| 1 | package org.apache.continuum.taskqueueexecutor; |
| 2 | |
| 3 | /* |
| 4 | * Licensed to the Apache Software Foundation (ASF) under one |
| 5 | * or more contributor license agreements. See the NOTICE file |
| 6 | * distributed with this work for additional information |
| 7 | * regarding copyright ownership. The ASF licenses this file |
| 8 | * to you under the Apache License, Version 2.0 (the |
| 9 | * "License"); you may not use this file except in compliance |
| 10 | * with the License. You may obtain a copy of the License at |
| 11 | * |
| 12 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 13 | * |
| 14 | * Unless required by applicable law or agreed to in writing, |
| 15 | * software distributed under the License is distributed on an |
| 16 | * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| 17 | * KIND, either express or implied. See the License for the |
| 18 | * specific language governing permissions and limitations |
| 19 | * under the License. |
| 20 | */ |
| 21 | |
| 22 | import org.codehaus.plexus.personality.plexus.lifecycle.phase.Initializable; |
| 23 | import org.codehaus.plexus.personality.plexus.lifecycle.phase.InitializationException; |
| 24 | import org.codehaus.plexus.personality.plexus.lifecycle.phase.Startable; |
| 25 | import org.codehaus.plexus.personality.plexus.lifecycle.phase.StartingException; |
| 26 | import org.codehaus.plexus.personality.plexus.lifecycle.phase.StoppingException; |
| 27 | import org.codehaus.plexus.taskqueue.Task; |
| 28 | import org.codehaus.plexus.taskqueue.TaskQueue; |
| 29 | import org.codehaus.plexus.taskqueue.execution.TaskExecutionException; |
| 30 | import org.codehaus.plexus.taskqueue.execution.TaskExecutor; |
| 31 | import org.codehaus.plexus.taskqueue.execution.TaskQueueExecutor; |
| 32 | import org.codehaus.plexus.util.StringUtils; |
| 33 | import org.slf4j.Logger; |
| 34 | import org.slf4j.LoggerFactory; |
| 35 | |
| 36 | import edu.emory.mathcs.backport.java.util.concurrent.CancellationException; |
| 37 | import edu.emory.mathcs.backport.java.util.concurrent.ExecutionException; |
| 38 | import edu.emory.mathcs.backport.java.util.concurrent.ExecutorService; |
| 39 | import edu.emory.mathcs.backport.java.util.concurrent.Executors; |
| 40 | import edu.emory.mathcs.backport.java.util.concurrent.Future; |
| 41 | import edu.emory.mathcs.backport.java.util.concurrent.TimeUnit; |
| 42 | import edu.emory.mathcs.backport.java.util.concurrent.TimeoutException; |
| 43 | |
| 44 | /** |
| 45 | * Modified plexus ThreadedTaskQueueExecutor |
| 46 | */ |
| 47 | public class ParallelBuildsThreadedTaskQueueExecutor |
| 48 | implements TaskQueueExecutor, Initializable, Startable |
| 49 | { |
| 50 | private static final Logger log = LoggerFactory.getLogger( ParallelBuildsThreadedTaskQueueExecutor.class ); |
| 51 | |
| 52 | private static final int SHUTDOWN = 1; |
| 53 | |
| 54 | private static final int CANCEL_TASK = 2; |
| 55 | |
| 56 | /** |
| 57 | * @requirement |
| 58 | */ |
| 59 | private TaskQueue queue; |
| 60 | |
| 61 | /** |
| 62 | * @requirement |
| 63 | */ |
| 64 | private TaskExecutor executor; |
| 65 | |
| 66 | /** |
| 67 | * @configuration |
| 68 | */ |
| 69 | private String name; |
| 70 | |
| 71 | // ---------------------------------------------------------------------- |
| 72 | // |
| 73 | // ---------------------------------------------------------------------- |
| 74 | |
| 75 | private ExecutorRunnable executorRunnable; |
| 76 | |
| 77 | private ExecutorService executorService; |
| 78 | |
| 79 | private Task currentTask; |
| 80 | |
| 81 | private class ExecutorRunnable |
| 82 | extends Thread |
| 83 | { |
| 84 | private volatile int command; |
| 85 | |
| 86 | private boolean done; |
| 87 | |
| 88 | public void run() |
| 89 | { |
| 90 | while ( command != SHUTDOWN ) |
| 91 | { |
| 92 | final Task task; |
| 93 | |
| 94 | currentTask = null; |
| 95 | |
| 96 | try |
| 97 | { |
| 98 | task = queue.poll( 100, TimeUnit.MILLISECONDS ); |
| 99 | } |
| 100 | catch ( InterruptedException e ) |
| 101 | { |
| 102 | log.info( "Executor thread interrupted, command: " + |
| 103 | ( command == SHUTDOWN ? "Shutdown" : command == CANCEL_TASK ? "Cancel task" : "Unknown" ) ); |
| 104 | continue; |
| 105 | } |
| 106 | |
| 107 | if ( task == null ) |
| 108 | { |
| 109 | continue; |
| 110 | } |
| 111 | |
| 112 | currentTask = task; |
| 113 | |
| 114 | Future future = executorService.submit( new Runnable() |
| 115 | { |
| 116 | public void run() |
| 117 | { |
| 118 | try |
| 119 | { |
| 120 | executor.executeTask( task ); |
| 121 | } |
| 122 | catch ( TaskExecutionException e ) |
| 123 | { |
| 124 | log.error( "Error executing task", e ); |
| 125 | } |
| 126 | } |
| 127 | } ); |
| 128 | |
| 129 | try |
| 130 | { |
| 131 | waitForTask( task, future ); |
| 132 | } |
| 133 | catch ( ExecutionException e ) |
| 134 | { |
| 135 | log.error( "Error executing task", e ); |
| 136 | } |
| 137 | } |
| 138 | |
| 139 | currentTask = null; |
| 140 | |
| 141 | log.info( "Executor thread '" + name + "' exited." ); |
| 142 | |
| 143 | done = true; |
| 144 | |
| 145 | synchronized ( this ) |
| 146 | { |
| 147 | notifyAll(); |
| 148 | } |
| 149 | } |
| 150 | |
| 151 | private void waitForTask( Task task, Future future ) |
| 152 | throws ExecutionException |
| 153 | { |
| 154 | boolean stop = false; |
| 155 | |
| 156 | while ( !stop ) |
| 157 | { |
| 158 | try |
| 159 | { |
| 160 | if ( task.getMaxExecutionTime() == 0 ) |
| 161 | { |
| 162 | log.debug( "Waiting indefinitely for task to complete" ); |
| 163 | future.get(); |
| 164 | return; |
| 165 | } |
| 166 | else |
| 167 | { |
| 168 | log.debug( "Waiting at most " + task.getMaxExecutionTime() + "ms for task completion" ); |
| 169 | future.get( task.getMaxExecutionTime(), TimeUnit.MILLISECONDS ); |
| 170 | log.debug( "Task completed within " + task.getMaxExecutionTime() + "ms" ); |
| 171 | return; |
| 172 | } |
| 173 | } |
| 174 | catch ( InterruptedException e ) |
| 175 | { |
| 176 | switch ( command ) |
| 177 | { |
| 178 | case SHUTDOWN: |
| 179 | { |
| 180 | log.info( "Shutdown command received. Cancelling task." ); |
| 181 | cancel( future ); |
| 182 | return; |
| 183 | } |
| 184 | |
| 185 | case CANCEL_TASK: |
| 186 | { |
| 187 | command = 0; |
| 188 | log.info( "Cancelling task" ); |
| 189 | cancel( future ); |
| 190 | return; |
| 191 | } |
| 192 | |
| 193 | default: |
| 194 | // when can this thread be interrupted, and should we ignore it if shutdown = false? |
| 195 | log.warn( "Interrupted while waiting for task to complete; ignoring", e ); |
| 196 | break; |
| 197 | } |
| 198 | } |
| 199 | catch ( TimeoutException e ) |
| 200 | { |
| 201 | log.warn( "Task " + task + " didn't complete within time, cancelling it." ); |
| 202 | cancel( future ); |
| 203 | return; |
| 204 | } |
| 205 | catch ( CancellationException e ) |
| 206 | { |
| 207 | log.warn( "The task was cancelled", e ); |
| 208 | return; |
| 209 | } |
| 210 | } |
| 211 | } |
| 212 | |
| 213 | private void cancel( Future future ) |
| 214 | { |
| 215 | if ( !future.cancel( true ) ) |
| 216 | { |
| 217 | if ( !future.isDone() && !future.isCancelled() ) |
| 218 | { |
| 219 | log.warn( "Unable to cancel task" ); |
| 220 | } |
| 221 | else |
| 222 | { |
| 223 | log.warn( |
| 224 | "Task not cancelled (Flags: done: " + future.isDone() + " cancelled: " + future.isCancelled() + |
| 225 | ")" ); |
| 226 | } |
| 227 | } |
| 228 | else |
| 229 | { |
| 230 | log.debug( "Task successfully cancelled" ); |
| 231 | } |
| 232 | } |
| 233 | |
| 234 | public synchronized void shutdown() |
| 235 | { |
| 236 | log.debug( "Signalling executor thread to shutdown" ); |
| 237 | |
| 238 | command = SHUTDOWN; |
| 239 | |
| 240 | interrupt(); |
| 241 | } |
| 242 | |
| 243 | public synchronized boolean cancelTask( Task task ) |
| 244 | { |
| 245 | if ( !task.equals( currentTask ) ) |
| 246 | { |
| 247 | log.debug( "Not cancelling task - it is not running" ); |
| 248 | return false; |
| 249 | } |
| 250 | |
| 251 | if ( command != SHUTDOWN ) |
| 252 | { |
| 253 | log.debug( "Signalling executor thread to cancel task" ); |
| 254 | |
| 255 | command = CANCEL_TASK; |
| 256 | |
| 257 | interrupt(); |
| 258 | } |
| 259 | else |
| 260 | { |
| 261 | log.debug( "Executor thread already stopping; task will be cancelled automatically" ); |
| 262 | } |
| 263 | |
| 264 | return true; |
| 265 | } |
| 266 | |
| 267 | public boolean isDone() |
| 268 | { |
| 269 | return done; |
| 270 | } |
| 271 | } |
| 272 | |
| 273 | // ---------------------------------------------------------------------- |
| 274 | // Component lifecycle |
| 275 | // ---------------------------------------------------------------------- |
| 276 | |
| 277 | public void initialize() |
| 278 | throws InitializationException |
| 279 | { |
| 280 | if ( StringUtils.isEmpty( name ) ) |
| 281 | { |
| 282 | throw new IllegalArgumentException( "'name' must be set." ); |
| 283 | } |
| 284 | } |
| 285 | |
| 286 | public void start() |
| 287 | throws StartingException |
| 288 | { |
| 289 | log.info( "Starting task executor, thread name '" + name + "'." ); |
| 290 | |
| 291 | this.executorService = Executors.newCachedThreadPool(); |
| 292 | |
| 293 | executorRunnable = new ExecutorRunnable(); |
| 294 | |
| 295 | executorRunnable.setDaemon( true ); |
| 296 | |
| 297 | executorRunnable.start(); |
| 298 | } |
| 299 | |
| 300 | public void stop() |
| 301 | throws StoppingException |
| 302 | { |
| 303 | executorRunnable.shutdown(); |
| 304 | |
| 305 | int maxSleep = 10 * 1000; // 10 seconds |
| 306 | |
| 307 | int interval = 1000; |
| 308 | |
| 309 | long endTime = System.currentTimeMillis() + maxSleep; |
| 310 | |
| 311 | while ( !executorRunnable.isDone() && executorRunnable.isAlive() ) |
| 312 | { |
| 313 | if ( System.currentTimeMillis() > endTime ) |
| 314 | { |
| 315 | log.warn( "Timeout waiting for executor thread '" + name + "' to stop, aborting" ); |
| 316 | break; |
| 317 | } |
| 318 | |
| 319 | log.info( "Waiting until task executor '" + name + "' is idling..." ); |
| 320 | |
| 321 | try |
| 322 | { |
| 323 | synchronized ( executorRunnable ) |
| 324 | { |
| 325 | executorRunnable.wait( interval ); |
| 326 | } |
| 327 | } |
| 328 | catch ( InterruptedException ex ) |
| 329 | { |
| 330 | // ignore |
| 331 | } |
| 332 | |
| 333 | // notify again, just in case. |
| 334 | executorRunnable.shutdown(); |
| 335 | } |
| 336 | } |
| 337 | |
| 338 | public Task getCurrentTask() |
| 339 | { |
| 340 | return currentTask; |
| 341 | } |
| 342 | |
| 343 | public synchronized boolean cancelTask( Task task ) |
| 344 | { |
| 345 | return executorRunnable.cancelTask( task ); |
| 346 | } |
| 347 | |
| 348 | public String getName() |
| 349 | { |
| 350 | return name; |
| 351 | } |
| 352 | |
| 353 | public void setName( String name ) |
| 354 | { |
| 355 | this.name = name; |
| 356 | } |
| 357 | |
| 358 | public TaskQueue getQueue() |
| 359 | { |
| 360 | return queue; |
| 361 | } |
| 362 | } |