allow an additional config to be provided to loadBackendConfig during runtime

Signed-off-by: Oleg S <97077423+RobotSail@users.noreply.github.com>

.changeset/curly-steaks-mate.md

@@ -0,0 +1,7 @@
+---
+'@backstage/backend-app-api': minor
+'@backstage/backend-common': minor
+'@backstage/config-loader': minor
+---
+
+Allow an additionalConfig to be provided to loadBackendConfig that fetches config values during runtime.

.changeset/spotty-cougars-wink.md

@@ -1,7 +1,6 @@
 ---
 '@backstage/backend-app-api': minor
 '@backstage/config-loader': minor
-'@backstage/types': minor
 ---
 
 Introduces the ability to merge configs and JsonObjects

packages/backend-app-api/api-report.md

@@ -5,6 +5,7 @@
 ```ts
 /// <reference types="node" />
 
+import type { AppConfig } from '@backstage/config';
 import { BackendFeature } from '@backstage/backend-plugin-api';
 import { CacheClient } from '@backstage/backend-common';
 import { Config } from '@backstage/config';
@@ -178,7 +179,7 @@ export const lifecycleServiceFactory: () => ServiceFactory<
 export function loadBackendConfig(options: {
   remote?: LoadConfigOptionsRemote;
   argv: string[];
-  config?: JsonObject;
+  additionalConfig?: AppConfig;
 }): Promise<{
   config: Config;
 }>;

packages/backend-app-api/src/config/ObservableConfigProxy.ts

@@ -16,8 +16,7 @@
 
 import { ConfigService } from '@backstage/backend-plugin-api';
 import { ConfigReader } from '@backstage/config';
-import type { JsonObject, JsonValue } from '@backstage/types';
-import { mergeJson } from '@backstage/types';
+import type { JsonValue } from '@backstage/types';
 
 export class ObservableConfigProxy implements ConfigService {
   private config: ConfigService = new ConfigReader({});
@@ -62,12 +61,6 @@ export class ObservableConfigProxy implements ConfigService {
       },
     };
   }
-  mergeConfig(configData: JsonObject) {
-    if (this.parent) {
-      throw new Error('immutable');
-    }
-    this.setConfig(new ConfigReader(mergeJson(this.config.get(), configData)));
-  }
 
   private select(required: true): ConfigService;
   private select(required: false): ConfigService | undefined;

packages/backend-app-api/src/config/config.ts

@@ -24,11 +24,11 @@ import {
   ConfigTarget,
   LoadConfigOptionsRemote,
 } from '@backstage/config-loader';
-import { type Config, ConfigReader } from '@backstage/config';
+import { ConfigReader } from '@backstage/config';
+import type { Config, AppConfig } from '@backstage/config';
 import { getPackages } from '@manypkg/get-packages';
 import { ObservableConfigProxy } from './ObservableConfigProxy';
 import { isValidUrl } from '../lib/urls';
-import type { JsonObject } from '@backstage/types';
 
 /** @public */
 export async function createConfigSecretEnumerator(options: {
@@ -71,7 +71,7 @@ export async function createConfigSecretEnumerator(options: {
 export async function loadBackendConfig(options: {
   remote?: LoadConfigOptionsRemote;
   argv: string[];
-  config?: JsonObject;
+  additionalConfig?: AppConfig;
 }): Promise<{ config: Config }> {
   const args = parseArgs(options.argv);
 
@@ -115,8 +115,12 @@ export async function loadBackendConfig(options: {
     `Loaded config from ${appConfigs.map(c => c.context).join(', ')}`,
   );
 
+  // add the additional config if provided
+  if (options.additionalConfig) {
+    appConfigs.push(options.additionalConfig);
+  }
+
   config.setConfig(ConfigReader.fromConfigs(appConfigs));
-  config.mergeConfig(options.config ?? {});
 
   return { config };
 }

packages/backend-common/api-report.md

@@ -7,6 +7,8 @@
 /// <reference types="webpack-env" />
 
 import { AwsCredentialsManager } from '@backstage/integration-aws-node';
+import type { AppConfig } from '@backstage/config';
+import aws from 'aws-sdk';
 import { AwsS3Integration } from '@backstage/integration';
 import { AzureIntegration } from '@backstage/integration';
 import { BackendFeature } from '@backstage/backend-plugin-api';
@@ -532,6 +534,7 @@ export const legacyPlugin: (
 export function loadBackendConfig(options: {
   logger: LoggerService;
   remote?: LoadConfigOptionsRemote;
+  additionalConfig?: AppConfig;
   argv: string[];
 }): Promise<Config>;
 

packages/backend-common/src/config.ts

@@ -19,7 +19,7 @@ import {
   loadBackendConfig as newLoadBackendConfig,
 } from '@backstage/backend-app-api';
 import { LoggerService } from '@backstage/backend-plugin-api';
-import { Config } from '@backstage/config';
+import type { AppConfig, Config } from '@backstage/config';
 import { LoadConfigOptionsRemote } from '@backstage/config-loader';
 import { setRootLoggerRedactionList } from './logging/createRootLogger';
 
@@ -34,6 +34,7 @@ export async function loadBackendConfig(options: {
   logger: LoggerService;
   // process.argv or any other overrides
   remote?: LoadConfigOptionsRemote;
+  additionalConfig?: AppConfig;
   argv: string[];
 }): Promise<Config> {
   const secretEnumerator = await createConfigSecretEnumerator({

packages/types/api-report.md

@@ -29,9 +29,6 @@ export type JsonPrimitive = number | string | boolean | null;
 // @public
 export type JsonValue = JsonObject | JsonArray | JsonPrimitive;
 
-// @public
-export const mergeJson: (a: JsonObject, b: JsonObject) => JsonObject;
-
 // @public
 export type Observable<T> = {
   [Symbol.observable](): Observable<T>;

packages/types/src/index.ts

@@ -21,6 +21,5 @@
  */
 
 export type { JsonArray, JsonObject, JsonPrimitive, JsonValue } from './json';
-export { mergeJson } from './json';
 export type { Observable, Observer, Subscription } from './observable';
 export type { HumanDuration } from './time';

packages/types/src/json.test.ts

@@ -14,13 +14,7 @@
  * limitations under the License.
  */
 
-import {
-  JsonPrimitive,
-  JsonArray,
-  JsonObject,
-  JsonValue,
-  mergeJson,
-} from './json';
+import { JsonPrimitive, JsonArray, JsonObject, JsonValue } from './json';
 
 describe('json', () => {
   it('JsonPrimitive', () => {
@@ -85,124 +79,3 @@ describe('json', () => {
     expect(true).toBe(true);
   });
 });
-
-describe('jsonMerge', () => {
-  it('should merge two objects', () => {
-    const obj1 = { a: 1, b: 2, c: 3 };
-    const obj2 = { b: 4, c: 5, d: 6 };
-    const merged = mergeJson(obj1, obj2);
-    expect(merged).toEqual({ a: 1, b: 4, c: 5, d: 6 });
-  });
-
-  it('should always prefer to merge the values of the second parameter', () => {
-    const obj1 = {
-      a: 1,
-      b: [1, 2, 3],
-      c: {
-        z: 1,
-        y: 2,
-        x: 3,
-      },
-    };
-    const obj2 = {
-      a: 2,
-      b: [2, 4, 6],
-      c: {
-        z: 2,
-        y: 4,
-        x: 6,
-      },
-    };
-    const merged = mergeJson(obj1, obj2);
-    expect(merged).toEqual(obj2);
-  });
-
-  it('should prefer the second argument whenever keys collide', () => {
-    const obj1 = {
-      a: 1,
-      b: [1, 2, 3],
-      c: {
-        z: 1,
-        y: 2,
-        x: 3,
-      },
-    };
-    const obj2 = {
-      a: 2,
-      c: {
-        y: 4,
-      },
-    };
-    const merged = mergeJson(obj1, obj2);
-    expect(merged).toEqual({
-      a: 2,
-      b: [1, 2, 3],
-      c: {
-        z: 1,
-        y: 4,
-        x: 3,
-      },
-    });
-  });
-
-  it('should merge recursively', () => {
-    const obj1 = {
-      backend: {
-        database: {
-          provider: 'sqlite3',
-        },
-      },
-    };
-    const obj2 = {
-      backend: {
-        database: {
-          password: 'password123',
-        },
-      },
-    };
-    const merged = mergeJson(obj1, obj2);
-    expect(merged).toEqual({
-      backend: {
-        database: {
-          provider: 'sqlite3',
-          password: 'password123',
-        },
-      },
-    });
-  });
-
-  it("should overwrite the array with the second argument's array", () => {
-    const obj1 = {
-      array: ['a', 'b', 'c'],
-    };
-    const obj2 = {
-      array: [1, 2, 3],
-    };
-    const merged = mergeJson(obj1, obj2);
-    expect(merged).toEqual({
-      array: [1, 2, 3],
-    });
-
-    const merged2 = mergeJson(obj2, obj1);
-    expect(merged2).toEqual({
-      array: ['a', 'b', 'c'],
-    });
-  });
-
-  it('should take only the defined value in the case of a collision', () => {
-    const obj1 = {
-      sqlite: undefined,
-    };
-    const obj2 = {
-      sqlite: 'sqlite3',
-    };
-    const merged = mergeJson(obj1, obj2);
-    expect(merged).toEqual({
-      sqlite: 'sqlite3',
-    });
-    const merged2 = mergeJson(obj2, obj1);
-    expect(merged2).toEqual({
-      sqlite: 'sqlite3',
-    });
-  });
-});

packages/types/src/json.ts

@@ -41,62 +41,3 @@ export interface JsonArray extends Array<JsonValue> {}
  * @public
  */
 export type JsonValue = JsonObject | JsonArray | JsonPrimitive;
-
-/**
- * Attempts to merge two JsonObjects together. In the case of collisions, this function
- * prefers values from b, unless the value is an object, in which case it recursively
- * merges the values.
- *
- * @param a - The base object
- * @param b - The object to merge into a
- * @returns The merged object
- * @public
- */
-export const mergeJson = (a: JsonObject, b: JsonObject): JsonObject => {
-  const final: JsonObject = {};
-  const bKeys = new Set(Object.keys(b));
-  const aKeys = new Set(Object.keys(a));
-  const intersectingKeys = new Set([...aKeys].filter(x => bKeys.has(x)));
-
-  // add all mutually exclusive keys to the final object
-  for (const key of aKeys.values()) {
-    if (!intersectingKeys.has(key)) {
-      final[key] = a[key];
-      continue;
-    }
-  }
-  for (const key of bKeys.values()) {
-    if (!intersectingKeys.has(key)) {
-      final[key] = b[key];
-      continue;
-    }
-  }
-
-  // values now are all overlapping and are either primitives, arrays, or objects.
-  // for all primitives and arrays, we want to assign the value from b
-  // for all objects, we want to recursively merge the values
-  for (const key of intersectingKeys.values()) {
-    // check if either value is undefined and default to the defined one
-    const aValue = a[key];
-    const bValue = b[key];
-    if (!aValue) {
-      final[key] = bValue;
-      continue;
-    }
-    if (!bValue) {
-      final[key] = aValue;
-      continue;
-    }
-
-    // check if value is an array or primitive
-    const value = bValue;
-    if (Array.isArray(value) || typeof value !== 'object') {
-      final[key] = value;
-      continue;
-    }
-
-    // recursively merge the values
-    final[key] = mergeJson(aValue as JsonObject, bValue as JsonObject);
-  }
-  return final;
-};