Adding an example script that polls a real account with STS credentials.

__tests__/poller.test.ts

@@ -25,7 +25,6 @@ describe('Poller', () => {
   let poller: Poller<string> | undefined;
 
   afterAll(() => {
-    console.log('Stopping poller');
     poller.stop();
   });
 

examples/infinitePoller.ts

@@ -0,0 +1,75 @@
+import { Poller } from '../src/poller.js';
+import { AppConfigDataClient } from '@aws-sdk/client-appconfigdata';
+import { parse } from 'yaml';
+import { fromTemporaryCredentials } from '@aws-sdk/credential-providers';
+import { STSClient, GetCallerIdentityCommand } from '@aws-sdk/client-sts';
+import { AwsCredentialIdentity, Provider } from '@smithy/types';
+
+/**
+ * This is a made-up format, corresponding to an AppConfig profile
+ * that I created in my personal AWS account for testing.
+ */
+interface SampleFormat {
+  Content: {
+    description: string;
+    advantages: string[];
+  };
+}
+
+/**
+ * This helps me avoid mentioning my AWS account id in a public repo.
+ * https://stackoverflow.com/a/74546015
+ *
+ * Normally there's no need for this.
+ */
+const getAWSAccountId = async (): Promise<string> => {
+  const response = await new STSClient().send(new GetCallerIdentityCommand({}));
+  return String(response.Account);
+};
+
+/**
+ * I'm using a temporary credentials provider (based on STS assumeRole)
+ * to give confidence that the credentials will refresh themselves after
+ * the duration expires.
+ */
+const getCredentialsProvider = (
+  awsAccountId: string,
+): Provider<AwsCredentialIdentity> => {
+  return fromTemporaryCredentials({
+    params: {
+      // This is a role I created in my personal AWS account for testing.
+      RoleArn: `arn:aws:iam::${awsAccountId}:role/AppConfigReader`,
+      DurationSeconds: 900,
+    },
+  });
+};
+
+const dataClient = new AppConfigDataClient({
+  credentials: getCredentialsProvider(await getAWSAccountId()),
+});
+
+const poller = new Poller<SampleFormat>({
+  dataClient: dataClient,
+  sessionConfig: {
+    // These refer to an AppConfig profile I created in my personal
+    // AWS account for testing.
+    ApplicationIdentifier: 'PollerTest',
+    EnvironmentIdentifier: 'Live',
+    ConfigurationProfileIdentifier: 'YamlTest',
+  },
+  configTransformer: (s): SampleFormat => parse(s),
+  logger: console.log,
+  pollIntervalSeconds: 60,
+});
+
+await poller.start();
+
+console.log('Starting at:', new Date());
+
+setInterval(() => {
+  const obj = poller.getConfigurationObject();
+  console.log('Current config entry', obj);
+}, 1000 * 60);
+
+// This will run forever until you manually terminate it.
+// Normally you would call poller.stop() if you want the program to exit.