API monitoring and logging are crucial aspects of developing and maintaining a successful application. They help to identify and troubleshoot issues, monitor performance, and ensure the stability of your API. In this blog post, we will explore how to document API monitoring and logging using Java Spring REST Docs.

What is Java Spring REST Docs?

Java Spring REST Docs is a powerful library that allows you to generate documentation for your RESTful APIs. It works seamlessly with the Spring Framework, enabling you to document your API endpoints, request-response payloads, and error handling.

Setting up Java Spring REST Docs

To get started with Java Spring REST Docs, you need to configure it in your Spring Boot project. Add the following dependencies to your pom.xml file:

<dependency>
  <groupId>org.springframework.restdocs</groupId>
  <artifactId>spring-restdocs-mockmvc</artifactId>
  <version>2.0.4.RELEASE</version>
  <scope>test</scope>
</dependency>
<dependency>
  <groupId>org.springframework.restdocs</groupId>
  <artifactId>spring-restdocs-restassured</artifactId>
  <version>2.0.4.RELEASE</version>
  <scope>test</scope>
</dependency>

Then, configure the RestDocs in your test class:

@RunWith(SpringRunner.class)
@SpringBootTest
@AutoConfigureMockMvc
@AutoConfigureRestDocs
public class ApiDocumentationTest {

  @Autowired
  private MockMvc mockMvc;

  // ...your tests here

}

Documenting API Monitoring

To document API monitoring, you can utilize the logging capabilities provided by Spring Boot’s logging framework. You can configure different log levels for different packages or components in your application. For example, to enable detailed logging for a specific package, you can set the log level in your application.properties file:

logging.level.com.example.api=DEBUG

This configuration will log all DEBUG level statements from the com.example.api package.

Documenting API Logging

Java Spring REST Docs provides support for documenting API logging through its request and response handlers. You can capture and log request and response information using interceptors or filters.

For example, you can create a LoggingFilter that logs the request and response information:

public class LoggingFilter implements Filter {

  private final Logger logger = LoggerFactory.getLogger(this.getClass());

  @Override
  public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
    HttpServletRequest httpRequest = (HttpServletRequest) request;
    HttpServletResponse httpResponse = (HttpServletResponse) response;

    // Log request information
    logger.info("Request: {} {}", httpRequest.getMethod(), httpRequest.getRequestURI());
  
    // Log response information
    chain.doFilter(request, response);
    logger.info("Response: {}", httpResponse.getStatus());
  }
}

You can then configure this filter in your Spring Boot application configuration:

@Configuration
public class ApplicationConfig {

  @Bean
  public FilterRegistrationBean<LoggingFilter> loggingFilter() {
    FilterRegistrationBean<LoggingFilter> registrationBean = new FilterRegistrationBean<>();
    registrationBean.setFilter(new LoggingFilter());
    registrationBean.addUrlPatterns("/api/*");
    return registrationBean;
  }
  
  // ...other configurations

}

With this setup, the LoggingFilter will log the request and response information for all API endpoints under /api.

Conclusion

Documenting API monitoring and logging is crucial for maintaining and debugging your APIs in production. Java Spring REST Docs provides an excellent solution for generating comprehensive documentation for your APIs. By configuring logging and integrating it with Java Spring REST Docs, you can ensure that your API documentation is accurate and up-to-date.

#API #JavaSpringRESTDocs