Deprecation check for audit log prefix settings (#36661)

Adds a deprecation check for removed
`xpack.security.audit.logfile.prefix.` settings

Author: gwbrown

x-pack/plugin/deprecation/src/main/java/org/elasticsearch/xpack/deprecation/DeprecationChecks.java

@@ -39,6 +39,7 @@ private DeprecationChecks() {
     static List<BiFunction<List<NodeInfo>, List<NodeStats>, DeprecationIssue>> NODE_SETTINGS_CHECKS =
         Collections.unmodifiableList(Arrays.asList(
             NodeDeprecationChecks::httpEnabledSettingRemoved,
+            NodeDeprecationChecks::auditLogPrefixSettingsCheck,
             NodeDeprecationChecks::indexThreadPoolCheck,
             NodeDeprecationChecks::tribeNodeCheck,
             NodeDeprecationChecks::httpPipeliningCheck,

x-pack/plugin/deprecation/src/main/java/org/elasticsearch/xpack/deprecation/NodeDeprecationChecks.java

@@ -35,6 +35,21 @@ static DeprecationIssue httpEnabledSettingRemoved(List<NodeInfo> nodeInfos, List
         return null;
     }
 
+    static DeprecationIssue auditLogPrefixSettingsCheck(List<NodeInfo> nodeInfos, List<NodeStats> nodeStats) {
+        List<String> nodesFound = nodeInfos.stream()
+            .filter(nodeInfo -> nodeInfo.getSettings().getByPrefix("xpack.security.audit.logfile.prefix").isEmpty() == false)
+            .map(nodeInfo -> nodeInfo.getNode().getName())
+            .collect(Collectors.toList());
+        if (nodesFound.size() > 0) {
+            return new DeprecationIssue(DeprecationIssue.Level.CRITICAL,
+                "Audit log node info settings renamed",
+                "https://www.elastic.co/guide/en/elasticsearch/reference/master/breaking_70_cluster_changes.html" +
+                    "#audit-logfile-local-node-info",
+                "nodes with audit log settings that have been renamed: " + nodesFound);
+        }
+        return null;
+    }
+
     static DeprecationIssue indexThreadPoolCheck(List<NodeInfo> nodeInfos, List<NodeStats> nodeStats) {
         List<String> nodesFound = nodeInfos.stream()
             .filter(nodeInfo -> nodeInfo.getSettings().getByPrefix("thread_pool.index.").isEmpty() == false)

x-pack/plugin/deprecation/src/test/java/org/elasticsearch/xpack/deprecation/NodeDeprecationChecksTests.java

@@ -68,6 +68,17 @@ public void testHttpEnabledCheck() {
         assertSettingsAndIssue("http.enabled", Boolean.toString(randomBoolean()), expected);
     }
 
+    public void testAuditLoggingPrefixSettingsCheck() {
+        DeprecationIssue expected = new DeprecationIssue(DeprecationIssue.Level.CRITICAL,
+            "Audit log node info settings renamed",
+            "https://www.elastic.co/guide/en/elasticsearch/reference/master/breaking_70_cluster_changes.html" +
+                "#audit-logfile-local-node-info",
+            "nodes with audit log settings that have been renamed: [node_check]");
+        assertSettingsAndIssue("xpack.security.audit.logfile.prefix.emit_node_host_address", Boolean.toString(randomBoolean()), expected);
+        assertSettingsAndIssue("xpack.security.audit.logfile.prefix.emit_node_host_name", Boolean.toString(randomBoolean()), expected);
+        assertSettingsAndIssue("xpack.security.audit.logfile.prefix.emit_node_name", Boolean.toString(randomBoolean()), expected);
+    }
+
     public void testIndexThreadPoolCheck() {
         DeprecationIssue expected = new DeprecationIssue(DeprecationIssue.Level.CRITICAL,
             "Index thread pool removed in favor of combined write thread pool",