Update prometheus client to 1.3.1

README.md

@@ -8,6 +8,15 @@ Collection of utilities to allow exposing prometheus metrics from pekko-http end
 
 [prometheus-akka-http](https://github.com/varwise/prometheus-akka-http) - same thing but for akka-http
 
+### Migration to 2.0.0
+
+Version 2.0.0 uses Prometheus Java client library 1.0.0 which introduced some breaking changes.
+
+Here's the quick migration guide:
+1. Replace occurrences of `io.prometheus.client.CollectorRegistry` with `io.prometheus.metrics.model.registry.PrometheusRegistry`. 
+2. Supply `ExecutionContext` instance to `MetricsEndpoint`.
+
+For more information about Prometheus Java client library please refer to https://prometheus.github.io/client_java/.
 ### Publishing
 
 Artifacts are published to Maven central using the [sbt-sonatype](https://github.com/xerial/sbt-sonatype) plugin

build.sbt

@@ -4,7 +4,7 @@ organization := "com.varwise"
 
 publishTo := sonatypePublishToBundle.value
 
-version := "1.0.1"
+version := "2.0.0"
 
 val scala2Version = "2.13.13"
 val scala3Version = "3.3.3"
@@ -15,21 +15,23 @@ crossScalaVersions := Seq(scala3Version, scala2Version)
 credentials += Credentials(Path.userHome / ".sbt" / ".credentials")
 
 libraryDependencies ++= {
-  val simpleclientVersion = "0.16.0"
+  val prometheusJavaClientVersion = "1.3.1"
   val pekkoVersion = "1.0.2"
   val pekkoHttpVersion = "1.0.1"
   val scalaTestVersion = "3.2.18"
+  val slf4jVersion = "2.0.13"
 
   Seq(
-    "org.apache.pekko" %% "pekko-actor"           % pekkoVersion     % Provided,
-    "org.apache.pekko" %% "pekko-stream"          % pekkoVersion     % Provided,
-    "org.apache.pekko" %% "pekko-http"            % pekkoHttpVersion % Provided,
-    "org.apache.pekko" %% "pekko-http-spray-json" % pekkoHttpVersion % Provided,
-    "io.prometheus"      % "simpleclient"         % simpleclientVersion,
-    "io.prometheus"      % "simpleclient_common"  % simpleclientVersion,
-    "org.apache.pekko" %% "pekko-testkit"         % pekkoVersion     % Test,
-    "org.apache.pekko" %% "pekko-http-testkit"    % pekkoHttpVersion % Test,
-    "org.scalatest"     %% "scalatest"            % scalaTestVersion % Test
+    "org.apache.pekko" %% "pekko-actor"                           % pekkoVersion     % Provided,
+    "org.apache.pekko" %% "pekko-stream"                          % pekkoVersion     % Provided,
+    "org.apache.pekko" %% "pekko-http"                            % pekkoHttpVersion % Provided,
+    "org.apache.pekko" %% "pekko-http-spray-json"                 % pekkoHttpVersion % Provided,
+    "io.prometheus"     % "prometheus-metrics-core"               % prometheusJavaClientVersion,
+    "io.prometheus"     % "prometheus-metrics-exposition-formats" % prometheusJavaClientVersion,
+    "org.slf4j"         % "slf4j-api"                             % slf4jVersion,
+    "org.apache.pekko" %% "pekko-testkit"                         % pekkoVersion     % Test,
+    "org.apache.pekko" %% "pekko-http-testkit"                    % pekkoHttpVersion % Test,
+    "org.scalatest"    %% "scalatest"                             % scalaTestVersion % Test
   )
 }
 

src/main/scala/com/varwise/pekko/http/prometheus/EventObserver.scala

@@ -1,6 +1,7 @@
 package com.varwise.pekko.http.prometheus
 
-import io.prometheus.client.{CollectorRegistry, Counter}
+import io.prometheus.metrics.core.metrics.Counter
+import io.prometheus.metrics.model.registry.PrometheusRegistry
 
 trait EventObserver {
   def observe(eventName: String, eventDetails: String): Unit
@@ -24,20 +25,19 @@ class PrometheusEventObserver(
     metricHelp: String,
     eventLabelName: String,
     eventDetailsLabelName: String,
-    registry: CollectorRegistry)
+    registry: PrometheusRegistry)
     extends EventObserver {
 
-  val counter: Counter = buildCounter.register(registry)
-
-  private def buildCounter: Counter.Builder =
+  private val counter: Counter =
     Counter
-      .build()
+      .builder()
       .name(metricName)
       .help(metricHelp)
       .labelNames(eventLabelName, eventDetailsLabelName)
+      .register(registry)
 
   override def observe(eventName: String, eventDetails: String): Unit =
-    counter.labels(eventName, eventDetails).inc()
+    counter.labelValues(eventName, eventDetails).inc()
 }
 
 object PrometheusEventObserver {
@@ -47,7 +47,7 @@ object PrometheusEventObserver {
   private val FailedOperationMetricHelp = "The number of observed failed operations"
   private val DefaultEventLabelName = "event"
   private val DefaultEventDetailsLabelName = "details"
-  private val DefaultRegistry = CollectorRegistry.defaultRegistry
+  private val DefaultRegistry = PrometheusRegistry.defaultRegistry
 
   // Common event observers used in scala projects in Open Planet micro-services
   lazy val SuccessfulOperations: PrometheusEventObserver =

src/main/scala/com/varwise/pekko/http/prometheus/ResponseTimeRecorder.scala

@@ -1,6 +1,7 @@
 package com.varwise.pekko.http.prometheus
 
-import io.prometheus.client.{CollectorRegistry, Histogram}
+import io.prometheus.metrics.core.metrics.Histogram
+import io.prometheus.metrics.model.registry.PrometheusRegistry
 
 import scala.concurrent.duration
 import scala.concurrent.duration.{FiniteDuration, TimeUnit}
@@ -30,23 +31,21 @@ class PrometheusResponseTimeRecorder(
     metricHelp: String,
     buckets: List[Double],
     endpointLabelName: String,
-    registry: CollectorRegistry,
+    registry: PrometheusRegistry,
     timeUnit: TimeUnit)
     extends ResponseTimeRecorder {
 
-  private val responseTimes = buildHistogram.register(registry)
-
-  override def recordResponseTime(endpoint: String, responseTime: FiniteDuration): Unit =
-    responseTimes.labels(endpoint).observe(responseTime.toUnit(timeUnit))
-
-  private def buildHistogram: Histogram.Builder =
+  private val responseTimes: Histogram =
     Histogram
-      .build()
+      .builder()
       .name(metricName)
       .help(metricHelp)
       .labelNames(endpointLabelName)
-      .buckets(buckets: _*)
+      .classicUpperBounds(buckets: _*)
+      .register(registry)
 
+  override def recordResponseTime(endpoint: String, responseTime: FiniteDuration): Unit =
+    responseTimes.labelValues(endpoint).observe(responseTime.toUnit(timeUnit))
 }
 
 object PrometheusResponseTimeRecorder {
@@ -58,7 +57,7 @@ object PrometheusResponseTimeRecorder {
   val DefaultEndpointLabel = "endpoint"
   val DefaultTimeUnit: TimeUnit = duration.SECONDS
 
-  lazy val DefaultRegistry: CollectorRegistry = CollectorRegistry.defaultRegistry
+  lazy val DefaultRegistry: PrometheusRegistry = PrometheusRegistry.defaultRegistry
 
   lazy val Default: PrometheusResponseTimeRecorder =
     new PrometheusResponseTimeRecorder(

src/main/scala/com/varwise/pekko/http/prometheus/api/MetricsEndpoint.scala

@@ -1,16 +1,38 @@
 package com.varwise.pekko.http.prometheus.api
 
+import io.prometheus.metrics.expositionformats.ExpositionFormats
+import io.prometheus.metrics.model.registry.PrometheusRegistry
+import org.apache.pekko.http.scaladsl.model.{HttpCharsets, HttpEntity, MediaType}
 import org.apache.pekko.http.scaladsl.server.Directives._
 import org.apache.pekko.http.scaladsl.server.Route
-import io.prometheus.client.CollectorRegistry
+import org.apache.pekko.stream.scaladsl.StreamConverters
+import org.slf4j.LoggerFactory
 
-class MetricsEndpoint(registry: CollectorRegistry) {
+import java.io.{PipedInputStream, PipedOutputStream}
+import scala.concurrent.{ExecutionContext, Future}
+
+class MetricsEndpoint(registry: PrometheusRegistry)(implicit ec: ExecutionContext) {
+
+  private val logger = LoggerFactory.getLogger(classOf[MetricsEndpoint])
+  private val prometheusTextType =
+    MediaType.customWithFixedCharset("text", "plain", HttpCharsets.`UTF-8`, params = Map("version" -> "0.0.4"))
+  private val writer = ExpositionFormats.init().getPrometheusTextFormatWriter()
 
   val routes: Route =
     get {
       path("metrics") {
         complete {
-          MetricFamilySamplesEntity.fromRegistry(registry)
+          val in = new PipedInputStream
+          val out = new PipedOutputStream(in)
+          val byteSource = StreamConverters.fromInputStream(() => in)
+          val f = Future {
+            try
+              writer.write(out, registry.scrape())
+            finally
+              out.close()
+          }
+          f.failed.foreach(e => logger.error("Error when writing Prometheus metrics", e))
+          HttpEntity(prometheusTextType, byteSource)
         }
       }
     }

src/test/scala/com/varwise/pekko/http/prometheus/PrometheusEventObserverSpec.scala

@@ -1,14 +1,17 @@
 package com.varwise.pekko.http.prometheus
 
 import com.varwise.pekko.http.prometheus.Utils._
-import io.prometheus.client.CollectorRegistry
+import io.prometheus.metrics.model.registry.PrometheusRegistry
+import io.prometheus.metrics.model.snapshots.{CounterSnapshot, Labels}
 import org.scalatest.flatspec.AnyFlatSpec
 import org.scalatest.matchers.should.Matchers
 
+import scala.jdk.CollectionConverters.IterableHasAsScala
+
 class PrometheusEventObserverSpec extends AnyFlatSpec with Matchers {
 
   "PrometheusEventObserver" should "record observed events in a counter" in {
-    val registry = new CollectorRegistry()
+    val registry = new PrometheusRegistry()
     val randomMetricName = generateRandomString
     val randomMetricHelp = generateRandomString
     val randomEventLabelName = generateRandomString
@@ -25,19 +28,29 @@ class PrometheusEventObserverSpec extends AnyFlatSpec with Matchers {
       registry
     )
 
-    def getCounterValue: java.lang.Double =
-      registry.getSampleValue(
-        randomMetricName + "_total",
-        Array(randomEventLabelName, randomEventDetailsLabelName),
-        Array(randomEventName, randomEventDetails)
+    def getCounterValue(): Option[Double] = {
+      val labels = Labels.of(
+        randomEventLabelName,
+        randomEventName,
+        randomEventDetailsLabelName,
+        randomEventDetails
       )
-
-    getCounterValue shouldBe null
+      registry
+        .scrape()
+        .asScala
+        .collect { case counter: CounterSnapshot => counter }
+        .filter(_.getMetadata.getName == randomMetricName)
+        .flatMap(_.getDataPoints.asScala)
+        .filter(_.getLabels.equals(labels))
+        .map(_.getValue)
+        .headOption
+    }
+
+    getCounterValue() shouldBe None
 
     eventObserver.observe(randomEventName, randomEventDetails)
 
-    getCounterValue should not be null
-    getCounterValue.intValue() shouldBe 1
-
+    getCounterValue() should not be None
+    getCounterValue().get.intValue() shouldBe 1
   }
 }

src/test/scala/com/varwise/pekko/http/prometheus/PrometheusResponseTimeRecorderSpec.scala

@@ -1,33 +1,38 @@
 package com.varwise.pekko.http.prometheus
 
 import com.varwise.pekko.http.prometheus.Utils._
-import io.prometheus.client.{Collector, CollectorRegistry}
+import io.prometheus.metrics.model.registry.PrometheusRegistry
+import io.prometheus.metrics.model.snapshots.{HistogramSnapshot, Labels}
 import org.scalatest.flatspec.AnyFlatSpec
 import org.scalatest.matchers.should.Matchers
 
 import scala.concurrent.duration
 import scala.concurrent.duration.FiniteDuration
+import scala.jdk.CollectionConverters.IterableHasAsScala
 import scala.util.Random
 
 class PrometheusResponseTimeRecorderSpec extends AnyFlatSpec with Matchers {
 
   private def getBucketValue(
-      registry: CollectorRegistry,
+      registry: PrometheusRegistry,
       metricName: String,
-      labelNames: List[String],
-      labelValues: List[String],
+      labels: Labels,
       bucket: Double
-  ): Int = {
-    val name = metricName + "_bucket"
+  ): Long =
+    registry
+      .scrape()
+      .asScala
+      .collect { case metric: HistogramSnapshot => metric }
+      .filter(_.getMetadata.getName == metricName)
+      .flatMap(_.getDataPoints.asScala)
+      .filter(_.getLabels.equals(labels))
+      .flatMap(_.getClassicBuckets.asScala)
+      .find(_.getUpperBound == bucket)
+      .get
+      .getCount
 
-    // 'le' should be the first label in the list
-    val allLabelNames = (Array("le") ++ labelNames).reverse
-    val allLabelValues = (Array(Collector.doubleToGoString(bucket)) ++ labelValues).reverse
-    registry.getSampleValue(name, allLabelNames, allLabelValues).intValue()
-  }
-
-  "PrometheusLatencyRecorder" should "register a histogram and record request latencies" in {
-    val registry = new CollectorRegistry()
+  "PrometheusResponseTimeRecorder" should "register a histogram and record request latencies" in {
+    val registry = new PrometheusRegistry()
     val randomMetricName = generateRandomString
     val randomMetricHelp = generateRandomString
     val randomLabelName = generateRandomString
@@ -48,20 +53,14 @@ class PrometheusResponseTimeRecorderSpec extends AnyFlatSpec with Matchers {
 
     recorder.recordResponseTime(randomEndpointName, FiniteDuration(randomLatency, duration.MILLISECONDS))
 
-    val first =
-      getBucketValue(registry, randomMetricName, List(randomLabelName), List(randomEndpointName), buckets.head)
-    val second =
-      getBucketValue(registry, randomMetricName, List(randomLabelName), List(randomEndpointName), buckets.last)
-    val positiveInf = getBucketValue(
-      registry,
-      randomMetricName,
-      List(randomLabelName),
-      List(randomEndpointName),
-      Double.PositiveInfinity
-    )
+    val labels = Labels.of(randomLabelName, randomEndpointName)
+
+    val first = getBucketValue(registry, randomMetricName, labels, buckets.head)
+    val second = getBucketValue(registry, randomMetricName, labels, buckets.last)
+    val positiveInf = getBucketValue(registry, randomMetricName, labels, Double.PositiveInfinity)
 
     first shouldBe 0
     second shouldBe 1
-    positiveInf shouldBe 1
+    positiveInf shouldBe 0
   }
 }