Added retry with exponential backoff

samples/snippets/src/main/java/com/example/bigquerystorage/WriteCommittedStream.java

@@ -16,6 +16,7 @@
 
 package com.example.bigquerystorage;
 
+import com.google.api.client.util.*;
 import com.google.api.core.ApiFuture;
 import com.google.cloud.bigquery.*;
 import com.google.cloud.bigquery.storage.v1beta2.*;
@@ -27,10 +28,20 @@
 
 public class WriteCommittedStream {
 
-  public static Status.Code getStatusCode(StatusRuntimeException e) {
+  static Status.Code getStatusCode(StatusRuntimeException e) {
     return e.getStatus().getCode();
   }
 
+  // Returns true if the operation should be retried.
+  static Boolean isRetryable(ExecutionException e) {
+    Throwable cause = e.getCause();
+    if (cause instanceof StatusRuntimeException) {
+        Status status = ((StatusRuntimeException)cause).getStatus();
+	return (status == Status.ABORTED);
+    }
+    return false;
+  }
+
   public static void runWriteCommittedStream() {
     // TODO(developer): Replace these variables before running the sample.
     String projectId = "MY_PROJECT_ID";
@@ -85,7 +96,7 @@ public static void writeCommittedStream(String projectId, String datasetName, St
       System.out.println("Appended records successfully.");
 
     } catch (Exception e) {
-      System.out.println("Failed to append records. \n" + e.toString());
+      System.out.println("Failed to append records.\n" + e.toString());
     }
   }
 
@@ -100,17 +111,41 @@ public static void writeToDefaultStream(String projectId, String datasetName, St
     try (JsonStreamWriter writer =
         JsonStreamWriter.newBuilder(parent.toString(), schema).createDefaultStream().build()) {
 
+      ExponentialBackOff backoff = new ExponentialBackOff();
+
       for (int i = 0; i < 10; i++) {
         JSONObject record = new JSONObject();
         record.put("col1", String.format("record %03d", i));
         JSONArray jsonArr = new JSONArray();
         jsonArr.put(record);
 
-        ApiFuture<AppendRowsResponse> future = writer.append(jsonArr);
-        AppendRowsResponse response = future.get();
+	backoff.reset();
+	Boolean retry = true;
+        while (retry) {
+	  try {
+
+            ApiFuture<AppendRowsResponse> future = writer.append(jsonArr);
+            AppendRowsResponse response = future.get();
+	    retry = false;
+
+	  } catch (ExecutionException ex) {
+	    // If the error is retryable, retry the operation with exponential backoff.
+	    // Don't retry past the maximum retry interval.
+	    long backOffMillis = backoff.nextBackOffMillis();
+            if (isRetryable(ex) && backOffMillis != BackOff.STOP) {
+	      Thread.sleep(backOffMillis);
+	    }
+	    else {
+              throw ex;
+	    }
+	  }
+	}
       }
+
+      System.out.println("Appended records successfully.");
+
     } catch (Exception e) {
-      System.out.println(e);
+      System.out.println("Failed to append records.\n" + e.toString());
     }
   }
 }