Refactoring checkstyle daemon into a more general purpose buck daemon.

Change-Id: I999541e8894f07061141b3a62414e491369f8d08

@@ -37,10 +37,11 @@ def checkstyle(
 
         sh_test(
                 name = name + '-checkstyle',
-                test = '//tools/build/conf:start-checkstyle',
+                test = '//tools/build/conf:start-buck-daemon',
                 deps = [ jar_target ],
                 args = [
-                    '$(location //tools/build/conf:checkstyle-jar)',
+                    '$(location //tools/build/conf:buck-daemon-jar)',
+                    'checkstyle',
                     '$(location :' + name + '-checkstyle-files)',
                     '$(location //tools/build/conf:checkstyle-xml)',
                     '$(location //tools/build/conf:suppressions-xml)',

@@ -14,7 +14,7 @@ export_file (
 )
 
 export_file (
-  name = 'start-checkstyle',
+  name = 'start-buck-daemon',
   visibility = [ 'PUBLIC' ],
 )
 
@@ -38,9 +38,9 @@ java_library (
 )
 
 java_binary (
-  name = 'checkstyle-jar',
+  name = 'buck-daemon-jar',
   deps = [ ':checkstyle' ] + RUN,
-  main_class = 'org.onosproject.checkstyle.Main',
+  main_class = 'org.onosproject.buckdaemon.BuckDaemon',
   blacklist = [ 'META-INF/.*' ],
   visibility = [ 'PUBLIC' ],
 )

 /*
- * Copyright 2016-present Open Networking Laboratory
+ * Copyright 2016 Open Networking Laboratory
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -14,54 +14,80 @@
  * limitations under the License.
  */
 
-package org.onosproject.checkstyle;
+package org.onosproject.buckdaemon;
 
+import com.google.common.io.ByteStreams;
 import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
+import org.onosproject.checkstyle.CheckstyleRunner;
 
 import java.io.IOException;
 import java.net.ServerSocket;
+import java.net.Socket;
 import java.nio.ByteBuffer;
 import java.nio.channels.FileChannel;
 import java.nio.channels.FileLock;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
+import java.util.HashMap;
+import java.util.Map;
 import java.util.Timer;
 import java.util.TimerTask;
+import java.util.concurrent.Callable;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 
 import static java.nio.file.StandardOpenOption.*;
 
 /**
- * Main program for executing scenario test warden.
+ * Buck daemon process.
  */
-public final class Main {
+public final class BuckDaemon {
 
     private static long POLLING_INTERVAL = 1000; //ms
 
+    private final Map<String, BuckTask> tasks = new HashMap<>();
+    private final String portLock;
+    private final String buckPid;
+
     // Public construction forbidden
-    private Main(String[] args) {
+    private BuckDaemon(String[] args) {
+        portLock = args[0];
+        buckPid = args[1];
     }
 
     /**
-     * Main entry point for the cell warden.
+     * Main entry point for the daemon.
      *
      * @param args command-line arguments
      */
     public static void main(String[] args)
             throws CheckstyleException, IOException {
-        startServer(args);
+        BuckDaemon daemon = new BuckDaemon(args);
+        daemon.registerTasks();
+        daemon.startServer();
+    }
+
+    /**
+     * Registers re-entrant tasks by their task name.
+     */
+    private void registerTasks() {
+        tasks.put("checkstyle", new CheckstyleRunner(System.getProperty("checkstyle.config"),
+                                                     System.getProperty("checkstyle.suppressions")));
+        // tasks.put("swagger", new SwaggerGenerator());
     }
 
-    // Monitors another PID and exit when that process exits
-    private static void watchProcess(String pid) {
+    /**
+     * Monitors another PID and exit when that process exits.
+     */
+    private void watchProcess(String pid) {
         if (pid == null || pid.equals("0")) {
             return;
         }
         Timer timer = new Timer(true); // start as a daemon, so we don't hang shutdown
         timer.scheduleAtFixedRate(new TimerTask() {
             private String cmd = "kill -s 0 " + pid;
+
             @Override
             public void run() {
                 try {
@@ -79,13 +105,10 @@ public final class Main {
         }, POLLING_INTERVAL, POLLING_INTERVAL);
     }
 
-    // Initiates a server.
-    private static void startServer(String[] args) throws IOException, CheckstyleException {
-        String portLock = args[0];
-        String buckPid = args[1];
-        String checkstyleFile = args[2];
-        String suppressionsFile = args[3];
-
+    /**
+     * Initiates a server.
+     */
+    private void startServer() throws IOException, CheckstyleException {
         // Use a file lock to ensure only one copy of the daemon runs
         Path portLockPath = Paths.get(portLock);
         FileChannel channel = FileChannel.open(portLockPath, WRITE, CREATE);
@@ -104,10 +127,8 @@ public final class Main {
         // Set up hook to clean up after ourselves
         Runtime.getRuntime().addShutdownHook(new Thread(() -> {
             try {
-                if (channel != null) {
                 channel.truncate(0);
                 channel.close();
-                }
                 System.err.println("tear down...");
                 Files.delete(portLockPath);
             } catch (IOException e) {
@@ -122,15 +143,58 @@ public final class Main {
         channel.write(ByteBuffer.wrap(Integer.toString(port).getBytes()));
 
         // Instantiate a Checkstyle runner and executor; serve until exit...
-        CheckstyleRunner runner = new CheckstyleRunner(checkstyleFile, suppressionsFile);
         ExecutorService executor = Executors.newCachedThreadPool();
         while (true) {
             try {
-                executor.submit(runner.checkClass(server.accept()));
+                executor.submit(new BuckTaskRunner(server.accept()));
             } catch (Exception e) {
                 e.printStackTrace();
                 //no-op
             }
         }
     }
+
+    /**
+     * Runnable capable of invoking the appropriate Buck task with input
+     * consumed form the specified socket and output produced back to that
+     * socket.
+     */
+    private class BuckTaskRunner implements Runnable {
+
+        private final Socket socket;
+
+        public BuckTaskRunner(Socket socket) {
+            this.socket = socket;
+        }
+
+        @Override
+        public void run() {
+            try {
+                BuckTaskContext context = new BuckTaskContext(socket.getInputStream());
+                String taskName = context.taskName();
+                if (!taskName.isEmpty()) {
+                    BuckTask task = tasks.get(taskName);
+                    if (task != null) {
+                        System.out.println(String.format("Executing task '%s'", taskName));
+                        task.execute(context);
+                        for (String line : context.output()) {
+                            output(socket, line);
+                        }
+                    } else {
+                        String message = String.format("No task named '%s'", taskName);
+                        System.out.print(message);
+                        output(socket, message);
+                    }
+                }
+                socket.getOutputStream().flush();
+                socket.close();
+            } catch (IOException e) {
+                e.printStackTrace();
+            }
+        }
+
+        private void output(Socket socket, String line) throws IOException {
+            socket.getOutputStream().write((line + "\n").getBytes());
+        }
+    }
 }

+/*
+ * Copyright 2016 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.onosproject.buckdaemon;
+
+/**
+ * Abstraction of a Buck task that can be spawned by the Buck daemon
+ */
+public interface BuckTask {
+
+    /**
+     * Executes the task, consuming the specified input and producing output.
+     *
+     * @param context context for the tast operation
+     */
+    void execute(BuckTaskContext context);
+
+}

+/*
+ * Copyright 2016 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.onosproject.buckdaemon;
+
+import com.google.common.collect.ImmutableList;
+import com.google.common.io.ByteStreams;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.ArrayList;
+import java.util.List;
+
+import static com.google.common.base.Preconditions.checkArgument;
+
+/**
+ * Context for executing a single Buck task.
+ */
+public class BuckTaskContext {
+
+    private final String taskName;
+    private final ImmutableList<String> input;
+    private final List<String> output = new ArrayList<>();
+
+    BuckTaskContext(InputStream inputString) throws IOException {
+        String[] split = new String(ByteStreams.toByteArray(inputString)).split("\n");
+        checkArgument(split.length >= 1, "Request must contain at least task type");
+        this.taskName = split[0];
+        ImmutableList.Builder<String> builder = ImmutableList.builder();
+        for (int i = 1; i < split.length; i++) {
+            builder.add(split[i]);
+        }
+        input = builder.build();
+    }
+
+    /**
+     * Returns the symbolic task name.
+     */
+    public String taskName() {
+        return taskName;
+    }
+
+    /**
+     * Returns the input data a list of strings.
+     *
+     * @return input data
+     */
+    public List<String> input() {
+        return ImmutableList.copyOf(input);
+    }
+
+    /**
+     * Returns the output data a list of strings.
+     *
+     * @return output data
+     */
+    List<String> output() {
+        return ImmutableList.copyOf(output);
+    }
+
+    /**
+     * Adds a line to the output data.
+     *
+     * @param line line of output data
+     */
+    public void output(String line) {
+        output.add(line);
+    }
+
+}

@@ -15,7 +15,6 @@
  */
 package org.onosproject.checkstyle;
 
-import com.google.common.io.ByteStreams;
 import com.puppycrawl.tools.checkstyle.Checker;
 import com.puppycrawl.tools.checkstyle.ConfigurationLoader;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
@@ -24,26 +23,28 @@ import com.puppycrawl.tools.checkstyle.api.AuditEvent;
 import com.puppycrawl.tools.checkstyle.api.AuditListener;
 import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
 import com.puppycrawl.tools.checkstyle.api.Configuration;
+import org.onosproject.buckdaemon.BuckTask;
+import org.onosproject.buckdaemon.BuckTaskContext;
 
 import java.io.File;
-import java.io.IOException;
-import java.net.Socket;
 import java.util.List;
 import java.util.concurrent.CountDownLatch;
 import java.util.stream.Collectors;
-import java.util.stream.Stream;
 
 import static com.google.common.base.Strings.isNullOrEmpty;
 
-public class CheckstyleRunner {
+/**
+ * Buck task for executing checkstyle on the specified project files.
+ */
+public class CheckstyleRunner implements BuckTask {
 
     private final Configuration config;
 
-    public CheckstyleRunner(String configLocation, String suppressionLocation)
-            throws CheckstyleException {
+    public CheckstyleRunner(String configLocation, String suppressionLocation) {
+        try {
             // create a configuration
-        DefaultConfiguration config = (DefaultConfiguration) ConfigurationLoader.loadConfiguration(
-                configLocation, new PropertiesExpander(System.getProperties()));
+            DefaultConfiguration config = (DefaultConfiguration) ConfigurationLoader
+                    .loadConfiguration(configLocation, new PropertiesExpander(System.getProperties()));
 
             // add the suppression file to the configuration
             DefaultConfiguration suppressions = new DefaultConfiguration("SuppressionFilter");
@@ -51,37 +52,22 @@ public class CheckstyleRunner {
             config.addChild(suppressions);
 
             this.config = config;
-    }
-
-    public Runnable checkClass(Socket socket) {
-        return () -> {
-            try {
-                String input = new String(ByteStreams.toByteArray(socket.getInputStream()));
-                String output = checkClass(input);
-                socket.getOutputStream().write(output.getBytes());
-                socket.getOutputStream().flush();
-                socket.close();
-            } catch (IOException e) {
-                e.printStackTrace();
         } catch (CheckstyleException e) {
-                e.printStackTrace();
-            } catch (InterruptedException e) {
-                e.printStackTrace();
+            throw new RuntimeException(e);
         }
-        };
     }
 
-    public String checkClass(String input) throws CheckstyleException, InterruptedException {
-        String[] split = input.split("\n", 3);
-        if (split.length < 3 || split[2].length() == 0) {
-            return "";
+    @Override
+    public void execute(BuckTaskContext context) {
+        List<String> input = context.input();
+        if (input.size() < 3 || input.get(2).length() == 0) {
+            return;
         }
-        String project = split[0];
-        String baseDir = split[1];
-        String files = split[2];
+        String project = input.get(0);
+        String baseDir = input.get(1);
 
         // create a listener for output
-        StringAuditor listener = new StringAuditor();
+        StringAuditor listener = new StringAuditor(context);
         listener.setProjectName(project);
         listener.setBaseDir(baseDir);
 
@@ -91,33 +77,38 @@ public class CheckstyleRunner {
         checker.setModuleClassLoader(moduleClassLoader);
 
         try {
-
             checker.configure(config);
             checker.addListener(listener);
 
             // run Checker
-            List<File> fileList = Stream.of(files.split("\n"))
+            List<File> fileList = input.subList(2, input.size() - 1).stream()
                     .map(File::new)
                     .collect(Collectors.toList());
             int errorCounter = checker.process(fileList);
             if (errorCounter > 0) {
-                listener.append("CHECKSTYLE ERROR\n");
+                context.output("CHECKSTYLE ERROR");
             }
+
+            listener.await();
+        } catch (CheckstyleException | InterruptedException e) {
+            throw new RuntimeException(e);
         } finally {
             checker.destroy();
         }
 
-        return listener.getAudit();
     }
-}
 
-class StringAuditor implements AuditListener {
+    static class StringAuditor implements AuditListener {
 
+        private final BuckTaskContext context;
         private CountDownLatch finishedLatch = new CountDownLatch(1);
-    private StringBuilder output = new StringBuilder();
         private String baseDir = "";
         private String project = "";
 
+        StringAuditor(BuckTaskContext context) {
+            this.context = context;
+        }
+
         public void setBaseDir(String base) {
             this.baseDir = base;
         }
@@ -126,18 +117,12 @@ class StringAuditor implements AuditListener {
             this.project = projectName;
         }
 
-    public void append(String s) {
-        output.append(s);
-    }
-
-    public String getAudit() throws InterruptedException {
+        public void await() throws InterruptedException {
             finishedLatch.await();
-        return output.toString();
         }
 
         @Override
         public void auditStarted(AuditEvent evt) {
-
         }
 
         @Override
@@ -147,18 +132,17 @@ class StringAuditor implements AuditListener {
 
         @Override
         public void fileStarted(AuditEvent evt) {
-
         }
 
         @Override
         public void fileFinished(AuditEvent evt) {
-
         }
 
         @Override
         public void addError(AuditEvent evt) {
             switch (evt.getSeverityLevel()) {
                 case ERROR:
+                    StringBuilder output = new StringBuilder();
                     String fileName = evt.getFileName();
                     if (!isNullOrEmpty(baseDir)) {
                         int index = fileName.indexOf(baseDir);
@@ -174,7 +158,7 @@ class StringAuditor implements AuditListener {
                         output.append(':').append(evt.getColumn());
                     }
                     output.append(": ").append(evt.getMessage());
-                output.append('\n');
+                    context.output(output.toString());
                     break;
                 case IGNORE:
                 case INFO:
@@ -187,6 +171,8 @@ class StringAuditor implements AuditListener {
         @Override
         public void addException(AuditEvent evt, Throwable throwable) {
             addError(evt);
-        output.append(throwable.getMessage());
+            context.output(throwable.getMessage());
         }
+    }
+
 }

 #!/bin/bash
-CHECKSTYLE=$1
-FILES=$2
-CONFIG=$3
-SUPPRESSIONS=$4
+# -----------------------------------------------------------------------------
+# Launches Buck daemon if not already running and requests Buck task execution.
+# -----------------------------------------------------------------------------
+
+BUCK_DAEMON=$1
+TASK=${2:-unspecified}
+DATA=${3}
+
+# TODO: Figure out how to parametrize better
+BUCK_PROPS="-Dcheckstyle.config=$4 -Dcheckstyle.suppressions=$5"
 
 PORT_FILE="$1.port"
 
@@ -39,15 +45,15 @@ function check_socket() {
     return $?
 }
 
-# check to see if checkstyle daemon is running; if not, start it
+# check to see if buck daemon is running; if not, start it
 if ! check_socket; then
-    # Starting checkstyle server...
+    # Starting buck daemon...
     #FIXME change to /dev/null if/when we are confident
-    nohup java -jar $CHECKSTYLE $PORT_FILE $(buck_pid) $3 $4 >>/tmp/checkstyle.daemon 2>&1 &
+    nohup java $BUCK_PROPS -jar $BUCK_DAEMON $PORT_FILE $(buck_pid) >>/tmp/buck.daemon 2>&1 &
 
     TRIES=20
     i=0
-    # Wait for checkstyle server to start for 2 seconds
+    # Wait for buck daemon to start for 2 seconds
     while [ $i -lt $TRIES ]; do
         if check_socket; then
             CONNECTED=true
@@ -57,15 +63,15 @@ if ! check_socket; then
         sleep 0.1
     done
     if [ -z "$CONNECTED" ]; then
-        echo "Failed to start checkstyle server"
+        echo "Failed to start buck daemon"
         exit 3
     fi
 fi
 
-# run the actual checkstyle client
-OUT=$(cat $FILES | nc localhost $(port))
+# run the actual buck daemon client
+OUT=$((printf "%s\n" $TASK; cat $DATA) | nc localhost $(port))
 if [ $? -ne 0 ]; then
-    echo "Error connecting to checkstyle server"
+    echo "Error connecting to buck daemon server"
     exit 2
 fi
 if [ -n "$OUT" ]; then