fix: don't reload already cached secrets (#2)

Author: rahlenjakob

lib/secretmanager.service.spec.ts

@@ -7,13 +7,14 @@ import { SecretManagerService } from './secretmanager.service'
 jest.mock('./secretloader.service')
 describe('SecretManagerService', () => {
   let secretManagerService: SecretManagerService
+  let secretLoaderService: SecretLoaderService
   const preloadedSecrets = {
     'project/test-project/secrets/some-secret/versions/latest': 'some-secret',
   }
   beforeEach(async () => {
     jest.resetAllMocks()
     // eslint-disable-next-line @typescript-eslint/no-explicit-any
-    const secretLoaderService = new SecretLoaderService(null as any)
+    secretLoaderService = new SecretLoaderService(null as any)
     ;(secretLoaderService.loadSecret as jest.Mock).mockImplementationOnce(() => 'some-secret')
 
     const moduleRef = await Test.createTestingModule({
@@ -60,4 +61,16 @@ describe('SecretManagerService', () => {
     await secretManagerService.loadSecretDynamic(secret)
     expect(secretManagerService.getSecret(secret)).toEqual('some-secret')
   })
+
+  it('does not do external lookups for cached secrets', async () => {
+    const secret = 'project/test-project/secrets/no-secret/versions/latest'
+    expect(() => {
+      secretManagerService.getSecret(secret)
+    }).toThrow(SecretNotLoadedException)
+
+    await secretManagerService.loadSecretDynamic(secret)
+    await secretManagerService.loadSecretDynamic(secret)
+    expect(secretLoaderService.loadSecret).toHaveBeenCalledTimes(1)
+    expect(secretManagerService.getSecret(secret)).toEqual('some-secret')
+  })
 })

lib/secretmanager.service.ts

@@ -24,6 +24,9 @@ export class SecretManagerService {
   }
 
   public async loadSecretDynamic(secret: string) {
+    if (this.secrets[secret]) {
+      return this.secrets[secret]
+    }
     const value = await this.secretLoaderService.loadSecret(secret)
     this.secrets = {
       ...this.secrets,