young_count",
+        "Collection count for the G1 young generation."
+    )
+
+    private val g1YoungTime = metricsContainer.registerLongGauge(
+        "jvm_g1_young_time",
+        "Collection time for the young G1 generation."
+    )
+
+    private val g1OldCount = metricsContainer.registerLongGauge(
+        "jvm_g1_old_count",
+        "Collection count for the G1 old generation."
+    )
+
+    private val g1OldTime = metricsContainer.registerLongGauge(
+        "jvm_g1_old_time",
+        "Collection time for the G1 old generation."
+    )
+
+    private val g1OldCapacity = metricsContainer.registerLongGauge(
+        "jvm_g1_old_capacity",
+        "Capacity of the G1 Old memory pool."
+    )
+
+    private val g1OldUsage = metricsContainer.registerLongGauge(
+        "jvm_g1_old_usage",
+        "Usage of the G1 Old memory pool."
+    )
+
+    private val openFdCount = metricsContainer.registerLongGauge(
+        "jvm_open_fd_count",
+        "Number of open file descriptors."
+    )
+
+    companion object {
+        val enable: Boolean by config {
+            "videobridge.stats.jvm.enabled".from(JitsiConfig.newConfig)
+        }
+
+        val INSTANCE = if (enable) JvmMetrics() else null
+        fun update() {
+            INSTANCE?.update()
+        }
+    }
+}

jvb/src/main/kotlin/org/jitsi/videobridge/metrics/Metrics.kt

@@ -40,7 +40,11 @@ object Metrics {
     val lock: Any
         get() = metricsUpdater
 
-    fun start() = metricsUpdater.addUpdateTask { ThreadsMetric.update() }
+    fun start() {
+        if (JvmMetrics.enable) {
+            metricsUpdater.addUpdateTask { JvmMetrics.update() }
+        }
+    }
     fun stop() {
         metricsUpdater.stop()
         executor.shutdown()

jvb/src/main/kotlin/org/jitsi/videobridge/stats/VideobridgeStatisticsShim.kt

@@ -20,8 +20,8 @@ import org.jitsi.videobridge.EndpointConnectionStatusMonitor
 import org.jitsi.videobridge.VersionConfig
 import org.jitsi.videobridge.health.JvbHealthChecker
 import org.jitsi.videobridge.load_management.JvbLoadManager
+import org.jitsi.videobridge.metrics.JvmMetrics
 import org.jitsi.videobridge.metrics.Metrics
-import org.jitsi.videobridge.metrics.ThreadsMetric
 import org.jitsi.videobridge.metrics.VideobridgeMetrics
 import org.jitsi.videobridge.metrics.VideobridgePeriodicMetrics
 import org.jitsi.videobridge.relay.RelayConfig
@@ -204,7 +204,9 @@ object VideobridgeStatisticsShim {
 
             put("average_participant_stress", JvbLoadManager.averageParticipantStress)
 
-            put(THREADS, ThreadsMetric.threadCount.get())
+            JvmMetrics.INSTANCE?.threadCount?.let {
+                put(THREADS, it.get())
+            }
 
             put(SHUTDOWN_IN_PROGRESS, VideobridgeMetrics.gracefulShutdown.get())
             put("shutting_down", VideobridgeMetrics.shuttingDown.get())

jvb/src/main/resources/reference.conf

@@ -236,6 +236,10 @@ videobridge {
       // /debug/jvb/stats/transit-time
       enable-jitter = false
     }
+    jvm {
+      // Whether to enable collection of JVM metrics (thread count, garbage collection)
+      enabled = true
+    }
   }
   websockets {
     enabled = false