Introduce TaskScheduler into backends

Signed-off-by: Fredrik Adelöw <freben@gmail.com>

.changeset/slimy-snakes-drop.md

@@ -0,0 +1,41 @@
+---
+'@backstage/create-app': patch
+---
+
+Add a `scheduler` to the plugin environment, which can schedule collaborative tasks across backends. To apply the same change in your backend, follow the steps below.
+
+First install the package:
+
+```shell
+# From the Backstage repository root
+cd packages/backend
+yarn add @backstage/backend-tasks
+```
+
+Add the scheduler to your plugin environment type:
+
+```diff
+ // In packages/backend/src/types.ts
++import { PluginTaskScheduler } from '@backstage/backend-tasks';
+
+ export type PluginEnvironment = {
++  scheduler: PluginTaskScheduler;
+```
+
+And finally make sure to add such an instance to each plugin's environment:
+
+```diff
+ // In packages/backend/src/index.ts
++import { TaskScheduler } from '@backstage/backend-tasks';
+
+ function makeCreateEnv(config: Config) {
+   // ...
++  const taskScheduler = TaskScheduler.fromConfig(config);
+
+   return (plugin: string): PluginEnvironment => {
+     // ...
++    const scheduler = taskScheduler.forPlugin(plugin);
+     return {
++      scheduler,
+       // ...
+```

packages/backend/package.json

@@ -25,6 +25,7 @@
   },
   "dependencies": {
     "@backstage/backend-common": "^0.10.0",
+    "@backstage/backend-tasks": "^0.1.0",
     "@backstage/catalog-client": "^0.5.3",
     "@backstage/catalog-model": "^0.9.8",
     "@backstage/config": "^0.1.10",

packages/backend/src/index.ts

@@ -35,6 +35,7 @@ import {
   useHotMemoize,
   ServerTokenManager,
 } from '@backstage/backend-common';
+import { TaskScheduler } from '@backstage/backend-tasks';
 import { Config } from '@backstage/config';
 import healthcheck from './plugins/healthcheck';
 import { metricsInit, metricsHandler } from './metrics';
@@ -68,16 +69,17 @@ function makeCreateEnv(config: Config) {
     discovery,
     tokenManager,
   });
-
-  root.info(`Created UrlReader ${reader}`);
-
   const databaseManager = DatabaseManager.fromConfig(config);
   const cacheManager = CacheManager.fromConfig(config);
+  const taskScheduler = TaskScheduler.fromConfig(config);
+
+  root.info(`Created UrlReader ${reader}`);
 
   return (plugin: string): PluginEnvironment => {
     const logger = root.child({ type: 'plugin', plugin });
     const database = databaseManager.forPlugin(plugin);
     const cache = cacheManager.forPlugin(plugin);
+    const scheduler = taskScheduler.forPlugin(plugin);
     return {
       logger,
       cache,
@@ -87,6 +89,7 @@ function makeCreateEnv(config: Config) {
       discovery,
       tokenManager,
       permissions,
+      scheduler,
     };
   };
 }

packages/backend/src/types.ts

@@ -24,6 +24,7 @@ import {
   UrlReader,
 } from '@backstage/backend-common';
 import { ServerPermissionClient } from '@backstage/plugin-permission-node';
+import { PluginTaskScheduler } from '@backstage/backend-tasks';
 
 export type PluginEnvironment = {
   logger: Logger;
@@ -34,4 +35,5 @@ export type PluginEnvironment = {
   discovery: PluginEndpointDiscovery;
   tokenManager: TokenManager;
   permissions: ServerPermissionClient;
+  scheduler: PluginTaskScheduler;
 };

packages/create-app/package.json

@@ -49,6 +49,7 @@
   },
   "peerDependencies": {
     "@backstage/backend-common": "*",
+    "@backstage/backend-tasks": "*",
     "@backstage/catalog-client": "*",
     "@backstage/catalog-model": "*",
     "@backstage/cli": "*",

packages/create-app/src/lib/versions.ts

@@ -32,6 +32,7 @@ leaving any imports in place.
 
 import { version as appDefaults } from '../../../app-defaults/package.json';
 import { version as backendCommon } from '../../../backend-common/package.json';
+import { version as backendTasks } from '../../../backend-tasks/package.json';
 import { version as catalogClient } from '../../../catalog-client/package.json';
 import { version as catalogModel } from '../../../catalog-model/package.json';
 import { version as cli } from '../../../cli/package.json';
@@ -71,6 +72,7 @@ import { version as pluginUserSettings } from '../../../../plugins/user-settings
 export const packageVersions = {
   '@backstage/app-defaults': appDefaults,
   '@backstage/backend-common': backendCommon,
+  '@backstage/backend-tasks': backendTasks,
   '@backstage/catalog-client': catalogClient,
   '@backstage/catalog-model': catalogModel,
   '@backstage/cli': cli,

packages/create-app/templates/default-app/packages/backend/package.json.hbs

@@ -16,6 +16,7 @@
   "dependencies": {
     "app": "0.0.0",
     "@backstage/backend-common": "^{{version '@backstage/backend-common'}}",
+    "@backstage/backend-tasks": "^{{version '@backstage/backend-tasks'}}",
     "@backstage/catalog-model": "^{{version '@backstage/catalog-model'}}",
     "@backstage/catalog-client": "^{{version '@backstage/catalog-client'}}",
     "@backstage/config": "^{{version '@backstage/config'}}",

packages/create-app/templates/default-app/packages/backend/src/index.ts

@@ -19,6 +19,7 @@ import {
   UrlReaders,
   ServerTokenManager,
 } from '@backstage/backend-common';
+import { TaskScheduler } from '@backstage/backend-tasks';
 import { Config } from '@backstage/config';
 import app from './plugins/app';
 import auth from './plugins/auth';
@@ -33,18 +34,28 @@ function makeCreateEnv(config: Config) {
   const root = getRootLogger();
   const reader = UrlReaders.default({ logger: root, config });
   const discovery = SingleHostDiscovery.fromConfig(config);
-
-  root.info(`Created UrlReader ${reader}`);
-
   const cacheManager = CacheManager.fromConfig(config);
   const databaseManager = DatabaseManager.fromConfig(config);
   const tokenManager = ServerTokenManager.noop();
+  const taskScheduler = TaskScheduler.fromConfig(config);
+
+  root.info(`Created UrlReader ${reader}`);
 
   return (plugin: string): PluginEnvironment => {
     const logger = root.child({ type: 'plugin', plugin });
     const database = databaseManager.forPlugin(plugin);
     const cache = cacheManager.forPlugin(plugin);
-    return { logger, database, cache, config, reader, discovery, tokenManager };
+    const scheduler = taskScheduler.forPlugin(plugin);
+    return {
+      logger,
+      database,
+      cache,
+      config,
+      reader,
+      discovery,
+      tokenManager,
+      scheduler,
+    };
   };
 }
 

packages/create-app/templates/default-app/packages/backend/src/types.ts

@@ -7,6 +7,7 @@ import {
   TokenManager,
   UrlReader,
 } from '@backstage/backend-common';
+import { PluginTaskScheduler } from '@backstage/backend-tasks';
 
 export type PluginEnvironment = {
   logger: Logger;
@@ -16,4 +17,5 @@ export type PluginEnvironment = {
   reader: UrlReader;
   discovery: PluginEndpointDiscovery;
   tokenManager: TokenManager;
+  scheduler: PluginTaskScheduler;
 };