servlet

This document contains documentation for the tracee-servlet module. Check the TracEE main documentation to get started.

tracee-servlet

tracee-servlet contains Servlet-Listeners and -Filters that allows you to use TracEE Context Propagation with Servlets.

• TraceeServletRequestListener: Parses a TracEE-Context from a ServletHttpRequest-Header before a request is processed by a servlet. It also cleans the TraceeBackend when the request processing is finished by the container.
• TraceeFilter: Writes a TracEE-Context back to a ServletHttpResponse-Header.
• TraceeSessionListener: Listens on Session.create() and Session.destroy() events and creates and deletes the tracee-sessionId from the TracEE-Backend accordingly.

Installation

Its super-easy for Servlet3+-Containers. Just add tracee-servlet-VERSION.jar to your webapp-classpath (WEB-INF/lib or as maven runtime dependency). tracee-servlet contains a web-fragment.xml that registers all required filters and event listeners.

If you're use Maven for your dependency management simple add this to your pom:

<dependencies>
...
    <dependency>
        <groupId>io.tracee.binding</groupId>
        <artifactId>tracee-servlet</artifactId>
        <version>${tracee.version}</version>
    </dependency>
...
</dependencies>

If you are on a Servlet-Container with servlet-version < 3, you need to register the following filters in your web.xml:

...
    <filter>
        <filter-name>traceeFilter</filter-name>
        <filter-class>io.tracee.binding.servlet.TraceeFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>traceeFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
	<listener>
		<listener-class>io.tracee.binding.servlet.TraceeServletRequestListener</listener-class>
	</listener>
	<listener>
		<listener-class>io.tracee.binding.servlet.TraceeSessionListener</listener-class>
	</listener>
...

You may change the filter-mapping:url-pattern according to your needs.

Spring Boot

If you're running in an embedded SpringBoot container you've to add the ServletListener and Filter to your application configuration:

@Bean
public FilterRegistrationBean traceeFilter() {
    FilterRegistrationBean frb = new FilterRegistrationBean();
    frb.setFilter(new TraceeFilter());
    frb.addUrlPatterns("/*");
    return frb;
}

@Bean
public ServletListenerRegistrationBean traceeServletListener() {
    return new ServletListenerRegistrationBean<TraceeServletRequestListener>(new TraceeServletRequestListener());
}