Add ellipsis when truncating payload

Author: dagnir

core/auth/src/main/java/software/amazon/awssdk/auth/signer/internal/BaseEventStreamAsyncAws4Signer.java

@@ -52,6 +52,8 @@ public abstract class BaseEventStreamAsyncAws4Signer extends BaseAsyncAws4Signer
     private static final String HTTP_CONTENT_SHA_256 = "STREAMING-AWS4-HMAC-SHA256-EVENTS";
     private static final String EVENT_STREAM_PAYLOAD = "AWS4-HMAC-SHA256-PAYLOAD";
 
+    private static final int PAYLOAD_TRUNCATE_LENGTH = 32;
+
 
     protected BaseEventStreamAsyncAws4Signer() {
     }
@@ -287,15 +289,26 @@ static String toDebugString(Message m, boolean truncatePayload) {
         sb.append("}, payload=");
 
         byte[] payload = m.getPayload();
-
         byte[] payloadToLog;
+
+        // We don't actually need to truncate if the payload length is already within the truncate limit
+        truncatePayload = truncatePayload && payload.length > PAYLOAD_TRUNCATE_LENGTH;
+
         if (truncatePayload) {
             // Would be nice if BinaryUtils.toHex() could take an array index range instead so we don't need to copy
-            payloadToLog = Arrays.copyOf(payload, Math.min(32, payload.length));
+            payloadToLog = Arrays.copyOf(payload, PAYLOAD_TRUNCATE_LENGTH);
         } else {
             payloadToLog = payload;
         }
 
-        return sb.append(BinaryUtils.toHex(payloadToLog)).append("}").toString();
+        sb.append(BinaryUtils.toHex(payloadToLog));
+
+        if (truncatePayload) {
+            sb.append("...");
+        }
+
+        sb.append("}");
+
+        return sb.toString();
     }
 }

core/auth/src/test/java/software/amazon/awssdk/auth/signer/internal/BaseEventStreamAsyncAws4SignerTest.java

@@ -62,7 +62,7 @@ public void toDebugString_largePayload_truncate_generatesCorrectString() {
         byte[] first32 = Arrays.copyOf(payload, 32);
         String expectedPayloadString = BinaryUtils.toHex(first32);
         assertThat(BaseEventStreamAsyncAws4Signer.toDebugString(m, true))
-                .isEqualTo("Message = {headers={header1={42}, header2={false}, header3={\"Hello world\"}}, payload=" + expectedPayloadString + "}");
+                .isEqualTo("Message = {headers={header1={42}, header2={false}, header3={\"Hello world\"}}, payload=" + expectedPayloadString + "...}");
     }
 
     @Test
@@ -75,4 +75,15 @@ public void toDebugString_largePayload_noTruncate_generatesCorrectString() {
         assertThat(BaseEventStreamAsyncAws4Signer.toDebugString(m, false))
                 .isEqualTo("Message = {headers={header1={42}, header2={false}, header3={\"Hello world\"}}, payload=" + expectedPayloadString + "}");
     }
+
+    @Test
+    public void toDebugString_smallPayload_truncate_doesNotAddEllipsis() {
+        byte[] payload = new byte[8];
+        new Random().nextBytes(payload);
+        Message m = new Message(headers, payload);
+
+        String expectedPayloadString = BinaryUtils.toHex(payload);
+        assertThat(BaseEventStreamAsyncAws4Signer.toDebugString(m, true))
+                .isEqualTo("Message = {headers={header1={42}, header2={false}, header3={\"Hello world\"}}, payload=" + expectedPayloadString + "}");
+    }
 }