fix(util-user-agent-node): should only load app id once

Author: AllanZhengYP

packages/util-user-agent-node/src/index.spec.ts

@@ -54,4 +54,14 @@ describe("defaultUserAgent", () => {
     const userAgent = await defaultUserAgent({ serviceId: "s3", clientVersion: "0.1.0" })();
     expect(userAgent).toContainEqual([`app/${appId}`]);
   });
+
+  it("should memoize app id", async () => {
+    mockAppIdLoader.mockClear();
+    const appId = "appId12345";
+    mockAppIdLoader.mockResolvedValue(appId);
+    const userAgnetProvider = defaultUserAgent({ serviceId: "s3", clientVersion: "0.1.0" });
+    await userAgnetProvider();
+    await userAgnetProvider();
+    expect(mockAppIdLoader).toBeCalledTimes(1);
+  });
 });

packages/util-user-agent-node/src/index.ts

@@ -14,10 +14,7 @@ interface DefaultUserAgentOptions {
 /**
  * Collect metrics from runtime to put into user agent.
  */
-export const defaultUserAgent = ({
-  serviceId,
-  clientVersion,
-}: DefaultUserAgentOptions): Provider<UserAgent> => async () => {
+export const defaultUserAgent = ({ serviceId, clientVersion }: DefaultUserAgentOptions): Provider<UserAgent> => {
   const sections: UserAgent = [
     // sdk-metadata
     ["aws-sdk-js", clientVersion],
@@ -40,14 +37,17 @@ export const defaultUserAgent = ({
     sections.push([`exec-env/${env.AWS_EXECUTION_ENV}`]);
   }
 
-  const appId = await loadConfig<string | undefined>({
+  const appIdPromise = loadConfig<string | undefined>({
     environmentVariableSelector: (env) => env[UA_APP_ID_ENV_NAME],
     configFileSelector: (profile) => profile[UA_APP_ID_INI_NAME],
     default: undefined,
   })();
-  if (appId) {
-    sections.push([`app/${appId}`]);
-  }
 
-  return sections;
+  return async () => {
+    const appId = await appIdPromise;
+    if (appId) {
+      sections.push([`app/${appId}`]);
+    }
+    return sections;
+  };
 };