From 9b3a579cb3b07689be05e65164a817b51a874e45 Mon Sep 17 00:00:00 2001
From: Iilun <korantin.tocze@free.fr>
Date: Tue, 25 Feb 2025 13:55:04 +0100
Subject: [PATCH] + prometheus: add configuration parameters to the accumulator

---
 .../src/main/resources/reference.conf              |  9 ++++++++-
 .../prometheus/PrometheusPushgatewayReporter.scala |  7 ++++++-
 .../kamon/prometheus/PrometheusReporter.scala      |  9 +++++++--
 .../kamon/prometheus/PrometheusSettings.scala      | 14 +++++++++++++-
 4 files changed, 34 insertions(+), 5 deletions(-)

diff --git a/reporters/kamon-prometheus/src/main/resources/reference.conf b/reporters/kamon-prometheus/src/main/resources/reference.conf
index fd9043f71..10e88d104 100644
--- a/reporters/kamon-prometheus/src/main/resources/reference.conf
+++ b/reporters/kamon-prometheus/src/main/resources/reference.conf
@@ -4,7 +4,7 @@
 
 kamon.prometheus {
 
-  # Enable or disable publishing the Prometheus scraping enpoint using a embedded server.
+  # Enable or disable publishing the Prometheus scraping endpoint using a embedded server.
   start-embedded-http-server = yes
 
   # Enable or disable including tags from kamon.environment.tags as labels
@@ -98,6 +98,13 @@ kamon.prometheus {
     ]
   }
 
+  periods {
+    # Period over which to accumulate snapshots in the reporter
+    accumulation = "1825d"
+    # Period after which metrics are considered stale and are removed from the prometheus exported data
+    stale = "1825d"
+  }
+
   embedded-server {
 
     # Hostname and port used by the embedded web server to publish the scraping enpoint.
diff --git a/reporters/kamon-prometheus/src/main/scala/kamon/prometheus/PrometheusPushgatewayReporter.scala b/reporters/kamon-prometheus/src/main/scala/kamon/prometheus/PrometheusPushgatewayReporter.scala
index 221a2a7b3..ea9e948ac 100644
--- a/reporters/kamon-prometheus/src/main/scala/kamon/prometheus/PrometheusPushgatewayReporter.scala
+++ b/reporters/kamon-prometheus/src/main/scala/kamon/prometheus/PrometheusPushgatewayReporter.scala
@@ -31,8 +31,13 @@ class PrometheusPushgatewayReporter(
 ) extends MetricReporter {
 
   private val _logger = LoggerFactory.getLogger(classOf[PrometheusPushgatewayReporter])
+  private val _initialSettings = PrometheusSettings.readSettings(Kamon.config().getConfig(configPath))
   private val _snapshotAccumulator =
-    PeriodSnapshot.accumulator(Duration.ofDays(365 * 5), Duration.ZERO, Duration.ofDays(365 * 5))
+    PeriodSnapshot.accumulator(
+      _initialSettings.periodSettings.accumulationPeriod,
+      Duration.ZERO,
+      _initialSettings.periodSettings.stalePeriod
+    )
 
   @volatile private var httpClient: HttpClient = _
   @volatile private var settings: PrometheusSettings.Generic = _
diff --git a/reporters/kamon-prometheus/src/main/scala/kamon/prometheus/PrometheusReporter.scala b/reporters/kamon-prometheus/src/main/scala/kamon/prometheus/PrometheusReporter.scala
index 4c9024838..10d1ec8e2 100644
--- a/reporters/kamon-prometheus/src/main/scala/kamon/prometheus/PrometheusReporter.scala
+++ b/reporters/kamon-prometheus/src/main/scala/kamon/prometheus/PrometheusReporter.scala
@@ -34,8 +34,6 @@ class PrometheusReporter(configPath: String = DefaultConfigPath, initialConfig:
 
   private val _logger = LoggerFactory.getLogger(classOf[PrometheusReporter])
   private var _embeddedHttpServer: Option[EmbeddedHttpServer] = None
-  private val _snapshotAccumulator =
-    PeriodSnapshot.accumulator(Duration.ofDays(365 * 5), Duration.ZERO, Duration.ofDays(365 * 5))
 
   @volatile private var _preparedScrapeData: String =
     "# The kamon-prometheus module didn't receive any data just yet.\n"
@@ -43,6 +41,13 @@ class PrometheusReporter(configPath: String = DefaultConfigPath, initialConfig:
   @volatile private var _config = initialConfig
   @volatile private var _reporterSettings = readSettings(initialConfig.getConfig(configPath))
 
+  private val _snapshotAccumulator =
+    PeriodSnapshot.accumulator(
+      _reporterSettings.generic.periodSettings.accumulationPeriod,
+      Duration.ZERO,
+      _reporterSettings.generic.periodSettings.stalePeriod
+    )
+
   {
     startEmbeddedServerIfEnabled()
   }
diff --git a/reporters/kamon-prometheus/src/main/scala/kamon/prometheus/PrometheusSettings.scala b/reporters/kamon-prometheus/src/main/scala/kamon/prometheus/PrometheusSettings.scala
index 07f51b8b9..dd7fd6aba 100644
--- a/reporters/kamon-prometheus/src/main/scala/kamon/prometheus/PrometheusSettings.scala
+++ b/reporters/kamon-prometheus/src/main/scala/kamon/prometheus/PrometheusSettings.scala
@@ -21,6 +21,8 @@ import kamon.tag.TagSet
 import kamon.util.Filter.Glob
 import kamon.{Kamon, UtilsOnConfig}
 
+import java.time.Duration
+
 import scala.collection.JavaConverters._
 
 object PrometheusSettings {
@@ -33,7 +35,8 @@ object PrometheusSettings {
     customBuckets: Map[String, Seq[java.lang.Double]],
     includeEnvironmentTags: Boolean,
     summarySettings: SummarySettings,
-    gaugeSettings: GaugeSettings
+    gaugeSettings: GaugeSettings,
+    periodSettings: PeriodSettings
   )
 
   case class SummarySettings(
@@ -41,6 +44,11 @@ object PrometheusSettings {
     metricMatchers: Seq[Glob]
   )
 
+  case class PeriodSettings(
+    accumulationPeriod: Duration,
+    stalePeriod: Duration
+  )
+
   case class GaugeSettings(metricMatchers: Seq[Glob])
 
   def readSettings(prometheusConfig: Config): Generic = {
@@ -57,6 +65,10 @@ object PrometheusSettings {
       ),
       gaugeSettings = GaugeSettings(
         metricMatchers = prometheusConfig.getStringList("gauges.metrics").asScala.map(Glob).toSeq
+      ),
+      periodSettings = PeriodSettings(
+        accumulationPeriod = prometheusConfig.getDuration("periods.accumulation"),
+        stalePeriod = prometheusConfig.getDuration("periods.stale")
       )
     )
   }