Introduce Mule ESB

Introduction

The video for this blog is available at:
http://www.youtube.com/watch?v=wVCmik-2xAM&feature=youtu.be

Mule and JBoss Fuse ESBs are most popular open source ESBs on the market. They are the leaders. I have been working with both for numerous years. Both of them have their strengths and weakness. I discuss these further in my later blog. Today, I am going to describe Mule 101 from development point of view. I am going to cover the following aspects:

• Install Mule Studio
• Install Mule MMC and Runtime
• Develop Hello World Mule Application
• Build Mule Project With Maven
• Mule Application Deployment

Install Mule Studio

You can download both Mule Studio and MMC from http://www.mulesoft.com/platform/soa/mule-esb-enterprise. You will need to fill a form so that Mule can track you down, and hopefully you will buy their product. I downloaded the following two file to ~/Downloads on my MacBook:

   mmc-distribution-mule-console-bundle-3.4.2.zip
   MuleStudio-for-macosx-64bit-3.5.0-201312091746.zip

As you can see the current mule run time is version 3.4.2 and Mule Studio is 3.5. Execute the following commands [My current dir is ~/Downloads]:

jar vxf mmc-distribution-mule-console-bundle-3.4.2.zip
jar vxf MuleStudio-for-macosx-64bit-3.5.0-201312091746.zip
mv MuleStudio ~/.
mv mule-enterprise-standalone-3.4.2 ~/.

Now, I have both Mule Studio and runtime under my home directory. Let's develop a Hello World Application.

Develop Hello World Mule Application

Start MuleStudio.app [Make sure it is executable]. Enable the maven setting by editing the Preferences as shown below:

To create a mule project, New -> Mule Project. Make sure create maven project as shown below:

As shown below, the MuleStudio will create a project with the following structures.

Now let's develop a simple application using HTTP component. Perform the flowing actions:

• Double click the mule flow file under flow directory
• Drag and drop the HTTP component
• Drag and drop the Logger component
• Double click the Logger icon in side the flow
• Fill the groovy script as shown below

Now, we can run the mule application inside the studio by right click the the file hello-world.mflow file, run as, Muel application. You should see the following output in the studio console:

NFO  2014-02-15 14:33:05,294 [main] org.mule.module.management.agent.JmxAgent: Registered Connector Service with name Mule.hello-world:type=Connector,name="connector.http.mule.default.1"
INFO  2014-02-15 14:33:05,297 [main] org.mule.DefaultMuleContext: 
**********************************************************************
* Application: hello-world                                           *
* OS encoding: US-ASCII, Mule encoding: UTF-8                        *
*                                                                    *
* Agents Running:                                                    *
*   Clustering Agent                                                 *
*   JMX Agent                                                        *
**********************************************************************
INFO  2014-02-15 14:33:05,297 [main] org.mule.module.launcher.MuleDeploymentService: 
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+ Started app 'hello-world'                                +
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Open a web browser, and enter the following URL

http://localhost:8081/echo?UserName=Gary Liu

You should see the following on your browser:

/echo?UserName=Gary%20Liu

At this point, we have created a simple mule application using HTTP and Logger components coming with mule. This process is good for development and unit testing. However, we normal build the application using maven and later perform continuous integration using other utility like Jenkins. Now, let me explain the build process using maven.

Build Mule Application With Maven

In order to build maven project created through MuleStudio, we need to uncomment all the following dependencies:

One more thing before we can build using maven. Execute the folloing script under MuleStudio installation dir [~/MuleStudio]. This is to install licm jar file to our local maven repo.

mvn install:install-file \
 -Dfile=plugins/org.mule.tooling.server.3.4.1.ee_3.4.1.201312062152/mule/plugins/mule-plugin-debugger-3.4.1/lib/licm-1.1.3.jar \
 -DgroupId=com.mulesoft.licm \
 -DartifactId=licm \
 -Dversion=1.1.3 \
 -Dpackaging=jar

Now, we can build the Hello World mule application we just developed. Let's do the following:

cd ~/MuleStudio/workspace/hello-world
mvn clean install

The maven build process takes now time. If you check the target directory, there is a file named as: hello-world-1.0.0-SNAPSHOT.zip. This is the file we will deploy to the mule runtime. If you are curious enough and wander what are the contents inside that zip file, you can do the following:

[/Users/Gary2013/MuleStudio/workspace/hello-world]$ cd target
[/Users/Gary2013/MuleStudio/workspace/hello-world/target]$ jar vtf hello-world-1.0.0-SNAPSHOT.zip 
   989 Sat Feb 15 14:33:02 CST 2014 hello-world.xml
     0 Sat Feb 15 14:14:20 CST 2014 mule-app.properties
   119 Sat Feb 15 14:33:02 CST 2014 mule-deploy.properties
     0 Sat Feb 15 15:01:22 CST 2014 classes/
   989 Sat Feb 15 15:01:22 CST 2014 classes/hello-world.xml
     0 Sat Feb 15 15:01:22 CST 2014 classes/mule-app.properties
   119 Sat Feb 15 15:01:22 CST 2014 classes/mule-deploy.properties
[/Users/Gary2013/MuleStudio/workspace/hello-world/target]$ 

This is the beauty about mule. Its application is very clean and minimum comparing with osgi bundles. Mule will be able to figure out dynamically what jar files should be linked during runtime. Once the application zip file is build, we can deploy it to the mule runtime.

Mule Application Deployment

There is a README.txt file under mule runtime installation [in my case, it is ~/mule-enterprise-standalone-3.4.2]. In that will, the start, stop and restart procedures are described. Let's start the mule as daemon by run the following command:

[/Users/Gary2013/mule-enterprise-standalone-3.4.2]$ bin/mule start
MULE_HOME is set to /Users/Gary2013/mule-enterprise-standalone-3.4.2
Starting Mule Enterprise Edition...
[/Users/Gary2013/mule-enterprise-standalone-3.4.2]$

Now, we can check what java process is mule runtime. Here is what I see:

[/Users/Gary2013/mule-enterprise-standalone-3.4.2]$ ps -eaf | egrep java | egrep -v egrep 
  501 17266 17265   0  3:19PM ??         0:32.28 /Library/Java/JavaVirtualMachines/jdk1.7.0_40.jdk/Contents/Home/bin/java -Dmule.home=/Users/Gary2013/mule-enterprise-standalone-3.4.2 -Dmule.base=/Users/Gary2013/mule-enterprise-standalone-3.4.2 -Djava.net.preferIPv4Stack=TRUE -XX:MaxPermSize=256m -Djava.endorsed.dirs=/Users/Gary2013/mule-enterprise-standalone-3.4.2/lib/endorsed -Xmx1024m -Djava.library.path=%LD_LIBRARY_PATH%:/Users/Gary2013/mule-enterprise-standalone-3.4.2/lib/boot -classpath %MULE_LIB%:/Users/Gary2013/mule-enterprise-standalone-3.4.2/conf:/Users/Gary2013/mule-enterprise-standalone-3.4.2/lib/boot/commons-cli-1.2.jar:/Users/Gary2013/mule-enterprise-standalone-3.4.2/lib/boot/commons-codec-1.3-osgi.jar:/Users/Gary2013/mule-enterprise-standalone-3.4.2/lib/boot/jul-to-slf4j-1.6.1.jar:/Users/Gary2013/mule-enterprise-standalone-3.4.2/lib/boot/licm-1.1.4.jar:/Users/Gary2013/mule-enterprise-standalone-3.4.2/lib/boot/log4j-1.2.16.jar:/Users/Gary2013/mule-enterprise-standalone-3.4.2/lib/boot/mule-module-boot-ee-3.4.2.jar:/Users/Gary2013/mule-enterprise-standalone-3.4.2/lib/boot/mule-module-logging-3.4.2.jar:/Users/Gary2013/mule-enterprise-standalone-3.4.2/lib/boot/oscore-2.2.4.jar:/Users/Gary2013/mule-enterprise-standalone-3.4.2/lib/boot/propertyset-1.3.jar:/Users/Gary2013/mule-enterprise-standalone-3.4.2/lib/boot/truelicense-1.29.jar:/Users/Gary2013/mule-enterprise-standalone-3.4.2/lib/boot/truexml-1.29.jar:/Users/Gary2013/mule-enterprise-standalone-3.4.2/lib/boot/wrapper-3.5.19.jar:/Users/Gary2013/mule-enterprise-standalone-3.4.2/data-mapper -Dwrapper.key=d4wYZG88GHn1riyEuxVDypA4M4y9i5w4 -Dwrapper.port=32000 -Dwrapper.jvm.port.min=31000 -Dwrapper.jvm.port.max=31999 -Dwrapper.disable_console_input=TRUE -Dwrapper.pid=17265 -Dwrapper.version=3.5.19-st -Dwrapper.native_library=wrapper -Dwrapper.arch=universal -Dwrapper.service=TRUE -Dwrapper.cpu.timeout=10 -Dwrapper.jvmid=1 -Dwrapper.lang.domain=wrapper -Dwrapper.lang.folder=../lang org.mule.module.reboot.MuleContainerBootstrap start0
[/Users/Gary2013/mule-enterprise-standalone-3.4.2]$ 

The deployment procedure is covered pretty well http://www.mulesoft.org/documentation/display/current/Application+Deployment. Simple, we can copy the zip file from target to the apps directory.

cp ~/MuleStudio/workspace/hello-world/target/hello-world-1.0.0-SNAPSHOT.zip  .

Mule has a feature called hot-deployment. Once the zip file is dropped to the apps dir, mule will unzip the archive, delete it, and create a file named like: hello-world-1.0.0-SNAPSHOT-anchor.txt. Inside that file, there is a line of text. The meaning of text is not important. Mule is just using it as key to monitor the application. To undeploy the application, you can simply delete the anchor file.