Lack of public methods for accessing Histogram/Summary.DataPoint values

[jpalharini]

I'm working on a refactor of a Clojure wrapper library (clj-commons/iapetos) and I stumbled upon a design change on the access of values for Histogram and Summary metrics.

When using simpleclient we used to be able to call get() on a Histogram/Summary.Child instance and obtain count, sum and bucket/quantile values. On client_java that is no longer possible, as there is no public method to get a value out of a Histogram/Summary.DataPoint.

The only way I found to get these was to call collect() on the StatefulMetric instance, but then it requires iterating through data points in the MetricSnapshot to find which one matches the label values I'm looking for.

• Was this change a design decision? If so, can you share the reasoning behind it?

[zeitlinger]

Sorry, I don't follow - what value do you want to access?

[jpalharini]

The values connected to a Histogram/Summary.DataPoint. In simpleclient one used to be able to call getSum(), getCount(), etc...

[zeitlinger]

OK, so this is the change.

@fstab do you know why this got removed?

Index: prometheus-metrics-core/src/main/java/io/prometheus/metrics/core/metrics/Summary.java
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/prometheus-metrics-core/src/main/java/io/prometheus/metrics/core/metrics/Summary.java b/prometheus-metrics-core/src/main/java/io/prometheus/metrics/core/metrics/Summary.java
--- a/prometheus-metrics-core/src/main/java/io/prometheus/metrics/core/metrics/Summary.java	(revision a1cd99774e110102a7cae740a6e58c445b2f1bf3)
+++ b/prometheus-metrics-core/src/main/java/io/prometheus/metrics/core/metrics/Summary.java	(date 1760000980459)
@@ -1,7 +1,5 @@
 package io.prometheus.metrics.core.metrics;
 
-import static java.util.Objects.requireNonNull;
-
 import io.prometheus.metrics.config.MetricsProperties;
 import io.prometheus.metrics.config.PrometheusProperties;
 import io.prometheus.metrics.core.datapoints.DistributionDataPoint;
@@ -12,13 +10,16 @@
 import io.prometheus.metrics.model.snapshots.Quantile;
 import io.prometheus.metrics.model.snapshots.Quantiles;
 import io.prometheus.metrics.model.snapshots.SummarySnapshot;
+
+import javax.annotation.Nullable;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.DoubleAdder;
 import java.util.concurrent.atomic.LongAdder;
-import javax.annotation.Nullable;
+
+import static java.util.Objects.requireNonNull;
 
 /**
  * Summary metric. Example:
@@ -143,6 +144,14 @@
       }
     }
 
+    public double getSum() {
+      return sum.sum();
+    }
+
+    public long getCount() {
+      return count.sum();
+    }
+
     @Override
     public void observe(double value) {
       if (Double.isNaN(value)) {