From 229a1fa92716a384f67850cfe887bbfa91668f01 Mon Sep 17 00:00:00 2001
From: Patrik Oldsberg <poldsberg@gmail.com>
Date: Thu, 8 Sep 2022 15:46:16 +0200
Subject: [PATCH 01/10] backend-{plugin,app}-api: introduce service scopes and
 update registry to support
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Co-authored-by: Fredrik Adelöw <freben@gmail.com>
Co-authored-by: blam <ben@blam.sh>
Co-authored-by: Johan Haals <johan.haals@gmail.com>
Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>
---
 .../src/wiring/ServiceRegistry.test.ts        | 155 +++++++--------
 .../src/wiring/ServiceRegistry.ts             | 185 ++++++++++++------
 packages/backend-app-api/src/wiring/types.ts  |   3 +-
 .../src/services/system/types.ts              | 135 ++++++++-----
 4 files changed, 284 insertions(+), 194 deletions(-)

diff --git a/packages/backend-app-api/src/wiring/ServiceRegistry.test.ts b/packages/backend-app-api/src/wiring/ServiceRegistry.test.ts
index a00f6c0b4b..ab709dcb77 100644
--- a/packages/backend-app-api/src/wiring/ServiceRegistry.test.ts
+++ b/packages/backend-app-api/src/wiring/ServiceRegistry.test.ts
@@ -21,28 +21,28 @@ import {
 } from '@backstage/backend-plugin-api';
 import { ServiceRegistry } from './ServiceRegistry';
 
-const ref1 = createServiceRef<{ x: number; pluginId: string }>({
+const ref1 = createServiceRef<{ x: number }>({
   id: '1',
 });
 const sf1 = createServiceFactory({
   service: ref1,
   deps: {},
   factory: async () => {
-    return async pluginId => {
-      return { x: 1, pluginId };
+    return async () => {
+      return { x: 1 };
     };
   },
 });
 
-const ref2 = createServiceRef<{ x: number; pluginId: string }>({
+const ref2 = createServiceRef<{ x: number }>({
   id: '2',
 });
 const sf2 = createServiceFactory({
   service: ref2,
   deps: {},
   factory: async () => {
-    return async pluginId => {
-      return { x: 2, pluginId };
+    return async () => {
+      return { x: 2 };
     };
   },
 });
@@ -50,126 +50,115 @@ const sf2b = createServiceFactory({
   service: ref2,
   deps: {},
   factory: async () => {
-    return async pluginId => {
-      return { x: 22, pluginId };
+    return async () => {
+      return { x: 22 };
     };
   },
 });
 
-const refDefault1 = createServiceRef<{ x: number; pluginId: string }>({
+const refDefault1 = createServiceRef<{ x: number }>({
   id: '1',
   defaultFactory: async service =>
     createServiceFactory({
       service,
       deps: {},
-      factory: async () => async pluginId => ({ x: 10, pluginId }),
+      factory: async () => async () => ({ x: 10 }),
     }),
 });
 
-const refDefault2a = createServiceRef<{ x: number; pluginId: string }>({
+const refDefault2a = createServiceRef<{ x: number }>({
   id: '2a',
   defaultFactory: async service =>
     createServiceFactory({
       service,
       deps: {},
-      factory: async () => async pluginId => ({ x: 20, pluginId }),
+      factory: async () => async () => ({ x: 20 }),
     }),
 });
 
-const refDefault2b = createServiceRef<{ x: number; pluginId: string }>({
+const refDefault2b = createServiceRef<{ x: number }>({
   id: '2b',
   defaultFactory: async service =>
     createServiceFactory({
       service,
       deps: {},
-      factory: async () => async pluginId => ({ x: 220, pluginId }),
+      factory: async () => async () => ({ x: 220 }),
     }),
 });
 
 describe('ServiceRegistry', () => {
   it('should return undefined if there is no factory defined', async () => {
     const registry = new ServiceRegistry([]);
-    expect(registry.get(ref1)).toBe(undefined);
+    expect(registry.get(ref1, 'catalog')).toBe(undefined);
   });
 
-  it('should return a factory for a registered ref', async () => {
+  it('should return an implementation for a registered ref', async () => {
     const registry = new ServiceRegistry([sf1]);
-    const factory = registry.get(ref1)!;
-    expect(factory).toEqual(expect.any(Function));
-    await expect(factory('catalog')).resolves.toEqual({
-      x: 1,
-      pluginId: 'catalog',
-    });
-    await expect(factory('scaffolder')).resolves.toEqual({
-      x: 1,
-      pluginId: 'scaffolder',
-    });
-    expect(await factory('catalog')).toBe(await factory('catalog'));
+    await expect(registry.get(ref1, 'catalog')).resolves.toEqual({ x: 1 });
+    await expect(registry.get(ref1, 'scaffolder')).resolves.toEqual({ x: 1 });
+    expect(await registry.get(ref1, 'catalog')).toBe(
+      await registry.get(ref1, 'catalog'),
+    );
+    expect(await registry.get(ref1, 'scaffolder')).toBe(
+      await registry.get(ref1, 'scaffolder'),
+    );
+    expect(await registry.get(ref1, 'catalog')).not.toBe(
+      await registry.get(ref1, 'scaffolder'),
+    );
   });
 
   it('should handle multiple factories with different serviceRefs', async () => {
     const registry = new ServiceRegistry([sf1, sf2]);
-    const factory1 = registry.get(ref1)!;
-    const factory2 = registry.get(ref2)!;
-    expect(factory1).toEqual(expect.any(Function));
-    expect(factory2).toEqual(expect.any(Function));
-    await expect(factory1('catalog')).resolves.toEqual({
+
+    await expect(registry.get(ref1, 'catalog')).resolves.toEqual({
       x: 1,
-      pluginId: 'catalog',
     });
-    await expect(factory2('catalog')).resolves.toEqual({
+    await expect(registry.get(ref2, 'catalog')).resolves.toEqual({
       x: 2,
-      pluginId: 'catalog',
     });
-    expect(await factory1('catalog')).not.toBe(await factory2('catalog'));
+    expect(await registry.get(ref1, 'catalog')).not.toBe(
+      await registry.get(ref2, 'catalog'),
+    );
   });
 
   it('should use the last factory for each ref', async () => {
     const registry = new ServiceRegistry([sf2, sf2b]);
-    const factory2 = registry.get(ref2)!;
-    await expect(factory2('catalog')).resolves.toEqual({
+    await expect(registry.get(ref2, 'catalog')).resolves.toEqual({
       x: 22,
-      pluginId: 'catalog',
     });
   });
 
-  it('should return the defaultFactory from the ref if not provided to the registry', async () => {
+  it('should use the defaultFactory from the ref if not provided to the registry', async () => {
     const registry = new ServiceRegistry([]);
-    const factory = registry.get(refDefault1)!;
-    expect(factory).toEqual(expect.any(Function));
-    await expect(factory('catalog')).resolves.toEqual({
+    await expect(registry.get(refDefault1, 'catalog')).resolves.toEqual({
       x: 10,
-      pluginId: 'catalog',
     });
   });
 
-  it('should not return the defaultFactory from the ref if provided to the registry', async () => {
+  it('should not use the defaultFactory from the ref if provided to the registry', async () => {
     const registry = new ServiceRegistry([sf1]);
-    const factory = registry.get(refDefault1)!;
-    expect(factory).toEqual(expect.any(Function));
-    await expect(factory('catalog')).resolves.toEqual({
+    await expect(registry.get(refDefault1, 'catalog')).resolves.toEqual({
       x: 1,
-      pluginId: 'catalog',
     });
   });
 
   it('should handle duplicate defaultFactories by duplicating the implementations', async () => {
     const registry = new ServiceRegistry([]);
-    const factoryA = registry.get(refDefault2a)!;
-    const factoryB = registry.get(refDefault2b)!;
-    expect(factoryA).toEqual(expect.any(Function));
-    expect(factoryB).toEqual(expect.any(Function));
-    await expect(factoryA('catalog')).resolves.toEqual({
+    await expect(registry.get(refDefault2a, 'catalog')).resolves.toEqual({
       x: 20,
-      pluginId: 'catalog',
     });
-    await expect(factoryB('catalog')).resolves.toEqual({
+    await expect(registry.get(refDefault2b, 'catalog')).resolves.toEqual({
       x: 220,
-      pluginId: 'catalog',
     });
-    expect(await factoryA('catalog')).toBe(await factoryA('catalog'));
-    expect(await factoryB('catalog')).toBe(await factoryB('catalog'));
-    expect(await factoryA('catalog')).not.toBe(await factoryB('catalog'));
+    expect(await registry.get(refDefault2a, 'catalog')).toBe(
+      await registry.get(refDefault2a, 'catalog'),
+    );
+    expect(await registry.get(refDefault2b, 'catalog')).toBe(
+      await registry.get(refDefault2b, 'catalog'),
+    );
+    expect(await registry.get(refDefault2a, 'catalog')).not.toBe(
+      await registry.get(refDefault2b, 'catalog'),
+    );
   });
 
   it('should only call each default factory loader once', async () => {
@@ -186,17 +175,16 @@ describe('ServiceRegistry', () => {
     });
 
     const registry = new ServiceRegistry([]);
-    const factory = registry.get(ref)!;
     await Promise.all([
-      expect(factory('catalog')).resolves.toBeUndefined(),
-      expect(factory('catalog')).resolves.toBeUndefined(),
+      expect(registry.get(ref, 'catalog')).resolves.toBeUndefined(),
+      expect(registry.get(ref, 'catalog')).resolves.toBeUndefined(),
     ]);
     expect(factoryLoader).toHaveBeenCalledTimes(1);
   });
 
   it('should not call factory functions more than once', async () => {
-    const innerFactory = jest.fn(async (pluginId: string) => {
-      return { x: 1, pluginId };
+    const innerFactory = jest.fn(async () => {
+      return { x: 1 };
     });
     const factory = jest.fn(async () => innerFactory);
     const myFactory = createServiceFactory({
@@ -208,17 +196,15 @@ describe('ServiceRegistry', () => {
     const registry = new ServiceRegistry([myFactory]);
 
     await Promise.all([
-      registry.get(ref1)!('catalog')!,
-      registry.get(ref1)!('catalog')!,
-      registry.get(ref1)!('catalog')!,
-      registry.get(ref1)!('scaffolder')!,
-      registry.get(ref1)!('scaffolder')!,
+      registry.get(ref1, 'catalog')!,
+      registry.get(ref1, 'catalog')!,
+      registry.get(ref1, 'catalog')!,
+      registry.get(ref1, 'scaffolder')!,
+      registry.get(ref1, 'scaffolder')!,
     ]);
 
     expect(factory).toHaveBeenCalledTimes(1);
     expect(innerFactory).toHaveBeenCalledTimes(2);
-    expect(innerFactory).toHaveBeenCalledWith('catalog');
-    expect(innerFactory).toHaveBeenCalledWith('scaffolder');
   });
 
   it('should throw if dependencies are not available', async () => {
@@ -231,9 +217,8 @@ describe('ServiceRegistry', () => {
     });
 
     const registry = new ServiceRegistry([myFactory]);
-    const factory = registry.get(ref1)!;
 
-    await expect(factory('catalog')).rejects.toThrow(
+    await expect(registry.get(ref1, 'catalog')).rejects.toThrow(
       "Failed to instantiate service '1' for 'catalog' because the following dependent services are missing: '2'",
     );
   });
@@ -247,8 +232,8 @@ describe('ServiceRegistry', () => {
     const factoryA = createServiceFactory({
       service: refA,
       deps: { b: refB },
-      async factory({ b }) {
-        return async pluginId => b(pluginId);
+      async factory() {
+        return async ({ b }) => b;
       },
     });
 
@@ -261,9 +246,8 @@ describe('ServiceRegistry', () => {
     });
 
     const registry = new ServiceRegistry([factoryA, factoryB]);
-    const factory = registry.get(refA)!;
 
-    await expect(factory('catalog')).rejects.toThrow(
+    await expect(registry.get(refA, 'catalog')).rejects.toThrow(
       "Failed to instantiate service 'a' for 'catalog' because the factory function threw an error, Error: Failed to instantiate service 'b' for 'catalog' because the following dependent services are missing: 'c', 'd'",
     );
   });
@@ -278,9 +262,8 @@ describe('ServiceRegistry', () => {
     });
 
     const registry = new ServiceRegistry([myFactory]);
-    const factory = registry.get(ref1)!;
 
-    await expect(factory('catalog')).rejects.toThrow(
+    await expect(registry.get(ref1, 'catalog')).rejects.toThrow(
       "Failed to instantiate service '1' because the top-level factory function threw an error, Error: top-level error",
     );
   });
@@ -290,17 +273,16 @@ describe('ServiceRegistry', () => {
       service: ref1,
       deps: {},
       async factory() {
-        return pluginId => {
-          throw new Error(`error in plugin ${pluginId}`);
+        return () => {
+          throw new Error(`error in plugin`);
         };
       },
     });
 
     const registry = new ServiceRegistry([myFactory]);
-    const factory = registry.get(ref1)!;
 
-    await expect(factory('catalog')).rejects.toThrow(
-      "Failed to instantiate service '1' for 'catalog' because the factory function threw an error, Error: error in plugin catalog",
+    await expect(registry.get(ref1, 'catalog')).rejects.toThrow(
+      "Failed to instantiate service '1' for 'catalog' because the factory function threw an error, Error: error in plugin",
     );
   });
 
@@ -313,9 +295,8 @@ describe('ServiceRegistry', () => {
     });
 
     const registry = new ServiceRegistry([]);
-    const factory = registry.get(ref)!;
 
-    await expect(factory('catalog')).rejects.toThrow(
+    await expect(registry.get(ref, 'catalog')).rejects.toThrow(
       "Failed to instantiate service '1' because the default factory loader threw an error, Error: default factory error",
     );
   });
diff --git a/packages/backend-app-api/src/wiring/ServiceRegistry.ts b/packages/backend-app-api/src/wiring/ServiceRegistry.ts
index e0509aecde..007ca00c88 100644
--- a/packages/backend-app-api/src/wiring/ServiceRegistry.ts
+++ b/packages/backend-app-api/src/wiring/ServiceRegistry.ts
@@ -16,8 +16,8 @@
 
 import {
   ServiceFactory,
-  FactoryFunc,
   ServiceRef,
+  pluginMetadataServiceRef,
 } from '@backstage/backend-plugin-api';
 import { stringifyError } from '@backstage/errors';
 
@@ -37,7 +37,9 @@ export class ServiceRegistry {
   readonly #implementations: Map<
     ServiceFactory,
     {
-      factoryFunc: Promise<FactoryFunc<unknown>>;
+      factoryFunc: Promise<
+        (deps: { [name in string]: unknown }) => Promise<unknown>
+      >;
       byPlugin: Map<string, Promise<unknown>>;
     }
   >;
@@ -58,67 +60,123 @@ export class ServiceRegistry {
     this.#implementations = new Map();
   }
 
-  get<T>(ref: ServiceRef<T>): FactoryFunc<T> | undefined {
-    let factory = this.#providedFactories.get(ref.id);
-    const { __defaultFactory: defaultFactory } = ref as InternalServiceRef<T>;
-    if (!factory && !defaultFactory) {
+  #resolveFactory(
+    ref: ServiceRef<unknown>,
+    pluginId: string,
+  ): Promise<ServiceFactory> | undefined {
+    // Special case handling of the plugin metadata service, generating a custom factory for it each time
+    if (ref.id === pluginMetadataServiceRef.id) {
+      return Promise.resolve({
+        scope: 'plugin',
+        service: pluginMetadataServiceRef,
+        deps: {},
+        factory: async () => async () => ({
+          getId() {
+            return pluginId;
+          },
+        }),
+      });
+    }
+
+    let resolvedFactory: Promise<ServiceFactory> | ServiceFactory | undefined =
+      this.#providedFactories.get(ref.id);
+    const { __defaultFactory: defaultFactory } =
+      ref as InternalServiceRef<unknown>;
+    if (!resolvedFactory && !defaultFactory) {
       return undefined;
     }
 
-    return async (pluginId: string): Promise<T> => {
-      if (!factory) {
-        let loadedFactory = this.#loadedDefaultFactories.get(defaultFactory!);
-        if (!loadedFactory) {
-          loadedFactory = Promise.resolve()
-            .then(() => defaultFactory!(ref))
-            .then(f =>
-              typeof f === 'function' ? f() : f,
-            ) as Promise<ServiceFactory>;
-          this.#loadedDefaultFactories.set(defaultFactory!, loadedFactory);
-        }
-        // NOTE: This await is safe as long as #providedFactories is not mutated.
-        factory = await loadedFactory.catch(error => {
-          throw new Error(
-            `Failed to instantiate service '${
-              ref.id
-            }' because the default factory loader threw an error, ${stringifyError(
-              error,
-            )}`,
+    if (!resolvedFactory) {
+      let loadedFactory = this.#loadedDefaultFactories.get(defaultFactory!);
+      if (!loadedFactory) {
+        loadedFactory = Promise.resolve()
+          .then(() => defaultFactory!(ref))
+          .then(f =>
+            typeof f === 'function' ? f() : f,
+          ) as Promise<ServiceFactory>;
+        this.#loadedDefaultFactories.set(defaultFactory!, loadedFactory);
+      }
+      resolvedFactory = loadedFactory.catch(error => {
+        throw new Error(
+          `Failed to instantiate service '${
+            ref.id
+          }' because the default factory loader threw an error, ${stringifyError(
+            error,
+          )}`,
+        );
+      });
+    }
+
+    return Promise.resolve(resolvedFactory);
+  }
+
+  #separateMapForTheRootService = new Map<ServiceFactory, Promise<unknown>>();
+
+  #checkForMissingDeps(factory: ServiceFactory, pluginId: string) {
+    const missingDeps = Object.values(factory.deps).filter(ref => {
+      if (ref.id === pluginMetadataServiceRef.id) {
+        return false;
+      }
+      if (this.#providedFactories.get(ref.id)) {
+        return false;
+      }
+
+      return !(ref as InternalServiceRef<unknown>).__defaultFactory;
+    });
+
+    if (missingDeps.length) {
+      const missing = missingDeps.map(r => `'${r.id}'`).join(', ');
+      throw new Error(
+        `Failed to instantiate service '${factory.service.id}' for '${pluginId}' because the following dependent services are missing: ${missing}`,
+      );
+    }
+  }
+
+  get<T>(ref: ServiceRef<T>, pluginId: string): Promise<T> | undefined {
+    return this.#resolveFactory(ref, pluginId)?.then(factory => {
+      if (factory.scope === 'root') {
+        let existing = this.#separateMapForTheRootService.get(factory);
+        if (!existing) {
+          this.#checkForMissingDeps(factory, pluginId);
+          const rootDeps = new Array<Promise<[name: string, impl: unknown]>>();
+
+          for (const [name, serviceRef] of Object.entries(factory.deps)) {
+            if (serviceRef.scope !== 'root') {
+              throw new Error(
+                `Failed to instantiate 'root' scoped service '${ref.id}' because it depends on '${serviceRef.scope}' scoped service '${serviceRef.id}'.`,
+              );
+            }
+            const target = this.get(serviceRef, pluginId)!;
+            rootDeps.push(target.then(impl => [name, impl]));
+          }
+
+          existing = Promise.all(rootDeps).then(entries =>
+            factory.factory(Object.fromEntries(entries)),
           );
-        });
+          this.#separateMapForTheRootService.set(factory, existing);
+        }
+        return existing as Promise<T>;
       }
 
       let implementation = this.#implementations.get(factory);
       if (!implementation) {
-        const missingRefs = new Array<ServiceRef<unknown>>();
-        const factoryDeps: { [name in string]: FactoryFunc<unknown> } = {};
+        this.#checkForMissingDeps(factory, pluginId);
+        const rootDeps = new Array<Promise<[name: string, impl: unknown]>>();
 
         for (const [name, serviceRef] of Object.entries(factory.deps)) {
-          const target = this.get(serviceRef);
-          if (!target) {
-            missingRefs.push(serviceRef);
-          } else {
-            factoryDeps[name] = target;
+          if (serviceRef.scope === 'root') {
+            const target = this.get(serviceRef, pluginId)!;
+            rootDeps.push(target.then(impl => [name, impl]));
           }
         }
 
-        if (missingRefs.length) {
-          const missing = missingRefs.map(r => `'${r.id}'`).join(', ');
-          throw new Error(
-            `Failed to instantiate service '${ref.id}' for '${pluginId}' because the following dependent services are missing: ${missing}`,
-          );
-        }
-
         implementation = {
-          factoryFunc: Promise.resolve()
-            .then(() => factory!.factory(factoryDeps))
+          factoryFunc: Promise.all(rootDeps)
+            .then(entries => factory.factory(Object.fromEntries(entries)))
             .catch(error => {
+              const cause = stringifyError(error);
               throw new Error(
-                `Failed to instantiate service '${
-                  ref.id
-                }' because the top-level factory function threw an error, ${stringifyError(
-                  error,
-                )}`,
+                `Failed to instantiate service '${ref.id}' because the top-level factory function threw an error, ${cause}`,
               );
             }),
           byPlugin: new Map(),
@@ -129,24 +187,29 @@ export class ServiceRegistry {
 
       let result = implementation.byPlugin.get(pluginId) as Promise<any>;
       if (!result) {
-        result = implementation.factoryFunc.then(func =>
-          Promise.resolve()
-            .then(() => func(pluginId))
-            .catch(error => {
-              throw new Error(
-                `Failed to instantiate service '${
-                  ref.id
-                }' for '${pluginId}' because the factory function threw an error, ${stringifyError(
-                  error,
-                )}`,
-              );
-            }),
-        );
+        const allDeps = new Array<Promise<[name: string, impl: unknown]>>();
 
+        for (const [name, serviceRef] of Object.entries(factory.deps)) {
+          const target = this.get(serviceRef, pluginId)!;
+          allDeps.push(target.then(impl => [name, impl]));
+        }
+
+        result = implementation.factoryFunc
+          .then(func =>
+            Promise.all(allDeps).then(entries =>
+              func(Object.fromEntries(entries)),
+            ),
+          )
+          .catch(error => {
+            const cause = stringifyError(error);
+            throw new Error(
+              `Failed to instantiate service '${ref.id}' for '${pluginId}' because the factory function threw an error, ${cause}`,
+            );
+          });
         implementation.byPlugin.set(pluginId, result);
       }
 
       return result;
-    };
+    });
   }
 }
diff --git a/packages/backend-app-api/src/wiring/types.ts b/packages/backend-app-api/src/wiring/types.ts
index febc6830c7..40ce6aa1ae 100644
--- a/packages/backend-app-api/src/wiring/types.ts
+++ b/packages/backend-app-api/src/wiring/types.ts
@@ -18,7 +18,6 @@ import {
   ServiceFactory,
   BackendFeature,
   ExtensionPoint,
-  FactoryFunc,
   ServiceRef,
 } from '@backstage/backend-plugin-api';
 import { BackstageBackend } from './BackstageBackend';
@@ -47,7 +46,7 @@ export interface CreateSpecializedBackendOptions {
 }
 
 export type ServiceHolder = {
-  get<T>(api: ServiceRef<T>): FactoryFunc<T> | undefined;
+  get<T>(api: ServiceRef<T>, pluginId: string): Promise<T> | undefined;
 };
 
 /**
diff --git a/packages/backend-plugin-api/src/services/system/types.ts b/packages/backend-plugin-api/src/services/system/types.ts
index a19c17bb9c..4a9f91541a 100644
--- a/packages/backend-plugin-api/src/services/system/types.ts
+++ b/packages/backend-plugin-api/src/services/system/types.ts
@@ -19,63 +19,84 @@
  *
  * @public
  */
-export type ServiceRef<T> = {
+export type ServiceRef<
+  TService,
+  TScope extends 'root' | 'plugin' = 'root' | 'plugin',
+> = {
   id: string;
 
+  /**
+   * This determines the scope at which this service is available.
+   *
+   * Root scoped services are available to all other services but
+   * may only depend on other root scoped services.
+   *
+   * Plugin scoped services are only available to other plugin scoped
+   * services but may depend on all other services.
+   */
+  scope: TScope;
+
   /**
    * Utility for getting the type of the service, using `typeof serviceRef.T`.
    * Attempting to actually read this value will result in an exception.
    */
-  T: T;
+  T: TService;
 
   toString(): string;
 
   $$ref: 'service';
 };
 
-/**
- * @internal
- */
-export type InternalServiceRef<T> = ServiceRef<T> & {
-  /**
-   * The default factory that will be used to create service
-   * instances if no other factory is provided.
-   */
-  __defaultFactory?: (
-    service: ServiceRef<T>,
-  ) => Promise<ServiceFactory<T> | (() => ServiceFactory<T>)>;
-};
-
 /** @public */
 export type TypesToServiceRef<T> = { [key in keyof T]: ServiceRef<T[key]> };
 
 /** @public */
-export type DepsToDepFactories<T> = {
-  [key in keyof T]: (pluginId: string) => Promise<T[key]>;
-};
-
-/** @public */
-export type FactoryFunc<Impl> = (pluginId: string) => Promise<Impl>;
-
-/** @public */
-export type ServiceFactory<TService = unknown> = {
-  service: ServiceRef<TService>;
-  deps: { [key in string]: ServiceRef<unknown> };
-  factory(deps: { [key in string]: unknown }): Promise<FactoryFunc<TService>>;
-};
+export type ServiceFactory<TService = unknown> =
+  | {
+      // This scope prop is needed in addition to the service ref, as TypeScript
+      // can't properly discriminate the two factory types otherwise.
+      scope: 'root';
+      service: ServiceRef<TService, 'root'>;
+      deps: { [key in string]: ServiceRef<unknown> };
+      factory(deps: { [key in string]: unknown }): Promise<TService>;
+    }
+  | {
+      scope: 'plugin';
+      service: ServiceRef<TService, 'plugin'>;
+      deps: { [key in string]: ServiceRef<unknown> };
+      factory(deps: { [key in string]: unknown }): Promise<
+        (deps: { [key in string]: unknown }) => Promise<TService>
+      >;
+    };
 
 /**
  * @public
  */
 export function createServiceRef<T>(options: {
   id: string;
+  scope?: 'plugin';
   defaultFactory?: (
     service: ServiceRef<T>,
   ) => Promise<ServiceFactory<T> | (() => ServiceFactory<T>)>;
-}): ServiceRef<T> {
-  const { id, defaultFactory } = options;
+}): ServiceRef<T, 'plugin'>;
+export function createServiceRef<T>(options: {
+  id: string;
+  scope: 'root';
+  defaultFactory?: (
+    service: ServiceRef<T>,
+  ) => Promise<ServiceFactory<T> | (() => ServiceFactory<T>)>;
+}): ServiceRef<T, 'root'>;
+export function createServiceRef<T>(options: {
+  id: string;
+  scope?: 'plugin' | 'root';
+  defaultFactory?: (
+    service: ServiceRef<T>,
+  ) => Promise<ServiceFactory<T> | (() => ServiceFactory<T>)>;
+}): ServiceRef<T, 'plugin' | 'root'> {
+  const { id, scope = 'plugin', defaultFactory } = options;
   return {
     id,
+    scope,
     get T(): T {
       throw new Error(`tried to read ServiceRef.T of ${this}`);
     },
@@ -84,32 +105,58 @@ export function createServiceRef<T>(options: {
     },
     $$ref: 'service', // TODO: declare
     __defaultFactory: defaultFactory,
-  } as InternalServiceRef<T>;
+  } as ServiceRef<T, typeof scope> & {
+    __defaultFactory?: (
+      service: ServiceRef<T>,
+    ) => Promise<ServiceFactory<T> | (() => ServiceFactory<T>)>;
+  };
 }
 
+type OnlyRootScopeDependencies<
+  TDeps extends { [key in string]: ServiceRef<unknown> },
+> = Pick<
+  TDeps,
+  {
+    [name in keyof TDeps]: TDeps[name]['scope'] extends 'root' ? name : never;
+  }[keyof TDeps]
+>;
+
+type DependencyRefsToInstances<
+  T extends { [key in string]: ServiceRef<unknown> },
+> = {
+  [key in keyof T]: T[key] extends ServiceRef<infer TImpl> ? TImpl : never;
+};
+
 /**
  * @public
  */
 export function createServiceFactory<
   TService,
+  TScope extends 'root' | 'plugin',
   TImpl extends TService,
-  TDeps extends { [name in string]: unknown },
+  TDeps extends { [name in string]: ServiceRef<unknown> },
   TOpts extends { [name in string]: unknown } | undefined = undefined,
->(factory: {
-  service: ServiceRef<TService>;
-  deps: TypesToServiceRef<TDeps>;
+>(config: {
+  service: ServiceRef<TService, TScope>;
+  deps: TDeps;
   factory(
-    deps: DepsToDepFactories<TDeps>,
+    deps: DependencyRefsToInstances<OnlyRootScopeDependencies<TDeps>>,
     options: TOpts,
-  ): Promise<FactoryFunc<TImpl>>;
+  ): TScope extends 'root'
+    ? Promise<TImpl>
+    : Promise<(deps: DependencyRefsToInstances<TDeps>) => Promise<TImpl>>;
 }): undefined extends TOpts
   ? (options?: TOpts) => ServiceFactory<TService>
   : (options: TOpts) => ServiceFactory<TService> {
-  return (options?: TOpts) => ({
-    service: factory.service,
-    deps: factory.deps,
-    factory(deps: DepsToDepFactories<TDeps>) {
-      return factory.factory(deps, options!);
-    },
-  });
+  return (options?: TOpts) =>
+    ({
+      scope: config.service.scope,
+      service: config.service,
+      deps: config.deps,
+      factory(
+        deps: DependencyRefsToInstances<OnlyRootScopeDependencies<TDeps>>,
+      ) {
+        return config.factory(deps, options!);
+      },
+    } as ServiceFactory<TService>);
 }

From 4b324c83f8bbc62f191139735cf9e4d43a100e54 Mon Sep 17 00:00:00 2001
From: Patrik Oldsberg <poldsberg@gmail.com>
Date: Thu, 8 Sep 2022 16:09:42 +0200
Subject: [PATCH 02/10] backend-app-api: 100% coverage of ServiceRegistry
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Co-authored-by: Fredrik Adelöw <freben@gmail.com>
Co-authored-by: blam <ben@blam.sh>
Co-authored-by: Johan Haals <johan.haals@gmail.com>
Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>
---
 .../src/wiring/ServiceRegistry.test.ts        | 72 ++++++++++++++++---
 1 file changed, 64 insertions(+), 8 deletions(-)

diff --git a/packages/backend-app-api/src/wiring/ServiceRegistry.test.ts b/packages/backend-app-api/src/wiring/ServiceRegistry.test.ts
index ab709dcb77..211f9ac31e 100644
--- a/packages/backend-app-api/src/wiring/ServiceRegistry.test.ts
+++ b/packages/backend-app-api/src/wiring/ServiceRegistry.test.ts
@@ -18,6 +18,7 @@ import {
   createServiceRef,
   createServiceFactory,
   ServiceRef,
+  pluginMetadataServiceRef,
 } from '@backstage/backend-plugin-api';
 import { ServiceRegistry } from './ServiceRegistry';
 
@@ -35,26 +36,23 @@ const sf1 = createServiceFactory({
 });
 
 const ref2 = createServiceRef<{ x: number }>({
+  scope: 'root',
   id: '2',
 });
 const sf2 = createServiceFactory({
   service: ref2,
   deps: {},
   factory: async () => {
-    return async () => {
-      return { x: 2 };
-    };
+    return { x: 2 };
   },
 });
 const sf2b = createServiceFactory({
   service: ref2,
   deps: {},
   factory: async () => {
-    return async () => {
-      return { x: 22 };
-    };
+    return { x: 22 };
   },
-});
+})();
 
 const refDefault1 = createServiceRef<{ x: number }>({
   id: '1',
@@ -63,7 +61,7 @@ const refDefault1 = createServiceRef<{ x: number }>({
       service,
       deps: {},
       factory: async () => async () => ({ x: 10 }),
-    }),
+    })(),
 });
 
 const refDefault2a = createServiceRef<{ x: number }>({
@@ -121,6 +119,64 @@ describe('ServiceRegistry', () => {
     );
   });
 
+  it('should not be possible for root scoped services to depend on plugin scoped services', async () => {
+    const factory = createServiceFactory({
+      service: ref2,
+      deps: { pluginDep: ref1 },
+      factory: async () => {
+        return { x: 2 };
+      },
+    });
+    const registry = new ServiceRegistry([factory, sf1]);
+    await expect(registry.get(ref2, 'catalog')).rejects.toThrow(
+      "Failed to instantiate 'root' scoped service '2' because it depends on 'plugin' scoped service '1'.",
+    );
+  });
+
+  it('should be possible for plugin scoped services to depend on root scoped services', async () => {
+    const factory = createServiceFactory({
+      service: ref1,
+      deps: { rootDep: ref2 },
+      factory: async ({ rootDep }) => {
+        return async () => ({ x: rootDep.x });
+      },
+    });
+    const registry = new ServiceRegistry([factory, sf2]);
+    await expect(registry.get(ref1, 'catalog')).resolves.toEqual({
+      x: 2,
+    });
+  });
+
+  it('should be possible for root scoped services to depend on root scoped services', async () => {
+    const ref = createServiceRef<{ x: number }>({ id: 'x', scope: 'root' });
+    const factory = createServiceFactory({
+      service: ref,
+      deps: { rootDep: ref2 },
+      factory: async ({ rootDep }) => {
+        return { x: rootDep.x };
+      },
+    });
+    const registry = new ServiceRegistry([factory, sf2]);
+    await expect(registry.get(ref, 'catalog')).resolves.toEqual({
+      x: 2,
+    });
+  });
+
+  it('should return the pluginId from the pluginMetadata service', async () => {
+    const ref = createServiceRef<{ pluginId: string }>({ id: 'x' });
+    const factory = createServiceFactory({
+      service: ref,
+      deps: { meta: pluginMetadataServiceRef },
+      factory: async ({}) => {
+        return async ({ meta }) => ({ pluginId: meta.getId() });
+      },
+    });
+    const registry = new ServiceRegistry([factory]);
+    await expect(registry.get(ref, 'catalog')).resolves.toEqual({
+      pluginId: 'catalog',
+    });
+  });
+
   it('should use the last factory for each ref', async () => {
     const registry = new ServiceRegistry([sf2, sf2b]);
     await expect(registry.get(ref2, 'catalog')).resolves.toEqual({

From dc74ebd10d57f8f290db50c172aad3435e46e6bf Mon Sep 17 00:00:00 2001
From: Patrik Oldsberg <poldsberg@gmail.com>
Date: Fri, 9 Sep 2022 15:29:44 +0200
Subject: [PATCH 03/10] backend-plugin-api: refactor createServiceFactory
 helper types
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Co-authored-by: Fredrik Adelöw <freben@gmail.com>
Co-authored-by: blam <ben@blam.sh>
Co-authored-by: Johan Haals <johan.haals@gmail.com>
Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>
---
 .../src/services/system/types.ts              | 24 +++++++------------
 1 file changed, 8 insertions(+), 16 deletions(-)

diff --git a/packages/backend-plugin-api/src/services/system/types.ts b/packages/backend-plugin-api/src/services/system/types.ts
index 4a9f91541a..579d7abaab 100644
--- a/packages/backend-plugin-api/src/services/system/types.ts
+++ b/packages/backend-plugin-api/src/services/system/types.ts
@@ -112,19 +112,13 @@ export function createServiceRef<T>(options: {
   };
 }
 
-type OnlyRootScopeDependencies<
-  TDeps extends { [key in string]: ServiceRef<unknown> },
-> = Pick<
-  TDeps,
-  {
-    [name in keyof TDeps]: TDeps[name]['scope'] extends 'root' ? name : never;
-  }[keyof TDeps]
->;
-
-type DependencyRefsToInstances<
+type ServiceRefsToInstances<
   T extends { [key in string]: ServiceRef<unknown> },
+  TScope extends 'root' | 'plugin' = 'root' | 'plugin',
 > = {
-  [key in keyof T]: T[key] extends ServiceRef<infer TImpl> ? TImpl : never;
+  [key in keyof T]: T[key] extends ServiceRef<infer TImpl, TScope>
+    ? TImpl
+    : never;
 };
 
 /**
@@ -140,11 +134,11 @@ export function createServiceFactory<
   service: ServiceRef<TService, TScope>;
   deps: TDeps;
   factory(
-    deps: DependencyRefsToInstances<OnlyRootScopeDependencies<TDeps>>,
+    deps: ServiceRefsToInstances<TDeps, 'root'>,
     options: TOpts,
   ): TScope extends 'root'
     ? Promise<TImpl>
-    : Promise<(deps: DependencyRefsToInstances<TDeps>) => Promise<TImpl>>;
+    : Promise<(deps: ServiceRefsToInstances<TDeps>) => Promise<TImpl>>;
 }): undefined extends TOpts
   ? (options?: TOpts) => ServiceFactory<TService>
   : (options: TOpts) => ServiceFactory<TService> {
@@ -153,9 +147,7 @@ export function createServiceFactory<
       scope: config.service.scope,
       service: config.service,
       deps: config.deps,
-      factory(
-        deps: DependencyRefsToInstances<OnlyRootScopeDependencies<TDeps>>,
-      ) {
+      factory(deps: ServiceRefsToInstances<TDeps, 'root'>) {
         return config.factory(deps, options!);
       },
     } as ServiceFactory<TService>);

From 2bf8855c1dc37ceb21dda11c1590795a96e8fa1e Mon Sep 17 00:00:00 2001
From: Patrik Oldsberg <poldsberg@gmail.com>
Date: Fri, 9 Sep 2022 15:30:08 +0200
Subject: [PATCH 04/10] core-app-api: switch to non-broken way of defining
 service factories
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Co-authored-by: blam <ben@blam.sh>
Co-authored-by: Fredrik Adelöw <freben@gmail.com>
Co-authored-by: Johan Haals <johan.haals@gmail.com>
Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>
---
 .../src/wiring/ServiceRegistry.test.ts        | 30 ++++++++++++-------
 1 file changed, 19 insertions(+), 11 deletions(-)

diff --git a/packages/backend-app-api/src/wiring/ServiceRegistry.test.ts b/packages/backend-app-api/src/wiring/ServiceRegistry.test.ts
index 211f9ac31e..897ed4e3cd 100644
--- a/packages/backend-app-api/src/wiring/ServiceRegistry.test.ts
+++ b/packages/backend-app-api/src/wiring/ServiceRegistry.test.ts
@@ -28,7 +28,7 @@ const ref1 = createServiceRef<{ x: number }>({
 const sf1 = createServiceFactory({
   service: ref1,
   deps: {},
-  factory: async () => {
+  async factory() {
     return async () => {
       return { x: 1 };
     };
@@ -42,14 +42,14 @@ const ref2 = createServiceRef<{ x: number }>({
 const sf2 = createServiceFactory({
   service: ref2,
   deps: {},
-  factory: async () => {
+  async factory() {
     return { x: 2 };
   },
 });
 const sf2b = createServiceFactory({
   service: ref2,
   deps: {},
-  factory: async () => {
+  async factory() {
     return { x: 22 };
   },
 })();
@@ -60,7 +60,9 @@ const refDefault1 = createServiceRef<{ x: number }>({
     createServiceFactory({
       service,
       deps: {},
-      factory: async () => async () => ({ x: 10 }),
+      async factory() {
+        return async () => ({ x: 10 });
+      },
     })(),
 });
 
@@ -70,7 +72,9 @@ const refDefault2a = createServiceRef<{ x: number }>({
     createServiceFactory({
       service,
       deps: {},
-      factory: async () => async () => ({ x: 20 }),
+      async factory() {
+        return async () => ({ x: 20 });
+      },
     }),
 });
 
@@ -80,7 +84,9 @@ const refDefault2b = createServiceRef<{ x: number }>({
     createServiceFactory({
       service,
       deps: {},
-      factory: async () => async () => ({ x: 220 }),
+      async factory() {
+        return async () => ({ x: 220 });
+      },
     }),
 });
 
@@ -123,7 +129,7 @@ describe('ServiceRegistry', () => {
     const factory = createServiceFactory({
       service: ref2,
       deps: { pluginDep: ref1 },
-      factory: async () => {
+      async factory() {
         return { x: 2 };
       },
     });
@@ -137,7 +143,7 @@ describe('ServiceRegistry', () => {
     const factory = createServiceFactory({
       service: ref1,
       deps: { rootDep: ref2 },
-      factory: async ({ rootDep }) => {
+      async factory({ rootDep }) {
         return async () => ({ x: rootDep.x });
       },
     });
@@ -152,7 +158,7 @@ describe('ServiceRegistry', () => {
     const factory = createServiceFactory({
       service: ref,
       deps: { rootDep: ref2 },
-      factory: async ({ rootDep }) => {
+      async factory({ rootDep }) {
         return { x: rootDep.x };
       },
     });
@@ -167,7 +173,7 @@ describe('ServiceRegistry', () => {
     const factory = createServiceFactory({
       service: ref,
       deps: { meta: pluginMetadataServiceRef },
-      factory: async ({}) => {
+      async factory() {
         return async ({ meta }) => ({ pluginId: meta.getId() });
       },
     });
@@ -222,7 +228,9 @@ describe('ServiceRegistry', () => {
       createServiceFactory({
         service,
         deps: {},
-        factory: async () => async () => {},
+        async factory() {
+          return async () => {};
+        },
       }),
     );
     const ref = createServiceRef<void>({

From f55c11f29d55cf2639b3d75976167f1506274cfa Mon Sep 17 00:00:00 2001
From: Patrik Oldsberg <poldsberg@gmail.com>
Date: Fri, 9 Sep 2022 15:34:29 +0200
Subject: [PATCH 05/10] core-plugin-api: narrow scope type of service refs
 passed to default factory loader

Co-authored-by: blam <ben@blam.sh>
Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>
---
 .../src/services/system/types.ts                 | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/packages/backend-plugin-api/src/services/system/types.ts b/packages/backend-plugin-api/src/services/system/types.ts
index 579d7abaab..e52ef5cc5a 100644
--- a/packages/backend-plugin-api/src/services/system/types.ts
+++ b/packages/backend-plugin-api/src/services/system/types.ts
@@ -76,23 +76,27 @@ export function createServiceRef<T>(options: {
   id: string;
   scope?: 'plugin';
   defaultFactory?: (
-    service: ServiceRef<T>,
+    service: ServiceRef<T, 'plugin'>,
   ) => Promise<ServiceFactory<T> | (() => ServiceFactory<T>)>;
 }): ServiceRef<T, 'plugin'>;
 export function createServiceRef<T>(options: {
   id: string;
   scope: 'root';
   defaultFactory?: (
-    service: ServiceRef<T>,
+    service: ServiceRef<T, 'root'>,
   ) => Promise<ServiceFactory<T> | (() => ServiceFactory<T>)>;
 }): ServiceRef<T, 'root'>;
 export function createServiceRef<T>(options: {
   id: string;
   scope?: 'plugin' | 'root';
-  defaultFactory?: (
-    service: ServiceRef<T>,
-  ) => Promise<ServiceFactory<T> | (() => ServiceFactory<T>)>;
-}): ServiceRef<T, 'plugin' | 'root'> {
+  defaultFactory?:
+    | ((
+        service: ServiceRef<T, 'plugin'>,
+      ) => Promise<ServiceFactory<T> | (() => ServiceFactory<T>)>)
+    | ((
+        service: ServiceRef<T, 'root'>,
+      ) => Promise<ServiceFactory<T> | (() => ServiceFactory<T>)>);
+}): ServiceRef<T> {
   const { id, scope = 'plugin', defaultFactory } = options;
   return {
     id,

From 06c744d142d7d9e8112dfe897ae0c3028560437a Mon Sep 17 00:00:00 2001
From: Patrik Oldsberg <poldsberg@gmail.com>
Date: Fri, 9 Sep 2022 15:35:21 +0200
Subject: [PATCH 06/10] backend-plugin-api: add initial PluginMetadataService
 definition
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Co-authored-by: Fredrik Adelöw <freben@gmail.com>
Co-authored-by: blam <ben@blam.sh>
Co-authored-by: Johan Haals <johan.haals@gmail.com>
Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>
---
 .../src/services/definitions/index.ts         |  1 +
 .../definitions/pluginMetadataServiceRef.ts   | 31 +++++++++++++++++++
 2 files changed, 32 insertions(+)
 create mode 100644 packages/backend-plugin-api/src/services/definitions/pluginMetadataServiceRef.ts

diff --git a/packages/backend-plugin-api/src/services/definitions/index.ts b/packages/backend-plugin-api/src/services/definitions/index.ts
index 797cfb5a76..fb204df495 100644
--- a/packages/backend-plugin-api/src/services/definitions/index.ts
+++ b/packages/backend-plugin-api/src/services/definitions/index.ts
@@ -26,3 +26,4 @@ export { discoveryServiceRef } from './discoveryServiceRef';
 export { tokenManagerServiceRef } from './tokenManagerServiceRef';
 export { permissionsServiceRef } from './permissionsServiceRef';
 export { schedulerServiceRef } from './schedulerServiceRef';
+export { pluginMetadataServiceRef } from './pluginMetadataServiceRef';
diff --git a/packages/backend-plugin-api/src/services/definitions/pluginMetadataServiceRef.ts b/packages/backend-plugin-api/src/services/definitions/pluginMetadataServiceRef.ts
new file mode 100644
index 0000000000..3af6e54900
--- /dev/null
+++ b/packages/backend-plugin-api/src/services/definitions/pluginMetadataServiceRef.ts
@@ -0,0 +1,31 @@
+/*
+ * Copyright 2022 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 { createServiceRef } from '../system/types';
+
+/**
+ * @public
+ */
+export interface PluginMetadata {
+  getId(): string;
+}
+
+/**
+ * @public
+ */
+export const pluginMetadataServiceRef = createServiceRef<PluginMetadata>({
+  id: 'core.plugin-metadata',
+});

From fb93ecad9cf98f0410fb7341eff7d427347b1ab2 Mon Sep 17 00:00:00 2001
From: Patrik Oldsberg <poldsberg@gmail.com>
Date: Fri, 9 Sep 2022 15:52:03 +0200
Subject: [PATCH 07/10] backend-plugin-api: remove services with scope mismatch
 from deps type

Co-authored-by: blam <ben@blam.sh>
Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>
---
 packages/backend-plugin-api/src/services/system/types.ts | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/packages/backend-plugin-api/src/services/system/types.ts b/packages/backend-plugin-api/src/services/system/types.ts
index e52ef5cc5a..3edee2ec0f 100644
--- a/packages/backend-plugin-api/src/services/system/types.ts
+++ b/packages/backend-plugin-api/src/services/system/types.ts
@@ -120,9 +120,9 @@ type ServiceRefsToInstances<
   T extends { [key in string]: ServiceRef<unknown> },
   TScope extends 'root' | 'plugin' = 'root' | 'plugin',
 > = {
-  [key in keyof T]: T[key] extends ServiceRef<infer TImpl, TScope>
-    ? TImpl
-    : never;
+  [name in {
+    [key in keyof T]: T[key] extends ServiceRef<unknown, TScope> ? key : never;
+  }[keyof T]]: T[name] extends ServiceRef<infer TImpl> ? TImpl : never;
 };
 
 /**

From 2a29d24519cd5ae64e6787eb55beaa4ff7665ca5 Mon Sep 17 00:00:00 2001
From: Patrik Oldsberg <poldsberg@gmail.com>
Date: Fri, 9 Sep 2022 16:10:59 +0200
Subject: [PATCH 08/10] backend-app-api,backend-plugin-api: refactor existing
 service factories and fix type issues

Co-authored-by: blam <ben@blam.sh>
Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>
---
 .../services/implementations/cacheService.ts  | 11 +++--
 .../services/implementations/configService.ts | 11 ++---
 .../implementations/databaseService.ts        | 11 +++--
 .../implementations/discoveryService.ts       |  5 +-
 .../implementations/httpRouterService.ts      | 11 +++--
 .../services/implementations/loggerService.ts | 33 ++++---------
 .../implementations/permissionsService.ts     | 22 ++++-----
 .../implementations/rootLoggerService.ts      | 48 +++++++++++++++++++
 .../implementations/schedulerService.ts       | 11 +++--
 .../implementations/tokenManagerService.ts    | 29 ++---------
 .../implementations/urlReaderService.ts       | 11 ++---
 .../src/wiring/BackendInitializer.ts          |  7 +--
 .../services/definitions/configServiceRef.ts  |  3 +-
 .../src/services/definitions/index.ts         |  1 +
 .../definitions/rootLoggerServiceRef.ts       | 26 ++++++++++
 .../src/services/system/index.ts              |  8 +---
 .../src/services/system/types.ts              |  1 +
 plugins/catalog-node/src/catalogService.ts    | 10 ++--
 18 files changed, 145 insertions(+), 114 deletions(-)
 create mode 100644 packages/backend-app-api/src/services/implementations/rootLoggerService.ts
 create mode 100644 packages/backend-plugin-api/src/services/definitions/rootLoggerServiceRef.ts

diff --git a/packages/backend-app-api/src/services/implementations/cacheService.ts b/packages/backend-app-api/src/services/implementations/cacheService.ts
index c5e58b4a41..7e15f031c6 100644
--- a/packages/backend-app-api/src/services/implementations/cacheService.ts
+++ b/packages/backend-app-api/src/services/implementations/cacheService.ts
@@ -18,6 +18,7 @@ import { CacheManager } from '@backstage/backend-common';
 import {
   configServiceRef,
   createServiceFactory,
+  pluginMetadataServiceRef,
   cacheServiceRef,
 } from '@backstage/backend-plugin-api';
 
@@ -25,13 +26,13 @@ import {
 export const cacheFactory = createServiceFactory({
   service: cacheServiceRef,
   deps: {
-    configFactory: configServiceRef,
+    config: configServiceRef,
+    plugin: pluginMetadataServiceRef,
   },
-  factory: async ({ configFactory }) => {
-    const config = await configFactory('root');
+  async factory({ config }) {
     const cacheManager = CacheManager.fromConfig(config);
-    return async (pluginId: string) => {
-      return cacheManager.forPlugin(pluginId);
+    return async ({ plugin }) => {
+      return cacheManager.forPlugin(plugin.getId());
     };
   },
 });
diff --git a/packages/backend-app-api/src/services/implementations/configService.ts b/packages/backend-app-api/src/services/implementations/configService.ts
index c4aa641f72..91327289df 100644
--- a/packages/backend-app-api/src/services/implementations/configService.ts
+++ b/packages/backend-app-api/src/services/implementations/configService.ts
@@ -19,23 +19,20 @@ import {
   configServiceRef,
   createServiceFactory,
   loggerToWinstonLogger,
-  loggerServiceRef,
+  rootLoggerServiceRef,
 } from '@backstage/backend-plugin-api';
 
 /** @public */
 export const configFactory = createServiceFactory({
   service: configServiceRef,
   deps: {
-    loggerFactory: loggerServiceRef,
+    logger: rootLoggerServiceRef,
   },
-  factory: async ({ loggerFactory }) => {
-    const logger = await loggerFactory('root');
+  async factory({ logger }) {
     const config = await loadBackendConfig({
       argv: process.argv,
       logger: loggerToWinstonLogger(logger),
     });
-    return async () => {
-      return config;
-    };
+    return config;
   },
 });
diff --git a/packages/backend-app-api/src/services/implementations/databaseService.ts b/packages/backend-app-api/src/services/implementations/databaseService.ts
index b2bc19de84..f6401528e6 100644
--- a/packages/backend-app-api/src/services/implementations/databaseService.ts
+++ b/packages/backend-app-api/src/services/implementations/databaseService.ts
@@ -19,19 +19,20 @@ import {
   configServiceRef,
   createServiceFactory,
   databaseServiceRef,
+  pluginMetadataServiceRef,
 } from '@backstage/backend-plugin-api';
 
 /** @public */
 export const databaseFactory = createServiceFactory({
   service: databaseServiceRef,
   deps: {
-    configFactory: configServiceRef,
+    config: configServiceRef,
+    plugin: pluginMetadataServiceRef,
   },
-  factory: async ({ configFactory }) => {
-    const config = await configFactory('root');
+  async factory({ config }) {
     const databaseManager = DatabaseManager.fromConfig(config);
-    return async (pluginId: string) => {
-      return databaseManager.forPlugin(pluginId);
+    return async ({ plugin }) => {
+      return databaseManager.forPlugin(plugin.getId());
     };
   },
 });
diff --git a/packages/backend-app-api/src/services/implementations/discoveryService.ts b/packages/backend-app-api/src/services/implementations/discoveryService.ts
index 3f1a584c61..7f35bf2447 100644
--- a/packages/backend-app-api/src/services/implementations/discoveryService.ts
+++ b/packages/backend-app-api/src/services/implementations/discoveryService.ts
@@ -25,10 +25,9 @@ import {
 export const discoveryFactory = createServiceFactory({
   service: discoveryServiceRef,
   deps: {
-    configFactory: configServiceRef,
+    config: configServiceRef,
   },
-  factory: async ({ configFactory }) => {
-    const config = await configFactory('root');
+  async factory({ config }) {
     const discovery = SingleHostDiscovery.fromConfig(config);
     return async () => {
       return discovery;
diff --git a/packages/backend-app-api/src/services/implementations/httpRouterService.ts b/packages/backend-app-api/src/services/implementations/httpRouterService.ts
index 6460a77eaf..be4af664c4 100644
--- a/packages/backend-app-api/src/services/implementations/httpRouterService.ts
+++ b/packages/backend-app-api/src/services/implementations/httpRouterService.ts
@@ -18,6 +18,7 @@ import {
   createServiceFactory,
   httpRouterServiceRef,
   configServiceRef,
+  pluginMetadataServiceRef,
 } from '@backstage/backend-plugin-api';
 import Router from 'express-promise-router';
 import { Handler } from 'express';
@@ -27,18 +28,20 @@ import { createServiceBuilder } from '@backstage/backend-common';
 export const httpRouterFactory = createServiceFactory({
   service: httpRouterServiceRef,
   deps: {
-    configFactory: configServiceRef,
+    config: configServiceRef,
+    plugin: pluginMetadataServiceRef,
   },
-  factory: async ({ configFactory }) => {
+  async factory({ config }) {
     const rootRouter = Router();
 
     const service = createServiceBuilder(module)
-      .loadConfig(await configFactory('root'))
+      .loadConfig(config)
       .addRouter('', rootRouter);
 
     await service.start();
 
-    return async (pluginId?: string) => {
+    return async ({ plugin }) => {
+      const pluginId = plugin.getId();
       const path = pluginId ? `/api/${pluginId}` : '';
       return {
         use(handler: Handler) {
diff --git a/packages/backend-app-api/src/services/implementations/loggerService.ts b/packages/backend-app-api/src/services/implementations/loggerService.ts
index e90b591302..ff72020140 100644
--- a/packages/backend-app-api/src/services/implementations/loggerService.ts
+++ b/packages/backend-app-api/src/services/implementations/loggerService.ts
@@ -14,38 +14,23 @@
  * limitations under the License.
  */
 
-import { createRootLogger } from '@backstage/backend-common';
 import {
   createServiceFactory,
-  Logger,
   loggerServiceRef,
+  pluginMetadataServiceRef,
+  rootLoggerServiceRef,
 } from '@backstage/backend-plugin-api';
-import { Logger as WinstonLogger } from 'winston';
-
-class BackstageLogger implements Logger {
-  static fromWinston(logger: WinstonLogger): BackstageLogger {
-    return new BackstageLogger(logger);
-  }
-
-  private constructor(private readonly winston: WinstonLogger) {}
-
-  info(message: string, ...meta: any[]): void {
-    this.winston.info(message, ...meta);
-  }
-
-  child(fields: { [name: string]: string }): Logger {
-    return new BackstageLogger(this.winston.child(fields));
-  }
-}
 
 /** @public */
 export const loggerFactory = createServiceFactory({
   service: loggerServiceRef,
-  deps: {},
-  factory: async () => {
-    const root = BackstageLogger.fromWinston(createRootLogger());
-    return async (pluginId: string) => {
-      return root.child({ pluginId });
+  deps: {
+    rootLogger: rootLoggerServiceRef,
+    plugin: pluginMetadataServiceRef,
+  },
+  async factory({ rootLogger }) {
+    return async ({ plugin }) => {
+      return rootLogger.child({ pluginId: plugin.getId() });
     };
   },
 });
diff --git a/packages/backend-app-api/src/services/implementations/permissionsService.ts b/packages/backend-app-api/src/services/implementations/permissionsService.ts
index 26fe012a20..32e8a1a9f9 100644
--- a/packages/backend-app-api/src/services/implementations/permissionsService.ts
+++ b/packages/backend-app-api/src/services/implementations/permissionsService.ts
@@ -27,20 +27,16 @@ import { ServerPermissionClient } from '@backstage/plugin-permission-node';
 export const permissionsFactory = createServiceFactory({
   service: permissionsServiceRef,
   deps: {
-    configFactory: configServiceRef,
-    discoveryFactory: discoveryServiceRef,
-    tokenManagerFactory: tokenManagerServiceRef,
+    config: configServiceRef,
+    discovery: discoveryServiceRef,
+    tokenManager: tokenManagerServiceRef,
   },
-  factory: async ({ configFactory, discoveryFactory, tokenManagerFactory }) => {
-    const config = await configFactory('root');
-    const discovery = await discoveryFactory('root');
-    const tokenManager = await tokenManagerFactory('root');
-    const permissions = ServerPermissionClient.fromConfig(config, {
-      discovery,
-      tokenManager,
-    });
-    return async (_pluginId: string) => {
-      return permissions;
+  async factory({ config }) {
+    return async ({ discovery, tokenManager }) => {
+      return ServerPermissionClient.fromConfig(config, {
+        discovery,
+        tokenManager,
+      });
     };
   },
 });
diff --git a/packages/backend-app-api/src/services/implementations/rootLoggerService.ts b/packages/backend-app-api/src/services/implementations/rootLoggerService.ts
new file mode 100644
index 0000000000..d7da11723e
--- /dev/null
+++ b/packages/backend-app-api/src/services/implementations/rootLoggerService.ts
@@ -0,0 +1,48 @@
+/*
+ * Copyright 2022 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 { createRootLogger } from '@backstage/backend-common';
+import {
+  createServiceFactory,
+  Logger,
+  rootLoggerServiceRef,
+} from '@backstage/backend-plugin-api';
+import { Logger as WinstonLogger } from 'winston';
+
+class BackstageLogger implements Logger {
+  static fromWinston(logger: WinstonLogger): BackstageLogger {
+    return new BackstageLogger(logger);
+  }
+
+  private constructor(private readonly winston: WinstonLogger) {}
+
+  info(message: string, ...meta: any[]): void {
+    this.winston.info(message, ...meta);
+  }
+
+  child(fields: { [name: string]: string }): Logger {
+    return new BackstageLogger(this.winston.child(fields));
+  }
+}
+
+/** @public */
+export const loggerFactory = createServiceFactory({
+  service: rootLoggerServiceRef,
+  deps: {},
+  async factory() {
+    return BackstageLogger.fromWinston(createRootLogger());
+  },
+});
diff --git a/packages/backend-app-api/src/services/implementations/schedulerService.ts b/packages/backend-app-api/src/services/implementations/schedulerService.ts
index 39dbf26ba9..40676344ec 100644
--- a/packages/backend-app-api/src/services/implementations/schedulerService.ts
+++ b/packages/backend-app-api/src/services/implementations/schedulerService.ts
@@ -17,6 +17,7 @@
 import {
   configServiceRef,
   createServiceFactory,
+  pluginMetadataServiceRef,
   schedulerServiceRef,
 } from '@backstage/backend-plugin-api';
 import { TaskScheduler } from '@backstage/backend-tasks';
@@ -25,13 +26,13 @@ import { TaskScheduler } from '@backstage/backend-tasks';
 export const schedulerFactory = createServiceFactory({
   service: schedulerServiceRef,
   deps: {
-    configFactory: configServiceRef,
+    config: configServiceRef,
+    plugin: pluginMetadataServiceRef,
   },
-  factory: async ({ configFactory }) => {
-    const config = await configFactory('root');
+  async factory({ config }) {
     const taskScheduler = TaskScheduler.fromConfig(config);
-    return async (pluginId: string) => {
-      return taskScheduler.forPlugin(pluginId);
+    return async ({ plugin }) => {
+      return taskScheduler.forPlugin(plugin.getId());
     };
   },
 });
diff --git a/packages/backend-app-api/src/services/implementations/tokenManagerService.ts b/packages/backend-app-api/src/services/implementations/tokenManagerService.ts
index 7767c17944..92f42c10db 100644
--- a/packages/backend-app-api/src/services/implementations/tokenManagerService.ts
+++ b/packages/backend-app-api/src/services/implementations/tokenManagerService.ts
@@ -27,32 +27,11 @@ import { ServerTokenManager } from '@backstage/backend-common';
 export const tokenManagerFactory = createServiceFactory({
   service: tokenManagerServiceRef,
   deps: {
-    configFactory: configServiceRef,
-    loggerFactory: loggerServiceRef,
+    config: configServiceRef,
+    logger: loggerServiceRef,
   },
-  factory: async ({ configFactory, loggerFactory }) => {
-    const logger = await loggerFactory('root');
-    const config = await configFactory('root');
-    return async (_pluginId: string) => {
-      // doesn't the logger want to be inferred from the plugin tho here?
-      // maybe ... also why do we recreate it every time otherwise
-      // we should memoize on a per plugin right? so I think it's should be fine to re-use the plugin one
-      // we shouldn't recreate on a per plugin basis.
-      // hm - on the other hand, is this really ever called more than once?
-      // not this function right. should only be called when the plugin requests this serviceRef
-      // yeah so no need to worry about memo probably
-      // but we still want to scope the logger to the ServrTokenmanagfer>?
-      // mm sure maybe
-      // maybe in this case it doesn't provide so much value b
-      // oh hang on - isn't it up to THE MANAGER to make a child internally if it wants to do that
-      // so that it becomes a property intrinsic to that class, no matter how it's constructed
-      // or is that too much responsibility for it - making the constructor complex so to speak, making it harder to tweak that behavior
-      // this is not ultra efficient :)
-
-      // I think the naming here is wrong to be gonest
-      // this isn't like the cache manager or the database manager
-      // the manager name is confusuion i think
-      // aye perhaps
+  async factory() {
+    return async ({ config, logger }) => {
       return ServerTokenManager.fromConfig(config, {
         logger: loggerToWinstonLogger(logger),
       });
diff --git a/packages/backend-app-api/src/services/implementations/urlReaderService.ts b/packages/backend-app-api/src/services/implementations/urlReaderService.ts
index df353a52d2..d7d7502a08 100644
--- a/packages/backend-app-api/src/services/implementations/urlReaderService.ts
+++ b/packages/backend-app-api/src/services/implementations/urlReaderService.ts
@@ -27,15 +27,14 @@ import {
 export const urlReaderFactory = createServiceFactory({
   service: urlReaderServiceRef,
   deps: {
-    configFactory: configServiceRef,
-    loggerFactory: loggerServiceRef,
+    config: configServiceRef,
+    logger: loggerServiceRef,
   },
-  factory: async ({ configFactory, loggerFactory }) => {
-    return async (pluginId: string) => {
-      const logger = await loggerFactory(pluginId);
+  async factory() {
+    return async ({ config, logger }) => {
       return UrlReaders.default({
+        config,
         logger: loggerToWinstonLogger(logger),
-        config: await configFactory(pluginId),
       });
     };
   },
diff --git a/packages/backend-app-api/src/wiring/BackendInitializer.ts b/packages/backend-app-api/src/wiring/BackendInitializer.ts
index afb5250504..c86cd8382d 100644
--- a/packages/backend-app-api/src/wiring/BackendInitializer.ts
+++ b/packages/backend-app-api/src/wiring/BackendInitializer.ts
@@ -50,11 +50,12 @@ export class BackendInitializer {
       if (extensionPoint) {
         result.set(name, extensionPoint);
       } else {
-        const factory = await this.#serviceHolder.get(
+        const impl = await this.#serviceHolder.get(
           ref as ServiceRef<unknown>,
+          pluginId,
         );
-        if (factory) {
-          result.set(name, await factory(pluginId));
+        if (impl) {
+          result.set(name, impl);
         } else {
           missingRefs.add(ref);
         }
diff --git a/packages/backend-plugin-api/src/services/definitions/configServiceRef.ts b/packages/backend-plugin-api/src/services/definitions/configServiceRef.ts
index ba5dcacdc8..f17c5f57bc 100644
--- a/packages/backend-plugin-api/src/services/definitions/configServiceRef.ts
+++ b/packages/backend-plugin-api/src/services/definitions/configServiceRef.ts
@@ -21,5 +21,6 @@ import { createServiceRef } from '../system/types';
  * @public
  */
 export const configServiceRef = createServiceRef<Config>({
-  id: 'core.config',
+  id: 'core.root.config',
+  scope: 'root',
 });
diff --git a/packages/backend-plugin-api/src/services/definitions/index.ts b/packages/backend-plugin-api/src/services/definitions/index.ts
index fb204df495..44ccb62978 100644
--- a/packages/backend-plugin-api/src/services/definitions/index.ts
+++ b/packages/backend-plugin-api/src/services/definitions/index.ts
@@ -26,4 +26,5 @@ export { discoveryServiceRef } from './discoveryServiceRef';
 export { tokenManagerServiceRef } from './tokenManagerServiceRef';
 export { permissionsServiceRef } from './permissionsServiceRef';
 export { schedulerServiceRef } from './schedulerServiceRef';
+export { rootLoggerServiceRef } from './rootLoggerServiceRef';
 export { pluginMetadataServiceRef } from './pluginMetadataServiceRef';
diff --git a/packages/backend-plugin-api/src/services/definitions/rootLoggerServiceRef.ts b/packages/backend-plugin-api/src/services/definitions/rootLoggerServiceRef.ts
new file mode 100644
index 0000000000..62e22c53d9
--- /dev/null
+++ b/packages/backend-plugin-api/src/services/definitions/rootLoggerServiceRef.ts
@@ -0,0 +1,26 @@
+/*
+ * Copyright 2022 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 { createServiceRef } from '../system/types';
+import { Logger } from './loggerServiceRef';
+
+/**
+ * @public
+ */
+export const rootLoggerServiceRef = createServiceRef<Logger>({
+  id: 'core.root.logger',
+  scope: 'root',
+});
diff --git a/packages/backend-plugin-api/src/services/system/index.ts b/packages/backend-plugin-api/src/services/system/index.ts
index 817b0a590f..8c666af42e 100644
--- a/packages/backend-plugin-api/src/services/system/index.ts
+++ b/packages/backend-plugin-api/src/services/system/index.ts
@@ -14,11 +14,5 @@
  * limitations under the License.
  */
 
-export type {
-  ServiceRef,
-  TypesToServiceRef,
-  DepsToDepFactories,
-  FactoryFunc,
-  ServiceFactory,
-} from './types';
+export type { ServiceRef, TypesToServiceRef, ServiceFactory } from './types';
 export { createServiceRef, createServiceFactory } from './types';
diff --git a/packages/backend-plugin-api/src/services/system/types.ts b/packages/backend-plugin-api/src/services/system/types.ts
index 3edee2ec0f..a7bce3d220 100644
--- a/packages/backend-plugin-api/src/services/system/types.ts
+++ b/packages/backend-plugin-api/src/services/system/types.ts
@@ -116,6 +116,7 @@ export function createServiceRef<T>(options: {
   };
 }
 
+/** @ignore */
 type ServiceRefsToInstances<
   T extends { [key in string]: ServiceRef<unknown> },
   TScope extends 'root' | 'plugin' = 'root' | 'plugin',
diff --git a/plugins/catalog-node/src/catalogService.ts b/plugins/catalog-node/src/catalogService.ts
index ddfff75462..c6a8fb44f5 100644
--- a/plugins/catalog-node/src/catalogService.ts
+++ b/plugins/catalog-node/src/catalogService.ts
@@ -31,13 +31,11 @@ export const catalogServiceRef = createServiceRef<CatalogApi>({
     createServiceFactory({
       service,
       deps: {
-        discoveryFactory: discoveryServiceRef,
+        discoveryApi: discoveryServiceRef,
       },
-      factory: async ({ discoveryFactory }) => {
-        const discoveryApi = await discoveryFactory('root');
-        const catalogClient = new CatalogClient({ discoveryApi });
-        return async _pluginId => {
-          return catalogClient;
+      async factory() {
+        return async ({ discoveryApi }) => {
+          return new CatalogClient({ discoveryApi });
         };
       },
     }),

From 06ad1b16de01f67d529e202e0aed997fd901b964 Mon Sep 17 00:00:00 2001
From: Patrik Oldsberg <poldsberg@gmail.com>
Date: Fri, 9 Sep 2022 16:15:09 +0200
Subject: [PATCH 09/10] update API reports + fixes

Co-authored-by: blam <ben@blam.sh>
Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>
---
 packages/backend-plugin-api/api-report.md     | 108 ++++++++++++------
 .../src/services/definitions/index.ts         |   1 +
 .../src/services/system/types.ts              |   5 +-
 plugins/catalog-node/api-report.md            |   2 +-
 4 files changed, 77 insertions(+), 39 deletions(-)

diff --git a/packages/backend-plugin-api/api-report.md b/packages/backend-plugin-api/api-report.md
index 30e58237af..3344576db8 100644
--- a/packages/backend-plugin-api/api-report.md
+++ b/packages/backend-plugin-api/api-report.md
@@ -66,10 +66,10 @@ export interface BackendRegistrationPoints {
 }
 
 // @public (undocumented)
-export const cacheServiceRef: ServiceRef<PluginCacheManager>;
+export const cacheServiceRef: ServiceRef<PluginCacheManager, 'plugin'>;
 
 // @public (undocumented)
-export const configServiceRef: ServiceRef<Config>;
+export const configServiceRef: ServiceRef<Config, 'root'>;
 
 // @public (undocumented)
 export function createBackendModule<
@@ -105,22 +105,25 @@ export function createExtensionPoint<T>(options: {
 // @public (undocumented)
 export function createServiceFactory<
   TService,
+  TScope extends 'root' | 'plugin',
   TImpl extends TService,
   TDeps extends {
-    [name in string]: unknown;
+    [name in string]: ServiceRef<unknown>;
   },
   TOpts extends
     | {
         [name in string]: unknown;
       }
     | undefined = undefined,
->(factory: {
-  service: ServiceRef<TService>;
-  deps: TypesToServiceRef<TDeps>;
+>(config: {
+  service: ServiceRef<TService, TScope>;
+  deps: TDeps;
   factory(
-    deps: DepsToDepFactories<TDeps>,
+    deps: ServiceRefsToInstances<TDeps, 'root'>,
     options: TOpts,
-  ): Promise<FactoryFunc<TImpl>>;
+  ): TScope extends 'root'
+    ? Promise<TImpl>
+    : Promise<(deps: ServiceRefsToInstances<TDeps>) => Promise<TImpl>>;
 }): undefined extends TOpts
   ? (options?: TOpts) => ServiceFactory<TService>
   : (options: TOpts) => ServiceFactory<TService>;
@@ -128,21 +131,26 @@ export function createServiceFactory<
 // @public (undocumented)
 export function createServiceRef<T>(options: {
   id: string;
+  scope?: 'plugin';
   defaultFactory?: (
-    service: ServiceRef<T>,
+    service: ServiceRef<T, 'plugin'>,
   ) => Promise<ServiceFactory<T> | (() => ServiceFactory<T>)>;
-}): ServiceRef<T>;
+}): ServiceRef<T, 'plugin'>;
 
 // @public (undocumented)
-export const databaseServiceRef: ServiceRef<PluginDatabaseManager>;
+export function createServiceRef<T>(options: {
+  id: string;
+  scope: 'root';
+  defaultFactory?: (
+    service: ServiceRef<T, 'root'>,
+  ) => Promise<ServiceFactory<T> | (() => ServiceFactory<T>)>;
+}): ServiceRef<T, 'root'>;
 
 // @public (undocumented)
-export type DepsToDepFactories<T> = {
-  [key in keyof T]: (pluginId: string) => Promise<T[key]>;
-};
+export const databaseServiceRef: ServiceRef<PluginDatabaseManager, 'plugin'>;
 
 // @public (undocumented)
-export const discoveryServiceRef: ServiceRef<PluginEndpointDiscovery>;
+export const discoveryServiceRef: ServiceRef<PluginEndpointDiscovery, 'plugin'>;
 
 // @public
 export type ExtensionPoint<T> = {
@@ -152,9 +160,6 @@ export type ExtensionPoint<T> = {
   $$ref: 'extension-point';
 };
 
-// @public (undocumented)
-export type FactoryFunc<Impl> = (pluginId: string) => Promise<Impl>;
-
 // @public (undocumented)
 export interface HttpRouterService {
   // (undocumented)
@@ -162,7 +167,7 @@ export interface HttpRouterService {
 }
 
 // @public (undocumented)
-export const httpRouterServiceRef: ServiceRef<HttpRouterService>;
+export const httpRouterServiceRef: ServiceRef<HttpRouterService, 'plugin'>;
 
 // @public (undocumented)
 export interface Logger {
@@ -173,7 +178,7 @@ export interface Logger {
 }
 
 // @public (undocumented)
-export const loggerServiceRef: ServiceRef<Logger>;
+export const loggerServiceRef: ServiceRef<Logger, 'plugin'>;
 
 // @public (undocumented)
 export function loggerToWinstonLogger(
@@ -183,33 +188,66 @@ export function loggerToWinstonLogger(
 
 // @public (undocumented)
 export const permissionsServiceRef: ServiceRef<
-  PermissionAuthorizer | PermissionEvaluator
+  PermissionAuthorizer | PermissionEvaluator,
+  'plugin'
 >;
 
 // @public (undocumented)
-export const schedulerServiceRef: ServiceRef<PluginTaskScheduler>;
+export interface PluginMetadata {
+  // (undocumented)
+  getId(): string;
+}
 
 // @public (undocumented)
-export type ServiceFactory<TService = unknown> = {
-  service: ServiceRef<TService>;
-  deps: {
-    [key in string]: ServiceRef<unknown>;
-  };
-  factory(deps: {
-    [key in string]: unknown;
-  }): Promise<FactoryFunc<TService>>;
-};
+export const pluginMetadataServiceRef: ServiceRef<PluginMetadata, 'plugin'>;
+
+// @public (undocumented)
+export const rootLoggerServiceRef: ServiceRef<Logger, 'root'>;
+
+// @public (undocumented)
+export const schedulerServiceRef: ServiceRef<PluginTaskScheduler, 'plugin'>;
+
+// @public (undocumented)
+export type ServiceFactory<TService = unknown> =
+  | {
+      scope: 'root';
+      service: ServiceRef<TService, 'root'>;
+      deps: {
+        [key in string]: ServiceRef<unknown>;
+      };
+      factory(deps: {
+        [key in string]: unknown;
+      }): Promise<TService>;
+    }
+  | {
+      scope: 'plugin';
+      service: ServiceRef<TService, 'plugin'>;
+      deps: {
+        [key in string]: ServiceRef<unknown>;
+      };
+      factory(deps: {
+        [key in string]: unknown;
+      }): Promise<
+        (deps: {
+          [key in string]: unknown;
+        }) => Promise<TService>
+      >;
+    };
 
 // @public
-export type ServiceRef<T> = {
+export type ServiceRef<
+  TService,
+  TScope extends 'root' | 'plugin' = 'root' | 'plugin',
+> = {
   id: string;
-  T: T;
+  scope: TScope;
+  T: TService;
   toString(): string;
   $$ref: 'service';
 };
 
 // @public (undocumented)
-export const tokenManagerServiceRef: ServiceRef<TokenManager>;
+export const tokenManagerServiceRef: ServiceRef<TokenManager, 'plugin'>;
 
 // @public (undocumented)
 export type TypesToServiceRef<T> = {
@@ -217,5 +255,5 @@ export type TypesToServiceRef<T> = {
 };
 
 // @public (undocumented)
-export const urlReaderServiceRef: ServiceRef<UrlReader>;
+export const urlReaderServiceRef: ServiceRef<UrlReader, 'plugin'>;
 ```
diff --git a/packages/backend-plugin-api/src/services/definitions/index.ts b/packages/backend-plugin-api/src/services/definitions/index.ts
index 44ccb62978..e5f032ef60 100644
--- a/packages/backend-plugin-api/src/services/definitions/index.ts
+++ b/packages/backend-plugin-api/src/services/definitions/index.ts
@@ -28,3 +28,4 @@ export { permissionsServiceRef } from './permissionsServiceRef';
 export { schedulerServiceRef } from './schedulerServiceRef';
 export { rootLoggerServiceRef } from './rootLoggerServiceRef';
 export { pluginMetadataServiceRef } from './pluginMetadataServiceRef';
+export type { PluginMetadata } from './pluginMetadataServiceRef';
diff --git a/packages/backend-plugin-api/src/services/system/types.ts b/packages/backend-plugin-api/src/services/system/types.ts
index a7bce3d220..d20fd6fd8f 100644
--- a/packages/backend-plugin-api/src/services/system/types.ts
+++ b/packages/backend-plugin-api/src/services/system/types.ts
@@ -69,9 +69,7 @@ export type ServiceFactory<TService = unknown> =
       >;
     };
 
-/**
- * @public
- */
+/** @public */
 export function createServiceRef<T>(options: {
   id: string;
   scope?: 'plugin';
@@ -79,6 +77,7 @@ export function createServiceRef<T>(options: {
     service: ServiceRef<T, 'plugin'>,
   ) => Promise<ServiceFactory<T> | (() => ServiceFactory<T>)>;
 }): ServiceRef<T, 'plugin'>;
+/** @public */
 export function createServiceRef<T>(options: {
   id: string;
   scope: 'root';
diff --git a/plugins/catalog-node/api-report.md b/plugins/catalog-node/api-report.md
index 3873e3376d..525516be54 100644
--- a/plugins/catalog-node/api-report.md
+++ b/plugins/catalog-node/api-report.md
@@ -109,7 +109,7 @@ export type CatalogProcessorResult =
   | CatalogProcessorRefreshKeysResult;
 
 // @alpha
-export const catalogServiceRef: ServiceRef<CatalogApi>;
+export const catalogServiceRef: ServiceRef<CatalogApi, 'plugin'>;
 
 // @public
 export type DeferredEntity = {

From 409ed984e8e506abc9327cb8381c2a12aa59b5ce Mon Sep 17 00:00:00 2001
From: Patrik Oldsberg <poldsberg@gmail.com>
Date: Fri, 9 Sep 2022 18:26:34 +0200
Subject: [PATCH 10/10] changesets: added changesets for scoped services

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>
---
 .changeset/flat-humans-dance.md  | 5 +++++
 .changeset/quick-items-invite.md | 5 +++++
 .changeset/slow-phones-count.md  | 5 +++++
 3 files changed, 15 insertions(+)
 create mode 100644 .changeset/flat-humans-dance.md
 create mode 100644 .changeset/quick-items-invite.md
 create mode 100644 .changeset/slow-phones-count.md

diff --git a/.changeset/flat-humans-dance.md b/.changeset/flat-humans-dance.md
new file mode 100644
index 0000000000..ea7571f5bc
--- /dev/null
+++ b/.changeset/flat-humans-dance.md
@@ -0,0 +1,5 @@
+---
+'@backstage/backend-plugin-api': patch
+---
+
+Service are now scoped to either `'plugin'` or `'root'` scope. Service factories have been updated to provide dependency instances directly rather than factory functions.
diff --git a/.changeset/quick-items-invite.md b/.changeset/quick-items-invite.md
new file mode 100644
index 0000000000..33f90cb662
--- /dev/null
+++ b/.changeset/quick-items-invite.md
@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-catalog-node': patch
+---
+
+Updated usage of experimental backend service APIs.
diff --git a/.changeset/slow-phones-count.md b/.changeset/slow-phones-count.md
new file mode 100644
index 0000000000..ce2f9c8432
--- /dev/null
+++ b/.changeset/slow-phones-count.md
@@ -0,0 +1,5 @@
+---
+'@backstage/backend-app-api': patch
+---
+
+Updated service implementations and backend wiring to support scoped service.