Changed behaviour to not throw an exception immediately if a key is m…

…issing. Update cache before and try again before fail

sts-token-auth/pom.xml

@@ -48,5 +48,10 @@
             <artifactId>mockito-core</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.springframework.retry</groupId>
+            <artifactId>spring-retry</artifactId>
+            <version>2.0.5</version>
+        </dependency>
     </dependencies>
 </project>

sts-token-auth/src/main/java/de/adorsys/sts/tokenauth/AuthServer.java

@@ -9,6 +9,8 @@
 import lombok.Setter;
 import lombok.SneakyThrows;
 import lombok.extern.slf4j.Slf4j;
+import org.springframework.retry.annotation.Backoff;
+import org.springframework.retry.annotation.Retryable;
 
 import java.net.URL;
 import java.security.Key;
@@ -68,6 +70,8 @@ private void updateJwkCache() throws JsonWebKeyRetrievalException {
         log.debug("Thread leaving updateJwkCache: " + Thread.currentThread().getId());
     }
 
+    @Retryable(maxAttempts = 2, backoff = @Backoff(delay = 1000, multiplier = 2), retryFor =
+            {JsonWebKeyNotFoundException.class}, noRetryFor = {JsonWebKeyRetrievalException.class})
     public Key getJWK(String keyID) throws JsonWebKeyRetrievalException {
         log.debug("Thread entering getJWK: {}", Thread.currentThread().getId());
 
@@ -84,7 +88,9 @@ public Key getJWK(String keyID) throws JsonWebKeyRetrievalException {
         JWK jwk = jwkCache.get(keyID);
         if (jwk == null) {
             log.error("Key with ID {} not found in cache", keyID);
-            throw new JsonWebKeyRetrievalException("Key with ID " + keyID + " not found in cache");
+            //Update cache and try again
+            updateJwkCache();
+            throw new JsonWebKeyNotFoundException("Key with ID " + keyID + " not found in cache");
         }
 
         log.debug("JWK for key ID {} found in cache", keyID);
@@ -119,4 +125,10 @@ public JsonWebKeyRetrievalException(String message) {
             super(message);
         }
     }
+
+    protected static class JsonWebKeyNotFoundException extends RuntimeException {
+        public JsonWebKeyNotFoundException(String message) {
+            super(message);
+        }
+    }
 }