[potential fixup] use centralised s3 functions

src/resourceIndex.js

@@ -2,9 +2,10 @@ import fs from 'fs';
 import * as utils from './utils/index.js';
 import zlib from 'zlib';
 import { promisify } from 'util';
-import AWS from 'aws-sdk';
 import { NotFound, BadRequest } from './httpErrors.js';
 import { RESOURCE_INDEX } from './config.js';
+import { signedUrl } from './s3.js';
+import { fetch } from './fetch.js';
 
 const gunzip = promisify(zlib.gunzip)
 
@@ -100,18 +101,14 @@ async function updateResourceVersions() {
   } else {
     const [Bucket, Key] = ['nextstrain-inventories', 'resources.json.gz'];
     utils.verbose(`Updating available resources index from s3://${Bucket}/${Key}`);
-    const S3 = new AWS.S3();
     try {
-      const newETag = (await S3.headObject({Bucket, Key}).promise()).ETag;
+      const newETag = (await fetch(await signedUrl({bucket:Bucket, key:Key, method: 'HEAD'}), {method: 'HEAD'}))
+        .headers.get('etag'); // value is enclosed in double quotes, but that doesn't matter for our purposes
       if (newETag && newETag === eTag) {
         utils.verbose("Skipping available resource update as eTag hasn't changed");
         return;
       }
-      /* NOTE: in AWS SDK v2 response.Body is a buffer; in v3 it's a stream */
-      const newResources = JSON.parse(
-        await S3.getObject({Bucket, Key}).promise()
-          .then((response) => gunzip(response.Body))
-      );
+      const newResources = JSON.parse(await gunzip(await (await fetch(await signedUrl({bucket:Bucket, key:Key, method: 'GET'}), {method: 'GET'})).buffer()));
       [resources, eTag] = [newResources, newETag];
     } catch (err) {
       utils.warn(`Resource updating failed: ${err.message}`)