Comments

Author: DaveCTurner

plugins/discovery-ec2/src/javaRestTest/java/org/elasticsearch/discovery/ec2/DiscoveryEc2InstanceProfileIT.java

@@ -28,6 +28,7 @@
 
 public class DiscoveryEc2InstanceProfileIT extends DiscoveryEc2ClusterFormationTestCase {
 
+    // Lazy-initialized so we can generate it randomly, which is not possible in static context.
     private static final Supplier<String> regionSupplier = new LazyInitializable<>(ESTestCase::randomIdentifier)::getOrCompute;
 
     private static final DynamicAwsCredentials dynamicCredentials = new DynamicAwsCredentials(regionSupplier, "ec2");

test/fixtures/aws-fixture-utils/src/main/java/fixture/aws/DynamicAwsCredentials.java

@@ -23,8 +23,21 @@
  */
 public class DynamicAwsCredentials {
 
+    /**
+     * Extra validation that requests are signed using the correct region. Lazy so it can be randomly generated after initialization, since
+     * randomness is not available in static context.
+     */
     private final Supplier<String> expectedRegionSupplier;
+
+    /**
+     * Extra validation that requests are directed to the correct service.
+     */
     private final String expectedServiceName;
+
+    /**
+     * The set of access keys for each session token registered with {@link #addValidCredentials}. It's this way round because the session
+     * token is a separate header so it's easier to extract.
+     */
     private final Map<String, Set<String>> validCredentialsMap = ConcurrentCollections.newConcurrentMap();
 
     /**