[FEATURE] Allow overriding the aws service identifier in AwsSigv4Signer

CHANGELOG.md

@@ -4,6 +4,7 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 ## [Unreleased]
 ### Added
 - Add release details to releasing.md ([319](https://github.com/opensearch-project/opensearch-js/pull/319))
+- Allow overriding the aws service identifier in AwsSigv4Signer ([333](https://github.com/opensearch-project/opensearch-js/pull/333))
 ### Dependencies
 ### Changed
 ### Deprecated

lib/aws/AwsSigv4Signer.js

@@ -58,19 +58,22 @@ const awsDefaultCredentialsProvider = () =>
       });
   });
 
-function AwsSigv4Signer(opts) {
+function AwsSigv4Signer(opts = {}) {
   const credentialsState = {
     credentials: null,
   };
-  if (opts && (!opts.region || opts.region === null || opts.region === '')) {
+  if (!opts.region) {
     throw new AwsSigv4SignerError('Region cannot be empty');
   }
-  if (opts && typeof opts.getCredentials !== 'function') {
+  if (!opts.service) {
+    opts.service = 'es';
+  }
+  if (typeof opts.getCredentials !== 'function') {
     opts.getCredentials = awsDefaultCredentialsProvider;
   }
 
   function buildSignedRequestObject(request = {}) {
-    request.service = 'es';
+    request.service = opts.service;
     request.region = opts.region;
     request.headers = request.headers || {};
     request.headers['host'] = request.hostname;

test/unit/lib/aws/awssigv4signer.test.js

@@ -16,7 +16,7 @@ const { Connection } = require('../../../../index');
 const { Client, buildServer } = require('../../../utils');
 
 test('Sign with SigV4', (t) => {
-  t.plan(2);
+  t.plan(3);
 
   const mockCreds = {
     accessKeyId: uuidv4(),
@@ -50,30 +50,70 @@ test('Sign with SigV4', (t) => {
   const signedRequest = auth.buildSignedRequestObject(request);
   t.hasProp(signedRequest.headers, 'X-Amz-Date');
   t.hasProp(signedRequest.headers, 'Authorization');
+  t.same(signedRequest.service, 'es');
 });
 
 test('Sign with SigV4 failure (with empty region)', (t) => {
-  t.plan(2);
+  const mockCreds = {
+    accessKeyId: uuidv4(),
+    secretAccessKey: uuidv4(),
+  };
+
+  const mockRegions = [{ region: undefined }, { region: null }, { region: '' }, {}];
+
+  const AwsSigv4SignerOptions = {
+    getCredentials: () =>
+      new Promise((resolve) => {
+        setTimeout(() => resolve(mockCreds), 100);
+      }),
+  };
+
+  mockRegions.forEach((region) => {
+    try {
+      AwsSigv4Signer(Object.assign({}, AwsSigv4SignerOptions, region));
+      t.fail('Should fail');
+    } catch (err) {
+      t.ok(err instanceof AwsSigv4SignerError);
+      t.same(err.message, 'Region cannot be empty');
+    }
+  });
+
+  t.end();
+});
+
+test('Sign with SigV4 and provided service', (t) => {
+  t.plan(1);
 
   const mockCreds = {
     accessKeyId: uuidv4(),
     secretAccessKey: uuidv4(),
   };
 
+  const mockRegion = 'us-west-2';
+  const mockService = 'foo';
+
   const AwsSigv4SignerOptions = {
     getCredentials: () =>
       new Promise((resolve) => {
         setTimeout(() => resolve(mockCreds), 100);
       }),
+    region: mockRegion,
+    service: mockService,
   };
 
-  try {
-    AwsSigv4Signer(AwsSigv4SignerOptions);
-    t.fail('Should fail');
-  } catch (err) {
-    t.ok(err instanceof AwsSigv4SignerError);
-    t.same(err.message, 'Region cannot be empty');
-  }
+  const auth = AwsSigv4Signer(AwsSigv4SignerOptions);
+
+  const connection = new Connection({
+    url: new URL('https://localhost:9200'),
+  });
+
+  const request = connection.buildRequestObject({
+    path: '/hello',
+    method: 'GET',
+  });
+
+  const signedRequest = auth.buildSignedRequestObject(request);
+  t.same(signedRequest.service, mockService);
 });
 
 test('Sign with SigV4 using default getCredentials provider', (t) => {