From 8c31125738e95d9c09d49e3672a487a0280d88d6 Mon Sep 17 00:00:00 2001
From: Martin Polden <mpolden@mpolden.no>
Date: Mon, 25 Sep 2023 14:02:10 +0200
Subject: Revert "Remove unused endpoint name building from config-model"

---
 .../model/api/ApplicationClusterEndpoint.java      | 75 +++++++++++++++++++++-
 1 file changed, 72 insertions(+), 3 deletions(-)

(limited to 'config-model-api')

diff --git a/config-model-api/src/main/java/com/yahoo/config/model/api/ApplicationClusterEndpoint.java b/config-model-api/src/main/java/com/yahoo/config/model/api/ApplicationClusterEndpoint.java
index 215439aa42a..69749ee6f96 100644
--- a/config-model-api/src/main/java/com/yahoo/config/model/api/ApplicationClusterEndpoint.java
+++ b/config-model-api/src/main/java/com/yahoo/config/model/api/ApplicationClusterEndpoint.java
@@ -2,8 +2,15 @@
 
 package com.yahoo.config.model.api;
 
+import com.yahoo.config.provision.ApplicationId;
+import com.yahoo.config.provision.ClusterSpec;
+import com.yahoo.config.provision.SystemName;
+
 import java.util.List;
 import java.util.Objects;
+import java.util.Optional;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 /**
  * Represents one endpoint for an application cluster
@@ -147,21 +154,83 @@ public class ApplicationClusterEndpoint {
 
     }
 
-    public record DnsName(String name) implements Comparable<DnsName> {
+    public static class DnsName implements Comparable<DnsName> {
+
+        private static final int MAX_LABEL_LENGTH = 63;
+
+        private final String name;
+
+        private DnsName(String name) {
+            this.name = name;
+        }
 
         public String value() {
             return name;
         }
 
+        public static DnsName sharedNameFrom(SystemName systemName, ClusterSpec.Id cluster, ApplicationId applicationId, String suffix) {
+            String name = dnsParts(systemName, cluster, applicationId)
+                    .filter(Objects::nonNull)             // remove null values that were "default"
+                    .collect(Collectors.joining("--"));
+            return new DnsName(sanitize(name) + suffix); // Need to sanitize name since it is considered one label
+        }
+
+        public static DnsName sharedL4NameFrom(SystemName systemName, ClusterSpec.Id cluster, ApplicationId applicationId, String suffix) {
+            String name = dnsParts(systemName, cluster, applicationId)
+                    .filter(Objects::nonNull) // remove null values that were "default"
+                    .map(DnsName::sanitize)
+                    .collect(Collectors.joining("."));
+            return new DnsName(name + suffix);
+        }
+
         public static DnsName from(String name) {
             return new DnsName(name);
         }
 
+        private static Stream<String> dnsParts(SystemName systemName, ClusterSpec.Id cluster, ApplicationId applicationId) {
+            return Stream.of(
+                    nullIfDefault(cluster.value()),
+                    systemPart(systemName),
+                    nullIfDefault(applicationId.instance().value()),
+                    applicationId.application().value(),
+                    applicationId.tenant().value()
+            );
+        }
+
+        /**
+         * Remove any invalid characters from the hostnames
+         */
+        private static String sanitize(String id) {
+            return shortenIfNeeded(id.toLowerCase()
+                                           .replace('_', '-')
+                                           .replaceAll("[^a-z0-9-]*", ""));
+        }
+
+        /**
+         * Truncate the given string at the front so its length does not exceed 63 characters.
+         */
+        private static String shortenIfNeeded(String id) {
+            return id.substring(Math.max(0, id.length() - MAX_LABEL_LENGTH));
+        }
+
+        private static String nullIfDefault(String string) {
+            return Optional.of(string).filter(s -> !s.equals("default")).orElse(null);
+        }
+
+        private static String systemPart(SystemName systemName) {
+            return "cd".equals(systemName.value()) ? systemName.value() : null;
+        }
+
+        @Override
+        public String toString() {
+            return "DnsName{" +
+                   "name='" + name + '\'' +
+                   '}';
+        }
+
         @Override
         public int compareTo(DnsName o) {
             return name.compareTo(o.name);
         }
-
     }
-
 }
-- 
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