Show progress during backup shell command

shell/src/main/java/alluxio/cli/fsadmin/command/BackupCommand.java

@@ -11,19 +11,20 @@
 
 package alluxio.cli.fsadmin.command;
 
-import alluxio.Constants;
 import alluxio.annotation.PublicApi;
 import alluxio.cli.CommandUtils;
 import alluxio.conf.AlluxioConfiguration;
+import alluxio.exception.status.AlluxioStatusException;
 import alluxio.exception.status.InvalidArgumentException;
 import alluxio.grpc.BackupPOptions;
-import alluxio.grpc.BackupPOptions.Builder;
-import alluxio.util.CommonUtils;
-import alluxio.wire.BackupResponse;
+import alluxio.grpc.BackupPRequest;
+import alluxio.grpc.BackupState;
+import alluxio.wire.BackupStatus;
 
 import org.apache.commons.cli.CommandLine;
 import org.apache.commons.cli.Option;
 import org.apache.commons.cli.Options;
+import org.apache.commons.lang.StringUtils;
 
 import java.io.IOException;
 
@@ -38,8 +39,16 @@ public class BackupCommand extends AbstractFsAdminCommand {
           .longOpt("local")
           .required(false)
           .hasArg(false)
-          .desc("whether to write the backup to the master's local filesystem instead of the root"
-              + " UFS")
+          .desc("whether to write the backup to the master's local filesystem"
+              + " instead of the root UFS")
+          .build();
+  private static final Option ALLOW_LEADER_OPTION =
+      Option.builder()
+          .longOpt("allow-leader")
+          .required(false)
+          .hasArg(false)
+          .desc("whether to allow leader to take the backup when"
+              + " HA cluster has no stand-by master.")
           .build();
   /**
    * @param context fsadmin command context
@@ -56,36 +65,71 @@ public String getCommandName() {
 
   @Override
   public Options getOptions() {
-    return new Options().addOption(LOCAL_OPTION);
+    return new Options()
+        .addOption(LOCAL_OPTION)
+        .addOption(ALLOW_LEADER_OPTION);
   }
 
   @Override
   public int run(CommandLine cl) throws IOException {
     String[] args = cl.getArgs();
-    Builder opts = BackupPOptions.newBuilder();
+    BackupPRequest.Builder opts = BackupPRequest.newBuilder();
     if (args.length >= 1) {
       opts.setTargetDirectory(args[0]);
     }
-    opts.setLocalFileSystem(cl.hasOption(LOCAL_OPTION.getLongOpt()));
-    // Create progress thread for showing progress while backup is in progress.
-    Thread progressThread = CommonUtils.createProgressThread(5 * Constants.SECOND_MS, System.out);
-    progressThread.start();
-    BackupResponse resp;
-    try {
-      resp = mMetaClient.backup(opts.build());
-    } finally {
-      progressThread.interrupt();
-    }
-    if (opts.getLocalFileSystem()) {
-      mPrintStream.printf("Successfully backed up journal to %s on master %s with %d entries%n",
-          resp.getBackupUri(), resp.getHostname(), resp.getEntryCount());
-    } else {
-      mPrintStream.printf("Successfully backed up journal to %s with %d entries%n",
-          resp.getBackupUri(), resp.getEntryCount());
-    }
+    opts.setOptions(
+        BackupPOptions.newBuilder()
+            .setRunAsync(true)
+            .setLocalFileSystem(cl.hasOption(LOCAL_OPTION.getLongOpt()))
+            .setAllowLeader(cl.hasOption(ALLOW_LEADER_OPTION.getLongOpt())));
+    // Take backup in async mode.
+    BackupStatus status = mMetaClient.backup(opts.build());
+    do {
+      // Backup could be after a fail-over.
+      if (status.getState() == BackupState.EMPTY) {
+        clearProgressLine();
+        mPrintStream.printf("Backup lost. Check Alluxio logs.%n");
+        return -1;
+      }
+      if (status.getState() == BackupState.COMPLETED) {
+        break;
+      } else if (status.getState() == BackupState.FAULTED) {
+        throw AlluxioStatusException.fromAlluxioException(status.getError());
+      } else {
+        // Generate progress line that will be replaced until backup is finished.
+        String progressMessage = String.format(" Backup state: %s", status.getState());
+        // Start showing entry count once backup started running.
+        if (status.getState() == BackupState.RUNNING) {
+          progressMessage += String.format(" | Entries processed: %d", status.getEntryCount());
+        }
+        clearProgressLine();
+        mPrintStream.write(progressMessage.getBytes());
+        mPrintStream.write("\r".getBytes());
+        mPrintStream.flush();
+      }
+      // Sleep 1sec before querying status again.
+      try {
+        Thread.sleep(1000);
+        status = mMetaClient.getBackupStatus();
+      } catch (InterruptedException ie) {
+        throw new RuntimeException("Interrupted while waiting for backup completion.");
+      }
+    } while (true);
+    clearProgressLine();
+    // Print final state.
+    mPrintStream.printf("Backup Host        : %s%n", status.getHostname());
+    mPrintStream.printf("Backup URI         : %s%n", status.getBackupUri());
+    mPrintStream.printf("Backup Entry Count : %d%n", status.getEntryCount());
     return 0;
   }
 
+  private void clearProgressLine() throws IOException {
+    final int progressLineLength = 75;
+    // Clear progress line.
+    mPrintStream.write(StringUtils.repeat(" ", progressLineLength).getBytes());
+    mPrintStream.write("\r".getBytes());
+  }
+
   @Override
   public String getUsage() {
     return "backup [directory] [--local]";
@@ -97,12 +141,13 @@ public String getDescription() {
         + " directory to back up to can be overridden by specifying a directory here. The directory"
         + " path is relative to the root UFS. To write the backup to the local disk of the primary"
         + " master, use --local and specify a filesystem path. Backing up metadata"
-        + " requires a pause in master metadata changes, so use this command sparingly to"
-        + " avoid interfering with other users of the system.";
+        + " will be delegated to secondary masters in HA cluster. Use --allow-leader for"
+        + " leader to take the backup when there are no secondaries.(This will pause"
+        + " metadata changes during the backup.";
   }
 
   @Override
   public void validateArgs(CommandLine cl) throws InvalidArgumentException {
-    CommandUtils.checkNumOfArgsNoMoreThan(this, cl, 1);
+    CommandUtils.checkNumOfArgsNoMoreThan(this, cl, 2);
   }
 }