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update system metadata service to be observable-first

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Signed-off-by: aramissennyeydd <aramis.sennyey@doordash.com>
This commit is contained in:
aramissennyeydd
2025-08-19 17:09:54 -07:00
parent 59ba9274df
commit a0d9373c3f
15 changed files with 420 additions and 121 deletions
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packages/backend-defaults/package.json
+1
View File
@@ -198,6 +198,7 @@
"winston-transport": "^4.5.0",
"yauzl": "^3.0.0",
"yn": "^4.0.0",
"zen-observable": "^0.10.0",
"zod": "^3.22.4",
"zod-to-json-schema": "^3.20.4"
},
packages/backend-defaults/report-systemMetadata.api.md
+2 -3
View File
@@ -19,6 +19,7 @@ export const actionsServiceFactory: ServiceFactory<
ActionsService,
import { BackstageInstance } from '@backstage/backend-plugin-api';
import { LoggerService } from '@backstage/backend-plugin-api';
import { Observable } from '@backstage/types';
import { RootConfigService } from '@backstage/backend-plugin-api';
import { ServiceFactory } from '@backstage/backend-plugin-api';
import { SystemMetadataService } from '@backstage/backend-plugin-api';
@@ -32,9 +33,7 @@ export class DefaultSystemMetadataService implements SystemMetadataService {
config: RootConfigService;
}): DefaultSystemMetadataService;
// (undocumented)
introspect(): Promise<{
instances: BackstageInstance[];
}>;
instances(): Observable<BackstageInstance[]>;
}
// @alpha
packages/backend-defaults/src/entrypoints/systemMetadata/SystemMetadataService.test.ts
+152 -92
View File
@@ -13,7 +13,7 @@
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import { createSpecializedBackend } from '@backstage/backend-app-api';
import { Backend, createSpecializedBackend } from '@backstage/backend-app-api';
import { systemMetadataServiceFactory } from './systemMetadataServiceFactory';
import { mockServices } from '@backstage/backend-test-utils';
import getPort from 'get-port';
@@ -29,111 +29,171 @@ const baseFactories = [
];
describe('SystemMetadataService', () => {
it('should list plugins across instances', async () => {
const instance1HttpPort = await getPort();
const instance2HttpPort = await getPort();
const instance1 = createSpecializedBackend({
defaultServiceFactories: [
...baseFactories,
systemMetadataServiceFactory,
mockServices.rootConfig.factory({
data: {
backend: {
listen: {
port: instance1HttpPort,
},
},
discovery: {
instances: [
{
baseUrl: `http://localhost:${instance1HttpPort}`,
},
{
baseUrl: `http://localhost:${instance2HttpPort}`,
},
],
describe('multiple backends testing', () => {
let instance1: Backend;
let instance2: Backend;
let instance1HttpPort: number;
let instance2HttpPort: number;
const configFactory = (port: number) =>
mockServices.rootConfig.factory({
data: {
backend: {
listen: {
port,
},
},
}),
],
discovery: {
instances: [
{
baseUrl: `http://localhost:${instance1HttpPort}`,
},
{
baseUrl: `http://localhost:${instance2HttpPort}`,
},
],
},
},
});
beforeEach(async () => {
instance1HttpPort = await getPort();
instance2HttpPort = await getPort();
// Setup code for multiple backend instances
instance1 = createSpecializedBackend({
defaultServiceFactories: [
...baseFactories,
systemMetadataServiceFactory,
configFactory(instance1HttpPort),
],
});
instance2 = createSpecializedBackend({
defaultServiceFactories: [
...baseFactories,
systemMetadataServiceFactory,
configFactory(instance2HttpPort),
],
});
});
const instance2 = createSpecializedBackend({
defaultServiceFactories: [
...baseFactories,
systemMetadataServiceFactory,
mockServices.rootConfig.factory({
data: {
backend: {
listen: {
port: instance2HttpPort,
it('should list plugins across instances', async () => {
instance1.add(
createBackendPlugin({
pluginId: 'test',
register(reg) {
reg.registerInit({
deps: {},
async init() {
// do nothing
},
},
discovery: {
instances: [
{
baseUrl: `http://localhost:${instance1HttpPort}`,
},
{
baseUrl: `http://localhost:${instance2HttpPort}`,
},
],
},
});
},
}),
],
);
instance2.add(
createBackendPlugin({
pluginId: 'test-other',
register(reg) {
reg.registerInit({
deps: {},
async init() {
// do nothing
},
});
},
}),
);
await instance1.start();
await instance2.start();
const instance1Response = await fetch(
`http://localhost:${instance1HttpPort}/.backstage/systemMetadata/v1/features/installed`,
);
expect(instance1Response.status).toBe(200);
await expect(instance1Response.json()).resolves.toMatchObject({
test: [
{
externalUrl: `http://localhost:${instance1HttpPort}`,
internalUrl: `http://localhost:${instance1HttpPort}`,
},
],
'test-other': [
{
externalUrl: `http://localhost:${instance2HttpPort}`,
internalUrl: `http://localhost:${instance2HttpPort}`,
},
],
});
const instance2Response = await fetch(
`http://localhost:${instance2HttpPort}/.backstage/systemMetadata/v1/features/installed`,
);
expect(instance2Response.status).toBe(200);
await expect(instance2Response.json()).resolves.toMatchObject({
test: [
{
externalUrl: `http://localhost:${instance1HttpPort}`,
internalUrl: `http://localhost:${instance1HttpPort}`,
},
],
'test-other': [
{
externalUrl: `http://localhost:${instance2HttpPort}`,
internalUrl: `http://localhost:${instance2HttpPort}`,
},
],
});
});
instance1.add(
createBackendPlugin({
pluginId: 'test',
register(reg) {
reg.registerInit({
deps: {},
async init() {
// do nothing
},
});
},
}),
);
it('should list all known instances', async () => {
await instance1.start();
await instance2.start();
instance2.add(
createBackendPlugin({
pluginId: 'test-other',
register(reg) {
reg.registerInit({
deps: {},
async init() {
// do nothing
},
});
},
}),
);
const instance1Response = await fetch(
`http://localhost:${instance1HttpPort}/.backstage/systemMetadata/v1/instances`,
);
await instance1.start();
await instance2.start();
expect(instance1Response.status).toBe(200);
await expect(instance1Response.json()).resolves.toMatchObject({
items: [
{
externalUrl: `http://localhost:${instance1HttpPort}`,
internalUrl: `http://localhost:${instance1HttpPort}`,
},
{
externalUrl: `http://localhost:${instance2HttpPort}`,
internalUrl: `http://localhost:${instance2HttpPort}`,
},
],
});
const installedFeatures = await fetch(
`http://localhost:${instance1HttpPort}/.backstage/systemMetadata/v1/features/installed`,
);
const instance2Response = await fetch(
`http://localhost:${instance2HttpPort}/.backstage/systemMetadata/v1/instances`,
);
expect(installedFeatures.status).toBe(200);
expect(instance2Response.status).toBe(200);
await expect(instance2Response.json()).resolves.toMatchObject({
items: [
{
externalUrl: `http://localhost:${instance1HttpPort}`,
internalUrl: `http://localhost:${instance1HttpPort}`,
},
{
externalUrl: `http://localhost:${instance2HttpPort}`,
internalUrl: `http://localhost:${instance2HttpPort}`,
},
],
});
});
await expect(installedFeatures.json()).resolves.toMatchObject({
test: [
{
externalUrl: `http://localhost:${instance1HttpPort}`,
internalUrl: `http://localhost:${instance1HttpPort}`,
},
],
'test-other': [
{
externalUrl: `http://localhost:${instance2HttpPort}`,
internalUrl: `http://localhost:${instance2HttpPort}`,
},
],
afterEach(async () => {
await instance1.stop();
await instance2.stop();
});
});
});
packages/backend-defaults/src/entrypoints/systemMetadata/lib/DefaultSystemMetadataService.ts
+113 -7
View File
@@ -22,18 +22,126 @@ import {
BackstageInstance,
SystemMetadataService,
} from '@backstage/backend-plugin-api';
import { Observable } from '@backstage/types';
import z from 'zod';
import ObservableImpl from 'zen-observable';
const targetObjectSchema = z.object({
internal: z.string(),
external: z.string(),
});
/**
* A basic implementation of ReactiveX behavior subjects.
*
* A subject is a convenient way to create an observable when you want
* to fan out a single value to all subscribers.
*
* The BehaviorSubject will emit the most recently emitted value or error
* whenever a new observer subscribes to the subject.
*
* See http://reactivex.io/documentation/subject.html
*
* FORKED FROM core-app-api - where should this live?
*/
export class BehaviorSubject<T>
implements Observable<T>, ZenObservable.SubscriptionObserver<T>
{
private isClosed: boolean;
private currentValue: T;
private terminatingError: Error | undefined;
private readonly observable: Observable<T>;
constructor(value: T) {
this.isClosed = false;
this.currentValue = value;
this.terminatingError = undefined;
this.observable = new ObservableImpl<T>(subscriber => {
if (this.isClosed) {
if (this.terminatingError) {
subscriber.error(this.terminatingError);
} else {
subscriber.complete();
}
return () => {};
}
subscriber.next(this.currentValue);
this.subscribers.add(subscriber);
return () => {
this.subscribers.delete(subscriber);
};
});
}
private readonly subscribers = new Set<
ZenObservable.SubscriptionObserver<T>
>();
[Symbol.observable]() {
return this;
}
get closed() {
return this.isClosed;
}
next(value: T) {
if (this.isClosed) {
throw new Error('BehaviorSubject is closed');
}
this.currentValue = value;
this.subscribers.forEach(subscriber => subscriber.next(value));
}
error(error: Error) {
if (this.isClosed) {
throw new Error('BehaviorSubject is closed');
}
this.isClosed = true;
this.terminatingError = error;
this.subscribers.forEach(subscriber => subscriber.error(error));
}
complete() {
if (this.isClosed) {
throw new Error('BehaviorSubject is closed');
}
this.isClosed = true;
this.subscribers.forEach(subscriber => subscriber.complete());
}
subscribe(observer: ZenObservable.Observer<T>): ZenObservable.Subscription;
subscribe(
onNext: (value: T) => void,
onError?: (error: any) => void,
onComplete?: () => void,
): ZenObservable.Subscription;
subscribe(
onNext: ZenObservable.Observer<T> | ((value: T) => void),
onError?: (error: any) => void,
onComplete?: () => void,
): ZenObservable.Subscription {
const observer =
typeof onNext === 'function'
? {
next: onNext,
error: onError,
complete: onComplete,
}
: onNext;
return this.observable.subscribe(observer);
}
}
/**
* @alpha
*/
export class DefaultSystemMetadataService implements SystemMetadataService {
private instances: BackstageInstance[];
private instance$: BehaviorSubject<BackstageInstance[]>;
constructor(
private options: { logger: LoggerService; config: RootConfigService },
) {
@@ -60,9 +168,9 @@ export class DefaultSystemMetadataService implements SystemMetadataService {
}
return instances;
};
this.instances = getInstances();
this.instance$ = new BehaviorSubject(getInstances());
this.options.config.subscribe?.(() => {
this.instances = getInstances();
this.instance$.next(getInstances());
});
}
@@ -73,9 +181,7 @@ export class DefaultSystemMetadataService implements SystemMetadataService {
return new DefaultSystemMetadataService(pluginEnv);
}
async introspect() {
return {
instances: this.instances,
};
instances(): Observable<BackstageInstance[]> {
return this.instance$;
}
}
packages/backend-defaults/src/entrypoints/systemMetadata/lib/createSystemMetadataRouter.ts
+12 -10
View File
@@ -16,7 +16,10 @@
import { LoggerService } from '@backstage/backend-plugin-api';
import { BackendFeatureMeta } from '@backstage/backend-plugin-api/alpha';
import type { SystemMetadataService } from '@backstage/backend-plugin-api';
import type {
BackstageInstance,
SystemMetadataService,
} from '@backstage/backend-plugin-api';
import Router from 'express-promise-router';
export async function createSystemMetadataRouter(options: {
@@ -25,23 +28,22 @@ export async function createSystemMetadataRouter(options: {
}) {
const { logger, systemMetadata } = options;
async function getInstances() {
const instances = await systemMetadata.introspect();
return instances.instances;
}
let instances: BackstageInstance[] = [];
systemMetadata.instances().subscribe({
next: value => {
instances = value;
},
});
logger.info(
`Instances in this system: ${JSON.stringify(await getInstances())}`,
);
logger.info(`Instances in this system: ${JSON.stringify(instances)}`);
const router = Router();
router.get('/instances', async (_, res) => {
res.json(await getInstances());
res.json({ items: instances });
});
router.get('/features/installed', async (_, res) => {
const instances = await getInstances();
const featurePromises = await Promise.allSettled(
instances.map(async instance => {
const response = await fetch(
packages/backend-plugin-api/report.api.md
+2 -3
View File
@@ -14,6 +14,7 @@ import { isChildPath } from '@backstage/cli-common';
import { JsonObject } from '@backstage/types';
import { JsonValue } from '@backstage/types';
import { Knex } from 'knex';
import { Observable } from '@backstage/types';
import { Permission } from '@backstage/plugin-permission-common';
import { PermissionAttributes } from '@backstage/plugin-permission-common';
import { PermissionEvaluator } from '@backstage/plugin-permission-common';
@@ -762,9 +763,7 @@ export interface ServiceRefOptions<
// @public (undocumented)
export interface SystemMetadataService {
// (undocumented)
introspect(): Promise<{
instances: BackstageInstance[];
}>;
instances(): Observable<BackstageInstance[]>;
}
// @public
packages/backend-plugin-api/src/services/definitions/SystemMetadataService.ts
+3 -1
View File
@@ -14,6 +14,8 @@
* limitations under the License.
*/
import { Observable } from '@backstage/types';
/**
* @public
*/
@@ -26,5 +28,5 @@ export interface BackstageInstance {
* @public
*/
export interface SystemMetadataService {
introspect(): Promise<{ instances: BackstageInstance[] }>;
instances(): Observable<BackstageInstance[]>;
}
packages/backend-test-utils/package.json
+1
View File
@@ -79,6 +79,7 @@
"text-extensions": "^2.4.0",
"uuid": "^11.0.0",
"yn": "^4.0.0",
"zen-observable": "^0.10.0",
"zod": "^3.22.4",
"zod-to-json-schema": "^3.20.4"
},
packages/backend-test-utils/report.api.md
+8 -2
View File
@@ -9,6 +9,7 @@ import { AuthService } from '@backstage/backend-plugin-api';
import { Backend } from '@backstage/backend-app-api';
import { BackendFeature } from '@backstage/backend-plugin-api';
import { BackstageCredentials } from '@backstage/backend-plugin-api';
import { BackstageInstance } from '@backstage/backend-plugin-api';
import { BackstageNonePrincipal } from '@backstage/backend-plugin-api';
import { BackstagePrincipalAccessRestrictions } from '@backstage/backend-plugin-api';
import { BackstageServicePrincipal } from '@backstage/backend-plugin-api';
@@ -397,12 +398,17 @@ export namespace mockServices {
partialImpl?: Partial<SchedulerService> | undefined,
) => ServiceMock<SchedulerService>;
}
export function systemMetadata(options: {
instances: BackstageInstance[];
}): SystemMetadataService;
// (undocumented)
export namespace systemMetadata {
const factory: () => ServiceFactory<
const factory: (options: {
instances: BackstageInstance[];
}) => ServiceFactory<
SystemMetadataService,
'root',
'singleton'
'singleton' | 'multiton'
>;
const mock: (
partialImpl?: Partial<SystemMetadataService> | undefined,
packages/backend-test-utils/src/services/MockObservable.ts
+25
View File
@@ -0,0 +1,25 @@
/*
* Copyright 2025 The Backstage Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import { Observable } from '@backstage/types';
import ObservableImpl from 'zen-observable';
export function createMockObservable<T>(value: T): Observable<T> {
return new ObservableImpl(observer => {
observer.next(value);
observer.complete();
});
}
packages/backend-test-utils/src/services/MockSystemMetadataService.test.ts
+34
View File
@@ -0,0 +1,34 @@
/*
* Copyright 2025 The Backstage Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import { BackstageInstance } from '@backstage/backend-plugin-api';
import { MockSystemMetadataService } from './MockSystemMetadataService';
describe('MockSystemMetadataService', () => {
it('should return the passed in instances', () => {
expect.assertions(1);
const instances: BackstageInstance[] = [
{ internalUrl: 'localhost:7007', externalUrl: 'external.url' },
{ internalUrl: 'localhost:7008', externalUrl: 'other.external.url' },
];
const service = MockSystemMetadataService.create({ instances });
service.instances().subscribe({
next: value => {
expect(value).toEqual(instances);
},
});
});
});
packages/backend-test-utils/src/services/MockSystemMetadataService.ts
+44
View File
@@ -0,0 +1,44 @@
/*
* Copyright 2025 The Backstage Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import {
BackstageInstance,
SystemMetadataService,
} from '@backstage/backend-plugin-api';
import { Observable } from '@backstage/types';
import ObservableImpl from 'zen-observable';
/**
* @public
*/
export class MockSystemMetadataService implements SystemMetadataService {
#instances: BackstageInstance[];
constructor(instances: BackstageInstance[]) {
this.#instances = instances;
}
public static create(options: { instances: BackstageInstance[] }) {
return new MockSystemMetadataService(options.instances);
}
instances(): Observable<BackstageInstance[]> {
return new ObservableImpl<BackstageInstance[]>(subscriber => {
subscriber.next(this.#instances);
subscriber.complete();
});
}
}
packages/backend-test-utils/src/services/mockServices.ts
+20 -3
View File
@@ -27,10 +27,10 @@ import { rootHealthServiceFactory } from '@backstage/backend-defaults/rootHealth
import { rootHttpRouterServiceFactory } from '@backstage/backend-defaults/rootHttpRouter';
import { rootLifecycleServiceFactory } from '@backstage/backend-defaults/rootLifecycle';
import { urlReaderServiceFactory } from '@backstage/backend-defaults/urlReader';
import { systemMetadataServiceFactory } from '@backstage/backend-defaults/systemMetadata';
import {
AuthService,
BackstageCredentials,
BackstageInstance,
BackstageUserInfo,
DatabaseService,
DiscoveryService,
@@ -41,6 +41,7 @@ import {
SchedulerService,
ServiceFactory,
ServiceRef,
SystemMetadataService,
UserInfoService,
coreServices,
createServiceFactory,
@@ -62,6 +63,8 @@ import { simpleMock } from './simpleMock';
import { MockSchedulerService } from './MockSchedulerService';
// eslint-disable-next-line @backstage/no-relative-monorepo-imports
import { ObservableConfigProxy } from '../../../config-loader/src/sources/ObservableConfigProxy';
import { MockSystemMetadataService } from './MockSystemMetadataService';
import { createMockObservable } from './MockObservable';
/** @internal */
function createLoggerMock() {
@@ -574,19 +577,33 @@ export namespace mockServices {
rootInstanceMetadata,
);
}
/**
* Creates a functional mock implementation for the
* {@link @backstage/backend-plugin-api#coreServices.systemMetadata}.
*/
export function systemMetadata(options: {
instances: BackstageInstance[];
}): SystemMetadataService {
return MockSystemMetadataService.create(options);
}
export namespace systemMetadata {
/**
* Creates a functional mock factory for the
* {@link @backstage/backend-plugin-api#coreServices.systemMetadata}.
*/
export const factory = () => systemMetadataServiceFactory;
export const factory = simpleFactoryWithOptions(
coreServices.systemMetadata,
systemMetadata,
);
/**
* Creates a mock of the
* {@link @backstage/backend-events-node#systemMetadata}, optionally
* with some given method implementations.
*/
export const mock = simpleMock(coreServices.systemMetadata, () => ({
introspect: jest.fn(),
instances: jest
.fn()
.mockReturnValue(createMockObservable<BackstageInstance[]>([])),
}));
}
}
packages/backend-test-utils/src/services/simpleMock.ts
+1
View File
@@ -39,6 +39,7 @@ export function simpleMock<TService>(
const mock = mockFactory();
if (partialImpl) {
for (const [key, impl] of Object.entries(partialImpl)) {
console.log(key, impl, mock);
if (typeof impl === 'function') {
(mock as any)[key].mockImplementation(impl);
} else {
yarn.lock
+2
View File
@@ -2951,6 +2951,7 @@ __metadata:
winston-transport: "npm:^4.5.0"
yauzl: "npm:^3.0.0"
yn: "npm:^4.0.0"
zen-observable: "npm:^0.10.0"
zod: "npm:^3.22.4"
zod-to-json-schema: "npm:^3.20.4"
peerDependencies:
@@ -3103,6 +3104,7 @@ __metadata:
text-extensions: "npm:^2.4.0"
uuid: "npm:^11.0.0"
yn: "npm:^4.0.0"
zen-observable: "npm:^0.10.0"
zod: "npm:^3.22.4"
zod-to-json-schema: "npm:^3.20.4"
languageName: unknown