ZOOKEEPER-3085: define exit codes in enum

Define the used exit codes in one enum. contrib projects are excluded, as they can have seperate exit codes (and they do use it differently then in core ZK).
Some exit codes overlap, but refactoring the exit code used is not backward compatible.

Author: Norbert Kalmar <nkalmar@yahoo.com>

Reviewers: lvfangmin@apache.org, breed@apache.org, andor@apache.org

Closes #572 from nkalmar/ZOOKEEPER-3085 and squashes the following commits:

dbc18a6 [Norbert Kalmar] ZOOKEEPER-3085 change comments to javadoc comment in enum code defs
908c171 [Norbert Kalmar] ZOOKEEPER-3085 add missing enum usage and some renames
c49dcef [Norbert Kalmar] ZOOKEEPER-3085 use the enum value in ZooKeeperMain.exitCode as well
611aa4e [Norbert Kalmar] ZOOKEEPER-3085 define exit codes in enum

src/java/main/org/apache/zookeeper/Shell.java

@@ -40,6 +40,7 @@
 import java.util.concurrent.atomic.AtomicBoolean;
 
 import org.apache.zookeeper.common.Time;
+import org.apache.zookeeper.server.ExitCode;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -151,7 +152,7 @@ protected void setWorkingDirectory(File dir) {
   protected void run() throws IOException {
     if (lastTime + interval > Time.currentElapsedTime())
       return;
-    exitCode = 0; // reset for next run
+    exitCode = ExitCode.EXECUTION_FINISHED.getValue(); // reset for next run
     runCommand();
   }
 
@@ -224,7 +225,7 @@ public void run() {
       completed.set(true);
       //the timeout thread handling
       //taken care in finally block
-      if (exitCode != 0) {
+      if (exitCode != ExitCode.EXECUTION_FINISHED.getValue()) {
         throw new ExitCodeException(exitCode, errMsg.toString());
       }
     } catch (InterruptedException ie) {

src/java/main/org/apache/zookeeper/Version.java

@@ -18,6 +18,8 @@
 
 package org.apache.zookeeper;
 
+import org.apache.zookeeper.server.ExitCode;
+
 public class Version implements org.apache.zookeeper.version.Info {
 
     /*
@@ -57,7 +59,7 @@ public static void printUsage() {
                 .print("Usage:\tjava -cp ... org.apache.zookeeper.Version "
                         + "[--full | --short | --revision],\n\tPrints --full version "
                         + "info if no arg specified.");
-        System.exit(1);
+        System.exit(ExitCode.UNEXPECTED_ERROR.getValue());
     }
 
     /**
@@ -77,14 +79,14 @@ public static void main(String[] args) {
         }
         if (args.length == 0 || (args.length == 1 && args[0].equals("--full"))) {
             System.out.println(getFullVersion());
-            System.exit(0);
+            System.exit(ExitCode.EXECUTION_FINISHED.getValue());
         }
         if (args[0].equals("--short"))
             System.out.println(getVersion());
         else if (args[0].equals("--revision"))
             System.out.println(getVersionRevision());
         else
             printUsage();
-        System.exit(0);
+        System.exit(ExitCode.EXECUTION_FINISHED.getValue());
     }
 }

src/java/main/org/apache/zookeeper/ZooKeeperMain.java

@@ -68,6 +68,7 @@
 import org.apache.zookeeper.cli.SyncCommand;
 import org.apache.zookeeper.client.ZKClientConfig;
 import org.apache.zookeeper.admin.ZooKeeperAdmin;
+import org.apache.zookeeper.server.ExitCode;
 
 /**
  * The command line client to ZooKeeper.
@@ -84,7 +85,7 @@ public class ZooKeeperMain {
     protected HashMap<Integer,String> history = new HashMap<Integer,String>( );
     protected int commandCount = 0;
     protected boolean printWatches = true;
-    protected int exitCode = 0;
+    protected int exitCode = ExitCode.EXECUTION_FINISHED.getValue();
 
     protected ZooKeeper zk;
     protected String host = "";
@@ -586,7 +587,7 @@ protected boolean processCmd(MyCommandOptions co) throws CliException, IOExcepti
         boolean watch = false;
         try {
             watch = processZKCmd(co);
-            exitCode = 0;
+            exitCode = ExitCode.EXECUTION_FINISHED.getValue();
         } catch (CliException ex) {
             exitCode = ex.getExitCode();
             System.err.println(ex.getMessage());

src/java/main/org/apache/zookeeper/server/ExitCode.java

@@ -20,8 +20,43 @@
 /**
  * Exit code used to exit server
  */
-public class ExitCode {
+public enum ExitCode {
+
+    /** Execution finished normally */
+    EXECUTION_FINISHED(0),
+
+    /** Unexpected errors like IO Exceptions */
+    UNEXPECTED_ERROR(1),
+
+    /** Invalid arguments during invocations */
+    INVALID_INVOCATION(2),
+
+    /** Cannot access datadir when trying to replicate server */
+    UNABLE_TO_ACCESS_DATADIR(3),
+
+    /** Unable to start admin server at ZooKeeper startup */
+    ERROR_STARTING_ADMIN_SERVER(4),
+
+    /** Severe error during snapshot IO */
+    TXNLOG_ERROR_TAKING_SNAPSHOT(10),
+
+    /** zxid from COMMIT does not match the one from pendingTxns queue */
+    UNMATCHED_TXN_COMMIT(12),
+
+    /** Unexpected packet from leader, or unable to truncate log on Leader.TRUNC */
+    QUORUM_PACKET_ERROR(13),
+
+    /** Unable to bind to the quorum (election) port after multiple retry */
+    UNABLE_TO_BIND_QUORUM_PORT(14);
+
+    private final int value;
+
+    ExitCode(final int newValue) {
+        value = newValue;
+    }
+
+    public int getValue() {
+        return value;
+    }
 
-    /* Represents unexpected error */
-    public final static int UNEXPECTED_ERROR = 1;
 }

src/java/main/org/apache/zookeeper/server/LogFormatter.java

@@ -46,7 +46,7 @@ public class LogFormatter {
     public static void main(String[] args) throws Exception {
         if (args.length != 1) {
             System.err.println("USAGE: LogFormatter log_file");
-            System.exit(2);
+            System.exit(ExitCode.INVALID_INVOCATION.getValue());
         }
         FileInputStream fis = new FileInputStream(args[0]);
         BinaryInputArchive logStream = BinaryInputArchive.getArchive(fis);
@@ -55,7 +55,7 @@ public static void main(String[] args) throws Exception {
 
         if (fhdr.getMagic() != FileTxnLog.TXNLOG_MAGIC) {
             System.err.println("Invalid magic number for " + args[0]);
-            System.exit(2);
+            System.exit(ExitCode.INVALID_INVOCATION.getValue());
         }
         System.out.println("ZooKeeper Transactional Log File with dbid "
                 + fhdr.getDbid() + " txnlog format version "

src/java/main/org/apache/zookeeper/server/PurgeTxnLog.java

@@ -231,6 +231,6 @@ private static int validateAndGetCount(String number) {
 
     private static void printUsageThenExit() {
         printUsage();
-        System.exit(1);
+        System.exit(ExitCode.UNEXPECTED_ERROR.getValue());
     }
 }

src/java/main/org/apache/zookeeper/server/SnapshotFormatter.java

@@ -47,7 +47,7 @@ public class SnapshotFormatter {
     public static void main(String[] args) throws Exception {
         if (args.length != 1) {
             System.err.println("USAGE: SnapshotFormatter snapshot_file");
-            System.exit(2);
+            System.exit(ExitCode.INVALID_INVOCATION.getValue());
         }
 
         new SnapshotFormatter().run(args[0]);

src/java/main/org/apache/zookeeper/server/TraceFormatter.java

@@ -83,7 +83,7 @@ public static String op2String(int op) {
     public static void main(String[] args) throws IOException {
         if (args.length != 1) {
             System.err.println("USAGE: TraceFormatter trace_file");
-            System.exit(2);
+            System.exit(ExitCode.INVALID_INVOCATION.getValue());
         }
         FileChannel fc = new FileInputStream(args[0]).getChannel();
         while (true) {

src/java/main/org/apache/zookeeper/server/ZooKeeperCriticalThread.java

@@ -46,6 +46,6 @@ public ZooKeeperCriticalThread(String threadName, ZooKeeperServerListener listen
     @Override
     protected void handleException(String threadName, Throwable e) {
         LOG.error("Severe unrecoverable error, from thread : {}", threadName, e);
-        listener.notifyStopping(threadName, ExitCode.UNEXPECTED_ERROR);
+        listener.notifyStopping(threadName, ExitCode.UNEXPECTED_ERROR.getValue());
     }
 }

src/java/main/org/apache/zookeeper/server/ZooKeeperServer.java

@@ -317,7 +317,7 @@ public void takeSnapshot(boolean syncSnap){
             LOG.error("Severe unrecoverable error, exiting", e);
             // This is a severe error that we cannot recover from,
             // so we need to exit
-            System.exit(10);
+            System.exit(ExitCode.TXNLOG_ERROR_TAKING_SNAPSHOT.getValue());
         }
     }
 

src/java/main/org/apache/zookeeper/server/ZooKeeperServerMain.java

@@ -66,25 +66,25 @@ public static void main(String[] args) {
             LOG.error("Invalid arguments, exiting abnormally", e);
             LOG.info(USAGE);
             System.err.println(USAGE);
-            System.exit(2);
+            System.exit(ExitCode.INVALID_INVOCATION.getValue());
         } catch (ConfigException e) {
             LOG.error("Invalid config, exiting abnormally", e);
             System.err.println("Invalid config, exiting abnormally");
-            System.exit(2);
+            System.exit(ExitCode.INVALID_INVOCATION.getValue());
         } catch (DatadirException e) {
             LOG.error("Unable to access datadir, exiting abnormally", e);
             System.err.println("Unable to access datadir, exiting abnormally");
-            System.exit(3);
+            System.exit(ExitCode.UNABLE_TO_ACCESS_DATADIR.getValue());
         } catch (AdminServerException e) {
             LOG.error("Unable to start AdminServer, exiting abnormally", e);
             System.err.println("Unable to start AdminServer, exiting abnormally");
-            System.exit(4);
+            System.exit(ExitCode.ERROR_STARTING_ADMIN_SERVER.getValue());
         } catch (Exception e) {
             LOG.error("Unexpected exception, exiting abnormally", e);
-            System.exit(1);
+            System.exit(ExitCode.UNEXPECTED_ERROR.getValue());
         }
         LOG.info("Exiting normally");
-        System.exit(0);
+        System.exit(ExitCode.EXECUTION_FINISHED.getValue());
     }
 
     protected void initializeAndRun(String[] args)

src/java/main/org/apache/zookeeper/server/persistence/TxnLogToolkit.java

@@ -28,6 +28,7 @@
 import org.apache.jute.BinaryInputArchive;
 import org.apache.jute.BinaryOutputArchive;
 import org.apache.jute.Record;
+import org.apache.zookeeper.server.ExitCode;
 import org.apache.zookeeper.server.TraceFormatter;
 import org.apache.zookeeper.server.util.SerializeUtils;
 import org.apache.zookeeper.txn.TxnHeader;
@@ -114,12 +115,12 @@ public TxnLogToolkit(boolean recoveryMode, boolean verbose, String txnLogFileNam
         this.force = force;
         txnLogFile = new File(txnLogFileName);
         if (!txnLogFile.exists() || !txnLogFile.canRead()) {
-            throw new TxnLogToolkitException(1, "File doesn't exist or not readable: %s", txnLogFile);
+            throw new TxnLogToolkitException(ExitCode.UNEXPECTED_ERROR.getValue(), "File doesn't exist or not readable: %s", txnLogFile);
         }
         if (recoveryMode) {
             recoveryLogFile = new File(txnLogFile.toString() + ".fixed");
             if (recoveryLogFile.exists()) {
-                throw new TxnLogToolkitException(1, "Recovery file %s already exists or not writable", recoveryLogFile);
+                throw new TxnLogToolkitException(ExitCode.UNEXPECTED_ERROR.getValue(), "Recovery file %s already exists or not writable", recoveryLogFile);
             }
         }
 
@@ -135,7 +136,7 @@ public void dump(Scanner scanner) throws Exception {
         FileHeader fhdr = new FileHeader();
         fhdr.deserialize(logStream, "fileheader");
         if (fhdr.getMagic() != TXNLOG_MAGIC) {
-            throw new TxnLogToolkitException(2, "Invalid magic number for %s", txnLogFile.getName());
+            throw new TxnLogToolkitException(ExitCode.INVALID_INVOCATION.getValue(), "Invalid magic number for %s", txnLogFile.getName());
         }
         System.out.println("ZooKeeper Transactional Log File with dbid "
                 + fhdr.getDbid() + " txnlog format version "
@@ -187,7 +188,7 @@ public void dump(Scanner scanner) throws Exception {
                 printTxn(bytes);
             }
             if (logStream.readByte("EOR") != 'B') {
-                throw new TxnLogToolkitException(1, "Last transaction was partial.");
+                throw new TxnLogToolkitException(ExitCode.UNEXPECTED_ERROR.getValue(), "Last transaction was partial.");
             }
             if (recoveryMode) {
                 filePadding.padFile(recoveryFos.getChannel());
@@ -209,7 +210,7 @@ private boolean askForFix(Scanner scanner) throws TxnLogToolkitException {
                 case 'N':
                     return false;
                 case 'A':
-                    throw new TxnLogToolkitException(0, "Recovery aborted.");
+                    throw new TxnLogToolkitException(ExitCode.EXECUTION_FINISHED.getValue(), "Recovery aborted.");
             }
         }
     }
@@ -289,7 +290,7 @@ private static TxnLogToolkit parseCommandLine(String[] args) throws TxnLogToolki
             }
             return new TxnLogToolkit(cli.hasOption("recover"), cli.hasOption("verbose"), cli.getArgs()[0], cli.hasOption("yes"));
         } catch (ParseException e) {
-            throw new TxnLogToolkitParseException(options, 1, e.getMessage());
+            throw new TxnLogToolkitParseException(options, ExitCode.UNEXPECTED_ERROR.getValue(), e.getMessage());
         }
     }
 

src/java/main/org/apache/zookeeper/server/quorum/FollowerZooKeeperServer.java

@@ -25,6 +25,7 @@
 import org.apache.jute.Record;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import org.apache.zookeeper.server.ExitCode;
 import org.apache.zookeeper.server.FinalRequestProcessor;
 import org.apache.zookeeper.server.Request;
 import org.apache.zookeeper.server.RequestProcessor;
@@ -105,7 +106,7 @@ public void commit(long zxid) {
             LOG.error("Committing zxid 0x" + Long.toHexString(zxid)
                     + " but next pending txn 0x"
                     + Long.toHexString(firstElementZxid));
-            System.exit(12);
+            System.exit(ExitCode.UNMATCHED_TXN_COMMIT.getValue());
         }
         Request request = pendingTxns.remove();
         commitProcessor.commit(request);

src/java/main/org/apache/zookeeper/server/quorum/Learner.java

@@ -38,6 +38,7 @@
 import org.apache.jute.InputArchive;
 import org.apache.jute.OutputArchive;
 import org.apache.jute.Record;
+import org.apache.zookeeper.server.ExitCode;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.apache.zookeeper.ZooDefs.OpCode;
@@ -50,8 +51,6 @@
 import org.apache.zookeeper.server.util.ZxidUtils;
 import org.apache.zookeeper.txn.SetDataTxn;
 import org.apache.zookeeper.txn.TxnHeader;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 /**
  * This class is the superclass of two of the three main actors in a ZK
@@ -409,15 +408,15 @@ else if (qp.getType() == Leader.SNAP) {
                     // not able to truncate the log
                     LOG.error("Not able to truncate the log "
                             + Long.toHexString(qp.getZxid()));
-                    System.exit(13);
+                    System.exit(ExitCode.QUORUM_PACKET_ERROR.getValue());
                 }
                 zk.getZKDatabase().setlastProcessedZxid(qp.getZxid());
 
             }
             else {
                 LOG.error("Got unexpected packet from leader: {}, exiting ... ",
                           LearnerHandler.packetToString(qp));
-                System.exit(13);
+                System.exit(ExitCode.QUORUM_PACKET_ERROR.getValue());
 
             }
             zk.getZKDatabase().initConfigInZKDatabase(self.getQuorumVerifier());

src/java/main/org/apache/zookeeper/server/quorum/QuorumCnxManager.java

@@ -47,6 +47,7 @@
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicLong;
 
+import org.apache.zookeeper.server.ExitCode;
 import org.apache.zookeeper.server.quorum.QuorumPeerConfig.ConfigException;
 import org.apache.zookeeper.server.util.ConfigUtils;
 import org.apache.zookeeper.server.ZooKeeperThread;
@@ -921,7 +922,7 @@ public void run() {
                     // After leaving listener thread, the host cannot join the
                     // quorum anymore, this is a severe error that we cannot
                     // recover from, so we need to exit
-                    System.exit(14);
+                    System.exit(ExitCode.UNABLE_TO_BIND_QUORUM_PORT.getValue());
                 }
             } else if (ss != null) {
                 // Clean up for shutdown.

src/java/main/org/apache/zookeeper/server/quorum/QuorumPeerMain.java

@@ -26,6 +26,7 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.apache.zookeeper.jmx.ManagedUtil;
+import org.apache.zookeeper.server.ExitCode;
 import org.apache.zookeeper.server.ServerCnxnFactory;
 import org.apache.zookeeper.server.ZKDatabase;
 import org.apache.zookeeper.server.DatadirCleanupManager;
@@ -84,25 +85,25 @@ public static void main(String[] args) {
             LOG.error("Invalid arguments, exiting abnormally", e);
             LOG.info(USAGE);
             System.err.println(USAGE);
-            System.exit(2);
+            System.exit(ExitCode.INVALID_INVOCATION.getValue());
         } catch (ConfigException e) {
             LOG.error("Invalid config, exiting abnormally", e);
             System.err.println("Invalid config, exiting abnormally");
-            System.exit(2);
+            System.exit(ExitCode.INVALID_INVOCATION.getValue());
         } catch (DatadirException e) {
             LOG.error("Unable to access datadir, exiting abnormally", e);
             System.err.println("Unable to access datadir, exiting abnormally");
-            System.exit(3);
+            System.exit(ExitCode.UNABLE_TO_ACCESS_DATADIR.getValue());
         } catch (AdminServerException e) {
             LOG.error("Unable to start AdminServer, exiting abnormally", e);
             System.err.println("Unable to start AdminServer, exiting abnormally");
-            System.exit(4);
+            System.exit(ExitCode.ERROR_STARTING_ADMIN_SERVER.getValue());
         } catch (Exception e) {
             LOG.error("Unexpected exception, exiting abnormally", e);
-            System.exit(1);
+            System.exit(ExitCode.UNEXPECTED_ERROR.getValue());
         }
         LOG.info("Exiting normally");
-        System.exit(0);
+        System.exit(ExitCode.EXECUTION_FINISHED.getValue());
     }
 
     protected void initializeAndRun(String[] args)