Updating APM labels from kibana.yml (#144036)

* register apm config
listen to config file changes and update apm labels

* lint

* code review

* fixes

packages/kbn-apm-config-loader/index.ts

@@ -10,3 +10,4 @@ export { getConfiguration } from './src/config_loader';
 export { initApm } from './src/init_apm';
 export { shouldInstrumentClient } from './src/rum_agent_configuration';
 export type { ApmConfiguration } from './src/config';
+export { apmConfigSchema } from './src/apm_config';

packages/kbn-apm-config-loader/src/apm_config.ts

@@ -0,0 +1,21 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+import { schema } from '@kbn/config-schema';
+
+export const apmConfigSchema = schema.object({
+  apm: schema.object(
+    {
+      active: schema.maybe(schema.boolean()),
+      serverUrl: schema.maybe(schema.uri()),
+      secretToken: schema.maybe(schema.string()),
+      globalLabels: schema.object({}, { unknowns: 'allow' }),
+    },
+    { unknowns: 'allow' }
+  ),
+});

src/core/server/root/elastic_config.ts

@@ -0,0 +1,22 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+import { schema, TypeOf } from '@kbn/config-schema';
+import { apmConfigSchema } from '@kbn/apm-config-loader';
+import type { ServiceConfigDescriptor } from '@kbn/core-base-server-internal';
+
+const elasticConfig = schema.object({
+  apm: apmConfigSchema,
+});
+
+export type ElasticConfigType = TypeOf<typeof elasticConfig>;
+
+export const elasticApmConfig: ServiceConfigDescriptor<ElasticConfigType> = {
+  path: 'elastic',
+  schema: elasticConfig,
+};

src/core/server/root/index.ts

@@ -7,10 +7,20 @@
  */
 
 import { ConnectableObservable, Subscription } from 'rxjs';
-import { first, publishReplay, switchMap, concatMap, tap } from 'rxjs/operators';
+import {
+  first,
+  publishReplay,
+  switchMap,
+  concatMap,
+  tap,
+  distinctUntilChanged,
+} from 'rxjs/operators';
 import type { Logger, LoggerFactory } from '@kbn/logging';
 import { Env, RawConfigurationProvider } from '@kbn/config';
 import { LoggingConfigType, LoggingSystem } from '@kbn/core-logging-server-internal';
+import apm from 'elastic-apm-node';
+import { isEqual } from 'lodash';
+import type { ElasticConfigType } from './elastic_config';
 import { Server } from '../server';
 
 /**
@@ -22,6 +32,7 @@ export class Root {
   private readonly loggingSystem: LoggingSystem;
   private readonly server: Server;
   private loggingConfigSubscription?: Subscription;
+  private apmConfigSubscription?: Subscription;
 
   constructor(
     rawConfigProvider: RawConfigurationProvider,
@@ -37,7 +48,9 @@ export class Root {
   public async preboot() {
     try {
       this.server.setupCoreConfig();
+      this.setupApmLabelSync();
       await this.setupLogging();
+
       this.log.debug('prebooting root');
       return await this.server.preboot();
     } catch (e) {
@@ -85,13 +98,34 @@ export class Root {
       this.loggingConfigSubscription.unsubscribe();
       this.loggingConfigSubscription = undefined;
     }
+    if (this.apmConfigSubscription !== undefined) {
+      this.apmConfigSubscription.unsubscribe();
+      this.apmConfigSubscription = undefined;
+    }
     await this.loggingSystem.stop();
 
     if (this.onShutdown !== undefined) {
       this.onShutdown(reason);
     }
   }
 
+  private setupApmLabelSync() {
+    const { configService } = this.server;
+
+    // Update APM labels on config change
+    this.apmConfigSubscription = configService
+      .getConfig$()
+      .pipe(
+        switchMap(() => configService.atPath<ElasticConfigType>('elastic')),
+        distinctUntilChanged(isEqual),
+        tap((elasticConfig) => {
+          const labels = elasticConfig.apm?.globalLabels || {};
+          apm.addLabels(labels);
+        })
+      )
+      .subscribe();
+  }
+
   private async setupLogging() {
     const { configService } = this.server;
     // Stream that maps config updates to logger updates, including update failures.

src/core/server/server.ts

@@ -80,6 +80,7 @@ import {
   config as pluginsConfig,
 } from '@kbn/core-plugins-server-internal';
 import { CoreApp } from './core_app';
+import { elasticApmConfig } from './root/elastic_config';
 
 const coreId = Symbol('core');
 const rootConfigPath = '';
@@ -457,6 +458,7 @@ export class Server {
       cspConfig,
       deprecationConfig,
       elasticsearchConfig,
+      elasticApmConfig,
       executionContextConfig,
       externalUrlConfig,
       httpConfig,