support AWS Polly RoleArn credential

lib/synth-audio.js

@@ -3,6 +3,7 @@ const fs = require('fs');
 const bent = require('bent');
 const ttsGoogle = require('@google-cloud/text-to-speech');
 const { PollyClient, SynthesizeSpeechCommand } = require('@aws-sdk/client-polly');
+const { STSClient, AssumeRoleCommand } = require('@aws-sdk/client-sts');
 
 const sdk = require('microsoft-cognitiveservices-speech-sdk');
 const TextToSpeechV1 = require('ibm-watson/text-to-speech/v1');
@@ -265,14 +266,30 @@ async function synthAudio(client, logger, stats, { account_sid,
 
 const synthPolly = async(logger, {credentials, stats, language, voice, engine, text}) => {
   try {
-    const {region, accessKeyId, secretAccessKey} = credentials;
-    const polly = new PollyClient({
-      region,
-      credentials: {
-        accessKeyId,
-        secretAccessKey
-      }
-    });
+    const {region, accessKeyId, secretAccessKey, roleArn} = credentials;
+    let polly;
+    if (accessKeyId && secretAccessKey) {
+      polly = new PollyClient({
+        region,
+        credentials: {
+          accessKeyId,
+          secretAccessKey
+        }
+      });
+    } else if (roleArn) {
+      const stsClient = new STSClient({ region});
+      const roleToAssume = { RoleArn: 'myRoleArn', RoleSessionName: 'session1' };
+      const command = new AssumeRoleCommand(roleToAssume);
+
+      const response = await stsClient.send(command);
+      const assumedRoleCreds = response.Credentials;
+      polly = new PollyClient({
+        region,
+        credentials: assumedRoleCreds,
+      });
+    } else {
+      throw new Error('Missing Polly credential');
+    }
     const opts = {
       Engine: engine,
       OutputFormat: 'mp3',

test/synth.js

@@ -162,6 +162,33 @@ test('AWS speech synth tests', async(t) => {
   client.quit();
 });
 
+test('AWS speech synth tests by RoleArn', async(t) => {
+  const fn = require('..');
+  const {synthAudio, client} = fn(opts, logger);
+
+  if (!process.env.AWS_ROLE_ARN || !process.env.AWS_REGION) {
+    t.pass('skipping AWS speech synth tests by RoleArn since AWS_ROLE_ARN or AWS_REGION not provided');
+    return t.end();
+  }
+  try {
+    let opts = await synthAudio(stats, {
+      vendor: 'aws',
+      credentials: {
+        roleArn: process.env.AWS_ROLE_ARN,
+        region: process.env.AWS_REGION,
+      },
+      language: 'en-US',
+      voice: 'Joey',
+      text: 'This is a test.  This is only a test',
+    });
+    t.ok(!opts.servedFromCache, `successfully synthesized aws by roleArn audio to ${opts.filePath}`);
+  } catch (err) {
+    console.error(err);
+    t.end(err);
+  }
+  client.quit();
+});
+
 test('Azure speech synth tests', async(t) => {
   const fn = require('..');
   const {synthAudio, client} = fn(opts, logger);