OpenTracing Spring Web Instrumentation
This library provides instrumentation for Spring Web applications (Boot and MVC). It creates tracing data for
server requests and also client requests (RestTemplate
and AsyncRestTemplate
).
opentracing-spring-cloud instead
UseAs it was mentioned above this library traces only inbound/outbound HTTP requests. If you would like to
get automatically traced different set of technologies e.g. spring-cloud-netflix
, JMS or even more then
use project opentracing-spring-cloud instead.
How does the server tracing work?
Server span is started in Web Servlet Filter,
then tracing interceptor adds spring related tags and logs. There are use case when spring boot invokes a handler after
a request processing in filter finished, in this case interceptor starts a new span as followsFrom
which references the initial span created in the servlet filter.
Configuration
Spring Boot Auto-configuration
If you are using Spring Boot the easiest way how to configure OpenTracing instrumentation is to use auto-configuration:
<dependency>
<groupId>io.opentracing.contrib</groupId>
<artifactId>opentracing-spring-web-starter</artifactId>
</dependency>
Just provide an OpenTracing tracer bean and all required configuration is automatically
done for you. It also instruments all RestTemplate
and AsyncRestTemplate
beans.
Manual configuration
Server
Configuration needs to add TracingFilter
and TracingHandlerInterceptor
. Both of these classes
are required!
Tracing interceptor can be instantiated manually or injected via CDI, but
it needs bean of type Tracer
configured.
Java based configuration:
@Configuration
@Import({TracingHandlerInterceptor.class})
public class MVCConfiguration extends WebMvcConfigurerAdapter {
@Autowired
private Tracer tracer;
@Override
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(new TracingHandlerInterceptor(tracer));
}
@Bean
public FilterRegistrationBean tracingFilter() {
TracingFilter tracingFilter = new TracingFilter(tracer);
FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean(tracingFilter);
filterRegistrationBean.addUrlPatterns("/*");
filterRegistrationBean.setOrder(Integer.MIN_VALUE);
filterRegistrationBean.setAsyncSupported(true);
return filterRegistrationBean;
}
}
XML based configuration can be used too. Filter can be also directly defined in web.xml
.
Client
RestTemplate restTemplate = new RestTemplate();
restTemplate.setInterceptors(Collections.singletonList(new TracingRestTemplateInterceptor(tracer)));
// the same applies for AsyncRestTemplate
Access server span
@RequestMapping("/hello")
public String hello(HttpServletRequest request) {
Span serverSpan = tracer.activeSpan();
Span span = tracer.buildSpan("localSpan")
.asChildOf(serverSpan.context())
.start();
try {
// Traced work happens between start() and deactivate();
return "Hello world!";
} finally {
span.finish();
}
}
Development
./mvnw clean install
Release
Follow instructions in RELEASE