lsd-interceptors

A library containing various automated message/event interceptors that can be used along with the lsd-core library to generate reports containing sequence diagrams of the captured events. e.g.

Autoconfig

This library is designed with @SpringBootTest in mind and attempts to minimise boilerplate code by wiring up default bean configurations based on the beans and classes available in the project.

The interceptors can be used outside of a spring project but will require some manual setup. The classes in the com/nickmcdowall/lsd/interceptor/autoconfigure package would be a good starting point for examples on how to configure the interceptors when autowiring is not an option.

To disable autoconfig so that the beans can be used in another library add the following property:

lsd.interceptors.autoconfig.enabled=false

Available Interceptors

LsdRestTemplateInterceptor

If a TestState bean exists and a RestTemplate class is on the classpath then a RestTemplateCustomizer bean will be loaded into the default RestTemplateBuilder bean.

This causes an interceptor to be injected along with a BufferingClientHttpRequestFactory to allow for multiple reads of the response stream (to avoid breaking the chain on additional reads).

• Don't instantiate a RestTemplate bean using the default constructor (or else you won't get the interceptor and factory out the box), avoid:

    // Wrong
@Bean
public RestTemplate restTemplate(){
        return new RestTemplate();
        }

instead use a RestTemplateBuilder bean which will provide a correctly configured bean:

    // Correct
@Bean
public RestTemplate restTemplate(RestTemplateBuilder builder){
        return builder.build();
        }

• TestRestTemplate beans just need to be @Autowired into your tests and will be instantiated and configured for you.

LsdFeignLoggerInterceptor

• For Feign clients
• Auto configured if a TestState bean exists and both FeignClientBuilder and Logger.Level classes are on the classpath. Note that if no feign Logger.Level bean exists one will be created (Logger.Level.BASIC) to enable the interceptor to work. If one exists it will not be replaced.

LsdOkHttpInterceptor

• For OkHttpClient clients.
• Auto configured if TestState and OkHttpClient.Builder beans exists and has spring property lsd.interceptors.autoconfig.okhttp.enabled=true (requires explicit property to prevent clashing with LsdFeignLoggerInterceptor - as it is a popular client implementation for Feign and the former interceptor should work across all Feign client implementations).

Spring AOP

Another option is to use Spring AOP for intercepting calls - e.g. if you want to capture method calls to any method in YourClass that takes one argument you may have something like this in your acceptance/component tests (requires spring aop dependencies):

@Aspect
@Component
@EnableAspectJAutoProxy
public class YourClassLsdInterceptor {

    @Before("execution(* com.your.package.YourClass.*(*) && args(yourArg))")
    public void captureEvents(JoinPoint joinpoint, Object yourArg) {
        var methodName = joinpoint.getSignature().getName();
        var yourArgType = yourArg.getClass().getSimpleName();
        testState.log(methodName + "( " + yourArgType + " ) from A to B", yourArg);
    }
}

(Additional interceptors and auto-configuration will be added over time).

Naming

Source Name

If you set the property info.app.name then this will be used as the default source name for interactions captured on the sequence diagrams. (i.e. your app is calling downstream services)

This can be overridden by setting the Source-Name http header on a request. For example if you want to create a client that represents a user calling into your app say from within a test then you can set the Source-Name header value to the name of the user.

If neither are set then the library will default to the value App.

Destination Name

Set the Target-Name header value to control the name of the destination service of an interaction on the sequence diagrams.

If this header is not set the library will attempt to derive a destination name based on the path of the http request.

Properties

The following properties can be overridden by adding a properties file called lsd.properties on the classpath of your application.

Property Name	Default	Description
lsd.interceptors.autoconfig.enabled	true	Used to disable the autoconfiguration of interceptors if necessary.

Build

Requirements

• Java 11

Git hooks

The custom hooks in .githooks will be configured when gradle clean is run.

Build

./gradlew clean build

Release

Releases are automated via the semantic-release github action when commits are merged into the remote master