HCK-10565: validate connection (#29)

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<table>
<td>
<a href="https://hackolade.atlassian.net/browse/HCK-10565"
title="HCK-10565" target="_blank"><img alt="Sub-task"
src="https://hackolade.atlassian.net/rest/api/2/universal_avatar/view/type/issuetype/avatar/10316?size=medium"
/>HCK-10565</a> Add disclaimer if instance metadata won't be fetched
  </td></table>
  <br />
 

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## Technical details

* implemented `validateConnection` method, to check whether the cluster
instance meta can be fetched

## Related PR's:

* hackolade/studio#3033

Author: chulanovskyi-bs

package.json

@@ -52,8 +52,7 @@
             "enableREQueryAndSortCriteria": true,
             "relationships": {
                 "entityNameSeparator": "."
-            },
-            "checkAwsCredentials": true
+            }
         }
     },
     "description": "Hackolade plugin for Amazon DocumentDB",

reverse_engineering/api.js

@@ -39,21 +39,60 @@ module.exports = {
 		}
 	},
 
-	async getDbCollectionsNames(connectionInfo, logger, cb, app) {
-		const sshService = app.require('@hackolade/ssh-service');
-
+	async validateConnection(connectionInfo, logger, cb) {
 		const log = createLogger({
-			title: 'Retrieving databases and collections information',
+			title: 'Validate connection',
 			hiddenKeys: connectionInfo.hiddenKeys,
 			logger,
 		});
 
 		try {
 			logger.clear();
-
 			log.info(getSystemInfo(connectionInfo.appVersion));
 			log.info(connectionInfo, 'connectionInfo');
 
+			const docDbClientInstance = await getDocDbClientInstance({
+				connectionInfo: {
+					...connectionInfo,
+					...parseHost(connectionInfo.host, log),
+				},
+				logger: log,
+			});
+
+			log.info('Getting cluster information');
+
+			try {
+				const cluster = await docDbClientInstance.getCluster();
+				if (!cluster) {
+					return cb(null, "Cluster doesn't exist in the chosen region.");
+				}
+			} catch (err) {
+				return cb(null, err);
+			}
+
+			log.info('Cluster information retrieved successfully');
+
+			cb();
+		} catch (error) {
+			log.error(error);
+
+			return cb({
+				message: error.message,
+				stack: error.stack,
+			});
+		}
+	},
+
+	async getDbCollectionsNames(connectionInfo, logger, cb, app) {
+		const sshService = app.require('@hackolade/ssh-service');
+
+		const log = createLogger({
+			title: 'Retrieving databases and collections information',
+			hiddenKeys: connectionInfo.hiddenKeys,
+			logger,
+		});
+
+		try {
 			await getDocDbClientInstance({
 				connectionInfo: {
 					...connectionInfo,