Add 429 to list of retryable HTTP status codes

Author: johngmyers

CHANGES

@@ -13,6 +13,10 @@ Platform 3.28
 
   - Remote errors, when detected, are now notified to async applications.
 
+* HTTP Client
+
+  We added 429 to the list of HTTP status codes that allow retrying requests.
+
 Platform 3.27
 
 * Java version support

http-client/src/main/java/com/proofpoint/http/client/balancing/RetryingResponseHandler.java

@@ -30,7 +30,7 @@
 final class RetryingResponseHandler<T, E extends Exception>
         implements ResponseHandler<T, RetryException>
 {
-    private static final Set<Integer> RETRYABLE_STATUS_CODES = Set.of(408, 499, 500, 502, 503, 504, 598, 599);
+    private static final Set<Integer> RETRYABLE_STATUS_CODES = Set.of(408, 429, 499, 500, 502, 503, 504, 598, 599);
     private static final Logger log = Logger.get(RetryingResponseHandler.class);
     private final ResponseHandler<T, E> innerHandler;
     private final RetryBudget retryBudget;

http-client/src/test/java/com/proofpoint/http/client/balancing/AbstractTestBalancingHttpClient.java

@@ -292,6 +292,7 @@ public Object[][] getRetryStatus()
     {
         return new Object[][] {
                 new Object[] {408},
+                new Object[] {429},
                 new Object[] {499},
                 new Object[] {500},
                 new Object[] {502},