Fetch Snapshot telemetry on UI nodes only (#180833)

Co-authored-by: kibanamachine <42973632+kibanamachine@users.noreply.github.com>

src/plugins/telemetry/server/plugin.test.ts

@@ -11,6 +11,7 @@ import { coreMock } from '@kbn/core/server/mocks';
 import { usageCollectionPluginMock } from '@kbn/usage-collection-plugin/server/mocks';
 import { telemetryCollectionManagerPluginMock } from '@kbn/telemetry-collection-manager-plugin/server/mocks';
 import { TelemetryPlugin } from './plugin';
+import type { NodeRoles } from '@kbn/core-node-server';
 
 describe('TelemetryPlugin', () => {
   describe('setup', () => {
@@ -66,4 +67,43 @@ describe('TelemetryPlugin', () => {
       });
     });
   });
+
+  describe('start', () => {
+    describe('per node behavior', () => {
+      function createPluginForNodeRole(roles: Partial<NodeRoles>) {
+        const initializerContext = coreMock.createPluginInitializerContext();
+        initializerContext.node.roles = { ...initializerContext.node.roles, ...roles };
+
+        const plugin = new TelemetryPlugin(initializerContext);
+
+        // eslint-disable-next-line dot-notation
+        const startFetcherMock = (plugin['startFetcher'] = jest.fn());
+
+        plugin.setup(coreMock.createSetup(), {
+          usageCollection: usageCollectionPluginMock.createSetupContract(),
+          telemetryCollectionManager: telemetryCollectionManagerPluginMock.createSetupContract(),
+        });
+
+        plugin.start(coreMock.createStart(), {
+          telemetryCollectionManager: telemetryCollectionManagerPluginMock.createStartContract(),
+        });
+
+        return { startFetcherMock };
+      }
+
+      afterEach(() => {
+        jest.resetAllMocks();
+      });
+
+      it('calls startFetcher when it is a UI node', () => {
+        const { startFetcherMock } = createPluginForNodeRole({ ui: true });
+        expect(startFetcherMock).toHaveBeenCalledTimes(1);
+      });
+
+      it('does not call startFetcher when not a UI node', () => {
+        const { startFetcherMock } = createPluginForNodeRole({ ui: false });
+        expect(startFetcherMock).toHaveBeenCalledTimes(0);
+      });
+    });
+  });
 });

src/plugins/telemetry/server/plugin.ts

@@ -103,6 +103,7 @@ export class TelemetryPlugin implements Plugin<TelemetryPluginSetup, TelemetryPl
   private isOptedIn?: boolean;
   private readonly isDev: boolean;
   private readonly fetcherTask: FetcherTask;
+  private readonly shouldStartSnapshotTelemetryFetcher: boolean;
   /**
    * @private Used to mark the completion of the old UI Settings migration
    */
@@ -133,6 +134,10 @@ export class TelemetryPlugin implements Plugin<TelemetryPluginSetup, TelemetryPl
       logger: this.logger,
     });
 
+    // Only generate and report the snapshot telemetry in the UI node.
+    // This allows better cache optimizations and allowing background tasks to focus on alerts and similar.
+    this.shouldStartSnapshotTelemetryFetcher = initializerContext.node.roles.ui;
+
     // If the opt-in selection cannot be changed, set it as early as possible.
     const { optIn, allowChangingOptInStatus } = this.initialConfig;
     this.isOptedIn = allowChangingOptInStatus === false ? optIn : undefined;
@@ -240,7 +245,10 @@ export class TelemetryPlugin implements Plugin<TelemetryPluginSetup, TelemetryPl
 
     this.security = security;
 
-    this.startFetcher(core, telemetryCollectionManager);
+    if (this.shouldStartSnapshotTelemetryFetcher) {
+      // Only generate and report the snapshot telemetry if we are on the appropriate node role
+      this.startFetcher(core, telemetryCollectionManager);
+    }
 
     return {
       getIsOptedIn: async () => this.isOptedIn === true,

src/plugins/telemetry/tsconfig.json

@@ -36,6 +36,7 @@
     "@kbn/core-http-browser",
     "@kbn/core-http-server",
     "@kbn/analytics-collection-utils",
+    "@kbn/core-node-server",
   ],
   "exclude": [
     "target/**/*",