[Monitoring] Support legacy use cases for passthrough (#21211) (#21487)

* Support legacy use cases for passthrough

* Support generic case too

* Add legacy flag

* Do not format api field names in legacy mode

* Add basic test for legacy parameter

* Add more tests

src/server/status/routes/api/register_stats.js

@@ -52,13 +52,15 @@ export function registerStatsApi(kbnServer, server, config) {
       config: {
         validate: {
           query: {
-            extended: Joi.string().valid('', 'true', 'false')
+            extended: Joi.string().valid('', 'true', 'false'),
+            legacy: Joi.string().valid('', 'true', 'false')
           }
         },
         tags: ['api'],
       },
       async handler(req, reply) {
         const isExtended = req.query.extended !== undefined && req.query.extended !== 'false';
+        const isLegacy = req.query.legacy !== undefined && req.query.legacy !== 'false';
 
         let extended;
         if (isExtended) {
@@ -69,7 +71,52 @@ export function registerStatsApi(kbnServer, server, config) {
               getUsage(callCluster),
               getClusterUuid(callCluster),
             ]);
-            extended = collectorSet.toApiFieldNames({ usage, clusterUuid });
+
+
+            let modifiedUsage = usage;
+            if (isLegacy) {
+              // In an effort to make telemetry more easily augmented, we need to ensure
+              // we can passthrough the data without every part of the process needing
+              // to know about the change; however, to support legacy use cases where this
+              // wasn't true, we need to be backwards compatible with how the legacy data
+              // looked and support those use cases here.
+              modifiedUsage = Object.keys(usage).reduce((accum, usageKey) => {
+                if (usageKey === 'kibana') {
+                  accum = {
+                    ...accum,
+                    ...usage[usageKey]
+                  };
+                }
+                else if (usageKey === 'reporting') {
+                  accum = {
+                    ...accum,
+                    xpack: {
+                      ...accum.xpack,
+                      reporting: usage[usageKey]
+                    },
+                  };
+                }
+                else {
+                  accum = {
+                    ...accum,
+                    [usageKey]: usage[usageKey]
+                  };
+                }
+
+                return accum;
+              }, {});
+
+              extended = {
+                usage: modifiedUsage,
+                clusterUuid,
+              };
+            }
+            else {
+              extended = collectorSet.toApiFieldNames({
+                usage: modifiedUsage,
+                clusterUuid
+              });
+            }
           } catch (e) {
             return reply(boomify(e));
           }

test/api_integration/apis/stats/stats.js

@@ -104,6 +104,20 @@ export default function ({ getService }) {
             assertStatsAndMetrics(body);
           });
       });
+
+      describe('legacy', () => {
+        it(`should return return the 'extended' data in the old format with 'legacy' query string param present`, () => {
+          return supertest
+            .get('/api/stats?extended&legacy')
+            .expect('Content-Type', /json/)
+            .expect(200)
+            .then(({ body }) => {
+              expect(body.clusterUuid).to.be.a('string');
+              expect(body.usage).to.be.an('object'); // no usage collectors have been registered so usage is an empty object
+              assertStatsAndMetrics(body, true);
+            });
+        });
+      });
     });
   });
 }

x-pack/test/api_integration/apis/kibana/stats/stats.js

@@ -59,6 +59,18 @@ export default function ({ getService }) {
           expect(body.usage.kibana.index).to.be('.kibana');
           expect(body.usage.kibana.dashboard.total).to.be(0);
         });
+
+        it('should return 200 for extended and legacy', async () => {
+          const { body } = await supertest
+            .get('/api/stats?extended&legacy')
+            .expect(200);
+          expect(body.kibana.uuid).to.eql('5b2de169-2785-441b-ae8c-186a1936b17d');
+          expect(body.process.uptime_ms).to.be.greaterThan(0);
+          expect(body.os.uptime_ms).to.be.greaterThan(0);
+          expect(body.usage.index).to.be('.kibana');
+          expect(body.usage.dashboard.total).to.be(0);
+          expect(body.usage.xpack.reporting.available).to.be(true);
+        });
       });
     });
   });