Merge pull request #1883 from nestjs/feat/skip-predefined-change-order

feat: order of reading variables, add skip predefined

lib/config.module.ts

@@ -53,8 +53,8 @@ export class ConfigModule {
    * Also, registers custom configurations globally.
    * @param options
    */
-  static async forRoot(
-    options: ConfigModuleOptions = {},
+  static async forRoot<ValidationOptions extends Record<string, any>>(
+    options: ConfigModuleOptions<ValidationOptions> = {},
   ): Promise<DynamicModule> {
     const envFilePaths = Array.isArray(options.envFilePath)
       ? options.envFilePath
@@ -65,12 +65,13 @@ export class ConfigModule {
       ? {}
       : this.loadEnvFile(envFilePaths, options);
 
-    if (!options.ignoreEnvVars) {
+    if (!options.ignoreEnvVars || options.validatePredefined) {
       config = {
         ...config,
         ...process.env,
       };
     }
+
     if (options.validate) {
       const validatedConfig = options.validate(config);
       validatedEnvConfig = validatedConfig;
@@ -101,9 +102,14 @@ export class ConfigModule {
     const configServiceProvider = {
       provide: ConfigService,
       useFactory: (configService: ConfigService) => {
+        const untypedConfigService = configService as any;
         if (options.cache) {
-          (configService as any).isCacheEnabled = true;
+          untypedConfigService.isCacheEnabled = true;
+        }
+        if (options.skipPredefined) {
+          untypedConfigService.skipPredefined = true;
         }
+
         configService.setEnvFilePaths(envFilePaths);
         return configService;
       },

lib/config.service.ts

@@ -54,8 +54,17 @@ export class ConfigService<
     return this._isCacheEnabled;
   }
 
+  private set skipPredefined(value: boolean) {
+    this._skipPredefined = value;
+  }
+
+  private get skipPredefined(): boolean {
+    return this._skipPredefined;
+  }
+
   private readonly cache: Partial<K> = {} as any;
   private readonly _changes$ = new Subject<ConfigChangeEvent>();
+  private _skipPredefined = false;
   private _isCacheEnabled = false;
   private envFilePaths: string[] = [];
 
@@ -122,6 +131,11 @@ export class ConfigService<
     defaultValueOrOptions?: T | ConfigGetOptions,
     options?: ConfigGetOptions,
   ): T | undefined {
+    const internalValue = this.getFromInternalConfig(propertyPath);
+    if (!isUndefined(internalValue)) {
+      return internalValue;
+    }
+
     const validatedEnvValue = this.getFromValidatedEnv(propertyPath);
     if (!isUndefined(validatedEnvValue)) {
       return validatedEnvValue;
@@ -132,14 +146,14 @@ export class ConfigService<
         ? undefined
         : defaultValueOrOptions;
 
-    const processEnvValue = this.getFromProcessEnv(propertyPath, defaultValue);
-    if (!isUndefined(processEnvValue)) {
-      return processEnvValue;
-    }
-
-    const internalValue = this.getFromInternalConfig(propertyPath);
-    if (!isUndefined(internalValue)) {
-      return internalValue;
+    if (!this.skipPredefined) {
+      const processEnvValue = this.getFromProcessEnv(
+        propertyPath,
+        defaultValue,
+      );
+      if (!isUndefined(processEnvValue)) {
+        return processEnvValue;
+      }
     }
 
     return defaultValue as T;

lib/interfaces/config-module-options.interface.ts

@@ -4,7 +4,9 @@ import { ConfigFactory } from './config-factory.interface';
 /**
  * @publicApi
  */
-export interface ConfigModuleOptions {
+export interface ConfigModuleOptions<
+  ValidationOptions extends Record<string, any> = Record<string, any>,
+> {
   /**
    * If "true", values from the process.env object will be cached in the memory.
    * This improves the overall application performance.
@@ -25,6 +27,7 @@ export interface ConfigModuleOptions {
 
   /**
    * If "true", predefined environment variables will not be validated.
+   * @deprecated Use `validatePredefined` instead.
    */
   ignoreEnvVars?: boolean;
 
@@ -42,6 +45,19 @@ export interface ConfigModuleOptions {
    */
   validate?: (config: Record<string, any>) => Record<string, any>;
 
+  /**
+   * If "true", predefined environment variables will be validated.
+   * Predefined environment variables are process variables that were set before the module was imported.
+   * @default true
+   */
+  validatePredefined?: boolean;
+
+  /**
+   * If "true", predefined environment variables will be ignored and not picked up by the `ConfigService#get` method.
+   * @default false
+   */
+  skipPredefined?: boolean;
+
   /**
    * Environment variables validation schema (Joi).
    */
@@ -51,7 +67,7 @@ export interface ConfigModuleOptions {
    * Schema validation options.
    * See: https://joi.dev/api/?v=17.3.0#anyvalidatevalue-options
    */
-  validationOptions?: Record<string, any>;
+  validationOptions?: ValidationOptions;
 
   /**
    * Array of custom configuration files to be loaded.

tests/e2e/load-priority.spec.ts

@@ -80,9 +80,9 @@ describe('Environment variables and .env files', () => {
       await app.init();
     });
 
-    it('should choose .env file vars over load configuration', () => {
+    it('should choose the load configuration over .env file vars', () => {
       const configService = app.get(ConfigService);
-      expect(configService.get('PORT')).toEqual('4000');
+      expect(configService.get('PORT')).toEqual('8000');
     });
   });
 

tests/e2e/skip-predefined.spec.ts

@@ -0,0 +1,29 @@
+import { INestApplication } from '@nestjs/common';
+import { Test } from '@nestjs/testing';
+import { ConfigModule, ConfigService } from '../../lib';
+import { AppModule } from '../src/app.module';
+
+describe('Environment variables (skip predefined)', () => {
+  let app: INestApplication;
+
+  beforeEach(async () => {
+    const module = await Test.createTestingModule({
+      imports: [AppModule.withSkipPredefined()],
+    }).compile();
+
+    app = module.createNestApplication();
+    await app.init();
+  });
+
+  it(`should ignore predefined environment variables`, async () => {
+    process.env.RANDOM_PREDEFINED = 'test';
+    await ConfigModule.envVariablesLoaded;
+
+    const configService = app.get(ConfigService);
+    expect(configService.get('RANDOM_PREDEFINED')).toBeUndefined();
+  });
+
+  afterEach(async () => {
+    await app.close();
+  });
+});

tests/src/app.module.ts

@@ -68,6 +68,19 @@ export class AppModule {
     };
   }
 
+  static withSkipPredefined(): DynamicModule {
+    return {
+      module: AppModule,
+      imports: [
+        ConfigModule.forRoot({
+          envFilePath: join(__dirname, '.env'),
+          load: [() => ({ obj: { test: 'true', test2: undefined } })],
+          skipPredefined: true,
+        }),
+      ],
+    };
+  }
+
   static withEnvVars(): DynamicModule {
     return {
       module: AppModule,