java - JBeret 和 JSR352，关于重启和持久数据的一些说明

Question

我目前正在使用 JBeret 作为 JSR 352 规范的批量实现。

第一期

我正在尝试重现处理器失败的 block 作业并存储重新启动位置，以便我可以从最后一个成功的索引重新启动。

这是Reader类

@Named
public class MyReaderFails extends AbstractItemReader {

    @Inject
    Logger logger;

    List<Integer> output;
    int index;

    @Inject
    StepContext stepContext;

    @Override
    public Object readItem() throws Exception {
        logger.info("reading item: {}", index);
        return output.get(index++);
    }

    @Override
    public void open(Serializable checkpoint) throws Exception {
        logger.info("open: {}", checkpoint);
        int startIndex = Optional.ofNullable(checkpoint).map(Integer.class::cast).orElse(0);
        output = IntStream.range(startIndex, 30).boxed().collect(Collectors.toList());
    }

    @Override
    public Serializable checkpointInfo() throws Exception {
        logger.info("current checkpoint: {}", index);
        return index;
    }
}

这是处理器

@Named
public class MyProcessorFails implements ItemProcessor {

    @Inject
    Logger logger;

    @Inject
    @BatchProperty(name = "itemnumerror")
    Integer itemnumerror;

    @Inject
    @BatchProperty(name = "error")
    Boolean error;

    @Override
    public Object processItem(Object o) throws Exception {
        logger.info("input: {}", o);
        if (itemnumerror == o && error) {
            throw new RuntimeException(); //first time batch is started, throws an error
        }
        Integer output = (Integer)o + 30;

        return output;
    }
}

作家

@Named
public class MyWriterFails extends AbstractItemWriter {

    @Inject
    Logger logger;

    @Inject
    StepContext stepContext;

    @SuppressWarnings("squid:S2629")
    @Override
    public void writeItems(List<Object> list) throws Exception {
        logger.info("output: {}", list.stream().map(String::valueOf).collect(Collectors.joining(" , ", "{", "}")));
        ArrayList<Integer> processed = Optional.ofNullable(stepContext.getPersistentUserData()).map(ArrayList.class::cast).orElse(new ArrayList<Integer>());
        processed.addAll(list.stream().map(Integer.class::cast).collect(Collectors.toList()));
        stepContext.setPersistentUserData(processed);
    }

    @Override
    public Serializable checkpointInfo() throws Exception {
        return Optional.of(stepContext.getPersistentUserData()).map(List.class::cast).map(List::size).orElse(0);
    }
}

现在我希望如果作业失败，它会将 JOB_EXECUTION.RESTART_POSITION 列设置为从 checkpointInfo 返回的索引，但是这个不会发生。

因此，当我尝试从最后一个 id 重新启 Action 业时，检查点始终为空。

如何存储检查点以便从 open 方法检索它？

第二期

在应用程序测试中，我经常看到从 stepContext 对象设置持久性用户数据(另请参阅我的编写器实现)。这个的真正用途是什么？我能用保存的数据做什么？

我还猜测，当处理数千条记录时，这种做法可能会导致严重的内存开销。

有什么提示吗？

Answer 1

这是我在测试中使用的作业 xml:

<?xml version="1.0" encoding="UTF-8"?>

<job id="fail-restart" xmlns="http://xmlns.jcp.org/xml/ns/javaee"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/jobXML_1_0.xsd"
     version="1.0">
    <step id="fail-restart.step1">
        <chunk item-count="10">
            <reader ref="myReaderFails">
                <properties>
                    <property name="logger" value="java.util.logging.Logger"/>
                </properties>
            </reader>
            <processor ref="myProcessorFails">
            <properties>
                <property name="logger" value="java.util.logging.Logger"/>
                <property name="error" value="#{jobParameters['error']}"/>
                <property name="itemnumerror" value="15"/>
            </properties>
            </processor>
            <writer ref="myWriterFails">
            <properties>
                <property name="logger" value="java.util.logging.Logger"/>
            </properties>
            </writer>
        </chunk>
    </step>
</job>

这是测试方法:

public class SimpleIT {
    private static final JobOperator jobOperator = BatchRuntime.getJobOperator();

    @Test
    public void failRestart() throws Exception {
        final Properties params = new Properties();
        params.setProperty("error", String.valueOf(Boolean.TRUE));

        final long jobExecutionId = jobOperator.start("fail-restart", params);
        JobExecutionImpl jobExecution = (JobExecutionImpl) jobOperator.getJobExecution(jobExecutionId);
        jobExecution.awaitTermination(5, TimeUnit.MINUTES);
        Assert.assertEquals(BatchStatus.FAILED, jobExecution.getBatchStatus());

        params.setProperty("error", String.valueOf(Boolean.FALSE));
        final long restartId = jobOperator.restart(jobExecutionId, params);
        jobExecution = (JobExecutionImpl) jobOperator.getJobExecution(restartId);
        jobExecution.awaitTermination(5, TimeUnit.MINUTES);
        Assert.assertEquals(BatchStatus.COMPLETED, jobExecution.getBatchStatus());
    }
}

输出:

Dec 09, 2019 11:36:18 AM sample.MyReaderFails open
INFO: open: null
output list: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29]
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 0
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 0
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 1
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 1
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 2
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 2
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 3
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 3
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 4
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 4
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 5
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 5
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 6
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 6
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 7
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 7
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 8
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 8
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 9
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 9
Dec 09, 2019 11:36:18 AM sample.MyWriterFails writeItems
INFO: output: {30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39}
Dec 09, 2019 11:36:18 AM sample.MyReaderFails checkpointInfo
INFO: current checkpoint: 10
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 10
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 10
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 11
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 11
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 12
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 12
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 13
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 13
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 14
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 14
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 15
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 15
Dec 09, 2019 11:36:18 AM org.jberet.runtime.runner.ChunkRunner readProcessWriteItems
ERROR: ProcessingInfo{count=6, timerExpired=false, itemState=RUNNING, chunkState=RUNNING, checkpointPosition=9, readPosition=15, failurePoint=null}
Dec 09, 2019 11:36:18 AM org.jberet.runtime.runner.ChunkRunner run
ERROR: item-count=10, time-limit=0, skip-limit=-1, skipCount=0, retry-limit=-1, retryCount=0
Dec 09, 2019 11:36:18 AM org.jberet.runtime.runner.ChunkRunner run
ERROR: JBERET000007: Failed to run job fail-restart, fail-restart.step1, org.jberet.job.model.Chunk@7f938562
java.lang.RuntimeException
    at sample.MyProcessorFails.processItem(MyProcessorFails.java:38)
    at org.jberet.runtime.runner.ChunkRunner.processItem(ChunkRunner.java:422)
    at org.jberet.runtime.runner.ChunkRunner.readProcessWriteItems(ChunkRunner.java:335)
    at org.jberet.runtime.runner.ChunkRunner.run(ChunkRunner.java:208)
    at org.jberet.runtime.runner.StepExecutionRunner.runBatchletOrChunk(StepExecutionRunner.java:225)
    at org.jberet.runtime.runner.StepExecutionRunner.run(StepExecutionRunner.java:144)
    at org.jberet.runtime.runner.CompositeExecutionRunner.runStep(CompositeExecutionRunner.java:164)
    at org.jberet.runtime.runner.CompositeExecutionRunner.runFromHeadOrRestartPoint(CompositeExecutionRunner.java:88)
    at org.jberet.runtime.runner.JobExecutionRunner.run(JobExecutionRunner.java:60)
    at org.jberet.spi.JobExecutor$1.run(JobExecutor.java:99)
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1135)
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
    at java.base/java.lang.Thread.run(Thread.java:844)

Dec 09, 2019 11:36:18 AM sample.MyReaderFails open
INFO: open: 10
output list: [10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29]
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 0
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 10
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 1
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 11
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 2
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 12
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 3
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 13
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 4
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 14
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 5
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 15
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 6
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 16
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 7
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 17
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 8
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 18
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 9
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 19
Dec 09, 2019 11:36:18 AM sample.MyWriterFails writeItems
INFO: output: {40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49}
Dec 09, 2019 11:36:18 AM sample.MyReaderFails checkpointInfo
INFO: current checkpoint: 10
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 10
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 20
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 11
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 21
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 12
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 22
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 13
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 23
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 14
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 24
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 15
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 25
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 16
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 26
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 17
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 27
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 18
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 28
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 19
Dec 09, 2019 11:36:18 AM sample.MyProcessorFails processItem
INFO: input: 29
Dec 09, 2019 11:36:18 AM sample.MyWriterFails writeItems
INFO: output: {50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59}
Dec 09, 2019 11:36:18 AM sample.MyReaderFails checkpointInfo
INFO: current checkpoint: 20
Dec 09, 2019 11:36:18 AM sample.MyReaderFails readItem
INFO: reading item: 20
Dec 09, 2019 11:36:18 AM sample.MyReaderFails checkpointInfo
INFO: current checkpoint: 21
Weld SE container STATIC_INSTANCE shut down by shutdown hook

Process finished with exit code 0