itqpleyva / springbootretrypattern

Example of Retry Pattern based on Spring Boot

SpringBootRetryPattern

Example of Retry Pattern based on Spring Boot

Main dependencies:

<dependencies>  
  <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
  </dependency>
   <dependency>
      <groupId>org.springframework.retry</groupId>
      <artifactId>spring-retry</artifactId>
  </dependency>
  <dependency>
       <groupId>org.springframework</groupId>
       <artifactId>spring-aspects</artifactId>
  </dependency>
 </dependencies>

Enabling Retry:

@SpringBootApplication
@EnableRetry
public class Main {

  public static void main(String[] args) {
    SpringApplication.run(Main.class, args);
  }
}

Defining controller class:

  @RestController
  public class Controller {

    @GetMapping(value = "/")
    @Retryable(
            value = {Exception.class}, 
            maxAttempts = 1,
            backoff = @Backoff(1000))//defining retry configuration
    public String home() {

      RestTemplate restTemplate = new RestTemplate(); //creating RestTemplate instance

      ResponseEntity<String> request_body = restTemplate.exchange("https://jsonplaceholder.typicode.com/posts/1", 
          HttpMethod.GET, null, String.class );//making a request to jsonplacholder api

      String answer = request_body.getBody();

      return answer;
    }

    @Recover//defining recover method to SQLExceptions errors
    public String recover(SQLException e) {

      return "from recover method";
    }
    @Recover//defining recover method to Exceptions errors
    public String recover1(Exception e) {

      return "from recover method2";
    }	
  }

Configuring retryable in method using @Retryable parameters:

• value = {Exception.class}//if any exception occurs the recover methos is triggered, you can define any exception class for example SQLException
• maxAttempts = 1, //attempts alloweds if any exception occurs before trigger the recover method
• backoff = @Backoff(1000)// setting the time for attempts

    @GetMapping(value = "/")
    @Retryable(
            value = {Exception.class}, 
            maxAttempts = 1,
            backoff = @Backoff(1000))//defining retry configuration
    public String home() {

      RestTemplate restTemplate = new RestTemplate(); //creating RestTemplate instance

      ResponseEntity<String> request_body = restTemplate.exchange("https://jsonplaceholder.typicode.com/posts/1", 
          HttpMethod.GET, null, String.class );//making a request to jsonplacholder api

      String answer = request_body.getBody();

      return answer;
    }

Defining recover method for Exception class errors in home method:

    @Recover//defining recover method to Exceptions errors
    public String recover1(Exception e) {

      return "from recover method1";
    }

Behavior:

If any error occurs in the home method call, the recover method recover 1 is triggered, you can make a test setting wrong the call to jsonplaceholder api, for example writing the api endpoint wrong, and the answer will be

"from recover method1"