Spring batch conditional flow creates infinite loop - spring

Question

I have a simple 3-step flow:
public Job myJob() {
Step extract = extractorStep();
Step process = filesProcessStep();
Step cleanup = cleanupStep();
return jobBuilderFactory.get("my-job")
.flow(echo("Starting job"))
.next(extract)
.next(process)
.next(cleanup)
.next(echo("Ending job"))
.end()
.build();
}
Now I want to add error processing using ExitStatus from StepExecutionListener.afterStep(). Any error should forward flow to cleanup step. So I changed to the code below:
public Job myJob() {
Step extract = extractorStep();
Step process = filesProcessStep();
Step cleanup = cleanupStep();
return jobBuilderFactory.get("my-job")
.start(echo("Starting batch job"))
.next(extract).on(ExitStatus.FAILED.getExitCode()).to(cleanup)
.from(extract).on("*").to(process)
.next(process).on(ExitStatus.FAILED.getExitCode()).to(cleanup)
.from(process).on("*").to(cleanup)
.next(echo("End batch job"))
.end()
.build();
}
Now I have an infinite loop to the cleanup step.
I would like some help to correct this flow.

Answer 1

In your example, the flow is undefined starting from cleanup. You should precise that from cleanup the flow must continue to echo using .from(cleanup).to(echo("End batch job")).end(). Here is an example:
import org.springframework.batch.core.ExitStatus;
import org.springframework.batch.core.Job;
import org.springframework.batch.core.JobParameters;
import org.springframework.batch.core.Step;
import org.springframework.batch.core.configuration.annotation.EnableBatchProcessing;
import org.springframework.batch.core.configuration.annotation.JobBuilderFactory;
import org.springframework.batch.core.configuration.annotation.StepBuilderFactory;
import org.springframework.batch.core.launch.JobLauncher;
import org.springframework.batch.repeat.RepeatStatus;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
#Configuration
#EnableBatchProcessing
public class MyJob {
#Autowired
private JobBuilderFactory jobs;
#Autowired
private StepBuilderFactory steps;
#Bean
public Step extractorStep() {
return steps.get("extractorStep")
.tasklet((contribution, chunkContext) -> {
System.out.println("extractorStep");
return RepeatStatus.FINISHED;
})
.build();
}
#Bean
public Step filesProcessStep() {
return steps.get("filesProcessStep")
.tasklet((contribution, chunkContext) -> {
System.out.println("filesProcessStep");
return RepeatStatus.FINISHED;
})
.build();
}
#Bean
public Step cleanupStep() {
return steps.get("cleanupStep")
.tasklet((contribution, chunkContext) -> {
System.out.println("cleanupStep");
return RepeatStatus.FINISHED;
})
.build();
}
public Step echo(String message) {
return steps.get("echo-" + message)
.tasklet((contribution, chunkContext) -> {
System.out.println(message);
return RepeatStatus.FINISHED;
})
.build();
}
#Bean
public Job job() {
Step start = echo("Starting batch job");
Step extract = extractorStep();
Step process = filesProcessStep();
Step cleanup = cleanupStep();
Step stop = echo("End batch job");
return jobs.get("job")
.start(start).on("*").to(extract)
.from(extract).on(ExitStatus.FAILED.getExitCode()).to(cleanup)
.from(extract).on("*").to(process)
.from(process).on("*").to(cleanup)
.from(cleanup).next(stop)
.build()
.build();
}
public static void main(String[] args) throws Exception {
ApplicationContext context = new AnnotationConfigApplicationContext(MyJob.class);
JobLauncher jobLauncher = context.getBean(JobLauncher.class);
Job job = context.getBean(Job.class);
jobLauncher.run(job, new JobParameters());
}
}
it prints:
Starting batch job
extractorStep
filesProcessStep
cleanupStep
End batch job
if the extractorStep fails, for example:
#Bean
public Step extractorStep() {
return steps.get("extractorStep")
.tasklet((contribution, chunkContext) -> {
System.out.println("extractorStep");
chunkContext.getStepContext().getStepExecution().setExitStatus(ExitStatus.FAILED);
return RepeatStatus.FINISHED;
})
.build();
}
the flow will skip filesProcessStep and go to cleanup:
Starting batch job
extractorStep
cleanupStep
End batch job
Hope this helps.