[Synthetics] allow retest on failure to be turned off (#189013)

## Summary

Resolves https://github.com/elastic/kibana/issues/188804

Allows retest on failure to be configured in the monitor creation UI.

https://www.loom.com/share/2302ccfd150b4668a61966be165478f8

### Testing
1. Create a monitor and toggle retest on failure off.
2. Navigate to edit that monitor. Ensure the setting remains off.

### Release note
Fixes a bug where retest on failure was not able to be turned off when
creating a monitor in the Synthetics app. Retest on failure can now be
turned off.

x-pack/plugins/observability_solution/synthetics/server/routes/monitor_cruds/add_monitor/add_monitor_api.ts

@@ -232,7 +232,7 @@ export class AddEditMonitorAPI {
       ...DEFAULT_FIELDS[monitorType],
       ...monitor,
       [ConfigKey.SCHEDULE]: getMonitorSchedule(schedule ?? defaultFields[ConfigKey.SCHEDULE]),
-      [ConfigKey.MAX_ATTEMPTS]: getMaxAttempts(retestOnFailure),
+      [ConfigKey.MAX_ATTEMPTS]: getMaxAttempts(retestOnFailure, monitor[ConfigKey.MAX_ATTEMPTS]),
       [ConfigKey.LOCATIONS]: locationsVal,
     } as MonitorFields;
   }

x-pack/plugins/observability_solution/synthetics/server/synthetics_service/project_monitor/normalizers/common_fields.ts

@@ -124,8 +124,11 @@ const getAlertConfig = (monitor: ProjectMonitor) => {
 
 const ONLY_ONE_ATTEMPT = 1;
 
-export const getMaxAttempts = (retestOnFailure?: boolean) => {
+export const getMaxAttempts = (retestOnFailure?: boolean, maxAttempts?: number) => {
   const defaultFields = DEFAULT_COMMON_FIELDS;
+  if (!retestOnFailure && maxAttempts) {
+    return maxAttempts;
+  }
   if (retestOnFailure) {
     return defaultFields[ConfigKey.MAX_ATTEMPTS];
   } else if (retestOnFailure === false) {

x-pack/test/api_integration/apis/synthetics/add_monitor.ts

@@ -5,6 +5,7 @@
  * 2.0.
  */
 import expect from '@kbn/expect';
+import epct from 'expect';
 import moment from 'moment/moment';
 import { v4 as uuidv4 } from 'uuid';
 import { omit, omitBy } from 'lodash';
@@ -141,6 +142,36 @@ export default function ({ getService }: FtrProviderContext) {
       );
     });
 
+    it('can disable retries', async () => {
+      const maxAttempts = 1;
+      const newMonitor = {
+        max_attempts: maxAttempts,
+        urls: 'https://elastic.co',
+        name: `Sample name ${uuidv4()}`,
+        type: 'http',
+        locations: [localLoc],
+      };
+
+      const { body: apiResponse } = await addMonitorAPI(newMonitor);
+
+      epct(apiResponse).toEqual(epct.objectContaining({ max_attempts: maxAttempts }));
+    });
+
+    it('can enable retries', async () => {
+      const maxAttempts = 2;
+      const newMonitor = {
+        max_attempts: maxAttempts,
+        urls: 'https://elastic.co',
+        name: `Sample name ${uuidv4()}`,
+        type: 'http',
+        locations: [localLoc],
+      };
+
+      const { body: apiResponse } = await addMonitorAPI(newMonitor);
+
+      epct(apiResponse).toEqual(epct.objectContaining({ max_attempts: maxAttempts }));
+    });
+
     it('cannot create a invalid monitor without a monitor type', async () => {
       // Delete a required property to make payload invalid
       const newMonitor = {

x-pack/test/api_integration/apis/synthetics/add_monitor_public_api.ts

@@ -5,6 +5,7 @@
  * 2.0.
  */
 import expect from '@kbn/expect';
+import { v4 as uuidv4 } from 'uuid';
 import { omitBy } from 'lodash';
 
 import { DEFAULT_FIELDS } from '@kbn/synthetics-plugin/common/constants/monitor_defaults';
@@ -135,6 +136,52 @@ export default function ({ getService }: FtrProviderContext) {
           })
         );
       });
+
+      it('can enable retries', async () => {
+        const name = `test name ${uuidv4()}`;
+        const monitor = {
+          type: 'http',
+          locations: ['dev'],
+          url: 'https://www.google.com',
+          name,
+          retest_on_failure: true,
+        };
+        const { body: result } = await addMonitorAPI(monitor);
+
+        expect(result).eql(
+          omitMonitorKeys({
+            ...defaultFields,
+            ...monitor,
+            locations: [localLoc],
+            name,
+            max_attempts: 2,
+            retest_on_failure: undefined, // this key is not part of the SO and should not be defined
+          })
+        );
+      });
+
+      it('can disable retries', async () => {
+        const name = `test name ${uuidv4()}`;
+        const monitor = {
+          type: 'http',
+          locations: ['dev'],
+          url: 'https://www.google.com',
+          name,
+          retest_on_failure: false,
+        };
+        const { body: result } = await addMonitorAPI(monitor);
+
+        expect(result).eql(
+          omitMonitorKeys({
+            ...defaultFields,
+            ...monitor,
+            locations: [localLoc],
+            name,
+            max_attempts: 1,
+            retest_on_failure: undefined, // this key is not part of the SO and should not be defined
+          })
+        );
+      });
     });
 
     describe('TCP Monitor', () => {