[Fleet] fix remote output health reporting if remote es output is def…

…ault (#178857)

## Summary

Closes #177927

Replaced "default" with real output id in full agent policy. This fixes
the issue that the remote es health reporting was incorrect if the
output was set as default.

More explanation on the bug:
#177927 (comment)

To verify:
- create a remote es output and set as default (both data and
monitoring)
- create an agent policy that uses default output 
- enroll an agent
- expect that the agent sends system and elastic-agent metrics/logs to
remote es
- verify that the remote es health badge shows up on UI

<img width="1283" alt="image"
src="https://github.com/elastic/kibana/assets/90178898/348406d4-69e6-4eda-b396-635771d1edf3">
<img width="695" alt="image"
src="https://github.com/elastic/kibana/assets/90178898/cd03310c-d50d-42ea-8f28-136bf068c52d">



### Checklist

- [x] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios

x-pack/plugins/fleet/server/services/agent_policies/full_agent_policy.test.ts

@@ -197,7 +197,7 @@ describe('getFullAgentPolicy', () => {
     expect(agentPolicy).toMatchObject({
       id: 'agent-policy',
       outputs: {
-        default: {
+        'test-id': {
           type: 'elasticsearch',
           hosts: ['http://127.0.0.1:9201'],
         },
@@ -228,7 +228,7 @@ describe('getFullAgentPolicy', () => {
     expect(agentPolicy).toMatchObject({
       id: 'agent-policy',
       outputs: {
-        default: {
+        'test-id': {
           type: 'elasticsearch',
           hosts: ['http://127.0.0.1:9201'],
         },
@@ -244,7 +244,7 @@ describe('getFullAgentPolicy', () => {
         },
         monitoring: {
           namespace: 'default',
-          use_output: 'default',
+          use_output: 'test-id',
           enabled: true,
           logs: true,
           metrics: false,
@@ -264,7 +264,7 @@ describe('getFullAgentPolicy', () => {
     expect(agentPolicy).toMatchObject({
       id: 'agent-policy',
       outputs: {
-        default: {
+        'test-id': {
           type: 'elasticsearch',
           hosts: ['http://127.0.0.1:9201'],
         },
@@ -280,7 +280,7 @@ describe('getFullAgentPolicy', () => {
         },
         monitoring: {
           namespace: 'default',
-          use_output: 'default',
+          use_output: 'test-id',
           enabled: true,
           logs: false,
           metrics: true,
@@ -358,7 +358,7 @@ describe('getFullAgentPolicy', () => {
     expect(agentPolicy).toMatchSnapshot();
   });
 
-  it('should use "default" as the default policy id', async () => {
+  it('should use output id from default policy id', async () => {
     mockAgentPolicy({
       id: 'policy',
       status: 'active',
@@ -372,7 +372,7 @@ describe('getFullAgentPolicy', () => {
 
     const agentPolicy = await getFullAgentPolicy(savedObjectsClientMock.create(), 'agent-policy');
 
-    expect(agentPolicy?.outputs.default).toBeDefined();
+    expect(agentPolicy?.outputs['test-id']).toBeDefined();
   });
 
   it('should return the sourceURI from the agent policy', async () => {
@@ -387,7 +387,7 @@ describe('getFullAgentPolicy', () => {
     expect(agentPolicy).toMatchObject({
       id: 'agent-policy',
       outputs: {
-        default: {
+        'test-id': {
           type: 'elasticsearch',
           hosts: ['http://127.0.0.1:9201'],
         },
@@ -403,7 +403,7 @@ describe('getFullAgentPolicy', () => {
         },
         monitoring: {
           namespace: 'default',
-          use_output: 'default',
+          use_output: 'test-id',
           enabled: true,
           logs: false,
           metrics: true,
@@ -427,7 +427,7 @@ describe('getFullAgentPolicy', () => {
     expect(agentPolicy).toMatchObject({
       id: 'agent-policy',
       outputs: {
-        default: {
+        'test-id': {
           type: 'elasticsearch',
           hosts: ['http://127.0.0.1:9201'],
         },
@@ -440,7 +440,7 @@ describe('getFullAgentPolicy', () => {
       agent: {
         monitoring: {
           namespace: 'default',
-          use_output: 'default',
+          use_output: 'test-id',
           enabled: true,
           logs: false,
           metrics: true,
@@ -626,7 +626,7 @@ describe('getFullAgentPolicy', () => {
             },
           ],
           type: 'test-logs',
-          use_output: 'default',
+          use_output: 'test-id',
         },
         {
           data_stream: {
@@ -652,11 +652,11 @@ describe('getFullAgentPolicy', () => {
             },
           ],
           type: 'test-logs',
-          use_output: 'default',
+          use_output: 'test-id',
         },
       ],
       output_permissions: {
-        default: {
+        'test-id': {
           _elastic_agent_checks: {
             cluster: ['monitor'],
           },
@@ -679,7 +679,7 @@ describe('getFullAgentPolicy', () => {
         },
       },
       outputs: {
-        default: {
+        'test-id': {
           hosts: ['http://127.0.0.1:9201'],
           preset: 'balanced',
           type: 'elasticsearch',

x-pack/plugins/fleet/server/services/agent_policies/full_agent_policy.ts

@@ -32,7 +32,6 @@ import type {
 } from '../../../common/types';
 import { agentPolicyService } from '../agent_policy';
 import { dataTypes, kafkaCompressionType, outputType } from '../../../common/constants';
-import { DEFAULT_OUTPUT } from '../../constants';
 
 import { getPackageInfo } from '../epm/packages';
 import { pkgToPkgKey, splitPkgKey } from '../epm/registry';
@@ -491,13 +490,8 @@ export function transformOutputToFullPolicyOutput(
 
 /**
  * Get id used in full agent policy (sent to the agents)
- * we use "default" for the default policy to avoid breaking changes
  */
 function getOutputIdForAgentPolicy(output: Output) {
-  if (output.is_default) {
-    return DEFAULT_OUTPUT.name;
-  }
-
   return output.id;
 }
 

x-pack/test/apm_api_integration/tests/fleet/input_only_package.spec.ts

@@ -88,13 +88,13 @@ export default function ApiTest(ftrProviderContext: FtrProviderContext) {
   registry.when('APM package policy', { config: 'basic', archives: [] }, () => {
     async function getAgentPolicyPermissions(agentPolicyId: string, packagePolicyId: string) {
       const res = await bettertest<{
-        item: { output_permissions: { default: Record<string, SecurityRoleDescriptor> } };
+        item: { output_permissions: { [key: string]: Record<string, SecurityRoleDescriptor> } };
       }>({
         pathname: `/api/fleet/agent_policies/${agentPolicyId}/full`,
         method: 'get',
       });
 
-      return res.body.item.output_permissions.default[packagePolicyId];
+      return Object.values(res.body.item.output_permissions)[0][packagePolicyId];
     }
 
     describe('input only package', () => {

x-pack/test/fleet_api_integration/apis/agent_policy/agent_policy_datastream_permissions.ts

@@ -110,7 +110,9 @@ export default function (providerContext: FtrProviderContext) {
           .set('kbn-xsrf', 'xxxx');
 
         // Check that the privileges are correct
-        expect(fullAgentPolicy.output_permissions.default[packagePolicyId].indices).to.eql([
+        expect(
+          (Object.values(fullAgentPolicy.output_permissions)[0] as any)[packagePolicyId].indices
+        ).to.eql([
           { names: ['logs-*-*'], privileges: ['auto_configure', 'create_doc'] },
           { names: ['metrics-*-*'], privileges: ['auto_configure', 'create_doc'] },
         ]);