From e47f7e4327af63793c97db88553ab21574aea303 Mon Sep 17 00:00:00 2001
From: Vincent <vincent@rawpixel.com>
Date: Sat, 1 Oct 2022 04:44:15 +0700
Subject: [PATCH] Feature/add default credentials provider (#295)

* add default credentials provider to AwsSigv4Signer

Signed-off-by: rawpixel-vincent <vincent@rawpixel.com>

* update default credentials function name

Signed-off-by: rawpixel-vincent <vincent@rawpixel.com>

Signed-off-by: rawpixel-vincent <vincent@rawpixel.com>
---
 lib/aws/AwsSigv4Signer.js                | 46 +++++++++++++++++++++++-
 lib/aws/index.d.ts                       |  2 +-
 test/unit/lib/aws/awssigv4signer.test.js | 44 +++++++++++++++++------
 3 files changed, 80 insertions(+), 12 deletions(-)

diff --git a/lib/aws/AwsSigv4Signer.js b/lib/aws/AwsSigv4Signer.js
index 6ab50f545..d3253e139 100644
--- a/lib/aws/AwsSigv4Signer.js
+++ b/lib/aws/AwsSigv4Signer.js
@@ -14,6 +14,50 @@ const Transport = require('../Transport');
 const aws4 = require('aws4');
 const AwsSigv4SignerError = require('./errors');
 
+const getAwsSDKCredentialsProvider = async () => {
+  // First try V3
+  try {
+    const awsV3 = await import('@aws-sdk/credential-provider-node');
+    if (typeof awsV3.defaultProvider === 'function') {
+      return awsV3.defaultProvider();
+    }
+  } catch (err) {
+    // Ignore
+  }
+  try {
+    const awsV2 = await import('aws-sdk');
+    if (awsV2.default && typeof awsV2.default.config.getCredentials === 'function') {
+      return () =>
+        new Promise((resolve, reject) => {
+          awsV2.default.config.getCredentials((err, credentials) => {
+            if (err) {
+              reject(err);
+            } else {
+              resolve(credentials);
+            }
+          });
+        });
+    }
+  } catch (err) {
+    // Ignore
+  }
+
+  throw new AwsSigv4SignerError(
+    'Unable to find a valid AWS SDK, please provide a valid getCredentials function to AwsSigv4Signer options.'
+  );
+};
+
+const awsDefaultCredentialsProvider = () =>
+  new Promise((resolve, reject) => {
+    getAwsSDKCredentialsProvider()
+      .then((provider) => {
+        provider().then(resolve).catch(reject);
+      })
+      .catch((err) => {
+        reject(err);
+      });
+  });
+
 function AwsSigv4Signer(opts) {
   const credentialsState = {
     credentials: null,
@@ -22,7 +66,7 @@ function AwsSigv4Signer(opts) {
     throw new AwsSigv4SignerError('Region cannot be empty');
   }
   if (opts && typeof opts.getCredentials !== 'function') {
-    throw new AwsSigv4SignerError('getCredentials function is required');
+    opts.getCredentials = awsDefaultCredentialsProvider;
   }
 
   function buildSignedRequestObject(request = {}) {
diff --git a/lib/aws/index.d.ts b/lib/aws/index.d.ts
index 0f9f79592..a36b701c8 100644
--- a/lib/aws/index.d.ts
+++ b/lib/aws/index.d.ts
@@ -17,7 +17,7 @@ import * as http from 'http';
 import { OpenSearchClientError } from '../errors';
 
 interface AwsSigv4SignerOptions {
-  getCredentials: () => Promise<Credentials>;
+  getCredentials?: () => Promise<Credentials>;
   region: string;
 }
 
diff --git a/test/unit/lib/aws/awssigv4signer.test.js b/test/unit/lib/aws/awssigv4signer.test.js
index c0f5a3465..f1dfc084f 100644
--- a/test/unit/lib/aws/awssigv4signer.test.js
+++ b/test/unit/lib/aws/awssigv4signer.test.js
@@ -76,20 +76,44 @@ test('Sign with SigV4 failure (with empty region)', (t) => {
   }
 });
 
-test('Sign with SigV4 failure (without getCredentials function)', (t) => {
+test('Sign with SigV4 using default getCredentials provider', (t) => {
   t.plan(2);
 
-  const mockRegion = 'us-west-2';
+  function handler(req, res) {
+    res.setHeader('Content-Type', 'application/json;utf=8');
+    res.end(JSON.stringify({ hello: 'world' }));
+  }
 
-  const AwsSigv4SignerOptions = { region: mockRegion };
+  buildServer(handler, ({ port }, server) => {
+    const mockRegion = 'us-east-1';
 
-  try {
-    AwsSigv4Signer(AwsSigv4SignerOptions);
-    t.fail('Should fail');
-  } catch (err) {
-    t.ok(err instanceof AwsSigv4SignerError);
-    t.same(err.message, 'getCredentials function is required');
-  }
+    const AwsSigv4SignerOptions = {
+      region: mockRegion,
+    };
+    const client = new Client({
+      ...AwsSigv4Signer(AwsSigv4SignerOptions),
+      node: `http://localhost:${port}`,
+    });
+
+    client
+      .search({
+        index: 'test',
+        q: 'foo:bar',
+      })
+      .then(() => {
+        t.fail('Should fail');
+      })
+      .catch((err) => {
+        t.ok(err instanceof AwsSigv4SignerError);
+        t.same(
+          err.message,
+          'Unable to find a valid AWS SDK, please provide a valid getCredentials function to AwsSigv4Signer options.'
+        );
+      })
+      .finally(() => {
+        server.stop();
+      });
+  });
 });
 
 test('Basic aws (promises)', (t) => {