DDevelopment & Design

Deploy WSDL file as OSGI Bundle in Apache Karaf

Introduction

WSDL file describes webservices. Java classes are often generated from WSDL. For this purpose, we could use command line tools (e. g. wsdl2Java or wsimport) or using maven plugin.

From the other side, we have Apache Karaf which is OSGI container. Karaf has installed by default many deployers for creating OSGi bundles from files, e. g. Blueprint deployer, Spring deployer or War deployer.

It is easy to generate java classes from WSDL file and also to create custom deployer for Karaf, so why do not join these two features?

Installation of WSDL deployer

Source code of my WSDL deployer is provided here. You can download and build it:

mvn clean install

We also need Karaf. I will use the newest version 4.0.5. It could be download from Karaf website. When you download and unpack it, you can run it:

$ cd PUT_PATH_TO_KARAF_DIR_HERE
$ ./bin/karaf
    __ __                  ____      
   / //_/____ __________ _/ __/      
  / ,<  / __ / ___/ __ / /_        
 / /| |/ /_/ / /  / /_/ / __/        
/_/ |_|\__,_/_/   \__,_/_/         

Apache Karaf (4.0.5)

Hit '<tab>' for a list of available commands
and '[cmd] --help' for help on a specific command.
Hit '<ctrl-d>' or type 'system:shutdown' or 'logout' to shutdown Karaf.

karaf@root()>

and install commons-io and wsdl-delpoyer bundles:

karaf@root()> install -s mvn:org.apache.servicemix.bundles/org.apache.servicemix.bundles.commons-io/1.4_3
Bundle ID: 52
karaf@root()> install -s mvn:com.github.alien11689.karaf/wsdl-deployer/1.0.0-SNAPSHOT
Bundle ID: 53

Install WSDL from Karaf shell

I will test deployer using WSDL file named exampleService-2.0.0.wsdl (provided WSDL is similar to this, but has another namespace in types schama for testing purpose):

<?xml version="1.0"?>
<wsdl:definitions
    xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/"
    xmlns:wsu="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd"
    xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/"
    xmlns:tns="http://Example.org"
    xmlns:sns="http://Example.org/schema"
    xmlns:wsa="http://schemas.xmlsoap.org/ws/2004/08/addressing"
    xmlns:wsp="http://schemas.xmlsoap.org/ws/2004/09/policy"
    xmlns:wsap="http://schemas.xmlsoap.org/ws/2004/08/addressing/policy"
    xmlns:xsd="http://www.w3.org/2001/XMLSchema"
    xmlns:msc="http://schemas.microsoft.com/ws/2005/12/wsdl/contract"
    xmlns:wsaw="http://www.w3.org/2006/05/addressing/wsdl"
    xmlns:soap12="http://schemas.xmlsoap.org/wsdl/soap12/"
    xmlns:wsa10="http://www.w3.org/2005/08/addressing"
    xmlns:wsx="http://schemas.xmlsoap.org/ws/2004/09/mex"
  targetNamespace="http://Example.org"
    xmlns:wsdl="http://schemas.xmlsoap.org/wsdl/">
    <wsdl:types>
        <xsd:schema targetNamespace="http://Example.org/schema" elementFormDefault="qualified" >
            <xsd:element name="Add">
                <xsd:complexType>
                    <xsd:sequence>
                        <xsd:element minOccurs="0" name="a" type="xsd:int" />
                        <xsd:element minOccurs="0" name="b" type="xsd:int" />
                    </xsd:sequence>
                </xsd:complexType>
            </xsd:element>
            <xsd:element name="AddResponse">
                <xsd:complexType>
                    <xsd:sequence>
                        <xsd:element minOccurs="0" name="result" type="xsd:int" />
                    </xsd:sequence>
                </xsd:complexType>
            </xsd:element>
            <xsd:element name="Subtract">
                <xsd:complexType>
                    <xsd:sequence>
                        <xsd:element minOccurs="0" name="a" type="xsd:int" />
                        <xsd:element minOccurs="0" name="b" type="xsd:int" />
                    </xsd:sequence>
                </xsd:complexType>
            </xsd:element>
            <xsd:element name="SubtractResponse">
                <xsd:complexType>
                    <xsd:sequence>
                        <xsd:element minOccurs="0" name="result" type="xsd:int" />
                    </xsd:sequence>
                </xsd:complexType>
            </xsd:element>
        </xsd:schema>
    </wsdl:types>
    <wsdl:message name="ICalculator_Add_InputMessage">
        <wsdl:part name="parameters" element="sns:Add" />
    </wsdl:message>
    <wsdl:message name="ICalculator_Add_OutputMessage">
        <wsdl:part name="parameters" element="sns:AddResponse" />
    </wsdl:message>
    <wsdl:message name="ICalculator_Subtract_InputMessage">
        <wsdl:part name="parameters" element="sns:Subtract" />
    </wsdl:message>
    <wsdl:message name="ICalculator_Subtract_OutputMessage">
        <wsdl:part name="parameters" element="sns:SubtractResponse" />
    </wsdl:message>
    <wsdl:portType name="ICalculator">
        <wsdl:operation name="Add">
            <wsdl:input wsaw:Action="http://Example.org/ICalculator/Add" message="tns:ICalculator_Add_InputMessage" />
            <wsdl:output wsaw:Action="http://Example.org/ICalculator/AddResponse" message="tns:ICalculator_Add_OutputMessage" />
        </wsdl:operation>
        <wsdl:operation name="Subtract">
            <wsdl:input wsaw:Action="http://Example.org/ICalculator/Subtract" message="tns:ICalculator_Subtract_InputMessage" />
            <wsdl:output wsaw:Action="http://Example.org/ICalculator/SubtractResponse" message="tns:ICalculator_Subtract_OutputMessage" />
        </wsdl:operation>
    </wsdl:portType>
    <wsdl:binding name="DefaultBinding_ICalculator" type="tns:ICalculator">
        <soap:binding transport="http://schemas.xmlsoap.org/soap/http" />
        <wsdl:operation name="Add">
            <soap:operation soapAction="http://Example.org/ICalculator/Add" style="document" />
            <wsdl:input>
                <soap:body use="literal" />
            </wsdl:input>
            <wsdl:output>
                <soap:body use="literal" />
            </wsdl:output>
        </wsdl:operation>
        <wsdl:operation name="Subtract">
            <soap:operation soapAction="http://Example.org/ICalculator/Subtract" style="document" />
            <wsdl:input>
                <soap:body use="literal" />
            </wsdl:input>
            <wsdl:output>
                <soap:body use="literal" />
            </wsdl:output>
        </wsdl:operation>
    </wsdl:binding>
    <wsdl:service name="CalculatorService">
        <wsdl:port name="ICalculator" binding="tns:DefaultBinding_ICalculator">
            <soap:address location="http://localhost/ICalculator" />
        </wsdl:port>
    </wsdl:service>
</wsdl:definitions>

We could install it via command:

karaf@root()> install -s wsdl:file:PUT_PATH_TO_WSDL_HERE/exampleService-2.0.0.wsdl\$package=org.github.alien11689.example&s1=http://Example.org/schema&t1=org.github.alien11689.example.schema
Bundle ID: 54

File must have format ${bundleSymbolicName}-${version}.wsdl.

Provided options are:

  • package – allows to change package of generated interface
  • pair s1 and t1 – maps schema in WSDL to package (WSDL deployer is in draft verion nowadays provides options to map only one schema).

Karaf has installed this file:

karaf@root()> headers 54

Bundle 54
---------
Manifest-Version = 2

Bundle-ManifestVersion = 2
Bundle-SymbolicName = exampleService-2.0.0.wsdl
Bundle-Version = 2.0.0

Export-Package =
    org.github.alien11689.example.schema;version=2.0.0,
    org.github.alien11689.example;version=2.0.0
Import-Package =
    javax.jws,
    javax.jws.soap,
    javax.xml.bind.annotation,
    javax.xml.namespace,
    javax.xml.ws

Install WSDL by putting it into Karaf drop folder

You can also install WSDL file by copying it to deploy directory:

cp PUT_PATH_TO_WSDL_HERE/exampleService-2.0.0.wsdl PUT_PATH_TO_KARAF_DIR_HERE/deploy/deployedExampleService-2.0.0.wsdl

It is much more simple to do, but do not allow for customization (e. g. namespace to package mapping). It creates bundle:

karaf@root()> list | grep deployedExampleService
55 | Active |  80 | 2.0.0          | deployedExampleService-2.0.0.wsdl
karaf@root()> headers 55

Bundle 55
---------
Manifest-Version = 2

Bundle-ManifestVersion = 2
Bundle-SymbolicName = deployedExampleService-2.0.0.wsdl
Bundle-Version = 2.0.0

Export-Package =
    org.example;version=2.0.0,
    org.example.schema;version=2.0.0
Import-Package =
    javax.jws,
    javax.jws.soap,
    javax.xml.bind.annotation,
    javax.xml.namespace,
    javax.xml.ws

How does it work?

Deployer uses wsimport command to create in temporary directory and compile generated java classes. Compiled class are packed with MANIFEST.MF into service.jar and such jar is really installed in OSGi container. For example, my temporary directory is /tmp/4ff81631-3c08-487a-b731-1f95c568026f:

$ tree /tmp/4ff81631-3c08-487a-b731-1f95c568026f
/tmp/4ff81631-3c08-487a-b731-1f95c568026f
├── Jaxb-binding.xml
├── Jaxws-binding.xml
├── service.wsdl
├── src
│   └── org
│       └── github
│           └── alien11689
│               └── example
│                   ├── CalculatorService.java
│                   ├── ICalculator.java
│                   └── schema
│                       ├── Add.java
│                       ├── AddResponse.java
│                       ├── ObjectFactory.java
│                       ├── package-info.java
│                       ├── Subtract.java
│                       └── SubtractResponse.java
└── target
    ├── org
    │   └── github
    │       └── alien11689
    │           └── example
    │               ├── CalculatorService.class
    │               ├── ICalculator.class
    │               └── schema
    │                   ├── Add.class
    │                   ├── AddResponse.class
    │                   ├── ObjectFactory.class
    │                   ├── package-info.class
    │                   ├── Subtract.class
    │                   └── SubtractResponse.class
    └── service.jar

And my service.jar contains:

$ jar tf /tmp/4ff81631-3c08-487a-b731-1f95c568026f/target/service.jar
META-INF/
META-INF/MANIFEST.MF
org/
org/github/
org/github/alien11689/
org/github/alien11689/example/
org/github/alien11689/example/schema/
org/github/alien11689/example/schema/Add.class
org/github/alien11689/example/schema/ObjectFactory.class
org/github/alien11689/example/schema/Subtract.class
org/github/alien11689/example/schema/SubtractResponse.class
org/github/alien11689/example/schema/package-info.class
org/github/alien11689/example/schema/AddResponse.class
org/github/alien11689/example/ICalculator.class
org/github/alien11689/example/CalculatorService.class

Conclusion

WSDL generation and Karaf deployers could be easily joined and simplified creation of OSGi bundles without explicite creation of jar. Provided WSDL deployer is just draft, but could be very useful when we have many WSDLs and do not want to create separate artifacts for them.

Source code of WSDL deployer is provided here.

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DDevelopment & Design

How to use mocks in controller tests

Even since I started to write tests for my Grails application I couldn't find many articles on using mocks. Everyone is talking about tests and TDD but if you search for it there isn't many articles.

Today I want to share with you a test with mocks for a simple and complete scenario. I have a simple application that can fetch Twitter tweets and present it to user. I use REST service and I use GET to fetch tweets by id like this: http://api.twitter.com/1/statuses/show/236024636775735296.json. You can copy and paste it into your browser to see a result.

My application uses Grails 2.1 with spock-0.6 for tests. I have TwitterReaderService that fetches tweets by id, then I parse a response into my Tweet class.


class TwitterReaderService {
    Tweet readTweet(String id) throws TwitterError {
        try {
            String jsonBody = callTwitter(id)
            Tweet parsedTweet = parseBody(jsonBody)
            return parsedTweet
        } catch (Throwable t) {
            throw new TwitterError(t)
        }
    }

    private String callTwitter(String id) {
        // TODO: implementation
    }

    private Tweet parseBody(String jsonBody) {
        // TODO: implementation
    }
}

class Tweet {
    String id
    String userId
    String username
    String text
    Date createdAt
}

class TwitterError extends RuntimeException {}

TwitterController plays main part here. Users call show action along with id of a tweet. This action is my subject under test. I've implemented some basic functionality. It's easier to focus on it while writing tests.


class TwitterController {
    def twitterReaderService

    def index() {
    }

    def show() {
        Tweet tweet = twitterReaderService.readTweet(params.id)
        if (tweet == null) {
            flash.message = 'Tweet not found'
            redirect(action: 'index')
            return
        }

        [tweet: tweet]
    }
}

Let's start writing a test from scratch. Most important thing here is that I use mock for my TwitterReaderService. I do not construct new TwitterReaderService(), because in this test I test only TwitterController. I am not interested in injected service. I know how this service is supposed to work and I am not interested in internals. So before every test I inject a twitterReaderServiceMock into controller:


import grails.test.mixin.TestFor
import spock.lang.Specification

@TestFor(TwitterController)
class TwitterControllerSpec extends Specification {
    TwitterReaderService twitterReaderServiceMock = Mock(TwitterReaderService)

    def setup() {
        controller.twitterReaderService = twitterReaderServiceMock
    }
}

Now it's time to think what scenarios I need to test. This line from TwitterReaderService is the most important:


Tweet readTweet(String id) throws TwitterError

You must think of this method like a black box right now. You know nothing of internals from controller's point of view. You're only interested what can be returned for you:

  • a TwitterError can be thrown
  • null can be returned
  • Tweet instance can be returned

This list is your test blueprint. Now answer a simple question for each element: "What do I want my controller to do in this situation?" and you have plan test:

  • show action should redirect to index if TwitterError is thrown and inform about error
  • show action should redirect to index and inform if tweet is not found
  • show action should show found tweet

That was easy and straightforward! And now is the best part: we use twitterReaderServiceMock to mock each of these three scenarios!

In Spock there is a good documentation about interaction with mocks. You declare what methods are called, how many times, what parameters are given and what should be returned. Remember a black box? Mock is your black box with detailed instruction, e.g.: I expect you that if receive exactly one call to readTweet with parameter '1' then you should throw me a TwitterError. Rephrase this sentence out loud and look at this:


1 * twitterReaderServiceMock.readTweet('1') >> { throw new TwitterError() }

This is a valid interaction definition on mock! It's that easy! Here is a complete test that fails for now:


import grails.test.mixin.TestFor
import spock.lang.Specification

@TestFor(TwitterController)
class TwitterControllerSpec extends Specification {
    TwitterReaderService twitterReaderServiceMock = Mock(TwitterReaderService)

    def setup() {
        controller.twitterReaderService = twitterReaderServiceMock
    }

    def "show should redirect to index if TwitterError is thrown"() {
        given:
            controller.params.id = '1'
        when:
            controller.show()
        then:
            1 * twitterReaderServiceMock.readTweet('1') >> { throw new TwitterError() }
            0 * _._
            flash.message == 'There was an error on fetching your tweet'
            response.redirectUrl == '/twitter/index'
    }
}

| Failure:  show should redirect to index if TwitterError is thrown(pl.refaktor.twitter.TwitterControllerSpec)
|  pl.refaktor.twitter.TwitterError
 at pl.refaktor.twitter.TwitterControllerSpec.show should redirect to index if TwitterError is thrown_closure1(TwitterControllerSpec.groovy:29)

You may notice 0 * _._ notation. It says: I don't want any other mocks or any other methods called. Fail this test if something is called! It's a good practice to ensure that there are no more interactions than you want.

Ok, now I need to implement controller logic to handle TwitterError.


class TwitterController {

    def twitterReaderService

    def index() {
    }

    def show() {
        Tweet tweet

        try {
            tweet = twitterReaderService.readTweet(params.id)
        } catch (TwitterError e) {
            log.error(e)
            flash.message = 'There was an error on fetching your tweet'
            redirect(action: 'index')
            return
        }

        [tweet: tweet]
    }
}

My tests passes! We have two scenarios left. Rule stays the same: TwitterReaderService returns something and we test against it. So this line is the heart of each test, change only returned values after >>:


1 * twitterReaderServiceMock.readTweet('1') >> { throw new TwitterError() }

Here is a complete test for three scenarios and controller that passes it.


import grails.test.mixin.TestFor
import spock.lang.Specification

@TestFor(TwitterController)
class TwitterControllerSpec extends Specification {

    TwitterReaderService twitterReaderServiceMock = Mock(TwitterReaderService)

    def setup() {
        controller.twitterReaderService = twitterReaderServiceMock
    }

    def "show should redirect to index if TwitterError is thrown"() {
        given:
            controller.params.id = '1'
        when:
            controller.show()
        then:
            1 * twitterReaderServiceMock.readTweet('1') >> { throw new TwitterError() }
            0 * _._
            flash.message == 'There was an error on fetching your tweet'
            response.redirectUrl == '/twitter/index'
    }

    def "show should inform about not found tweet"() {
        given:
            controller.params.id = '1'
        when:
            controller.show()
        then:
            1 * twitterReaderServiceMock.readTweet('1') >> null
            0 * _._
            flash.message == 'Tweet not found'
            response.redirectUrl == '/twitter/index'
    }


    def "show should show found tweet"() {
        given:
            controller.params.id = '1'
        when:
            controller.show()
        then:
            1 * twitterReaderServiceMock.readTweet('1') >> new Tweet()
            0 * _._
            flash.message == null
            response.status == 200
    }
}

class TwitterController {

    def twitterReaderService

    def index() {
    }

    def show() {
        Tweet tweet

        try {
            tweet = twitterReaderService.readTweet(params.id)
        } catch (TwitterError e) {
            log.error(e)
            flash.message = 'There was an error on fetching your tweet'
            redirect(action: 'index')
            return
        }

        if (tweet == null) {
            flash.message = 'Tweet not found'
            redirect(action: 'index')
            return
        }

        [tweet: tweet]
    }
}

The most important thing here is that we've tested controller-service interaction without logic implementation in service! That's why mock technique is so useful. It decouples your dependencies and let you focus on exactly one subject under test. Happy testing!