Initial dump

22 files changed, 596 insertions, 1 deletions

diff --git a/tenant-cd/pom.xml b/tenant-cd/pom.xml
index 8907e56762c..99350c332c2 100644
--- a/tenant-cd/pom.xml
+++ b/tenant-cd/pom.xml
@@ -20,6 +20,12 @@
 
     <dependencies>
         <dependency>
+            <groupId>com.yahoo.vespa</groupId>
+            <artifactId>vespajlib</artifactId>
+            <version>7-SNAPSHOT</version>
+        </dependency>
+
+        <dependency>
             <groupId>junit</groupId>
             <artifactId>junit</artifactId>
             <version>4.12</version>
diff --git a/tenant-cd/src/main/java/ai/vespa/hosted/cd/ProductionTest.java b/tenant-cd/src/main/java/ai/vespa/hosted/cd/ProductionTest.java
index a756b665c1a..6cf5fb07f58 100644
--- a/tenant-cd/src/main/java/ai/vespa/hosted/cd/ProductionTest.java
+++ b/tenant-cd/src/main/java/ai/vespa/hosted/cd/ProductionTest.java
@@ -1,6 +1,23 @@
 // Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package ai.vespa.hosted.cd;
 
-public class ProductionTest {
+/**
+ * Tests that verify the health of production deployments of Vespa applications.
+ *
+ * These tests are typically run some time after deployment to a production zone, to ensure
+ * the deployment is still healthy and working as expected. When these tests fail, deployment
+ * of the tested change is halted until it succeeds, or is superseded by a remedying change.
+ *
+ * A typical production test is to verify that a set of metrics, measured by the Vespa
+ * deployment itself, are within specified parameters, or that some higher-level measure
+ * of quality, such as engagement among end users of the application, is as expected.
+ *
+ * @author jonmv
+ */
+public interface ProductionTest {
+
+    // Want to verify metrics (Vespa).
+    // Want to verify external metrics (YAMAS, other).
+    // May want to verify search gives expected results.
 
 }
diff --git a/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/Deployment.java b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/Deployment.java
new file mode 100644
index 00000000000..02627ae7c9e
--- /dev/null
+++ b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/Deployment.java
@@ -0,0 +1,16 @@
+package com.yahoo.vespa.tenant.cd;
+
+/**
+ * A deployment of a Vespa application, which contains endpoints for document and metrics retrieval.
+ *
+ * @author jonmv
+ */
+public interface Deployment {
+
+    /** Returns an Endpoint in the cluster with the "default" id. */
+    Endpoint endpoint();
+
+    /** Returns an Endpoint in the cluster with the given id. */
+    Endpoint endpoint(String id);
+
+}
diff --git a/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/Digest.java b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/Digest.java
new file mode 100644
index 00000000000..73b804dc33c
--- /dev/null
+++ b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/Digest.java
@@ -0,0 +1,28 @@
+package com.yahoo.vespa.tenant.cd;
+
+import java.util.Set;
+
+/**
+ * An immutable report of the outcome of a {@link Feed} sent to a {@link TestEndpoint}.
+ *
+ * @author jonmv
+ */
+public class Digest {
+
+    public Set<DocumentId> created() {
+        return null;
+    }
+
+    public Set<DocumentId> updated() {
+        return null;
+    }
+
+    public Set<DocumentId> deleted() {
+        return null;
+    }
+
+    public Set<DocumentId> failed() {
+        return null;
+    }
+
+}
diff --git a/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/Document.java b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/Document.java
new file mode 100644
index 00000000000..acb1ea08623
--- /dev/null
+++ b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/Document.java
@@ -0,0 +1,16 @@
+package com.yahoo.vespa.tenant.cd;
+
+/**
+ * A schema-less representation of a generic Vespa document.
+ *
+ * @author jonmv
+ */
+public class Document {
+
+
+    /** Returns a copy of this document, updated with the data in the given document. */
+    public Document updatedBy(Document update) {
+        return null;
+    }
+
+}
diff --git a/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/DocumentId.java b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/DocumentId.java
new file mode 100644
index 00000000000..c4fc7103b05
--- /dev/null
+++ b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/DocumentId.java
@@ -0,0 +1,71 @@
+package com.yahoo.vespa.tenant.cd;
+
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * Unique, immutable ID of a Vespa document, which contains information pertinent to its storage.
+ *
+ * @author jonmv
+ */
+public class DocumentId {
+
+    private final String namespace;
+    private final String documentType;
+    private final String group;
+    private final Long number;
+    private final String userDefined;
+
+    private DocumentId(String namespace, String documentType, String group, Long number, String userDefined) {
+        this.namespace = namespace;
+        this.documentType = documentType;
+        this.group = group;
+        this.number = number;
+        this.userDefined = userDefined;
+    }
+
+    public static DocumentId of(String namespace, String documentType, String id) {
+        return new DocumentId(requireNonEmpty(namespace), requireNonEmpty(documentType), null, null, requireNonEmpty(id));
+    }
+
+    public static DocumentId of(String namespace, String documentType, String group, String id) {
+        return new DocumentId(requireNonEmpty(namespace), requireNonEmpty(documentType), requireNonEmpty(group), null, requireNonEmpty(id));
+    }
+
+    public static DocumentId of(String namespace, String documentType, long number, String id) {
+        return new DocumentId(requireNonEmpty(namespace), requireNonEmpty(documentType), null, number, requireNonEmpty(id));
+    }
+
+    public static DocumentId ofValue(String value) {
+        List<String> parts = Arrays.asList(value.split(":"));
+        String id = String.join(":", parts.subList(4, parts.size()));
+        if (     parts.size() < 5
+            || ! parts.get(0).equals("id")
+            ||   id.isEmpty()
+            || ! parts.get(3).matches("((n=\\d+)|(g=\\w+))?"))
+            throw new IllegalArgumentException("Document id must be on the form" +
+                                               " 'id:<namespace>:<document type>:n=<integer>|g=<name>|<empty>:<user defined id>'," +
+                                               " but was '" + value + "'.");
+
+        if (parts.get(3).matches("n=\\d+"))
+            return of(parts.get(1), parts.get(2), Long.parseLong(parts.get(3).substring(2)), id);
+        if (parts.get(3).matches("g=\\w+"))
+            return of(parts.get(1), parts.get(2), parts.get(3).substring(2), id);
+        return of(parts.get(1), parts.get(2), id);
+    }
+
+    public String asValue() {
+        return "id:" + namespace + ":" + documentType + ":" + grouper() + ":" + userDefined;
+    }
+
+    private String grouper() {
+        return group != null ? group : number != null ? number.toString() : "";
+    }
+
+    private static String requireNonEmpty(String string) {
+        if (string.isEmpty())
+            throw new IllegalArgumentException("The empty string is not allowed.");
+        return string;
+    }
+
+}
diff --git a/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/Endpoint.java b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/Endpoint.java
new file mode 100644
index 00000000000..e238d38112b
--- /dev/null
+++ b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/Endpoint.java
@@ -0,0 +1,21 @@
+package com.yahoo.vespa.tenant.cd;
+
+import com.yahoo.vespa.tenant.cd.metrics.Metrics;
+
+/**
+ * An endpoint in a Vespa application {@link Deployment}, which allows document and metrics retrieval.
+ *
+ * The endpoint translates {@link Query}s to {@link Search}s, and {@link Selection}s to {@link Visit}s.
+ * It also supplies {@link Metrics}.
+ *
+ * @author jonmv
+ */
+public interface Endpoint {
+
+    Search search(Query query);
+
+    Visit visit(Selection selection);
+
+    Metrics metrics();
+
+}
diff --git a/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/Feed.java b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/Feed.java
new file mode 100644
index 00000000000..0b6b1702c80
--- /dev/null
+++ b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/Feed.java
@@ -0,0 +1,25 @@
+package com.yahoo.vespa.tenant.cd;
+
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * An immutable set of document feed / update / delete operations, which can be sent to a Vespa {@link TestEndpoint}.
+ *
+ * @author jonmv
+ */
+public class Feed {
+
+    Map<DocumentId, Document> creations() {
+        return null;
+    }
+
+    Map<DocumentId, Document> updates() {
+        return null;
+    }
+
+    Set<DocumentId> deletions() {
+        return null;
+    }
+
+}
diff --git a/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/FunctionalTest.java b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/FunctionalTest.java
new file mode 100644
index 00000000000..3c48e2d32f0
--- /dev/null
+++ b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/FunctionalTest.java
@@ -0,0 +1,31 @@
+package com.yahoo.vespa.tenant.cd;
+
+/**
+ * Tests that compare the behaviour of a Vespa application deployment against a fixed specification.
+ *
+ * These tests are run whenever a change is pushed to a Vespa application, and whenever the Vespa platform
+ * is upgraded, and before any deployments to production zones. When these tests fails, the tested change to
+ * the Vespa application is not rolled out.
+ *
+ * A typical functional test is to feed some documents, optionally verifying that the documents have been processed
+ * as expected, and then to see that queries give the expected results. Another common use is to verify integration
+ * with external services.
+ *
+ * @author jonmv
+ */
+public interface FunctionalTest {
+
+    // Want to feed some documents.
+    // Want to verify document processing and routing is as expected.
+    // Want to check recall on those documents.
+    // Want to verify queries give expected documents.
+    // Want to verify searchers.
+    // Want to verify updates.
+    // Want to verify deletion.
+    // May want to verify reprocessing.
+    // Must likely delete documents between tests.
+    // Must be able to feed documents, setting route.
+    // Must be able to search.
+    // Must be able to visit.
+
+}
diff --git a/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/Query.java b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/Query.java
new file mode 100644
index 00000000000..e7b6baa1406
--- /dev/null
+++ b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/Query.java
@@ -0,0 +1,10 @@
+package com.yahoo.vespa.tenant.cd;
+
+/**
+ * An immutable query to send to a Vespa {@link Endpoint}, to receive a {@link Search}.
+ *
+ * @author jonmv
+ */
+public class Query {
+
+}
diff --git a/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/Search.java b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/Search.java
new file mode 100644
index 00000000000..c53553628d9
--- /dev/null
+++ b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/Search.java
@@ -0,0 +1,24 @@
+package com.yahoo.vespa.tenant.cd;
+
+import java.util.SortedMap;
+
+/**
+ * The immutable result of sending a {@link Query} to a Vespa {@link Endpoint}.
+ *
+ * @author jonmv
+ */
+public class Search {
+
+    // hits
+    // coverage
+    // searched
+    // full?
+    // results?
+    // resultsFull?
+
+    /** Returns the documents that were returned as the result, with an iteration order of decreasing relevance. */
+    SortedMap<DocumentId, Document> documents() {
+        return null;
+    }
+
+}
diff --git a/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/Selection.java b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/Selection.java
new file mode 100644
index 00000000000..b06ac67950a
--- /dev/null
+++ b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/Selection.java
@@ -0,0 +1,10 @@
+package com.yahoo.vespa.tenant.cd;
+
+/**
+ * A document selection expression, used for streaming search and visit against a {@link Endpoint}.
+ *
+ * @author jonmv
+ */
+public class Selection {
+
+}
diff --git a/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/TestDeployment.java b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/TestDeployment.java
new file mode 100644
index 00000000000..21bae8545e4
--- /dev/null
+++ b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/TestDeployment.java
@@ -0,0 +1,14 @@
+package com.yahoo.vespa.tenant.cd;
+
+/**
+ * A deployment of a Vespa application, which also contains endpoints for document manipulation.
+ *
+ * @author jonmv
+ */
+public interface TestDeployment extends Deployment {
+
+    TestEndpoint endpoint();
+
+    TestEndpoint endpoint(String id);
+
+}
diff --git a/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/TestEndpoint.java b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/TestEndpoint.java
new file mode 100644
index 00000000000..479ae1d17d2
--- /dev/null
+++ b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/TestEndpoint.java
@@ -0,0 +1,15 @@
+package com.yahoo.vespa.tenant.cd;
+
+import java.util.concurrent.Future;
+
+/**
+ * An endpoint in a Vespa application {@link TestDeployment}, which also translates {@link Feed}s to {@link Digest}s.
+ *
+ * @author jonmv
+ */
+public interface TestEndpoint extends Endpoint {
+
+    /** Sends the given Feed to this TestEndpoint, blocking until it is digested, and returns a feed report. */
+    Digest digest(Feed feed);
+
+}
diff --git a/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/UpgradeTest.java b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/UpgradeTest.java
new file mode 100644
index 00000000000..329e58b5a89
--- /dev/null
+++ b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/UpgradeTest.java
@@ -0,0 +1,23 @@
+package com.yahoo.vespa.tenant.cd;
+
+/**
+ * Tests that assert continuity of behaviour for Vespa application deployments, through upgrades.
+ *
+ * These tests are run whenever a change is pushed to a Vespa application, and whenever the Vespa platform
+ * is upgraded, and before any deployments to production zones. When these tests fails, the tested change to
+ * the Vespa application is not rolled out.
+ *
+ * A typical upgrade test is to do some operations against a test deployment prior to upgrade, like feed and
+ * search for some documents, perhaps recording some metrics from the deployment, and then to upgrade it,
+ * repeat the exercise, and compare the results from pre and post upgrade.
+ *
+ * TODO Split in platform upgrades and application upgrades?
+ *
+ * @author jonmv
+ */
+public interface UpgradeTest {
+
+    // Want to verify documents are not damaged by upgrade.
+    // May want to verify metrics during upgrade.
+
+}
diff --git a/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/Visit.java b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/Visit.java
new file mode 100644
index 00000000000..3e36b9434aa
--- /dev/null
+++ b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/Visit.java
@@ -0,0 +1,17 @@
+package com.yahoo.vespa.tenant.cd;
+
+import java.util.Map;
+
+/**
+ * A stateful visit operation against a {@link Endpoint}.
+ *
+ * @author jonmv
+ */
+public class Visit {
+
+    // Delegate to a blocking iterator, which can be used for iteration as visit is ongoing.
+    public Map<DocumentId, Document> documents() {
+        return null;
+    }
+
+}
diff --git a/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/VisitEndpoint.java b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/VisitEndpoint.java
new file mode 100644
index 00000000000..6eb4df625aa
--- /dev/null
+++ b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/VisitEndpoint.java
@@ -0,0 +1,10 @@
+package com.yahoo.vespa.tenant.cd;
+
+/**
+ * A remote endpoint in a Vespa application {@link Deployment}, which translates {@link Selection}s to {@link Visit}s.
+ *
+ * @author jonmv
+ */
+public interface VisitEndpoint {
+
+}
diff --git a/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/http/HttpEndpoint.java b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/http/HttpEndpoint.java
new file mode 100644
index 00000000000..c736244e7a8
--- /dev/null
+++ b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/http/HttpEndpoint.java
@@ -0,0 +1,9 @@
+package com.yahoo.vespa.tenant.cd.http;
+
+import java.net.http.HttpClient;
+
+public class HttpEndpoint {
+
+    HttpClient client = HttpClient.newBuilder().build();
+
+}
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
new file mode 100644
index 00000000000..5da4c3fb750
--- /dev/null
+++ b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/metrics/Metric.java
@@ -0,0 +1,74 @@
+package com.yahoo.vespa.tenant.cd.metrics;
+
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.Set;
+import java.util.StringJoiner;
+
+import static java.util.Map.copyOf;
+import static java.util.stream.Collectors.toUnmodifiableMap;
+
+/**
+ * A set of statistics for a metric, for points over a String-indexed space.
+ *
+ * @author jonmv
+ */
+public class Metric {
+
+    private final Map<Map<String, ?>, Statistic> statistics;
+
+    private Metric(Map<Map<String, ?>, Statistic> statistics) {
+        this.statistics = copyOf(statistics);
+    }
+
+    /** Creates a new Metric with a copy of the given data. */
+    public static Metric of(Map<Map<String, ?>, Statistic> data) {
+        if (data.isEmpty())
+            throw new IllegalArgumentException("No data given.");
+
+        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() + "'.");
+
+            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 + "'.");
+        }
+
+        return new Metric(data);
+    }
+
+    /** Returns a Metric view of the subset of points in the given hyperplane; its dimensions must be a subset of those of this Metric. */
+    public Metric at(Map<String, ?> hyperplane) {
+        return new Metric(statistics.keySet().stream()
+                                    .filter(point -> point.entrySet().containsAll(hyperplane.entrySet()))
+                                    .collect(toUnmodifiableMap(point -> point, statistics::get)));
+    }
+
+    /** If this Metric contains a single point, returns the Statistic of that point; otherwise, throws an exception. */
+    public Statistic statistic() {
+        if (statistics.size() == 1)
+            return statistics.values().iterator().next();
+
+        if (statistics.isEmpty())
+            throw new NoSuchElementException("This Metric has no data.");
+
+        throw new IllegalStateException("This Metric has more than one point of data.");
+    }
+
+    /** Returns the underlying, unmodifiable Map. */
+    public Map<Map<String, ?>, Statistic> asMap() {
+        return statistics;
+    }
+
+    @Override
+    public String toString() {
+        return new StringJoiner(", ", Metric.class.getSimpleName() + "[", "]")
+                .add("statistics=" + statistics)
+                .toString();
+    }
+
+}
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
new file mode 100644
index 00000000000..c080d82a343
--- /dev/null
+++ b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/metrics/Metrics.java
@@ -0,0 +1,76 @@
+package com.yahoo.vespa.tenant.cd.metrics;
+
+import com.yahoo.vespa.tenant.cd.Endpoint;
+
+import java.time.Instant;
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.StringJoiner;
+
+import static java.util.Map.copyOf;
+
+/**
+ * Metrics from a Vespa application {@link Endpoint}, indexed by their names, and optionally by a set of custom dimensions.
+ *
+ * Metrics are collected from the <a href="https://docs.vespa.ai/documentation/reference/metrics-health-format.html>metrics</a>
+ * API of a Vespa endpoint, and contain the current health status of the endpoint, values for all configured metrics in
+ * that endpoint, and the time interval from which these metrics were sampled.
+ *
+ * Each metric is indexed by a name, and, optionally, along a custom set of dimensions, given by a {@code Map<String, String>}.
+ *
+ * @author jonmv
+ */
+public class Metrics {
+
+    private final Instant start, end;
+    private final Map<String, Metric> metrics;
+
+    private Metrics(Instant start, Instant end, Map<String, Metric> metrics) {
+        this.start = start;
+        this.end = end;
+        this.metrics = copyOf(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);
+    }
+
+    /** Returns the start of the time window from which these metrics were sampled, or throws if the status is {@code Status.down}. */
+    public Instant start() {
+        return start;
+    }
+
+    /** Returns the end of the time window from which these metrics were sampled, or throws if the status is {@code Status.down}. */
+    public Instant end() {
+        return end;
+    }
+
+    /** Returns the metric with the given name, or throws a NoSuchElementException if no such Metric is known. */
+    public Metric get(String name) {
+        if ( ! metrics.containsKey(name))
+            throw new NoSuchElementException("No metric with name '" + name + "'.");
+
+        return metrics.get(name);
+    }
+
+    /** Returns the underlying, unmodifiable Map. */
+    public Map<String, Metric> asMap() {
+        return metrics;
+    }
+
+    @Override
+    public String toString() {
+        return new StringJoiner(", ", Metrics.class.getSimpleName() + "[", "]")
+                .add("start=" + start)
+                .add("end=" + end)
+                .add("metrics=" + metrics)
+                .toString();
+    }
+
+}
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
new file mode 100644
index 00000000000..65c6dc3ed3f
--- /dev/null
+++ b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/metrics/Statistic.java
@@ -0,0 +1,50 @@
+package com.yahoo.vespa.tenant.cd.metrics;
+
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.StringJoiner;
+
+import static java.util.Map.copyOf;
+
+/**
+ * Known statistic about a metric, at a certain point.
+ *
+ * @author jonmv
+ */
+public class Statistic {
+
+    private final Map<Type, Double> data;
+
+    /** Creates a new Statistic with a copy of the given data. */
+    private Statistic(Map<Type, Double> data) {
+        this.data = copyOf(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);
+    }
+
+    /** Returns the value of the given type, or throws a NoSuchElementException if this isn't known. */
+    public double get(Type key) {
+        if ( ! data.containsKey(key))
+            throw new NoSuchElementException("No value with key '" + key + "' is known.");
+
+        return data.get(key);
+    }
+
+    /** Returns the underlying, unmodifiable Map. */
+    public Map<Type, Double> asMap() {
+        return data;
+    }
+
+    @Override
+    public String toString() {
+        return new StringJoiner(", ", Statistic.class.getSimpleName() + "[", "]")
+                .add("data=" + data)
+                .toString();
+    }
+
+}
diff --git a/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/metrics/Type.java b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/metrics/Type.java
new file mode 100644
index 00000000000..b8b168cc649
--- /dev/null
+++ b/tenant-cd/src/main/java/com/yahoo/vespa/tenant/cd/metrics/Type.java
@@ -0,0 +1,32 @@
+package com.yahoo.vespa.tenant.cd.metrics;
+
+/**
+ * Known statistic types.
+ */
+public enum Type {
+
+    /** 95th percentile measurement. */
+    percentile95,
+
+    /** 99th percentile measurement. */
+    percentile99,
+
+    /** Average over all measurements. */
+    average,
+
+    /** Number of measurements. */
+    count,
+
+    /** Last measurement. */
+    last,
+
+    /** Maximum measurement. */
+    max,
+
+    /** Minimum measurement. */
+    min,
+
+    /** Number of measurements per second. */
+    rate;
+
+}