[Rule Registry] ignore some errors while updating index mappings (ela…

…stic#140778)

resolves elastic#139969

Changes the ResourceInstaller to ignore cases when the elasticsearch
simulateIndexTemplate() API returns an error or empty mappings, logging an
error instead. This will hopefully allow initialization to continue to set
up the alerts-as-data indices and backing resources for future indexing.

Also adds _meta: { managed: true } to the ILM policy, which should show a
warning in Kibana UX when attempting to make changes to the policy. Which
was the cause of why simulateIndexTemplate() could return empty mappings.

(cherry picked from commit 01daf31)

# Conflicts:
#	x-pack/plugins/rule_registry/server/rule_data_plugin_service/resource_installer.test.ts
#	x-pack/plugins/rule_registry/server/rule_data_plugin_service/resource_installer.ts

x-pack/plugins/rule_registry/common/assets/lifecycle_policies/default_lifecycle_policy.ts

@@ -7,6 +7,9 @@
 
 export const defaultLifecyclePolicy = {
   policy: {
+    _meta: {
+      managed: true,
+    },
     phases: {
       hot: {
         actions: {

x-pack/plugins/rule_registry/server/rule_data_plugin_service/resource_installer.ts

@@ -159,11 +159,26 @@ export class ResourceInstaller {
   private async updateAliasWriteIndexMapping({ index, alias }: ConcreteIndexInfo) {
     const { logger, getClusterClient } = this.options;
     const clusterClient = await getClusterClient();
-    const simulatedIndexMapping = await clusterClient.indices.simulateIndexTemplate({
-      name: index,
-    });
+
+    let simulatedIndexMapping: estypes.IndicesSimulateIndexTemplateResponse;
+    try {
+      simulatedIndexMapping = await clusterClient.indices.simulateIndexTemplate({
+        name: index,
+      });
+    } catch (err) {
+      logger.error(
+        `Ignored PUT mappings for alias ${alias}; error generating simulated mappings: ${err.message}`
+      );
+      return;
+    }
+
     const simulatedMapping = get(simulatedIndexMapping, ['body', 'template', 'mappings']);
 
+    if (simulatedMapping == null) {
+      logger.error(`Ignored PUT mappings for alias ${alias}; simulated mappings were empty`);
+      return;
+    }
+
     try {
       await clusterClient.indices.putMapping({
         index,