feat: added GC metrics collector

common/src/main/kotlin/dev/cubxity/plugins/metrics/common/metric/system/GCCollector.kt

@@ -0,0 +1,33 @@
+/*
+ *     UnifiedMetrics is a fully-featured metrics collection plugin for Minecraft servers.
+ *     Copyright (C) 2021  Cubxity
+ *
+ *     This program is free software: you can redistribute it and/or modify
+ *     it under the terms of the GNU Affero General Public License as published
+ *     by the Free Software Foundation, either version 3 of the License, or
+ *     (at your option) any later version.
+ *
+ *     This program is distributed in the hope that it will be useful,
+ *     but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *     GNU Affero General Public License for more details.
+ *
+ *     You should have received a copy of the GNU Affero General Public License
+ *     along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package dev.cubxity.plugins.metrics.common.metric.system
+
+import dev.cubxity.plugins.metrics.api.metric.collector.MILLISECONDS_PER_SECOND
+import dev.cubxity.plugins.metrics.api.metric.collector.MetricCollector
+import dev.cubxity.plugins.metrics.api.metric.data.CounterSample
+import dev.cubxity.plugins.metrics.api.metric.data.MetricSample
+import java.lang.management.ManagementFactory
+
+class GCCollector : MetricCollector {
+    private val beans = ManagementFactory.getGarbageCollectorMXBeans()
+
+    override fun collect(): List<MetricSample> = beans.map {
+        CounterSample("jvm_gc_seconds_total", it.collectionTime / MILLISECONDS_PER_SECOND, mapOf("gc" to it.name))
+    }
+}

common/src/main/kotlin/dev/cubxity/plugins/metrics/common/metric/system/SystemMetric.kt

@@ -25,6 +25,7 @@ class SystemMetric : Metric {
     override val collectors: List<MetricCollector> = listOf(
         MemoryCollector(),
         ProcessCollector(),
-        ThreadCollector()
+        ThreadCollector(),
+        GCCollector()
     )
 }