1 files changed, 105 insertions, 0 deletions
diff --git a/metrics/src/main/java/ai/vespa/metrics/docs/MetricSetDocumentation.java b/metrics/src/main/java/ai/vespa/metrics/docs/MetricSetDocumentation.java
new file mode 100644
index 00000000000..bafefbfedd6
--- /dev/null
+++ b/metrics/src/main/java/ai/vespa/metrics/docs/MetricSetDocumentation.java
@@ -0,0 +1,105 @@
+package ai.vespa.metrics.docs;
+
+import ai.vespa.metrics.Suffix;
+import ai.vespa.metrics.VespaMetrics;
+import ai.vespa.metrics.set.MetricSet;
+
+import java.io.FileWriter;
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.util.Arrays;
+import java.util.LinkedHashMap;
+import java.util.LinkedHashSet;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+/**
+ * @author olaa
+ */
+public class MetricSetDocumentation {
+
+    protected static void writeMetricSetDocumentation(String path, String name, MetricSet metricSet, Map<String, VespaMetrics[]> metricsByType) {
+
+        var groupedBySuffix = metricSet.getMetrics()
+                .keySet()
+                .stream()
+                .map(MetricSetDocumentation::withSuffix)
+                .collect(Collectors.groupingBy(Map.Entry::getKey, Collectors.mapping(Map.Entry::getValue, Collectors.toCollection(LinkedHashSet::new))));
+
+        var metricTypeByName = metricsByType.entrySet()
+                .stream()
+                .collect(Collectors.toMap(Map.Entry::getKey,
+                        entry -> Arrays.stream(entry.getValue())
+                                .filter(val -> groupedBySuffix.containsKey(val.baseName()))
+                                .collect(Collectors.toMap(
+                                        val -> val,
+                                        val -> groupedBySuffix.get(val.baseName()),
+                                        (a, b) -> a,
+                                        LinkedHashMap::new
+                                )),
+                        (a, b) -> a,
+                        LinkedHashMap::new));
+
+        var referenceBuilder = new StringBuilder();
+        referenceBuilder.append(String.format("""
+                ---
+                # Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+                title: "%s Metric Set"
+                ---""", name));
+        metricsByType.keySet()
+                .stream()
+                .sorted()
+                .filter(m -> !metricTypeByName.get(m).isEmpty())
+                .forEach(type ->
+                        referenceBuilder.append(String.format("""
+
+                            <h2 id="%s-metrics">%s Metrics</h2>
+                            <table class="table">
+                              <thead>
+                                 <tr><th>Name</th><th>Description</th><th>Unit</th><th>Suffixes</th></tr>
+                              </thead>
+                              <tbody>
+                             %s  </tbody>
+                            </table>
+                            """, type.toLowerCase(), type, htmlRows(metricTypeByName.get(type))))
+                );
+        try (FileWriter fileWriter = new FileWriter(path + "/" + metricSet.getId().toLowerCase() + "-set-metrics-reference.html")) {
+            fileWriter.write(referenceBuilder.toString());
+        } catch (IOException e) {
+            throw new UncheckedIOException(e);
+        }
+    }
+
+    private static String htmlRows(Map<VespaMetrics, LinkedHashSet<String>> metrics) {
+        return metrics.entrySet()
+                .stream()
+                .map(entry ->
+                        String.format(
+                                """
+                                    <tr>
+                                       <td><p id="%s">%s</p></td>
+                                       <td>%s</td>
+                                       <td>%s</td>
+                                       <td>%s</td>
+                                    </tr>
+                                 """,
+                                entry.getKey().baseName().replaceAll("\\.", "_"),
+                                entry.getKey().baseName(),
+                                entry.getKey().description(),
+                                entry.getKey().unit().toString().toLowerCase(),
+                                String.join(", ", entry.getValue()))
+
+                ).collect(Collectors.joining());
+    }
+
+    private static Map.Entry<String, String> withSuffix(String metricName) {
+        try {
+            var suffixIndex = metricName.lastIndexOf(".");
+            var suffix = Suffix.valueOf(metricName.substring(suffixIndex + 1));
+            return Map.entry(metricName.substring(0, suffixIndex), suffix.toString());
+        } catch (Exception e) {
+            return Map.entry(metricName, "N/A");
+        }
+    }
+
+}