[APM] Aggregated transactions telemetry

Add a task to gather transasctions telemetry as described in elastic#71593.

Also:

* Fix typo in mapping for country code mapping
* Add back `mergeTelemetryMapping` function to fix broken `upload-telemetry-data` script.

x-pack/plugins/apm/common/apm_telemetry.test.ts

@@ -4,7 +4,10 @@
  * you may not use this file except in compliance with the Elastic License.
  */
 
-import { getApmTelemetryMapping } from './apm_telemetry';
+import {
+  getApmTelemetryMapping,
+  mergeApmTelemetryMapping,
+} from './apm_telemetry';
 
 // Add this snapshot serializer for this test. The default snapshot serializer
 // prints "Object" next to objects in the JSON output, but we want to be able to
@@ -43,4 +46,43 @@ describe('APM telemetry helpers', () => {
       }).toMatchSnapshot();
     });
   });
+
+  describe('mergeApmTelemetryMapping', () => {
+    describe('with an invalid mapping', () => {
+      it('throws an error', () => {
+        expect(() => mergeApmTelemetryMapping({})).toThrowError();
+      });
+    });
+
+    describe('with a valid mapping', () => {
+      it('merges the mapping', () => {
+        // This is "valid" in the sense that it has all of the deep fields
+        // needed to merge. It's not a valid mapping opbject.
+        const validTelemetryMapping = {
+          mappings: {
+            properties: {
+              stack_stats: {
+                properties: {
+                  kibana: {
+                    properties: {
+                      plugins: {
+                        properties: {
+                          apm: getApmTelemetryMapping(),
+                        },
+                      },
+                    },
+                  },
+                },
+              },
+            },
+          },
+        };
+
+        expect(
+          mergeApmTelemetryMapping(validTelemetryMapping)?.mappings.properties
+            .stack_stats.properties.kibana.properties.plugins.properties.apm
+        ).toEqual(getApmTelemetryMapping());
+      });
+    });
+  });
 });

x-pack/plugins/apm/common/apm_telemetry.ts

@@ -3,6 +3,7 @@
  * or more contributor license agreements. Licensed under the Elastic License;
  * you may not use this file except in compliance with the Elastic License.
  */
+import { produce } from 'immer';
 import { AGENT_NAMES } from './agent_name';
 
 /**
@@ -73,6 +74,13 @@ export function getApmTelemetryMapping() {
     },
   };
 
+  const aggregatedTransactionsProperties = {
+    properties: {
+      expected_metric_document_count: long,
+      transaction_count: long,
+    },
+  };
+
   return {
     properties: {
       agents: {
@@ -90,6 +98,16 @@ export function getApmTelemetryMapping() {
           {}
         ),
       },
+      aggregated_transactions: {
+        properties: {
+          current_implementation: aggregatedTransactionsProperties,
+          no_observer_name: aggregatedTransactionsProperties,
+          no_rum: aggregatedTransactionsProperties,
+          no_rum_no_observer_name: aggregatedTransactionsProperties,
+          only_rum: aggregatedTransactionsProperties,
+          only_rum_no_observer_name: aggregatedTransactionsProperties,
+        },
+      },
       cloud: {
         properties: {
           availability_zone: keyword,
@@ -117,8 +135,8 @@ export function getApmTelemetryMapping() {
           client: {
             properties: {
               geo: {
-                properites: {
-                  country_iso_code: { rum: oneDayProperties },
+                properties: {
+                  country_iso_code: { properties: { rum: oneDayProperties } },
                 },
               },
             },
@@ -204,6 +222,7 @@ export function getApmTelemetryMapping() {
       },
       tasks: {
         properties: {
+          aggregated_transactions: tookProperties,
           agent_configuration: tookProperties,
           agents: tookProperties,
           cardinality: tookProperties,
@@ -230,3 +249,16 @@ export function getApmTelemetryMapping() {
     },
   };
 }
+
+/**
+ * Merge a telemetry mapping object (from https://github.com/elastic/telemetry/blob/master/config/templates/xpack-phone-home.json)
+ * with the output from `getApmTelemetryMapping`.
+ */
+export function mergeApmTelemetryMapping(
+  xpackPhoneHomeMapping: Record<string, any>
+) {
+  return produce(xpackPhoneHomeMapping, (draft: Record<string, any>) => {
+    draft.mappings.properties.stack_stats.properties.kibana.properties.plugins.properties.apm = getApmTelemetryMapping();
+    return draft;
+  });
+}

x-pack/plugins/apm/common/elasticsearch_fieldnames.test.ts

@@ -16,6 +16,7 @@ describe('Transaction', () => {
     '@timestamp': new Date().toString(),
     '@metadata': 'whatever',
     observer: {
+      name: 'an observer',
       version: 'whatever',
       version_major: 8,
     },
@@ -72,6 +73,7 @@ describe('Span', () => {
     '@timestamp': new Date().toString(),
     '@metadata': 'whatever',
     observer: {
+      name: 'an observer',
       version: 'whatever',
       version_major: 8,
     },
@@ -124,6 +126,7 @@ describe('Error', () => {
   const errorDoc: AllowUnknownProperties<APMError> = {
     '@metadata': 'whatever',
     observer: {
+      name: 'an observer',
       version: 'whatever',
       version_major: 8,
     },

x-pack/plugins/apm/common/elasticsearch_fieldnames.ts

@@ -31,6 +31,7 @@ export const USER_AGENT_NAME = 'user_agent.name';
 
 export const DESTINATION_ADDRESS = 'destination.address';
 
+export const OBSERVER_NAME = 'observer.name';
 export const OBSERVER_VERSION_MAJOR = 'observer.version_major';
 export const OBSERVER_LISTENING = 'observer.listening';
 export const PROCESSOR_EVENT = 'processor.event';