Test: Do not remove xpack templates when cleaning (#31642)

At the end of every `ESRestTestCase` we clean the cluster which includes
deleting all of the templates. If xpack is installed it'll automatically
recreate a few templates every time they are removed. Which is slow.

This change stops the cleanup from removing the xpack templates. It cuts
the time to run the docs tests more than in half and it probably saves a
bit more time on other tests as well.

test/framework/src/main/java/org/elasticsearch/test/rest/ESRestTestCase.java

@@ -30,6 +30,7 @@
 import org.apache.http.message.BasicHeader;
 import org.apache.http.nio.conn.ssl.SSLIOSessionStrategy;
 import org.apache.http.ssl.SSLContexts;
+import org.apache.http.util.EntityUtils;
 import org.elasticsearch.action.admin.cluster.node.tasks.list.ListTasksAction;
 import org.elasticsearch.client.Request;
 import org.elasticsearch.client.Response;
@@ -259,7 +260,7 @@ private void wipeCluster() throws IOException {
         if (preserveIndicesUponCompletion() == false) {
             // wipe indices
             try {
-                adminClient().performRequest("DELETE", "*");
+                adminClient().performRequest(new Request("DELETE", "*"));
             } catch (ResponseException e) {
                 // 404 here just means we had no indexes
                 if (e.getResponse().getStatusLine().getStatusCode() != 404) {
@@ -270,7 +271,30 @@ private void wipeCluster() throws IOException {
 
         // wipe index templates
         if (preserveTemplatesUponCompletion() == false) {
-            adminClient().performRequest("DELETE", "_template/*");
+            if (hasXPack()) {
+                /*
+                 * Delete only templates that xpack doesn't automatically
+                 * recreate. Deleting them doesn't hurt anything, but it
+                 * slows down the test because xpack will just recreate
+                 * them.
+                 */
+                Request request = new Request("GET", "_cat/templates");
+                request.addParameter("h", "name");
+                String templates = EntityUtils.toString(adminClient().performRequest(request).getEntity());
+                if (false == "".equals(templates)) {
+                    for (String template : templates.split("\n")) {
+                        if (isXPackTemplate(template)) continue;
+                        if ("".equals(template)) {
+                            throw new IllegalStateException("empty template in templates list:\n" + templates);
+                        }
+                        logger.debug("Clearing template [{}]", template);
+                        adminClient().performRequest(new Request("DELETE", "_template/" + template));
+                    }
+                }
+            } else {
+                logger.debug("Clearing all templates");
+                adminClient().performRequest(new Request("DELETE", "_template/*"));
+            }
         }
 
         wipeSnapshots();
@@ -585,4 +609,29 @@ protected static Map<String, Object> getAsMap(final String endpoint) throws IOEx
         assertNotNull(responseEntity);
         return responseEntity;
     }
+
+    /**
+     * Is this template one that is automatically created by xpack?
+     */
+    private static boolean isXPackTemplate(String name) {
+        if (name.startsWith(".monitoring-")) {
+            return true;
+        }
+        if (name.startsWith(".watch-history-")) {
+            return true;
+        }
+        if (name.startsWith(".ml-")) {
+            return true;
+        }
+        switch (name) {
+        case ".triggered_watches":
+        case ".watches":
+        case "logstash-index-template":
+        case "security_audit_log":
+            return true;
+        default:
+            return false;
+        }
+    }
+
 }