NIFI-842 Updating org.apache.nifi.NiFi so it sends a started signal to bootstrap which can then be used to make retsart decisions

nifi-bootstrap/src/main/java/org/apache/nifi/bootstrap/BootstrapCodec.java

@@ -87,6 +87,22 @@ public class BootstrapCodec {
                 writer.flush();
             }
             break;
+            case "STARTED": {
+                if (args.length != 1) {
+                    throw new InvalidCommandException("STARTED command must contain a status argument");
+                }
+
+                if (!"true".equals(args[0]) && !"false".equals(args[0])) {
+                    throw new InvalidCommandException("Invalid status for STARTED command; should be true or false, but was '" + args[0] + "'");
+                }
+
+                final boolean started = Boolean.parseBoolean(args[0]);
+                runner.setNiFiStarted(started);
+                writer.write("OK");
+                writer.newLine();
+                writer.flush();
+            }
+            break;
         }
     }
 }

nifi-bootstrap/src/main/java/org/apache/nifi/bootstrap/RunNiFi.java

@@ -92,7 +92,9 @@ public class RunNiFi {
     private volatile long nifiPid = -1L;
     private volatile String secretKey;
     private volatile ShutdownHook shutdownHook;
+    private volatile boolean nifiStarted;
 
+    private final Lock startedLock = new ReentrantLock();
     private final Lock lock = new ReentrantLock();
     private final Condition startupCondition = lock.newCondition();
 
@@ -799,10 +801,18 @@ public class RunNiFi {
                 if (autoRestartNiFi) {
                     final File statusFile = getStatusFile(defaultLogger);
                     if (!statusFile.exists()) {
-                        defaultLogger.debug("Status File no longer exists. Will not restart NiFi");
+                        defaultLogger.info("Status File no longer exists. Will not restart NiFi");
                         return;
                     }
 
+                    final boolean previouslyStarted = getNifiStarted();
+                    if (!previouslyStarted) {
+                        defaultLogger.info("NiFi never started. Will not restart NiFi");
+                        return;
+                    } else {
+                        setNiFiStarted(false);
+                    }
+
                     defaultLogger.warn("Apache NiFi appears to have died. Restarting...");
                     process = builder.start();
                     handleLogging(process);
@@ -973,6 +983,24 @@ public class RunNiFi {
         return this.ccPort;
     }
 
+    void setNiFiStarted(final boolean nifiStarted) {
+        startedLock.lock();
+        try {
+            this.nifiStarted = nifiStarted;
+        } finally {
+            startedLock.unlock();
+        }
+    }
+
+    boolean getNifiStarted() {
+        startedLock.lock();
+        try {
+            return nifiStarted;
+        } finally {
+            startedLock.unlock();
+        }
+    }
+
     private static class Status {
 
         private final Integer port;

nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-runtime/src/main/java/org/apache/nifi/BootstrapListener.java

@@ -80,13 +80,37 @@ public class BootstrapListener {
         listenThread.start();
 
         logger.debug("Notifying Bootstrap that local port is {}", localPort);
+        sendCommand("PORT", new String[] { String.valueOf(localPort), secretKey});
+    }
+
+    public void stop() {
+        if (listener != null) {
+            listener.stop();
+        }
+    }
+
+    public void sendStartedStatus(boolean status) throws IOException {
+        logger.debug("Notifying Bootstrap that the status of starting NiFi is {}", status);
+        sendCommand("STARTED", new String[]{ String.valueOf(status) });
+    }
+
+    private void sendCommand(final String command, final String[] args) throws IOException {
         try (final Socket socket = new Socket()) {
             socket.setSoTimeout(60000);
             socket.connect(new InetSocketAddress("localhost", bootstrapPort));
             socket.setSoTimeout(60000);
 
+            final StringBuilder commandBuilder = new StringBuilder(command);
+            for (final String arg : args) {
+                commandBuilder.append(" ").append(arg);
+            }
+            commandBuilder.append("\n");
+
+            final String commandWithArgs = commandBuilder.toString();
+            logger.debug("Sending command to Bootstrap: " + commandWithArgs);
+
             final OutputStream out = socket.getOutputStream();
-            out.write(("PORT " + localPort + " " + secretKey + "\n").getBytes(StandardCharsets.UTF_8));
+            out.write((commandWithArgs).getBytes(StandardCharsets.UTF_8));
             out.flush();
 
             logger.debug("Awaiting response from Bootstrap...");
@@ -100,12 +124,6 @@ public class BootstrapListener {
         }
     }
 
-    public void stop() {
-        if (listener != null) {
-            listener.stop();
-        }
-    }
-
     private class Listener implements Runnable {
 
         private final ServerSocket serverSocket;

nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-runtime/src/main/java/org/apache/nifi/NiFi.java

@@ -136,6 +136,10 @@ public class NiFi {
         } else {
             nifiServer.start();
 
+            if (bootstrapListener != null) {
+                bootstrapListener.sendStartedStatus(true);
+            }
+
             final long endTime = System.nanoTime();
             logger.info("Controller initialization took " + (endTime - startTime) + " nanoseconds.");
         }