JENKINS-72643: Fixed listing regions when using ec2 instance profile …

…credentials

In the case where a user specified an ARN Role in the advanced section of cloud config we need to use that information when pulling the list of regions.

In my case without this ARN Role being used with credentials I would get an empty drop-down list with no errors.

I added a log message with the exception to expose a bit of information in case of failures.

src/main/java/hudson/plugins/ec2/AmazonEC2Cloud.java

@@ -185,14 +185,20 @@ public FormValidation doCheckAltEC2Endpoint(@QueryParameter String value) {
         public ListBoxModel doFillRegionItems(
                 @QueryParameter String altEC2Endpoint,
                 @QueryParameter boolean useInstanceProfileForCredentials,
+                @QueryParameter String roleArn,
+                @QueryParameter String roleSessionName,
+                @QueryParameter String region,
                 @QueryParameter String credentialsId)
 
                 throws IOException, ServletException {
             ListBoxModel model = new ListBoxModel();
             if (Jenkins.get().hasPermission(Jenkins.ADMINISTER)) {
                 try {
                     AWSCredentialsProvider credentialsProvider = createCredentialsProvider(useInstanceProfileForCredentials,
-                            credentialsId);
+                            credentialsId,
+                            roleArn,
+                            roleSessionName,
+                            region);
                     AmazonEC2 client = AmazonEC2Factory.getInstance().connect(credentialsProvider, determineEC2EndpointURL(altEC2Endpoint));
                     DescribeRegionsResult regions = client.describeRegions();
                     List<Region> regionList = regions.getRegions();
@@ -201,6 +207,7 @@ public ListBoxModel doFillRegionItems(
                         model.add(name, name);
                     }
                 } catch (SdkClientException ex) {
+                    LOGGER.log(Level.INFO, "AmazonEC2Cloud.doFillRegionItems() got exception: " + ex);
                     // Ignore, as this may happen before the credentials are specified
                 }
             }