feat: impact metrics serialization and wiring

src/main/java/io/getunleash/impactmetrics/HistogramImpl.java

@@ -84,8 +84,7 @@ public CollectedMetric collect() {
                 countSnapshot = data.count;
                 sumSnapshot = data.sum;
                 for (Double le : buckets) {
-                    bucketSamples.add(
-                            new HistogramBucket(le, data.buckets.getOrDefault(le, 0L)));
+                    bucketSamples.add(new HistogramBucket(le, data.buckets.getOrDefault(le, 0L)));
                 }
             }
 

src/main/java/io/getunleash/metric/ClientMetrics.java

@@ -4,8 +4,10 @@
 import io.getunleash.engine.UnleashEngine;
 import io.getunleash.event.UnleashEvent;
 import io.getunleash.event.UnleashSubscriber;
+import io.getunleash.impactmetrics.CollectedMetric;
 import io.getunleash.lang.Nullable;
 import io.getunleash.util.UnleashConfig;
+import java.util.List;
 
 public class ClientMetrics implements UnleashEvent {
 
@@ -18,8 +20,16 @@ public class ClientMetrics implements UnleashEvent {
     @Nullable private final String platformName;
     @Nullable private final String platformVersion;
     @Nullable private final String yggdrasilVersion;
+    @Nullable private final List<CollectedMetric> impactMetrics;
 
     ClientMetrics(UnleashConfig config, @Nullable MetricsBucket bucket) {
+        this(config, bucket, null);
+    }
+
+    ClientMetrics(
+            UnleashConfig config,
+            @Nullable MetricsBucket bucket,
+            @Nullable List<CollectedMetric> impactMetrics) {
         this.environment = config.getEnvironment();
         this.appName = config.getAppName();
         this.instanceId = config.getInstanceId();
@@ -29,6 +39,7 @@ public class ClientMetrics implements UnleashEvent {
         this.platformName = System.getProperty("java.vm.name");
         this.platformVersion = System.getProperty("java.version");
         this.yggdrasilVersion = UnleashEngine.getCoreVersion();
+        this.impactMetrics = impactMetrics;
     }
 
     public String getAppName() {
@@ -71,6 +82,11 @@ public String getYggdrasilVersion() {
         return yggdrasilVersion;
     }
 
+    @Nullable
+    public List<CollectedMetric> getImpactMetrics() {
+        return impactMetrics;
+    }
+
     @Override
     public void publishTo(UnleashSubscriber unleashSubscriber) {
         unleashSubscriber.clientMetrics(this);

src/main/java/io/getunleash/metric/DefaultHttpMetricsSender.java

@@ -5,8 +5,10 @@
 import com.google.gson.*;
 import io.getunleash.UnleashException;
 import io.getunleash.event.EventDispatcher;
+import io.getunleash.impactmetrics.HistogramBucket;
 import io.getunleash.util.AtomicLongSerializer;
 import io.getunleash.util.DateTimeSerializer;
+import io.getunleash.util.HistogramBucketSerializer;
 import io.getunleash.util.InstantSerializer;
 import io.getunleash.util.UnleashConfig;
 import io.getunleash.util.UnleashURLs;
@@ -38,6 +40,7 @@ public DefaultHttpMetricsSender(UnleashConfig unleashConfig) {
                         .registerTypeAdapter(LocalDateTime.class, new DateTimeSerializer())
                         .registerTypeAdapter(Instant.class, new InstantSerializer())
                         .registerTypeAdapter(AtomicLong.class, new AtomicLongSerializer())
+                        .registerTypeAdapter(HistogramBucket.class, new HistogramBucketSerializer())
                         .create();
     }
 

src/main/java/io/getunleash/metric/OkHttpMetricsSender.java

@@ -6,8 +6,10 @@
 import com.google.gson.GsonBuilder;
 import io.getunleash.UnleashException;
 import io.getunleash.event.EventDispatcher;
+import io.getunleash.impactmetrics.HistogramBucket;
 import io.getunleash.util.AtomicLongSerializer;
 import io.getunleash.util.DateTimeSerializer;
+import io.getunleash.util.HistogramBucketSerializer;
 import io.getunleash.util.OkHttpClientConfigurer;
 import io.getunleash.util.UnleashConfig;
 import java.io.IOException;
@@ -58,6 +60,7 @@ public OkHttpMetricsSender(UnleashConfig config) {
                 new GsonBuilder()
                         .registerTypeAdapter(LocalDateTime.class, new DateTimeSerializer())
                         .registerTypeAdapter(AtomicLong.class, new AtomicLongSerializer())
+                        .registerTypeAdapter(HistogramBucket.class, new HistogramBucketSerializer())
                         .create();
     }
 

src/main/java/io/getunleash/util/HistogramBucketSerializer.java

@@ -0,0 +1,24 @@
+package io.getunleash.util;
+
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+import com.google.gson.JsonSerializationContext;
+import com.google.gson.JsonSerializer;
+import io.getunleash.impactmetrics.HistogramBucket;
+import java.lang.reflect.Type;
+
+public class HistogramBucketSerializer implements JsonSerializer<HistogramBucket> {
+
+    @Override
+    public JsonElement serialize(
+            HistogramBucket src, Type typeOfSrc, JsonSerializationContext context) {
+        JsonObject jsonObject = new JsonObject();
+        if (Double.isInfinite(src.getLe()) && src.getLe() > 0) {
+            jsonObject.addProperty("le", "+Inf");
+        } else {
+            jsonObject.addProperty("le", src.getLe());
+        }
+        jsonObject.addProperty("count", src.getCount());
+        return jsonObject;
+    }
+}

src/main/java/io/getunleash/util/UnleashConfig.java

@@ -6,6 +6,7 @@
 import io.getunleash.UnleashException;
 import io.getunleash.event.NoOpSubscriber;
 import io.getunleash.event.UnleashSubscriber;
+import io.getunleash.impactmetrics.ImpactMetricsDataSource;
 import io.getunleash.lang.Nullable;
 import io.getunleash.metric.DefaultHttpMetricsSender;
 import io.getunleash.repository.HttpFeatureFetcher;
@@ -73,6 +74,7 @@ public class UnleashConfig {
     @Nullable private final ToggleBootstrapProvider toggleBootstrapProvider;
     @Nullable private final Proxy proxy;
     @Nullable private final Consumer<UnleashException> startupExceptionHandler;
+    @Nullable private final ImpactMetricsDataSource impactMetricsRegistry;
 
     private UnleashConfig(
             @Nullable URI unleashAPI,
@@ -106,7 +108,8 @@ private UnleashConfig(
             @Nullable ToggleBootstrapProvider unleashBootstrapProvider,
             @Nullable Proxy proxy,
             @Nullable Authenticator proxyAuthenticator,
-            @Nullable Consumer<UnleashException> startupExceptionHandler) {
+            @Nullable Consumer<UnleashException> startupExceptionHandler,
+            @Nullable ImpactMetricsDataSource impactMetricsRegistry) {
 
         if (appName == null) {
             throw new IllegalStateException("You are required to specify the unleash appName");
@@ -172,6 +175,7 @@ private UnleashConfig(
         this.clientSpecificationVersion =
                 UnleashProperties.getProperty("client.specification.version");
         this.startupExceptionHandler = startupExceptionHandler;
+        this.impactMetricsRegistry = impactMetricsRegistry;
     }
 
     public static Builder builder() {
@@ -352,6 +356,11 @@ public Proxy getProxy() {
         return proxy;
     }
 
+    @Nullable
+    public ImpactMetricsDataSource getImpactMetricsRegistry() {
+        return impactMetricsRegistry;
+    }
+
     public MetricSenderFactory getMetricSenderFactory() {
         return this.metricSenderFactory;
     }
@@ -462,6 +471,7 @@ public static class Builder {
         private @Nullable Authenticator proxyAuthenticator;
 
         private @Nullable Consumer<UnleashException> startupExceptionHandler;
+        private @Nullable ImpactMetricsDataSource impactMetricsRegistry;
 
         private static String getHostname() {
             String hostName = System.getProperty("hostname");
@@ -715,6 +725,12 @@ public Builder startupExceptionHandler(
             return this;
         }
 
+        public Builder impactMetricsRegistry(
+                @Nullable ImpactMetricsDataSource impactMetricsRegistry) {
+            this.impactMetricsRegistry = impactMetricsRegistry;
+            return this;
+        }
+
         public UnleashConfig build() {
             return new UnleashConfig(
                     unleashAPI,
@@ -749,7 +765,8 @@ public UnleashConfig build() {
                     toggleBootstrapProvider,
                     proxy,
                     proxyAuthenticator,
-                    startupExceptionHandler);
+                    startupExceptionHandler,
+                    impactMetricsRegistry);
         }
 
         public String getDefaultSdkVersion() {

src/test/java/io/getunleash/impactmetrics/MetricTypeTest.java

@@ -2,6 +2,9 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import io.getunleash.util.HistogramBucketSerializer;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
@@ -300,4 +303,60 @@ private NumericMetricSample sample(long value) {
     private NumericMetricSample sample(Map<String, String> labels, long value) {
         return new NumericMetricSample(labels, value);
     }
+
+    @Test
+    public void should_serialize_histogram_with_positive_infinity_as_plus_inf_string() {
+        InMemoryMetricRegistry registry = new InMemoryMetricRegistry();
+        Histogram histogram =
+                registry.histogram(
+                        new BucketMetricOptions(
+                                "serialization_test", "test serialization", List.of(1.0, 5.0)));
+
+        histogram.observe(10.0, Map.of("env", "prod"));
+
+        List<CollectedMetric> metrics = registry.collect();
+        assertThat(metrics).hasSize(1);
+
+        Gson gson =
+                new GsonBuilder()
+                        .registerTypeAdapter(HistogramBucket.class, new HistogramBucketSerializer())
+                        .create();
+
+        String json = gson.toJson(metrics.get(0));
+
+        assertThat(json).contains("\"le\":\"+Inf\"");
+        assertThat(json).contains("\"le\":1.0");
+        assertThat(json).contains("\"le\":5.0");
+    }
+
+    @Test
+    public void should_serialize_histogram_buckets_correctly() {
+        InMemoryMetricRegistry registry = new InMemoryMetricRegistry();
+        Histogram histogram =
+                registry.histogram(
+                        new BucketMetricOptions(
+                                "bucket_serialization", "test buckets", List.of(0.5, 2.0)));
+
+        histogram.observe(0.3);
+        histogram.observe(1.5);
+        histogram.observe(10.0);
+
+        List<CollectedMetric> metrics = registry.collect();
+        assertThat(metrics).hasSize(1);
+
+        BucketMetricSample sample = (BucketMetricSample) metrics.get(0).getSamples().get(0);
+        assertThat(sample.getBuckets()).hasSize(3);
+
+        Gson gson =
+                new GsonBuilder()
+                        .registerTypeAdapter(HistogramBucket.class, new HistogramBucketSerializer())
+                        .create();
+
+        String json = gson.toJson(sample);
+
+        assertThat(json).contains("\"le\":0.5");
+        assertThat(json).contains("\"le\":2.0");
+        assertThat(json).contains("\"le\":\"+Inf\"");
+        assertThat(json).contains("\"count\":");
+    }
 }