fix: Logging headers when retrying request (#1164)

Author: antusus

src/main/java/com/box/sdk/BackoffCounter.java

@@ -22,11 +22,20 @@ public int getAttemptsRemaining() {
         return this.attemptsRemaining;
     }
 
+    /**
+     * Waits for some random amount of time {@link BackoffCounter#calculateDelay()}
+     * @throws InterruptedException
+     */
     public void waitBackoff() throws InterruptedException {
         int delay = this.calculateDelay();
         this.waitBackoff(delay);
     }
 
+    /**
+     * Waits for specified amount of miliseconds.
+     * @param delay Time to wait for in miliseconds.
+     * @throws InterruptedException
+     */
     public void waitBackoff(int delay) throws InterruptedException {
         if (LOGGER.isWarnEnabled()) {
             LOGGER.warn(String.format(
@@ -50,12 +59,16 @@ public void reset(int maxAttempts) {
         this.attemptsRemaining = maxAttempts;
     }
 
+    /**
+     * Generates some random amount of time to backoff.
+     * Time is within <16000, 48000) ms
+     * @return Time in miliseconds.
+     */
     private int calculateDelay() {
         int exponent = this.maxAttempts - this.attemptsRemaining;
         double minWindow = 1 - RANDOM_FACTOR;
         double maxWindow = 1 + RANDOM_FACTOR;
         double jitter = (Math.random() * (maxWindow - minWindow)) + minWindow;
-
         return (int) (Math.pow(2, exponent) * BASE_TIMEOUT * jitter);
     }
 }

src/main/java/com/box/sdk/BoxAPIRequest.java

@@ -1,5 +1,6 @@
 package com.box.sdk;
 
+import static com.box.sdk.internal.utils.CollectionUtils.mapToString;
 import static java.lang.String.format;
 
 import com.box.sdk.http.ContentType;
@@ -389,9 +390,10 @@ public BoxAPIResponse send(ProgressListener listener) {
                 }
 
                 LOGGER.warn(
-                    format("Retrying request due to transient error status=%d body=%s",
+                    format("Retrying request due to transient error status=%d body=%s headers=%s",
                         apiException.getResponseCode(),
-                        apiException.getResponse())
+                        apiException.getResponse(),
+                        mapToString(apiException.getHeaders()))
                 );
 
                 try {

src/main/java/com/box/sdk/internal/utils/CollectionUtils.java

@@ -4,6 +4,8 @@
 import java.util.Collection;
 import java.util.LinkedList;
 import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
 
 /**
  * {@link Collection} related utlities.
@@ -49,6 +51,12 @@ public static <T> List<T> createListFrom(Iterable<T> iterable) {
         return result;
     }
 
+    public static String mapToString(Map<?, ?> map) {
+        return map.keySet().stream()
+            .map(k -> k + "=" + map.get(k))
+            .collect(Collectors.joining(",\n", "{\n", "\n}"));
+    }
+
     /**
      * Contract for {@link Collection}-s mapping.
      *

src/test/java/com/box/sdk/BoxAPIRequestTest.java

@@ -18,6 +18,7 @@
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.fail;
+import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.mock;
 
 import com.eclipsesource.json.ParseException;
@@ -30,6 +31,7 @@
 import java.util.zip.GZIPOutputStream;
 import org.junit.Rule;
 import org.junit.Test;
+import org.mockito.Mockito;
 
 public class BoxAPIRequestTest {
     @Rule
@@ -110,6 +112,30 @@ public void requestRetriesTheNumberOfTimesConfiguredInTheAPIConnection() {
         }
     }
 
+    @Test
+    public void requestRetriesUsingSecondsProvidedInRetryHeader() throws InterruptedException {
+        final int expectedNumRetryAttempts = 1;
+        stubFor(get(urlEqualTo("/")).willReturn(aResponse()
+            .withStatus(429)
+            .withBody("{}")
+            .withHeader("Retry-After", "20")
+        ));
+        Time mockTime = mock(Time.class);
+        BackoffCounter backoffCounter = new BackoffCounter(mockTime);
+
+        BoxAPIConnection api = createConnectionWith(boxMockUrl().toString());
+        api.setMaxRetryAttempts(expectedNumRetryAttempts);
+
+        BoxAPIRequest request = new BoxAPIRequest(api, boxMockUrl(), "GET");
+        request.setBackoffCounter(backoffCounter);
+
+        try {
+            request.send();
+        } catch (BoxAPIException e) {
+            Mockito.verify(mockTime).waitDuration(eq(20000));
+        }
+    }
+
     @Test
     public void requestSendsXBoxUAHeader() {