Support bucket configuration for Histograms

lenin-jaganathan · Aug 8, 2024 · 6be37b0 · 6be37b0
1 parent 718f3c2
commit 6be37b0
Show file tree

Hide file tree

Showing 5 changed files with 58 additions and 4 deletions.
diff --git a/...micrometer-registry-otlp/src/main/java/io/micrometer/registry/otlp/OtlpMeterRegistry.java b/...micrometer-registry-otlp/src/main/java/io/micrometer/registry/otlp/OtlpMeterRegistry.java
@@ -266,6 +266,7 @@ protected TimeUnit getBaseTimeUnit() {
     protected DistributionStatisticConfig defaultHistogramConfig() {
         return DistributionStatisticConfig.builder()
             .expiry(this.config.step())
+            .maxBucketCount(this.config.maxBucketCount())
             .build()
             .merge(DistributionStatisticConfig.DEFAULT);
     }
@@ -405,11 +406,14 @@ static Histogram getHistogram(final Clock clock, final DistributionStatisticConf
                     minimumExpectedValue = 0.0;
                 }
 
+                final int maxBucketCount = distributionStatisticConfig.getMaxBucketCount() != null ?
+                    distributionStatisticConfig.getMaxBucketCount() : otlpConfig.maxBucketCount();
                 return otlpConfig.aggregationTemporality() == AggregationTemporality.DELTA
-                        ? new DeltaBase2ExponentialHistogram(otlpConfig.maxScale(), otlpConfig.maxBucketCount(),
-                                minimumExpectedValue, baseTimeUnit, clock, otlpConfig.step().toMillis())
-                        : new CumulativeBase2ExponentialHistogram(otlpConfig.maxScale(), otlpConfig.maxBucketCount(),
-                                minimumExpectedValue, baseTimeUnit);
+                        ? new DeltaBase2ExponentialHistogram(otlpConfig.maxScale(),
+                    maxBucketCount, minimumExpectedValue, baseTimeUnit,
+                                clock, otlpConfig.step().toMillis())
+                        : new CumulativeBase2ExponentialHistogram(otlpConfig.maxScale(),
+                            maxBucketCount, minimumExpectedValue, baseTimeUnit);
             }
 
             Histogram explicitBucketHistogram = getExplicitBucketHistogram(clock, distributionStatisticConfig,

diff --git a/micrometer-core/src/main/java/io/micrometer/core/instrument/AbstractTimerBuilder.java b/micrometer-core/src/main/java/io/micrometer/core/instrument/AbstractTimerBuilder.java
@@ -194,6 +194,13 @@ public B maximumExpectedValue(@Nullable Duration max) {
         return (B) this;
     }
 
+    public B maxBucketCount(@Nullable Integer maxBucketCount) {
+        if (maxBucketCount != null) {
+            this.distributionConfigBuilder.maxBucketCount(maxBucketCount);
+        }
+        return (B) this;
+    }
+
     /**
      * Statistics emanating from a timer like max, percentiles, and histogram counts decay
      * over time to give greater weight to recent samples (exception: histogram counts are

diff --git a/micrometer-core/src/main/java/io/micrometer/core/instrument/DistributionSummary.java b/micrometer-core/src/main/java/io/micrometer/core/instrument/DistributionSummary.java
@@ -345,6 +345,13 @@ public Builder maximumExpectedValue(@Nullable Double max) {
             return this;
         }
 
+        public Builder maxBucketCount(@Nullable Integer maxBucketCount) {
+            if (maxBucketCount != null) {
+                this.distributionConfigBuilder.maxBucketCount(maxBucketCount);
+            }
+            return this;
+        }
+
         /**
          * Statistics emanating from a distribution summary like max, percentiles, and
          * histogram counts decay over time to give greater weight to recent samples

diff --git a/micrometer-core/src/main/java/io/micrometer/core/instrument/LongTaskTimer.java b/micrometer-core/src/main/java/io/micrometer/core/instrument/LongTaskTimer.java
@@ -386,6 +386,13 @@ public Builder maximumExpectedValue(@Nullable Duration max) {
             return this;
         }
 
+        public Builder maxBucketCount(@Nullable Integer maxBucketCount) {
+            if (maxBucketCount != null) {
+                this.distributionConfigBuilder.maxBucketCount(maxBucketCount);
+            }
+            return this;
+        }
+
         /**
          * Statistics emanating from a timer like max, percentiles, and histogram counts
          * decay over time to give greater weight to recent samples (exception: histogram

diff --git a/...src/main/java/io/micrometer/core/instrument/distribution/DistributionStatisticConfig.java b/...src/main/java/io/micrometer/core/instrument/distribution/DistributionStatisticConfig.java
@@ -22,6 +22,7 @@
 import java.time.Duration;
 import java.util.NavigableSet;
 import java.util.TreeSet;
+import java.util.stream.Collectors;
 import java.util.stream.LongStream;
 
 /**
@@ -41,6 +42,7 @@ public class DistributionStatisticConfig implements Mergeable<DistributionStatis
         .percentilePrecision(1)
         .minimumExpectedValue(1.0)
         .maximumExpectedValue(Double.POSITIVE_INFINITY)
+        .maxBucketCount(Integer.MAX_VALUE)
         .expiry(Duration.ofMinutes(2))
         .bufferLength(3)
         .build();
@@ -71,6 +73,9 @@ public class DistributionStatisticConfig implements Mergeable<DistributionStatis
     @Nullable
     private Integer bufferLength;
 
+    @Nullable
+    private Integer maxBucketCount;
+
     public static Builder builder() {
         return new Builder();
     }
@@ -96,6 +101,7 @@ public DistributionStatisticConfig merge(DistributionStatisticConfig parent) {
                     this.minimumExpectedValue == null ? parent.minimumExpectedValue : this.minimumExpectedValue)
             .maximumExpectedValue(
                     this.maximumExpectedValue == null ? parent.maximumExpectedValue : this.maximumExpectedValue)
+            .maxBucketCount(this.maxBucketCount == null ? parent.maxBucketCount : this.maxBucketCount)
             .expiry(this.expiry == null ? parent.expiry : this.expiry)
             .bufferLength(this.bufferLength == null ? parent.bufferLength : this.bufferLength)
             .build();
@@ -121,6 +127,10 @@ public NavigableSet<Double> getHistogramBuckets(boolean supportsAggregablePercen
             }
         }
 
+        if (maxBucketCount != null && buckets.size() > maxBucketCount) {
+            return buckets.stream().limit(maxBucketCount).collect(Collectors.toCollection(TreeSet::new));
+        }
+
         return buckets;
     }
 
@@ -210,6 +220,11 @@ public Double getMaximumExpectedValueAsDouble() {
         return maximumExpectedValue;
     }
 
+    @Nullable
+    public Integer getMaxBucketCount() {
+        return maxBucketCount;
+    }
+
     /**
      * Statistics like max, percentiles, and histogram counts decay over time to give
      * greater weight to recent samples (exception: histogram counts are cumulative for
@@ -453,6 +468,16 @@ public Builder bufferLength(@Nullable Integer bufferLength) {
             return this;
         }
 
+        /**
+         * Restricts the number of buckets/bin ranges used in histogram.
+         * @param maxBucketCount maximum number of buckets
+         * @return This buffer
+         */
+        public Builder maxBucketCount(@Nullable Integer maxBucketCount) {
+            config.maxBucketCount = maxBucketCount;
+            return this;
+        }
+
         /**
          * @return A new immutable distribution configuration.
          */
@@ -489,6 +514,10 @@ private void validate(DistributionStatisticConfig distributionStatisticConfig) {
                         + ").");
             }
 
+            if (config.maxBucketCount != null && config.maxBucketCount <= 0) {
+                rejectConfig("maxBucketCount (" + config.maxBucketCount + ") must be greater than zero");
+            }
+
             if (distributionStatisticConfig.getServiceLevelObjectiveBoundaries() != null) {
                 for (double slo : distributionStatisticConfig.getServiceLevelObjectiveBoundaries()) {
                     if (slo <= 0) {