Initial commit

Author: WtfJoke

.gitignore

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+node_modules
+build

lib/SecretCache.test.ts

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+import {
+  GetSecretValueCommand,
+  SecretsManager,
+} from "@aws-sdk/client-secrets-manager";
+import { mockClient } from "aws-sdk-client-mock";
+import { SecretCacheImpl } from "./SecretCache.js";
+
+describe("SecretCache", () => {
+  it("should return secret value object", async () => {
+    // ARRANGE
+    const secretManagerMock = mockClient(SecretsManager);
+    const secretCache = new SecretCacheImpl({
+      secretsManager: new SecretsManager({}),
+    });
+
+    secretManagerMock.on(GetSecretValueCommand).resolves({
+      SecretString: JSON.stringify({ foo: "bar" }),
+    });
+
+    // ACT
+    const secretObject = await secretCache.getSecretValue("secret1");
+
+    // ASSERT
+    expect(secretObject).toEqual({ foo: "bar" });
+    expect(secretManagerMock).toHaveReceivedCommandWith(GetSecretValueCommand, {
+      SecretId: "secret1",
+    });
+  });
+});

lib/SecretCache.ts

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+import { SecretsManager } from "@aws-sdk/client-secrets-manager";
+
+interface Dependencies {
+  secretsManager: SecretsManager;
+}
+
+export interface SecretCache {
+  getSecretValue<T>(secretName: string): Promise<T>;
+}
+
+export class SecretCacheImpl implements SecretCache {
+  private readonly secretsManager: SecretsManager;
+  private readonly cache = new Map<string, string>();
+
+  constructor(dep: Dependencies) {
+    this.secretsManager = dep.secretsManager;
+  }
+
+  getSecretValue = async <T>(secretId: string): Promise<T> => {
+    const cacheValue = this.cache.get(secretId);
+    if (cacheValue) {
+      return JSON.parse(cacheValue) as T;
+    }
+
+    const { SecretString: secretValue } =
+      await this.secretsManager.getSecretValue({
+        SecretId: secretId,
+      });
+    if (!secretValue) {
+      throw new Error(`Could not retrieve secret '${secretId}'.`);
+    }
+    this.cache.set(secretId, secretValue);
+    return JSON.parse(secretValue) as T;
+  };
+}