Adding suggested delay

Author: LikeTheSalad

opamp-client/src/main/java/io/opentelemetry/opamp/client/internal/request/service/HttpRequestService.java

@@ -2,6 +2,7 @@
 
 import io.opentelemetry.opamp.client.internal.connectivity.http.HttpErrorException;
 import io.opentelemetry.opamp.client.internal.connectivity.http.HttpSender;
+import io.opentelemetry.opamp.client.internal.connectivity.http.RetryAfterParser;
 import io.opentelemetry.opamp.client.internal.request.Request;
 import io.opentelemetry.opamp.client.internal.request.delay.AcceptsDelaySuggestion;
 import io.opentelemetry.opamp.client.internal.request.delay.PeriodicDelay;
@@ -28,6 +29,7 @@ public final class HttpRequestService implements RequestService, Runnable {
   private final PeriodicDelay periodicRetryDelay;
   private final AtomicBoolean retryModeEnabled = new AtomicBoolean(false);
   private final AtomicBoolean isRunning = new AtomicBoolean(false);
+  private final RetryAfterParser retryAfterParser;
   @Nullable private Callback callback;
   @Nullable private Supplier<Request> requestSupplier;
   public static final PeriodicDelay DEFAULT_DELAY_BETWEEN_REQUESTS =
@@ -57,18 +59,21 @@ public static HttpRequestService create(
         requestSender,
         PeriodicTaskExecutor.create(periodicRequestDelay),
         periodicRequestDelay,
-        periodicRetryDelay);
+        periodicRetryDelay,
+        RetryAfterParser.getInstance());
   }
 
   HttpRequestService(
       HttpSender requestSender,
       PeriodicTaskExecutor executor,
       PeriodicDelay periodicRequestDelay,
-      PeriodicDelay periodicRetryDelay) {
+      PeriodicDelay periodicRetryDelay,
+      RetryAfterParser retryAfterParser) {
     this.requestSender = requestSender;
     this.executor = executor;
     this.periodicRequestDelay = periodicRequestDelay;
     this.periodicRetryDelay = periodicRetryDelay;
+    this.retryAfterParser = retryAfterParser;
   }
 
   @Override
@@ -154,7 +159,7 @@ private void handleHttpError(HttpSender.Response response) {
       String retryAfterHeader = response.getHeader("Retry-After");
       Duration retryAfter = null;
       if (retryAfterHeader != null) {
-        retryAfter = Duration.ofSeconds(Long.parseLong(retryAfterHeader));
+        retryAfter = retryAfterParser.parse(retryAfterHeader);
       }
       enableRetryMode(retryAfter);
     }

opamp-client/src/test/java/io/opentelemetry/opamp/client/internal/request/service/HttpRequestServiceTest.java

@@ -16,6 +16,7 @@
 
 import io.opentelemetry.opamp.client.internal.connectivity.http.HttpErrorException;
 import io.opentelemetry.opamp.client.internal.connectivity.http.HttpSender;
+import io.opentelemetry.opamp.client.internal.connectivity.http.RetryAfterParser;
 import io.opentelemetry.opamp.client.internal.request.Request;
 import io.opentelemetry.opamp.client.internal.request.delay.AcceptsDelaySuggestion;
 import io.opentelemetry.opamp.client.internal.request.delay.PeriodicDelay;
@@ -53,7 +54,12 @@ class HttpRequestServiceTest {
   @BeforeEach
   void setUp() {
     httpRequestService =
-        new HttpRequestService(requestSender, executor, periodicRequestDelay, periodicRetryDelay);
+        new HttpRequestService(
+            requestSender,
+            executor,
+            periodicRequestDelay,
+            periodicRetryDelay,
+            RetryAfterParser.getInstance());
   }
 
   @Test
@@ -186,6 +192,23 @@ void verifySendingRequest_whenThereIsATooManyRequestsError() {
 
     verify(callback).onRequestFailed(new HttpErrorException(429, "Error message"));
     verify(executor).setPeriodicDelay(periodicRetryDelay);
+    verify(periodicRetryDelay, never()).suggestDelay(any());
+  }
+
+  @Test
+  void verifySendingRequest_whenThereIsATooManyRequestsError_withSuggestedDelay() {
+    HttpSender.Response response = mock();
+    when(response.statusCode()).thenReturn(429);
+    when(response.statusMessage()).thenReturn("Error message");
+    when(response.getHeader("Retry-After")).thenReturn("5");
+    prepareRequest();
+    enqueueResponse(response);
+
+    httpRequestService.run();
+
+    verify(callback).onRequestFailed(new HttpErrorException(429, "Error message"));
+    verify(executor).setPeriodicDelay(periodicRetryDelay);
+    verify(periodicRetryDelay).suggestDelay(Duration.ofSeconds(5));
   }
 
   @Test
@@ -241,6 +264,23 @@ void verifySendingRequest_whenThereIsAServiceUnavailableError() {
 
     verify(callback).onRequestFailed(new HttpErrorException(503, "Error message"));
     verify(executor).setPeriodicDelay(periodicRetryDelay);
+    verify(periodicRetryDelay, never()).suggestDelay(any());
+  }
+
+  @Test
+  void verifySendingRequest_whenThereIsAServiceUnavailableError_withSuggestedDelay() {
+    HttpSender.Response response = mock();
+    when(response.getHeader("Retry-After")).thenReturn("2");
+    when(response.statusCode()).thenReturn(503);
+    when(response.statusMessage()).thenReturn("Error message");
+    prepareRequest();
+    enqueueResponse(response);
+
+    httpRequestService.run();
+
+    verify(callback).onRequestFailed(new HttpErrorException(503, "Error message"));
+    verify(executor).setPeriodicDelay(periodicRetryDelay);
+    verify(periodicRetryDelay).suggestDelay(Duration.ofSeconds(2));
   }
 
   @Test