[APM] Fallback to terms agg search if terms enum doesn’t return resul…

…ts (#143619)

* [APM] Fallback to terms agg search if terms enum doesn’t return results

* Add api test for suggestions

x-pack/plugins/apm/server/routes/suggestions/get_suggestions_with_terms_aggregation.ts

@@ -23,7 +23,7 @@ export async function getSuggestionsWithTermsAggregation({
   fieldName: string;
   fieldValue: string;
   searchAggregatedTransactions: boolean;
-  serviceName: string;
+  serviceName?: string;
   setup: Setup;
   size: number;
   start: number;

x-pack/plugins/apm/server/routes/suggestions/get_suggestions.ts → x-pack/plugins/apm/server/routes/suggestions/get_suggestions_with_terms_enum.ts

@@ -8,7 +8,7 @@ import { ProcessorEvent } from '@kbn/observability-plugin/common';
 import { getProcessorEventForTransactions } from '../../lib/helpers/transactions';
 import { Setup } from '../../lib/helpers/setup_request';
 
-export async function getSuggestions({
+export async function getSuggestionsWithTermsEnum({
   fieldName,
   fieldValue,
   searchAggregatedTransactions,
@@ -27,30 +27,33 @@ export async function getSuggestions({
 }) {
   const { apmEventClient } = setup;
 
-  const response = await apmEventClient.termsEnum('get_suggestions', {
-    apm: {
-      events: [
-        getProcessorEventForTransactions(searchAggregatedTransactions),
-        ProcessorEvent.error,
-        ProcessorEvent.metric,
-      ],
-    },
-    body: {
-      case_insensitive: true,
-      field: fieldName,
-      size,
-      string: fieldValue,
-      index_filter: {
-        range: {
-          ['@timestamp']: {
-            gte: start,
-            lte: end,
-            format: 'epoch_millis',
+  const response = await apmEventClient.termsEnum(
+    'get_suggestions_with_terms_enum',
+    {
+      apm: {
+        events: [
+          getProcessorEventForTransactions(searchAggregatedTransactions),
+          ProcessorEvent.error,
+          ProcessorEvent.metric,
+        ],
+      },
+      body: {
+        case_insensitive: true,
+        field: fieldName,
+        size,
+        string: fieldValue,
+        index_filter: {
+          range: {
+            ['@timestamp']: {
+              gte: start,
+              lte: end,
+              format: 'epoch_millis',
+            },
           },
         },
       },
-    },
-  });
+    }
+  );
 
   return { terms: response.terms };
 }

x-pack/plugins/apm/server/routes/suggestions/route.ts

@@ -7,7 +7,7 @@
 
 import * as t from 'io-ts';
 import { maxSuggestions } from '@kbn/observability-plugin/common';
-import { getSuggestions } from './get_suggestions';
+import { getSuggestionsWithTermsEnum } from './get_suggestions_with_terms_enum';
 import { getSuggestionsWithTermsAggregation } from './get_suggestions_with_terms_aggregation';
 import { getSearchTransactionsEvents } from '../../lib/helpers/transactions';
 import { setupRequest } from '../../lib/helpers/setup_request';
@@ -41,28 +41,35 @@ const suggestionsRoute = createApmServerRoute({
       maxSuggestions
     );
 
-    const suggestions = serviceName
-      ? await getSuggestionsWithTermsAggregation({
-          fieldName,
-          fieldValue,
-          searchAggregatedTransactions,
-          serviceName,
-          setup,
-          size,
-          start,
-          end,
-        })
-      : await getSuggestions({
-          fieldName,
-          fieldValue,
-          searchAggregatedTransactions,
-          setup,
-          size,
-          start,
-          end,
-        });
+    if (!serviceName) {
+      const suggestions = await getSuggestionsWithTermsEnum({
+        fieldName,
+        fieldValue,
+        searchAggregatedTransactions,
+        setup,
+        size,
+        start,
+        end,
+      });
 
-    return suggestions;
+      // if no terms are found using terms enum it will fall back to using ordinary terms agg search
+      // This is useful because terms enum can only find terms that start with the search query
+      // whereas terms agg approach can find terms that contain the search query
+      if (suggestions.terms.length > 0) {
+        return suggestions;
+      }
+    }
+
+    return getSuggestionsWithTermsAggregation({
+      fieldName,
+      fieldValue,
+      searchAggregatedTransactions,
+      serviceName,
+      setup,
+      size,
+      start,
+      end,
+    });
   },
 });
 

x-pack/test/apm_api_integration/tests/suggestions/generate_data.ts

@@ -0,0 +1,77 @@
+/*
+ * 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; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+import { apm, timerange } from '@kbn/apm-synthtrace';
+import type { ApmSynthtraceEsClient } from '@kbn/apm-synthtrace';
+import { times } from 'lodash';
+
+export async function generateData({
+  synthtraceEsClient,
+  start,
+  end,
+}: {
+  synthtraceEsClient: ApmSynthtraceEsClient;
+  start: number;
+  end: number;
+}) {
+  const services = times(5).flatMap((serviceId) => {
+    return ['go', 'java'].flatMap((agentName) => {
+      return ['production', 'development', 'staging'].flatMap((environment) => {
+        return times(5).flatMap((envId) => {
+          const service = apm
+            .service({
+              name: `${agentName}-${serviceId}`,
+              environment: `${environment}-${envId}`,
+              agentName,
+            })
+            .instance('instance-a');
+
+          return service;
+        });
+      });
+    });
+  });
+
+  const transactionNames = [
+    'GET /api/product/:id',
+    'PUT /api/product/:id',
+    'GET /api/user/:id',
+    'PUT /api/user/:id',
+  ];
+
+  const phpService = apm
+    .service({
+      name: `custom-php-service`,
+      environment: `custom-php-environment`,
+      agentName: 'php',
+    })
+    .instance('instance-a');
+
+  const docs = timerange(start, end)
+    .ratePerMinute(1)
+    .generator((timestamp) => {
+      const autoGeneratedDocs = services.flatMap((service) => {
+        return transactionNames.flatMap((transactionName) => {
+          return service
+            .transaction({ transactionName, transactionType: 'my-custom-type' })
+            .timestamp(timestamp)
+            .duration(1000);
+        });
+      });
+
+      const customDoc = phpService
+        .transaction({
+          transactionName: 'GET /api/php/memory',
+          transactionType: 'custom-php-type',
+        })
+        .timestamp(timestamp)
+        .duration(1000);
+
+      return [...autoGeneratedDocs, customDoc];
+    });
+
+  return await synthtraceEsClient.index(docs);
+}