implemented 09-system-metrics.md: added system metrics: introduced system monitoring with a metrics collector, REST API endpoint, Thymeleaf UI rendering, and lifecycle management

2026-07-07 12:55:11 +02:00
parent 67c9f0ade9
commit a6a2c9de0b
21 changed files with 1069 additions and 6 deletions
@@ -0,0 +1,54 @@
+package de.hoennig.gittally.metrics
+
+import java.time.Instant
+
+/** Current value of one metric plus its min/max/avg over all recorded samples. */
+data class MetricAggregate(
+    val current: Double,
+    val min: Double,
+    val max: Double,
+    val avg: Double,
+)
+
+/**
+ * One system snapshot with aggregates, the payload of `GET /api/system`
+ * (the legacy `system.json`, with camelCase names like the rest of the API).
+ * A metric is null when its source is unavailable — e.g. no `/proc` outside
+ * Linux — and the UI shows `n/a`; the endpoint itself works everywhere.
+ */
+data class SystemMetrics(
+    val timestamp: Instant?,
+    val sampleCount: Long,
+    val cpuCount: Int,
+    val ramTotalGib: Double?,
+    val diskTotalGib: Double?,
+    val cpuUsed: MetricAggregate?,
+    val cpuIdle: MetricAggregate?,
+    val ramUsedGib: MetricAggregate?,
+    val ramFreeGib: MetricAggregate?,
+    val diskUsedGib: MetricAggregate?,
+    val diskFreeGib: MetricAggregate?,
+    val repoSizeGib: MetricAggregate?,
+)
+
+/** Running aggregation of one metric; persisted so restarts continue the series. */
+data class MetricSeries(
+    val min: Double,
+    val max: Double,
+    val sum: Double,
+    val count: Long,
+) {
+    operator fun plus(value: Double) =
+        MetricSeries(
+            min = minOf(min, value),
+            max = maxOf(max, value),
+            sum = sum + value,
+            count = count + 1,
+        )
+
+    fun aggregate(current: Double) = MetricAggregate(current = current, min = min, max = max, avg = sum / count)
+
+    companion object {
+        fun of(value: Double) = MetricSeries(min = value, max = value, sum = value, count = 1)
+    }
+}