Spring Batch：重新启动一个作业，然后自动启动下一个作业 [英] Spring batch :Restart a job and then start next job automatically

问题描述

我需要创建恢复模式。 在我的模式中，我只能在给定的时间窗口启动作业。 如果作业失败，它将仅在下一个时间窗口重新启动，完成后，我希望启动为此窗口预先计划的计划作业。 作业之间唯一的区别是时间窗口参数。

我考虑将JobExecutionDecider与JobExplorer结合使用，或者覆盖Joblauncher。但这一切似乎都太具侵扰性了。

我找不到符合我需要的示例，任何想法都将是最受欢迎的。

推荐答案

简单回顾一下根据Included-co.de提供的建议实际做了些什么。 我创建了一个类似于下面的恢复流。恢复流包装我的实际批处理，并且只负责向内部作业提供正确的作业参数。它可以是第一次执行时的初始参数，可以是正常执行时的新参数，也可以是上次执行失败时的旧参数。

<batch:job id="recoveryWrapper"
       incrementer="wrapperRunIdIncrementer"
       restartable="true">
    <batch:decision id="recoveryFlowDecision" decider="recoveryFlowDecider">
        <batch:next on="FIRST_RUN" to="defineParametersOnFirstRun" />
        <batch:next on="RECOVER" to="recover.batchJob " />
        <batch:next on="CURRENT" to="current.batchJob " />
    </batch:decision>
    <batch:step id="defineParametersOnFirstRun" next="current.batchJob">
        <batch:tasklet ref="defineParametersOnFirstRunTasklet"/>
    </batch:step>
    <batch:step id="recover.batchJob " next="current.batchJob">
        <batch:job ref="batchJob" job-launcher="jobLauncher"
                            job-parameters-extractor="jobParametersExtractor" />
    </batch:step>
    <batch:step id="current.batchJob" >
       <batch:job ref="batchJob" job-launcher="jobLauncher"
                            job-parameters-extractor="jobParametersExtractor" />
    </batch:step>
</batch:job>

解决方案的核心是RecoveryFlowDecider使用Spring Batch Restart机制时的JobParametersExtractor。 RecoveryFlowDecider将查询JobExplorer和JobRepository，以确定我们在上次运行时是否失败。它将把最后一次执行放在包装器的执行上下文上，以便稍后在JobParametersExtractor中使用。 请注意，使用runIdIncreeter允许重新执行包装作业。

@Component
 public class RecoveryFlowDecider implements JobExecutionDecider {
        private static final String FIRST_RUN = "FIRST_RUN";
        private static final String CURRENT = "CURRENT";
        private static final String RECOVER = "RECOVER";

        @Autowired
        private JobExplorer jobExplorer;
        @Autowired
        private JobRepository jobRepository;

        @Override
        public FlowExecutionStatus decide(JobExecution jobExecution
                                         ,StepExecution stepExecution) {
            // the wrapper is named as the wrapped job + WRAPPER
            String wrapperJobName = jobExecution.getJobInstance().getJobName();
            String jobName;
             jobName = wrapperJobName.substring(0,wrapperJobName.indexOf(EtlConstants.WRAPPER));
            List<JobInstance> instances = jobExplorer.getJobInstances(jobName, 0, 1);
                JobInstance internalJobInstance = instances.size() > 0 ? instances.get(0) : null;

            if (null == internalJobInstance) {
                return new FlowExecutionStatus(FIRST_RUN);
            }
            JobExecution lastExecution = jobRepository.getLastJobExecution(internalJobInstance.getJobName()
    ,internalJobInstance.getJobParameters());
            //place the last execution on the context (wrapper context to use later)
            jobExecution.getExecutionContext().put(EtlConstants.LAST_EXECUTION, lastExecution);
                ExitStatus exitStatus = lastExecution.getExitStatus();

            if (ExitStatus.FAILED.equals(exitStatus) || ExitStatus.UNKNOWN.equals(exitStatus)) {
                return new FlowExecutionStatus(RECOVER);
            }else if(ExitStatus.COMPLETED.equals(exitStatus)){
                return new FlowExecutionStatus(CURRENT);    
            }
            //We should never get here unless we have a defect
            throw new RuntimeException("Unexpecded batch status: "+exitStatus+" in decider!");

        }

}

然后，JobParametersExtractor将再次测试上次执行的结果，如果作业失败，它将提供用于执行失败作业的原始参数，从而触发Spring Bacth重启机制。否则，它将创建一组新参数，并将按其正常进程执行。

    @Component
    public class JobExecutionWindowParametersExtractor implements
            JobParametersExtractor {
        @Override
        public JobParameters getJobParameters(Job job, StepExecution stepExecution) {

            // Read the last execution from the wrapping job
            // in order to build Next Execution Window
            JobExecution lastExecution= (JobExecution) stepExecution.getJobExecution().getExecutionContext().get(EtlConstants.LAST_EXECUTION);;

            if(null!=lastExecution){
                if (ExitStatus.FAILED.equals(lastExecution.getExitStatus())) {
                    JobInstance instance = lastExecution.getJobInstance();
                    JobParameters parameters = instance.getJobParameters();                 
                                return parameters;
                }
            }       
            //We do not have failed execution or have no execution at all we need to create a new execution window
            return buildJobParamaters(lastExecution,stepExecution);
        }
...
}

这篇关于Spring Batch：重新启动一个作业，然后自动启动下一个作业的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！