| 1 | /* |
| 2 | * Copyright 2006-2007 the original author or authors. |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package org.springframework.batch.core.step.item; |
| 18 | |
| 19 | import java.util.ArrayList; |
| 20 | import java.util.Collections; |
| 21 | import java.util.List; |
| 22 | import java.util.concurrent.atomic.AtomicInteger; |
| 23 | |
| 24 | import org.apache.commons.logging.Log; |
| 25 | import org.apache.commons.logging.LogFactory; |
| 26 | import org.springframework.batch.classify.BinaryExceptionClassifier; |
| 27 | import org.springframework.batch.classify.Classifier; |
| 28 | import org.springframework.batch.core.StepContribution; |
| 29 | import org.springframework.batch.core.step.skip.LimitCheckingItemSkipPolicy; |
| 30 | import org.springframework.batch.core.step.skip.NonSkippableProcessException; |
| 31 | import org.springframework.batch.core.step.skip.SkipListenerFailedException; |
| 32 | import org.springframework.batch.core.step.skip.SkipPolicy; |
| 33 | import org.springframework.batch.item.ItemProcessor; |
| 34 | import org.springframework.batch.item.ItemWriter; |
| 35 | import org.springframework.batch.retry.ExhaustedRetryException; |
| 36 | import org.springframework.batch.retry.RecoveryCallback; |
| 37 | import org.springframework.batch.retry.RetryCallback; |
| 38 | import org.springframework.batch.retry.RetryContext; |
| 39 | import org.springframework.batch.retry.RetryException; |
| 40 | import org.springframework.batch.retry.support.DefaultRetryState; |
| 41 | |
| 42 | /** |
| 43 | * FaultTolerant implementation of the {@link ChunkProcessor} interface, that |
| 44 | * allows for skipping or retry of items that cause exceptions during writing. |
| 45 | * |
| 46 | */ |
| 47 | public class FaultTolerantChunkProcessor<I, O> extends SimpleChunkProcessor<I, O> { |
| 48 | |
| 49 | private SkipPolicy itemProcessSkipPolicy = new LimitCheckingItemSkipPolicy(0); |
| 50 | |
| 51 | private SkipPolicy itemWriteSkipPolicy = new LimitCheckingItemSkipPolicy(0); |
| 52 | |
| 53 | private final BatchRetryTemplate batchRetryTemplate; |
| 54 | |
| 55 | private Classifier<Throwable, Boolean> rollbackClassifier = new BinaryExceptionClassifier(true); |
| 56 | |
| 57 | private Log logger = LogFactory.getLog(getClass()); |
| 58 | |
| 59 | private boolean buffering = true; |
| 60 | |
| 61 | private KeyGenerator keyGenerator; |
| 62 | |
| 63 | private ChunkMonitor chunkMonitor = new ChunkMonitor(); |
| 64 | |
| 65 | /** |
| 66 | * The {@link KeyGenerator} to use to identify failed items across rollback. |
| 67 | * Not used in the case of the {@link #setBuffering(boolean) buffering flag} |
| 68 | * being true (the default). |
| 69 | * |
| 70 | * @param keyGenerator the {@link KeyGenerator} to set |
| 71 | */ |
| 72 | public void setKeyGenerator(KeyGenerator keyGenerator) { |
| 73 | this.keyGenerator = keyGenerator; |
| 74 | } |
| 75 | |
| 76 | /** |
| 77 | * @param SkipPolicy the {@link SkipPolicy} for item processing |
| 78 | */ |
| 79 | public void setProcessSkipPolicy(SkipPolicy SkipPolicy) { |
| 80 | this.itemProcessSkipPolicy = SkipPolicy; |
| 81 | } |
| 82 | |
| 83 | /** |
| 84 | * @param SkipPolicy the {@link SkipPolicy} for item writing |
| 85 | */ |
| 86 | public void setWriteSkipPolicy(SkipPolicy SkipPolicy) { |
| 87 | this.itemWriteSkipPolicy = SkipPolicy; |
| 88 | } |
| 89 | |
| 90 | /** |
| 91 | * A classifier that can distinguish between exceptions that cause rollback |
| 92 | * (return true) or not (return false). |
| 93 | * |
| 94 | * @param rollbackClassifier |
| 95 | */ |
| 96 | public void setRollbackClassifier(Classifier<Throwable, Boolean> rollbackClassifier) { |
| 97 | this.rollbackClassifier = rollbackClassifier; |
| 98 | } |
| 99 | |
| 100 | /** |
| 101 | * @param chunkMonitor |
| 102 | */ |
| 103 | public void setChunkMonitor(ChunkMonitor chunkMonitor) { |
| 104 | this.chunkMonitor = chunkMonitor; |
| 105 | } |
| 106 | |
| 107 | /** |
| 108 | * A flag to indicate that items have been buffered and therefore will |
| 109 | * always come back as a chunk after a rollback. Otherwise things are more |
| 110 | * complicated because after a rollback the new chunk might or moght not |
| 111 | * contain items from the previous failed chunk. |
| 112 | * |
| 113 | * @param buffering |
| 114 | */ |
| 115 | public void setBuffering(boolean buffering) { |
| 116 | this.buffering = buffering; |
| 117 | } |
| 118 | |
| 119 | public FaultTolerantChunkProcessor(ItemProcessor<? super I, ? extends O> itemProcessor, |
| 120 | ItemWriter<? super O> itemWriter, BatchRetryTemplate batchRetryTemplate) { |
| 121 | super(itemProcessor, itemWriter); |
| 122 | this.batchRetryTemplate = batchRetryTemplate; |
| 123 | } |
| 124 | |
| 125 | @Override |
| 126 | protected void initializeUserData(Chunk<I> inputs) { |
| 127 | @SuppressWarnings("unchecked") |
| 128 | UserData<O> data = (UserData<O>) inputs.getUserData(); |
| 129 | if (data == null) { |
| 130 | data = new UserData<O>(inputs.size()); |
| 131 | inputs.setUserData(data); |
| 132 | data.setOutputs(new Chunk<O>()); |
| 133 | } |
| 134 | } |
| 135 | |
| 136 | @Override |
| 137 | protected int getFilterCount(Chunk<I> inputs, Chunk<O> outputs) { |
| 138 | @SuppressWarnings("unchecked") |
| 139 | UserData<O> data = (UserData<O>) inputs.getUserData(); |
| 140 | return data.size() - outputs.size() - inputs.getSkips().size(); |
| 141 | } |
| 142 | |
| 143 | @Override |
| 144 | protected boolean isComplete(Chunk<I> inputs) { |
| 145 | |
| 146 | /* |
| 147 | * Need to remember the write skips across transactions, otherwise they |
| 148 | * keep coming back. Since we register skips with the inputs they will |
| 149 | * not be processed again but the output skips need to be saved for |
| 150 | * registration later with the listeners. The inputs are going to be the |
| 151 | * same for all transactions processing the same chunk, but the outputs |
| 152 | * are not, so we stash them in user data on the inputs. |
| 153 | */ |
| 154 | |
| 155 | @SuppressWarnings("unchecked") |
| 156 | UserData<O> data = (UserData<O>) inputs.getUserData(); |
| 157 | Chunk<O> previous = data.getOutputs(); |
| 158 | |
| 159 | return inputs.isEmpty() && previous.getSkips().isEmpty(); |
| 160 | |
| 161 | } |
| 162 | |
| 163 | @Override |
| 164 | protected Chunk<O> getAdjustedOutputs(Chunk<I> inputs, Chunk<O> outputs) { |
| 165 | |
| 166 | @SuppressWarnings("unchecked") |
| 167 | UserData<O> data = (UserData<O>) inputs.getUserData(); |
| 168 | Chunk<O> previous = data.getOutputs(); |
| 169 | |
| 170 | Chunk<O> next = new Chunk<O>(outputs.getItems(), previous.getSkips()); |
| 171 | next.setBusy(previous.isBusy()); |
| 172 | |
| 173 | // Remember for next time if there are skips accumulating |
| 174 | data.setOutputs(next); |
| 175 | |
| 176 | return next; |
| 177 | |
| 178 | } |
| 179 | |
| 180 | @Override |
| 181 | protected Chunk<O> transform(final StepContribution contribution, Chunk<I> inputs) throws Exception { |
| 182 | |
| 183 | Chunk<O> outputs = new Chunk<O>(); |
| 184 | @SuppressWarnings("unchecked") |
| 185 | UserData<O> data = (UserData<O>) inputs.getUserData(); |
| 186 | Chunk<O> cache = data.getOutputs(); |
| 187 | final Chunk<O>.ChunkIterator cacheIterator = cache.isEmpty() ? null : cache.iterator(); |
| 188 | final AtomicInteger count = new AtomicInteger(0); |
| 189 | |
| 190 | for (final Chunk<I>.ChunkIterator iterator = inputs.iterator(); iterator.hasNext();) { |
| 191 | |
| 192 | final I item = iterator.next(); |
| 193 | |
| 194 | RetryCallback<O> retryCallback = new RetryCallback<O>() { |
| 195 | |
| 196 | public O doWithRetry(RetryContext context) throws Exception { |
| 197 | O output = null; |
| 198 | try { |
| 199 | count.incrementAndGet(); |
| 200 | O cached = (cacheIterator != null) ? cacheIterator.next() : null; |
| 201 | if (cached != null && count.get() > 1) { |
| 202 | /* |
| 203 | * If there is a cached chunk then we must be |
| 204 | * scanning for errors in the writer, in which case |
| 205 | * only the first one will be written, and for the |
| 206 | * rest we need to fill in the output from the |
| 207 | * cache. |
| 208 | */ |
| 209 | output = cached; |
| 210 | } |
| 211 | else { |
| 212 | output = doProcess(item); |
| 213 | } |
| 214 | } |
| 215 | catch (Exception e) { |
| 216 | if (rollbackClassifier.classify(e)) { |
| 217 | // Default is to rollback unless the classifier |
| 218 | // allows us to continue |
| 219 | throw e; |
| 220 | } |
| 221 | else if (itemProcessSkipPolicy.shouldSkip(e, contribution.getStepSkipCount())) { |
| 222 | // If we are not re-throwing then we should check if |
| 223 | // this is skippable |
| 224 | contribution.incrementProcessSkipCount(); |
| 225 | logger.debug("Skipping after failed process with no rollback", e); |
| 226 | } |
| 227 | else { |
| 228 | // If it's not skippable that's an error in |
| 229 | // configuration - it doesn't make sense to not roll |
| 230 | // back if we are also not allowed to skip |
| 231 | throw new NonSkippableProcessException( |
| 232 | "Non-skippable exception in processor. Make sure any exceptions that do not cause a rollback are skippable.", |
| 233 | e); |
| 234 | } |
| 235 | } |
| 236 | if (output == null) { |
| 237 | // No need to re-process filtered items |
| 238 | iterator.remove(); |
| 239 | } |
| 240 | return output; |
| 241 | } |
| 242 | |
| 243 | }; |
| 244 | |
| 245 | RecoveryCallback<O> recoveryCallback = new RecoveryCallback<O>() { |
| 246 | |
| 247 | public O recover(RetryContext context) throws Exception { |
| 248 | Exception e = (Exception) context.getLastThrowable(); |
| 249 | if (itemProcessSkipPolicy.shouldSkip(e, contribution.getStepSkipCount())) { |
| 250 | contribution.incrementProcessSkipCount(); |
| 251 | iterator.remove(e); |
| 252 | logger.debug("Skipping after failed process", e); |
| 253 | return null; |
| 254 | } |
| 255 | else { |
| 256 | throw new RetryException("Non-skippable exception in recoverer while processing", e); |
| 257 | } |
| 258 | } |
| 259 | |
| 260 | }; |
| 261 | |
| 262 | O output = batchRetryTemplate.execute(retryCallback, recoveryCallback, new DefaultRetryState( |
| 263 | getInputKey(item), rollbackClassifier)); |
| 264 | if (output != null) { |
| 265 | outputs.add(output); |
| 266 | } |
| 267 | |
| 268 | } |
| 269 | |
| 270 | return outputs; |
| 271 | |
| 272 | } |
| 273 | |
| 274 | @Override |
| 275 | protected void write(final StepContribution contribution, final Chunk<I> inputs, final Chunk<O> outputs) |
| 276 | throws Exception { |
| 277 | |
| 278 | RetryCallback<Object> retryCallback = new RetryCallback<Object>() { |
| 279 | public Object doWithRetry(RetryContext context) throws Exception { |
| 280 | |
| 281 | if (!inputs.isBusy()) { |
| 282 | chunkMonitor.setChunkSize(inputs.size()); |
| 283 | try { |
| 284 | doWrite(outputs.getItems()); |
| 285 | } |
| 286 | catch (Exception e) { |
| 287 | if (rollbackClassifier.classify(e)) { |
| 288 | throw e; |
| 289 | } |
| 290 | /* |
| 291 | * If the exception is marked as no-rollback, we need to |
| 292 | * override that, otherwise there's no way to write the |
| 293 | * rest of the chunk or to honour the skip listener |
| 294 | * contract. |
| 295 | */ |
| 296 | throw new ForceRollbackForWriteSkipException( |
| 297 | "Force rollback on skippable exception so that skipped item can be located.", e); |
| 298 | } |
| 299 | contribution.incrementWriteCount(outputs.size()); |
| 300 | } |
| 301 | else { |
| 302 | scan(contribution, inputs, outputs, chunkMonitor); |
| 303 | } |
| 304 | return null; |
| 305 | |
| 306 | } |
| 307 | }; |
| 308 | |
| 309 | if (!buffering) { |
| 310 | |
| 311 | RecoveryCallback<Object> batchRecoveryCallback = new RecoveryCallback<Object>() { |
| 312 | |
| 313 | public Object recover(RetryContext context) throws Exception { |
| 314 | |
| 315 | Exception e = (Exception) context.getLastThrowable(); |
| 316 | if (outputs.size() > 1 && !rollbackClassifier.classify(e)) { |
| 317 | throw new RetryException("Invalid retry state during write caused by " |
| 318 | + "exception that does not classify for rollback: ", e); |
| 319 | } |
| 320 | |
| 321 | Chunk<I>.ChunkIterator inputIterator = inputs.iterator(); |
| 322 | for (Chunk<O>.ChunkIterator outputIterator = outputs.iterator(); outputIterator.hasNext();) { |
| 323 | |
| 324 | inputIterator.next(); |
| 325 | outputIterator.next(); |
| 326 | |
| 327 | checkSkipPolicy(inputIterator, outputIterator, e, contribution); |
| 328 | if (!rollbackClassifier.classify(e)) { |
| 329 | throw new RetryException( |
| 330 | "Invalid retry state during recovery caused by exception that does not classify for rollback: ", |
| 331 | e); |
| 332 | } |
| 333 | |
| 334 | } |
| 335 | |
| 336 | return null; |
| 337 | |
| 338 | } |
| 339 | |
| 340 | }; |
| 341 | |
| 342 | batchRetryTemplate.execute(retryCallback, batchRecoveryCallback, BatchRetryTemplate.createState( |
| 343 | getInputKeys(inputs), rollbackClassifier)); |
| 344 | |
| 345 | } |
| 346 | else { |
| 347 | |
| 348 | RecoveryCallback<Object> recoveryCallback = new RecoveryCallback<Object>() { |
| 349 | |
| 350 | public Object recover(RetryContext context) throws Exception { |
| 351 | |
| 352 | /* |
| 353 | * If the last exception was not skippable we don't need to |
| 354 | * do any scanning. We can just bomb out with a retry |
| 355 | * exhausted. |
| 356 | */ |
| 357 | if (!itemWriteSkipPolicy.shouldSkip(context.getLastThrowable(), -1)) { |
| 358 | throw new ExhaustedRetryException( |
| 359 | "Retry exhausted after last attempt in recovery path, but exception is not skippable.", |
| 360 | context.getLastThrowable()); |
| 361 | } |
| 362 | |
| 363 | inputs.setBusy(true); |
| 364 | scan(contribution, inputs, outputs, chunkMonitor); |
| 365 | return null; |
| 366 | } |
| 367 | |
| 368 | }; |
| 369 | |
| 370 | logger.debug("Attempting to write: " + inputs); |
| 371 | batchRetryTemplate.execute(retryCallback, recoveryCallback, new DefaultRetryState(inputs, |
| 372 | rollbackClassifier)); |
| 373 | |
| 374 | } |
| 375 | |
| 376 | callSkipListeners(inputs, outputs); |
| 377 | |
| 378 | } |
| 379 | |
| 380 | private void callSkipListeners(final Chunk<I> inputs, final Chunk<O> outputs) { |
| 381 | |
| 382 | for (SkipWrapper<I> wrapper : inputs.getSkips()) { |
| 383 | I item = wrapper.getItem(); |
| 384 | if (item == null) { |
| 385 | continue; |
| 386 | } |
| 387 | Exception e = wrapper.getException(); |
| 388 | try { |
| 389 | getListener().onSkipInProcess(item, e); |
| 390 | } |
| 391 | catch (RuntimeException ex) { |
| 392 | throw new SkipListenerFailedException("Fatal exception in SkipListener.", ex, e); |
| 393 | } |
| 394 | } |
| 395 | |
| 396 | for (SkipWrapper<O> wrapper : outputs.getSkips()) { |
| 397 | Exception e = wrapper.getException(); |
| 398 | try { |
| 399 | getListener().onSkipInWrite(wrapper.getItem(), e); |
| 400 | } |
| 401 | catch (RuntimeException ex) { |
| 402 | throw new SkipListenerFailedException("Fatal exception in SkipListener.", ex, e); |
| 403 | } |
| 404 | } |
| 405 | |
| 406 | // Clear skips if we are possibly going to process this chunk again |
| 407 | outputs.clearSkips(); |
| 408 | inputs.clearSkips(); |
| 409 | |
| 410 | } |
| 411 | |
| 412 | private Object getInputKey(I item) { |
| 413 | if (keyGenerator == null) { |
| 414 | return item; |
| 415 | } |
| 416 | return keyGenerator.getKey(item); |
| 417 | } |
| 418 | |
| 419 | private List<?> getInputKeys(final Chunk<I> inputs) { |
| 420 | if (keyGenerator == null) { |
| 421 | return inputs.getItems(); |
| 422 | } |
| 423 | List<Object> keys = new ArrayList<Object>(); |
| 424 | for (I item : inputs.getItems()) { |
| 425 | keys.add(keyGenerator.getKey(item)); |
| 426 | } |
| 427 | return keys; |
| 428 | } |
| 429 | |
| 430 | private void checkSkipPolicy(Chunk<I>.ChunkIterator inputIterator, Chunk<O>.ChunkIterator outputIterator, |
| 431 | Exception e, StepContribution contribution) { |
| 432 | logger.debug("Checking skip policy after failed write"); |
| 433 | if (itemWriteSkipPolicy.shouldSkip(e, contribution.getStepSkipCount())) { |
| 434 | contribution.incrementWriteSkipCount(); |
| 435 | inputIterator.remove(); |
| 436 | outputIterator.remove(e); |
| 437 | logger.debug("Skipping after failed write", e); |
| 438 | } |
| 439 | else { |
| 440 | throw new RetryException("Non-skippable exception in recoverer", e); |
| 441 | } |
| 442 | } |
| 443 | |
| 444 | private void scan(final StepContribution contribution, final Chunk<I> inputs, final Chunk<O> outputs, |
| 445 | ChunkMonitor chunkMonitor) throws Exception { |
| 446 | |
| 447 | logger.debug("Scanning for failed item on write: " + inputs); |
| 448 | if (outputs.isEmpty()) { |
| 449 | inputs.setBusy(false); |
| 450 | return; |
| 451 | } |
| 452 | |
| 453 | Chunk<I>.ChunkIterator inputIterator = inputs.iterator(); |
| 454 | Chunk<O>.ChunkIterator outputIterator = outputs.iterator(); |
| 455 | |
| 456 | List<O> items = Collections.singletonList(outputIterator.next()); |
| 457 | inputIterator.next(); |
| 458 | try { |
| 459 | writeItems(items); |
| 460 | // If successful we are going to return and allow |
| 461 | // the driver to commit... |
| 462 | doAfterWrite(items); |
| 463 | contribution.incrementWriteCount(1); |
| 464 | inputIterator.remove(); |
| 465 | outputIterator.remove(); |
| 466 | } |
| 467 | catch (Exception e) { |
| 468 | if (!itemWriteSkipPolicy.shouldSkip(e, -1) && !rollbackClassifier.classify(e)) { |
| 469 | inputIterator.remove(); |
| 470 | outputIterator.remove(); |
| 471 | } |
| 472 | else { |
| 473 | checkSkipPolicy(inputIterator, outputIterator, e, contribution); |
| 474 | } |
| 475 | if (rollbackClassifier.classify(e)) { |
| 476 | throw e; |
| 477 | } |
| 478 | } |
| 479 | chunkMonitor.incrementOffset(); |
| 480 | if (outputs.isEmpty()) { |
| 481 | inputs.setBusy(false); |
| 482 | chunkMonitor.resetOffset(); |
| 483 | } |
| 484 | } |
| 485 | |
| 486 | private static class UserData<O> { |
| 487 | |
| 488 | private final int size; |
| 489 | |
| 490 | private Chunk<O> outputs; |
| 491 | |
| 492 | public UserData(int size) { |
| 493 | this.size = size; |
| 494 | } |
| 495 | |
| 496 | public int size() { |
| 497 | return size; |
| 498 | } |
| 499 | |
| 500 | public Chunk<O> getOutputs() { |
| 501 | return outputs; |
| 502 | } |
| 503 | |
| 504 | public void setOutputs(Chunk<O> outputs) { |
| 505 | this.outputs = outputs; |
| 506 | } |
| 507 | |
| 508 | } |
| 509 | |
| 510 | } |