update get aws voices

lib/get-tts-voices.js

@@ -6,6 +6,7 @@ const TextToSpeechV1 = require('ibm-watson/text-to-speech/v1');
 const { IamAuthenticator } = require('ibm-watson/auth');
 const ttsGoogle = require('@google-cloud/text-to-speech');
 const { PollyClient, DescribeVoicesCommand } = require('@aws-sdk/client-polly');
+const { STSClient, AssumeRoleCommand } = require('@aws-sdk/client-sts');
 
 const getIbmVoices = async(client, logger, credentials) => {
   const {tts_region, tts_api_key} = credentials;
@@ -89,14 +90,30 @@ const getGoogleVoices = async(_client, logger, credentials) => {
 
 const getAwsVoices = async(_client, logger, credentials) => {
   try {
-    const {region, accessKeyId, secretAccessKey} = credentials;
-    const client = new PollyClient({
-      region,
-      credentials: {
-        accessKeyId,
-        secretAccessKey
-      }
-    });
+    const {region, accessKeyId, secretAccessKey, roleArn} = credentials;
+    let client = null;
+    if (accessKeyId && secretAccessKey) {
+      client = new PollyClient({
+        region,
+        credentials: {
+          accessKeyId,
+          secretAccessKey
+        }
+      });
+    } else if (roleArn) {
+      const stsClient = new STSClient({ region});
+      const roleToAssume = { RoleArn: roleArn, RoleSessionName: 'Jambonz Speech' };
+      const command = new AssumeRoleCommand(roleToAssume);
+
+      const response = await stsClient.send(command);
+      const assumedRoleCreds = response.Credentials;
+      client = new PollyClient({
+        region,
+        credentials: assumedRoleCreds,
+      });
+    } else {
+      throw new Error('Missing Polly credential');
+    }
     const command = new DescribeVoicesCommand({});
     const response = await client.send(command);
     return response;