Request Timer Spring Boot Starter

A Spring Boot starter that adds an elapsed time header to HTTP responses. It automatically calculates the time taken from the moment the request is received until the response is about to be committed.

• Spring Boot: 4.x
• Java: 21 (LTS)
• Web Support: WebMvc (Servlet) & WebFlux (Reactive)

Features

• Automatic Timing: Capture request duration without any code changes.
• Dual Support: Works seamlessly with both Spring WebMvc and Spring WebFlux.
• Customizable: Change the header name and filter order via simple properties.
• High Precedence: By default, it runs at the highest precedence to capture the full request lifecycle.

Modules

• request-timer-spring-boot-starter: The autoconfiguration starter providing the request timing filters.
• demo-webmvc: Demo application using Spring WebMvc and H2.
• demo-webflux: Demo application using Spring WebFlux and H2.

Quick Start

Requirements

• Java 21
• Maven 3.9+

Run all tests

./mvnw test

Run the Demo Applications

To run the WebMvc demo:

./mvnw -pl demo-webmvc spring-boot:run

To run the WebFlux demo:

./mvnw -pl demo-webflux spring-boot:run

The APIs provide a simple book management service:

• GET /api/v1/books - Retrieve all books (includes X-ElapsedTime header in response).

Configuration

The starter can be configured using the request-timer prefix in your application.yml or application.properties.

request-timer:
  # Name of the response header. Default is X-ElapsedTime.
  header-name: X-ElapsedTime
  # Order of the filter/WebFilter. Default is Ordered.HIGHEST_PRECEDENCE.
  order: -2147483648
  # The date pattern for the elapsed time value. Default is yyyyMMddHHmmssSSS.
  default-header-date-pattern: yyyyMMddHHmmssSSS

Customization

You can provide your own HeaderValueProvider bean to customize how the elapsed time value is generated (e.g. to return duration in milliseconds):

import co.ke.xently.request.timer.utils.HeaderValueProvider;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class MyConfig {
    @Bean
    public HeaderValueProvider customHeaderValueProvider() {
        return startTime -> String.valueOf(System.currentTimeMillis() - startTime) + "ms";
    }
}