Merge pull request #2145 from softwaremill/prometheus-update

Updated Prometheus to 1.2.1

build.sbt

@@ -937,7 +937,7 @@ lazy val prometheusBackend = (projectMatrix in file("observability/prometheus-ba
   .settings(
     name := "prometheus-backend",
     libraryDependencies ++= Seq(
-      "io.prometheus" % "simpleclient" % "0.16.0"
+      "io.prometheus" % "prometheus-metrics-core" % "1.2.1"
     ),
     scalaTest
   )

observability/prometheus-backend/src/main/scala/sttp/client4/prometheus/PrometheusBackend.scala

@@ -1,8 +1,11 @@
 package sttp.client4.prometheus
 
+import io.prometheus.metrics.core.datapoints.{GaugeDataPoint, Timer}
+import io.prometheus.metrics.core.metrics.{Counter, Gauge, Histogram, Summary}
+import io.prometheus.metrics.model.registry.{Collector, PrometheusRegistry}
+
 import java.util.concurrent.ConcurrentHashMap
 import sttp.client4.{wrappers, _}
-import io.prometheus.client.{CollectorRegistry, Counter, Gauge, Histogram, Summary}
 import sttp.client4.listener.{ListenerBackend, RequestListener}
 import sttp.client4.prometheus.PrometheusBackend.RequestCollectors
 import sttp.client4.wrappers.FollowRedirectsBackend
@@ -11,6 +14,7 @@ import sttp.model.StatusCode
 import scala.collection.mutable
 
 object PrometheusBackend {
+  // TODO: Refactor metrics names according to Prometheus/OpenTelemetry standards
   val DefaultHistogramName = "sttp_request_latency"
   val DefaultRequestsInProgressGaugeName = "sttp_requests_in_progress"
   val DefaultSuccessCounterName = "sttp_requests_success_count"
@@ -64,11 +68,11 @@ object PrometheusBackend {
       (r: (GenericRequest[_, _], Throwable)) => config.requestToFailureCounterMapper(r._1, r._2),
       (req: GenericRequest[_, _]) => config.requestToSizeSummaryMapper(req),
       (rr: (GenericRequest[_, _], Response[_])) => config.responseToSizeSummaryMapper(rr._1, rr._2),
-      config.collectorRegistry,
-      cacheFor(histograms, config.collectorRegistry),
-      cacheFor(gauges, config.collectorRegistry),
-      cacheFor(counters, config.collectorRegistry),
-      cacheFor(summaries, config.collectorRegistry)
+      config.prometheusRegistry,
+      cacheFor(histograms, config.prometheusRegistry),
+      cacheFor(gauges, config.prometheusRegistry),
+      cacheFor(counters, config.prometheusRegistry),
+      cacheFor(summaries, config.prometheusRegistry)
     )
 
   /** Add, if not present, a "method" label. That is, if the user already supplied such a label, it is left as-is.
@@ -117,13 +121,11 @@ object PrometheusBackend {
 
   /** Clear cached collectors (gauges and histograms) both from the given collector registry, and from the backend.
     */
-  def clear(collectorRegistry: CollectorRegistry): Unit = {
-    collectorRegistry.clear()
-    histograms.remove(collectorRegistry)
-    gauges.remove(collectorRegistry)
-    counters.remove(collectorRegistry)
-    summaries.remove(collectorRegistry)
-    ()
+  def clear(prometheusRegistry: PrometheusRegistry): Unit = {
+    clear(prometheusRegistry, histograms)
+    clear(prometheusRegistry, gauges)
+    clear(prometheusRegistry, counters)
+    clear(prometheusRegistry, summaries)
   }
 
   /*
@@ -132,19 +134,28 @@ object PrometheusBackend {
   Hence, we need to store a global cache o created histograms/gauges, so that we can properly re-use them.
    */
 
-  private val histograms = new mutable.WeakHashMap[CollectorRegistry, ConcurrentHashMap[String, Histogram]]
-  private val gauges = new mutable.WeakHashMap[CollectorRegistry, ConcurrentHashMap[String, Gauge]]
-  private val counters = new mutable.WeakHashMap[CollectorRegistry, ConcurrentHashMap[String, Counter]]
-  private val summaries = new mutable.WeakHashMap[CollectorRegistry, ConcurrentHashMap[String, Summary]]
+  private def clear[T <: Collector](prometheusRegistry: PrometheusRegistry, collectors: mutable.WeakHashMap[PrometheusRegistry, ConcurrentHashMap[String, T]]): Unit = {
+    collectors
+      .getOrElse(prometheusRegistry, new ConcurrentHashMap[String, T]())
+      .values()
+      .forEach(c => prometheusRegistry.unregister(c))
+    collectors.remove(prometheusRegistry)
+  }
+
+  private val histograms = new mutable.WeakHashMap[PrometheusRegistry, ConcurrentHashMap[String, Histogram]]
+  private val gauges = new mutable.WeakHashMap[PrometheusRegistry, ConcurrentHashMap[String, Gauge]]
+  private val counters = new mutable.WeakHashMap[PrometheusRegistry, ConcurrentHashMap[String, Counter]]
+  private val summaries = new mutable.WeakHashMap[PrometheusRegistry, ConcurrentHashMap[String, Summary]]
 
   private def cacheFor[T](
-      cache: mutable.WeakHashMap[CollectorRegistry, ConcurrentHashMap[String, T]],
-      collectorRegistry: CollectorRegistry
+      cache: mutable.WeakHashMap[PrometheusRegistry, ConcurrentHashMap[String, T]],
+      prometheusRegistry: PrometheusRegistry
   ): ConcurrentHashMap[String, T] =
     cache.synchronized {
-      cache.getOrElseUpdate(collectorRegistry, new ConcurrentHashMap[String, T]())
+      // TODO remove synchronized and improve caching
+      cache.getOrElseUpdate(prometheusRegistry, new ConcurrentHashMap[String, T]())
     }
-  final case class RequestCollectors(maybeTimer: Option[Histogram.Timer], maybeGauge: Option[Gauge.Child])
+  final case class RequestCollectors(maybeTimer: Option[Timer], maybeGauge: Option[GaugeDataPoint])
 }
 
 class PrometheusListener(
@@ -155,22 +166,22 @@ class PrometheusListener(
     requestToFailureCounterMapper: ((GenericRequest[_, _], Exception)) => Option[CollectorConfig],
     requestToSizeSummaryMapper: GenericRequest[_, _] => Option[CollectorConfig],
     responseToSizeSummaryMapper: ((GenericRequest[_, _], Response[_])) => Option[CollectorConfig],
-    collectorRegistry: CollectorRegistry,
+    prometheusRegistry: PrometheusRegistry,
     histogramsCache: ConcurrentHashMap[String, Histogram],
     gaugesCache: ConcurrentHashMap[String, Gauge],
     countersCache: ConcurrentHashMap[String, Counter],
     summariesCache: ConcurrentHashMap[String, Summary]
 ) extends RequestListener[Identity, RequestCollectors] {
 
   override def beforeRequest(request: GenericRequest[_, _]): RequestCollectors = {
-    val requestTimer: Option[Histogram.Timer] = for {
+    val requestTimer: Option[Timer] = for {
       histogramData <- requestToHistogramNameMapper(request)
       histogram: Histogram = getOrCreateMetric(histogramsCache, histogramData, createNewHistogram)
-    } yield histogram.labels(histogramData.labelValues: _*).startTimer()
+    } yield histogram.labelValues(histogramData.labelValues: _*).startTimer()
 
-    val gauge: Option[Gauge.Child] = for {
+    val gauge: Option[GaugeDataPoint] = for {
       gaugeData <- requestToInProgressGaugeNameMapper(request)
-    } yield getOrCreateMetric(gaugesCache, gaugeData, createNewGauge).labels(gaugeData.labelValues: _*)
+    } yield getOrCreateMetric(gaugesCache, gaugeData, createNewGauge).labelValues(gaugeData.labelValues: _*)
 
     observeRequestContentLengthSummaryIfMapped(request, requestToSizeSummaryMapper)
 
@@ -214,7 +225,7 @@ class PrometheusListener(
       mapper: T => Option[BaseCollectorConfig]
   ): Unit =
     mapper(request).foreach { data =>
-      getOrCreateMetric(countersCache, data, createNewCounter).labels(data.labelValues: _*).inc()
+      getOrCreateMetric(countersCache, data, createNewCounter).labelValues(data.labelValues: _*).inc()
     }
 
   private def observeResponseContentLengthSummaryIfMapped(
@@ -224,7 +235,7 @@ class PrometheusListener(
   ): Unit =
     mapper((request, response)).foreach { data =>
       response.contentLength.map(_.toDouble).foreach { size =>
-        getOrCreateMetric(summariesCache, data, createNewSummary).labels(data.labelValues: _*).observe(size)
+        getOrCreateMetric(summariesCache, data, createNewSummary).labelValues(data.labelValues: _*).observe(size)
       }
     }
 
@@ -234,7 +245,7 @@ class PrometheusListener(
   ): Unit =
     mapper(request).foreach { data =>
       (request.contentLength: Option[Long]).map(_.toDouble).foreach { size =>
-        getOrCreateMetric(summariesCache, data, createNewSummary).labels(data.labelValues: _*).observe(size)
+        getOrCreateMetric(summariesCache, data, createNewSummary).labelValues(data.labelValues: _*).observe(size)
       }
     }
 
@@ -252,36 +263,36 @@ class PrometheusListener(
 
   private def createNewHistogram(data: HistogramCollectorConfig): Histogram =
     Histogram
-      .build()
-      .buckets(data.buckets: _*)
+      .builder()
+      .classicUpperBounds(data.buckets: _*)
       .name(data.collectorName)
       .labelNames(data.labelNames: _*)
       .help(data.collectorName)
-      .register(collectorRegistry)
+      .register(prometheusRegistry)
 
   private def createNewGauge(data: BaseCollectorConfig): Gauge =
     Gauge
-      .build()
+      .builder()
       .name(data.collectorName)
       .labelNames(data.labelNames: _*)
       .help(data.collectorName)
-      .register(collectorRegistry)
+      .register(prometheusRegistry)
 
   private def createNewCounter(data: BaseCollectorConfig): Counter =
     Counter
-      .build()
+      .builder()
       .name(data.collectorName)
       .labelNames(data.labelNames: _*)
       .help(data.collectorName)
-      .register(collectorRegistry)
+      .register(prometheusRegistry)
 
   private def createNewSummary(data: BaseCollectorConfig): Summary =
     Summary
-      .build()
+      .builder()
       .name(data.collectorName)
       .labelNames(data.labelNames: _*)
       .help(data.collectorName)
-      .register(collectorRegistry)
+      .register(prometheusRegistry)
 }
 
 trait BaseCollectorConfig {

observability/prometheus-backend/src/main/scala/sttp/client4/prometheus/PrometheusConfig.scala

@@ -1,6 +1,6 @@
 package sttp.client4.prometheus
 
-import io.prometheus.client.CollectorRegistry
+import io.prometheus.metrics.model.registry.PrometheusRegistry
 import sttp.client4.GenericRequest
 import sttp.client4.Response
 import sttp.client4.prometheus.PrometheusBackend._
@@ -25,7 +25,7 @@ final case class PrometheusConfig(
     responseToSizeSummaryMapper: (GenericRequest[_, _], Response[_]) => Option[CollectorConfig] =
       (req: GenericRequest[_, _], resp: Response[_]) =>
         Some(addStatusLabel(addMethodLabel(CollectorConfig(DefaultResponseSizeName), req), resp)),
-    collectorRegistry: CollectorRegistry = CollectorRegistry.defaultRegistry
+    prometheusRegistry: PrometheusRegistry = PrometheusRegistry.defaultRegistry
 )
 
 object PrometheusConfig {