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");
  }
}