Sunday, July 18, 2010

jetty webapp osgi way

I will show how to expose simple Jetty OSGi service and use it to register hello world webapp. This app will serve static content from OSGi bundle and implement sample request handler under ServiceMix 4. Code is available here:
Alternative solutions are: using standard OSGi HTTP service to register servlet; and wrap existing WAR application using PAX WEB I won't consider those two, since Jetty itself provides flexible way to handle webapps (including registering servlets). So those two are unnecessary overhead and are less flexible. Anyway those two are usually implemented on top of Jetty.
So the first thing to do is to create Jetty OSGi service. Basicly it will be a Spring Bean exposed to OSGi. Following snippet does the job:
<bean id="jetty-service" class="org.apache.jetty.service.JettyServiceImpl" init-method="init" destroy-method="destroy"/>
<osgi:service id="jetty-service-osgi" ref="jetty-service" interface="org.apache.jetty.service.api.JettyService" />

This will expose jetty-service to OSGi. All other components, which connect to it will wait automaticly until it's registered. Exposed interface has following methods:
public Handler registerApp(String name, Handler handler) throws Exception;
public void unregisterApp(Handler handler) throws Exception;

Those will be invoked to register Hello World application. JettyServiceImpl on the other hand, starts embedded Jetty Server and handles apps registration.
package org.apache.jetty.service;

import org.apache.jetty.service.api.JettyService;
import org.mortbay.jetty.Handler;
import org.mortbay.jetty.Server;
import org.mortbay.jetty.handler.ContextHandler;
import org.mortbay.jetty.handler.ContextHandlerCollection;

public class JettyServiceImpl implements JettyService {
 private Server server;
 private ContextHandlerCollection rootContext;

 public void init() throws Exception {
  server = new Server(8080);
  rootContext = new ContextHandlerCollection();

 public void destroy() throws Exception {

 public Handler registerApp(String name, Handler handler) throws Exception {
  ContextHandler h = rootContext.addContext("/" + name, name);
  return h;

 public void unregisterApp(Handler handler) throws Exception {

Next step is to implement sample web app. First, we need to connect jetty-service bean to make it visible in our app.
  <osgi:reference id="jetty-service" interface="org.apache.jetty.service.api.JettyService" bean-name="jetty-service"/>

  <bean class="org.apache.jetty.service.example.HelloWorld" init-method="init" destroy-method="destroy">
    <property name="jettyService" ref="jetty-service"/>

Then, we need to implement sample app.
package org.apache.jetty.service.example;


import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.jetty.service.api.JettyService;
import org.apache.jetty.service.util.BundleResource;
import org.mortbay.jetty.Handler;
import org.mortbay.jetty.HttpConnection;
import org.mortbay.jetty.Request;
import org.mortbay.jetty.handler.AbstractHandler;
import org.mortbay.jetty.handler.ContextHandler;
import org.mortbay.jetty.handler.ContextHandlerCollection;
import org.mortbay.jetty.handler.ResourceHandler;

public class HelloWorld {

 private JettyService jettyService;
 private Handler registered;

 public void setJettyService(JettyService jettyService) {
  this.jettyService = jettyService;

 public void init() throws Exception {
  ContextHandlerCollection handler = new ContextHandlerCollection();

  handler.addContext("/app", "app").setHandler(new AbstractHandler() {
   public void handle(String target, HttpServletRequest request,
     HttpServletResponse response, int arg3) throws IOException,
     ServletException {
          response.getWriter().println("<h1>Hello World from Java</h1>" + request.getParameterMap());

          Request base_request = (request instanceof Request) ? (Request)request:HttpConnection.getCurrentConnection().getRequest();

  ResourceHandler resourceHandler = new ResourceHandler();
  resourceHandler.setBaseResource(new BundleResource(getClass().getResource("/static")));
  ContextHandler contextHandler = handler.addContext("","");

  registered = jettyService.registerApp("helloWorld", handler);

 public void destroy() throws Exception {

Here, we register sample request handler at 'app' sub path and serve static content from jar using BundleResource. Last thing is registering app using jettyService under 'helloWorld' context. So our application will be exposed under http://localhost:8080/helloWorld/ address.
ServiceMix has also so called features. This is the way to collect multiple dependencies under a single name. So we have to create features.xml file, like this:
    <feature name="jetty-service" version="${project.version}">

    <feature name="example-jetty-service-helloworld" version="${project.version}">
        <feature version="${project.version}">jetty-service</feature>

Basicly, we can provide particular dependencies for our project.
Next, we do 'mvn install' on our project and run apache-servicemix-4.2.0-fuse-01-00/bin/servicemix karaf console. On the console, we need to type following commands:
features:addUrl mvn:org.apache.jetty.service/service-karaf/0.1.0-SNAPSHOT/xml/features
features:install example-jetty-service-helloworld

[ 230] [Active     ] [            ] [Started] [   60] Unnamed - org.apache.jetty.service:service:bundle:0.1.0-SNAPSHOT (0.1.0.SNAPSHOT)
[ 231] [Active     ] [            ] [Started] [   60] Unnamed - org.apache.jetty.service:example-helloworld:bundle:0.1.0-SNAPSHOT (0.1.0.SNAPSHOT)

Now, we can enter http://localhost:8080/helloWorld/ to test our app.
And that's it. OSGi and ServiceMix 4 features enable easy way to use dynamic modules in web apps. For example, it's very easy to build simple web framework with loadable components on page (something like mini implementation of Portlets).

Saturday, July 10, 2010

Integration Tests for SMX4 with Python

Integration tests and unit tests are important for project quality. Unit tests usually are well suited for developer to verify his changes in runtime. On the other hand, integration tests, are for target user to verify that project's features in the way he interacts with project, work properly. In this article, I will show how to automate integration tests for ServiceMix 4 using SoapUI testrunner and a simple python script.
The idea is to spawn ServiceMix 4 Karaf console and interact with it using python expect library. During this interaction, SoapUI testrunner script is invoked in order to run SoapUI tests.
First, we need to grab SMX4_DIR and SOAPUI_DIR environment variables in our script, like this:

This way, we can invoke later our script using following shell command:
SMX4_DIR=/some/path SOAPUI_DIR=/some/other/path ./our-python-script

Then, we need to spawn ServiceMix 4 console by using python expect library:
import pexpect
import time
import sys
child = pexpect.spawn("bin/servicemix")
child.logfile = sys.stdout

Here, we set logfile to stdout in order to see our automated interaction with ServiceMix console. Then we need to wait for ServiceMix console command prompt, which would mean console is ready. Additionally, we need to wait a few seconds to avoid problems with running commands too early (which is a kind of small bug in ServiceMix). Then, we can install our features, which we want to test. This example starts Apache HISE test bundle, which loads also Apache HISE engine from dependencies.
child.sendline("features:addUrl mvn:org.apache.hise/hise-karaf/0.3.0-SNAPSHOT/xml/features");
child.sendline("features:install hise-h2-test-example-osgi")

Next, we need to wait until the feature is properly started. ServiceMix 4 OSGi container initializes bundles in background, so it's not enough to wait for command prompt to have it started (there doesn't seem to exist a "wait-until-started" console command). So we grep in a loop over installed bundles and see if status is started. In this example, we do 30 retries every second and fail our integration test script after this period, by raising exception.
child.sendline("features:addUrl mvn:org.apache.hise/hise-karaf/0.3.0-SNAPSHOT/xml/features");
while True:
    child.sendline("osgi:list|grep -i hise-test-example-osgi")
    if re.match(".*Started", l) != None:
    if rep>30:
        raise Exception("Bundle not installed")

Next, we need to run SoapUI testrunner in order to execute test cases. We need to implement syscall method in order to fail integration tests if SoapUI testrunner completes with fault (non-zero exit code).
import os
def syscall(c):
    if os.system(c) != 0:
        raise Exception("Sys call failed: " + c)

syscall(SOAPUI_DIR + "/bin/ -f results hise-soapui-project.xml")

At the end, we can exit gracefully from ServiceMix console by using shutdown command, like this:

And that's it. Full code of integration test script is available in Apache HISE sources, from Apache repository