Add aggregation to metrics

3 files changed, 49 insertions, 19 deletions

diff --git a/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/metrics/Metric.java b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/metrics/Metric.java
index 5da4c3fb750..b7517668e8f 100644
--- a/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/metrics/Metric.java
+++ b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/metrics/Metric.java
@@ -1,5 +1,6 @@
 package com.yahoo.vespa.tenant.cd.metrics;
 
+import java.util.HashMap;
 import java.util.Map;
 import java.util.NoSuchElementException;
 import java.util.Set;
@@ -18,7 +19,7 @@ public class Metric {
     private final Map<Map<String, ?>, Statistic> statistics;
 
     private Metric(Map<Map<String, ?>, Statistic> statistics) {
-        this.statistics = copyOf(statistics);
+        this.statistics = statistics;
     }
 
     /** Creates a new Metric with a copy of the given data. */
@@ -26,19 +27,16 @@ public class Metric {
         if (data.isEmpty())
             throw new IllegalArgumentException("No data given.");
 
+        Map<Map<String, ?>, Statistic> copies = new HashMap<>();
         Set<String> dimensions = data.keySet().iterator().next().keySet();
-        for (Map<String, ?> point : data.keySet()) {
-            if (point.keySet().contains(null))
-                throw new IllegalArgumentException("Dimensions may not be null: '" + point.keySet() + "'.");
-
+        data.forEach((point, statistic) -> {
             if ( ! point.keySet().equals(dimensions))
                 throw new IllegalArgumentException("Given data has inconsistent dimensions: '" + dimensions + "' vs '" + point.keySet() + "'.");
 
-            if (point.values().contains(null))
-                throw new IllegalArgumentException("Position along a dimension may not be null: '" + point + "'.");
-        }
+            copies.put(copyOf(point), statistic);
+        });
 
-        return new Metric(data);
+        return new Metric(copyOf(copies));
     }
 
     /** Returns a Metric view of the subset of points in the given hyperplane; its dimensions must be a subset of those of this Metric. */
@@ -48,6 +46,21 @@ public class Metric {
                                     .collect(toUnmodifiableMap(point -> point, statistics::get)));
     }
 
+    /** Returns a version of this where statistics along the given hyperspace are aggregated. This does not preserve last, 95 and 99 percentile values. */
+    public Metric collapse(Set<String> hyperspace) {
+        return new Metric(statistics.keySet().stream()
+                                    .collect(toUnmodifiableMap(point -> point.keySet().stream()
+                                                                             .filter(dimension -> ! hyperspace.contains(dimension))
+                                                                             .collect(toUnmodifiableMap(dimension -> dimension, point::get)),
+                                                               statistics::get,
+                                                               Statistic::mergedWith)));
+    }
+
+    /** Returns a collapsed version of this, with all statistics aggregated. This does not preserve last, 95 and 99 percentile values. */
+    public Metric collapse() {
+        return collapse(statistics.keySet().iterator().next().keySet());
+    }
+
     /** If this Metric contains a single point, returns the Statistic of that point; otherwise, throws an exception. */
     public Statistic statistic() {
         if (statistics.size() == 1)
diff --git a/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/metrics/Metrics.java b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/metrics/Metrics.java
index c080d82a343..fb2528c4df5 100644
--- a/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/metrics/Metrics.java
+++ b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/metrics/Metrics.java
@@ -28,17 +28,14 @@ public class Metrics {
     private Metrics(Instant start, Instant end, Map<String, Metric> metrics) {
         this.start = start;
         this.end = end;
-        this.metrics = copyOf(metrics);
+        this.metrics = metrics;
     }
 
     public static Metrics of(Instant start, Instant end, Map<String, Metric> metrics) {
-        if (metrics.containsKey(null) || metrics.containsValue(null))
-            throw new IllegalArgumentException("Metrics may not contain null keys or values: '" + metrics + "'.");
-
         if ( ! start.isBefore(end))
             throw new IllegalArgumentException("Given time interval must be positive: '" + start + "' to '" + end + "'.");
 
-        return new Metrics(start, end, metrics);
+        return new Metrics(start, end, copyOf(metrics));
     }
 
     /** Returns the start of the time window from which these metrics were sampled, or throws if the status is {@code Status.down}. */
diff --git a/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/metrics/Statistic.java b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/metrics/Statistic.java
index 65c6dc3ed3f..e3315bcd181 100644
--- a/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/metrics/Statistic.java
+++ b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/metrics/Statistic.java
@@ -1,8 +1,11 @@
 package com.yahoo.vespa.tenant.cd.metrics;
 
+import java.util.HashMap;
 import java.util.Map;
 import java.util.NoSuchElementException;
 import java.util.StringJoiner;
+import java.util.function.Function;
+import java.util.stream.Collectors;
 
 import static java.util.Map.copyOf;
 
@@ -17,14 +20,11 @@ public class Statistic {
 
     /** Creates a new Statistic with a copy of the given data. */
     private Statistic(Map<Type, Double> data) {
-        this.data = copyOf(data);
+        this.data = data;
     }
 
     public static Statistic of(Map<Type, Double> data) {
-        if (data.containsKey(null) || data.containsValue(null))
-            throw new IllegalArgumentException("Data may not contain null keys or values: '" + data + "'.");
-
-        return new Statistic(data);
+        return new Statistic(copyOf(data));
     }
 
     /** Returns the value of the given type, or throws a NoSuchElementException if this isn't known. */
@@ -40,6 +40,26 @@ public class Statistic {
         return data;
     }
 
+    Statistic mergedWith(Statistic other) {
+        if (data.keySet().equals(other.data.keySet()))
+            throw new IllegalArgumentException("Incompatible key sets '" + data.keySet() + "' and '" + other.data.keySet() + "'.");
+
+        Map<Type, Double> merged = new HashMap<>();
+        double n1 = get(Type.count), n2 = other.get(Type.count);
+        for (Type type : data.keySet()) switch (type) {
+            case count: merged.put(type, n1 + n2); break;
+            case rate: merged.put(type, get(Type.rate) + other.get(Type.rate)); break;
+            case max: merged.put(type, Math.max(get(Type.max), other.get(Type.max))); break;
+            case min: merged.put(type, Math.min(get(Type.min), other.get(Type.min))); break;
+            case average: merged.put(type, (n1 * get(Type.average) + n2 * other.get(Type.average)) / (n1 + n2)); break;
+            case last:
+            case percentile95:
+            case percentile99: break;
+            default: throw new IllegalArgumentException("Unexpected type '" + type + "'.");
+        }
+        return of(merged);
+    }
+
     @Override
     public String toString() {
         return new StringJoiner(", ", Statistic.class.getSimpleName() + "[", "]")