Refactoring checkstyle daemon into a more general purpose buck daemon.
Change-Id: I999541e8894f07061141b3a62414e491369f8d08
diff --git a/tools/build/conf/src/main/java/org/onosproject/buckdaemon/BuckDaemon.java b/tools/build/conf/src/main/java/org/onosproject/buckdaemon/BuckDaemon.java
new file mode 100644
index 0000000..2c79b5f
--- /dev/null
+++ b/tools/build/conf/src/main/java/org/onosproject/buckdaemon/BuckDaemon.java
@@ -0,0 +1,200 @@
+/*
+ * 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.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.*;
+
+/**
+ * Buck daemon process.
+ */
+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 BuckDaemon(String[] args) {
+ portLock = args[0];
+ buckPid = args[1];
+ }
+
+ /**
+ * Main entry point for the daemon.
+ *
+ * @param args command-line arguments
+ */
+ public static void main(String[] args)
+ throws CheckstyleException, IOException {
+ 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 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 {
+ Process p = Runtime.getRuntime().exec(cmd);
+ p.waitFor();
+ if (p.exitValue() != 0) {
+ System.err.println("shutting down...");
+ System.exit(0);
+ }
+ } catch (IOException | InterruptedException e) {
+ //no-op
+ e.printStackTrace();
+ }
+ }
+ }, POLLING_INTERVAL, POLLING_INTERVAL);
+ }
+
+ /**
+ * 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);
+ FileLock lock = channel.tryLock();
+ if (lock == null) {
+ System.out.println("Server is already running");
+ System.exit(1);
+ } //else, hold the lock until the JVM exits
+
+ // Start the server and bind it to a random port
+ ServerSocket server = new ServerSocket(0);
+
+ // Monitor the parent buck process
+ watchProcess(buckPid);
+
+ // Set up hook to clean up after ourselves
+ Runtime.getRuntime().addShutdownHook(new Thread(() -> {
+ try {
+ channel.truncate(0);
+ channel.close();
+ System.err.println("tear down...");
+ Files.delete(portLockPath);
+ } catch (IOException e) {
+ //no-op: shutting down
+ e.printStackTrace();
+ }
+ }));
+
+ // Write the bound port to the port file
+ int port = server.getLocalPort();
+ channel.truncate(0);
+ channel.write(ByteBuffer.wrap(Integer.toString(port).getBytes()));
+
+ // Instantiate a Checkstyle runner and executor; serve until exit...
+ ExecutorService executor = Executors.newCachedThreadPool();
+ while (true) {
+ try {
+ 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());
+ }
+ }
+}
diff --git a/tools/build/conf/src/main/java/org/onosproject/buckdaemon/BuckTask.java b/tools/build/conf/src/main/java/org/onosproject/buckdaemon/BuckTask.java
new file mode 100644
index 0000000..fb6a8dc
--- /dev/null
+++ b/tools/build/conf/src/main/java/org/onosproject/buckdaemon/BuckTask.java
@@ -0,0 +1,31 @@
+/*
+ * 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);
+
+}
diff --git a/tools/build/conf/src/main/java/org/onosproject/buckdaemon/BuckTaskContext.java b/tools/build/conf/src/main/java/org/onosproject/buckdaemon/BuckTaskContext.java
new file mode 100644
index 0000000..dc5b753
--- /dev/null
+++ b/tools/build/conf/src/main/java/org/onosproject/buckdaemon/BuckTaskContext.java
@@ -0,0 +1,83 @@
+/*
+ * 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);
+ }
+
+}