Spring boot + spring batch without DataSource

Question

I'm trying to configure spring batch inside spring boot project and I want to use it without data source. I've found that ResourcelessTransactionManager is the way to go but I cannot make it work. Problem is I already have 3 another dataSources defined, but I don't want to use any of them in springBatch.

I've checked default implementation DefaultBatchConfigurer and if it is not able to find dataSource it will do exactly what I want. Problem is I've 3 of them and dont want to use any.

Please dont suggest to use hsql or other in memory DB as I dont want that.

Answer 1

I got around this problem by extending the DefaultBatchConfigurer class so that it ignores any DataSource, as a consequence it will configure a map-based JobRepository.

Example:

@Configuration
@EnableBatchProcessing
public class BatchConfig extends DefaultBatchConfigurer {   

    @Override
    public void setDataSource(DataSource dataSource) {
        //This BatchConfigurer ignores any DataSource
    }
}

Answer 2

In my case I persist data to Cassandra. If you are using spring-boot-starter-batch it is expected to provide a DataSource which is not yet implemented but you can trick the configuration like in the following steps:

Step1:

@SpringBootApplication(exclude = { DataSourceAutoConfiguration.class })
public class SampleSpringBatchApplication{

    public static void main(String[] args) {
        System.setProperty("spring.devtools.restart.enabled", "true");
        SpringApplication.run(SampleSpringBatchApplication.class, args);
    }

}

Step2:

    @Configuration
    @EnableBatchProcessing
    public class SampleBatchJob extends DefaultBatchConfigurer {

        //..

        @Override
        public void setDataSource(DataSource dataSource) {
        }

        //..
    }

Answer 3

You can try excluding the DataSourceAutoConfiguration in @SpringBootApplication. See the sample code below.

import org.springframework.batch.core.Job;
import org.springframework.batch.core.Step;
import org.springframework.batch.core.StepContribution;
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.scope.context.ChunkContext;
import org.springframework.batch.core.step.tasklet.Tasklet;
import org.springframework.batch.repeat.RepeatStatus;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
import org.springframework.context.annotation.Bean;

@SpringBootApplication(exclude = { DataSourceAutoConfiguration.class })
@EnableBatchProcessing
public class SampleBatchApplication {

@Autowired
private JobBuilderFactory jobs;

@Autowired
private StepBuilderFactory steps;

@Bean
protected Tasklet tasklet() {

    return new Tasklet() {
        @Override
        public RepeatStatus execute(StepContribution contribution, ChunkContext context) {
            return RepeatStatus.FINISHED;
        }
    };
}

@Bean
public Job job() throws Exception {
    return this.jobs.get("job").start(step1()).build();
}

@Bean
protected Step step1() throws Exception {
    return this.steps.get("step1").tasklet(tasklet()).build();
}

public static void main(String[] args) throws Exception {
    System.exit(SpringApplication.exit(SpringApplication.run(SampleBatchApplication.class, args)));
   }
}

And sample test class

import org.junit.Rule;
import org.junit.Test;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.test.rule.OutputCapture;
import static org.assertj.core.api.Assertions.assertThat;
public class SampleBatchApplicationTests {
@Rule
public OutputCapture outputCapture = new OutputCapture();

@Test
public void testDefaultSettings() throws Exception {
    assertThat(SpringApplication.exit(SpringApplication.run(SampleBatchApplication.class))).isEqualTo(0);
    String output = this.outputCapture.toString();
    assertThat(output).contains("completed with the following parameters");
  }
}

Answer 4

If you have more than one DataSource in your configuration (regardless of if you want to use them or not) you need to define your own BatchConfigurer. It's the only way the framework knows what to do in situations like that.

You can read more about the BatchConfigurer in the documentation here: http://docs.spring.io/spring-batch/trunk/apidocs/org/springframework/batch/core/configuration/annotation/BatchConfigurer.html

Answer 5

We had the similar problem, we were using spring boot JDBC and we did not want to store spring batch tables in the DB, but we still wanted to use spring's transaction management for our DataSource.

We ended up implementing own BatchConfigurer.

@Component
public class TablelessBatchConfigurer implements BatchConfigurer {
    private final PlatformTransactionManager transactionManager;
    private final JobRepository jobRepository;
    private final JobLauncher jobLauncher;
    private final JobExplorer jobExplorer;
    private final DataSource dataSource;

    @Autowired
    public TablelessBatchConfigurer(DataSource dataSource) {
        this.dataSource = dataSource;
        this.transactionManager = new DataSourceTransactionManager(this.dataSource);

        try {
            final MapJobRepositoryFactoryBean jobRepositoryFactory = new MapJobRepositoryFactoryBean(this.transactionManager);
            jobRepositoryFactory.afterPropertiesSet();
            this.jobRepository = jobRepositoryFactory.getObject();

            final MapJobExplorerFactoryBean jobExplorerFactory = new MapJobExplorerFactoryBean(jobRepositoryFactory);
            jobExplorerFactory.afterPropertiesSet();
            this.jobExplorer = jobExplorerFactory.getObject();

            final SimpleJobLauncher simpleJobLauncher = new SimpleJobLauncher();
            simpleJobLauncher.setJobRepository(this.jobRepository);
            simpleJobLauncher.afterPropertiesSet();
            this.jobLauncher = simpleJobLauncher;
        } catch (Exception e) {
            throw new BatchConfigurationException(e);
        }
    }
    // ... override getters
}

and setting up initializer to false

spring.batch.initializer.enabled=false