PaaSify Mule using Azure and SpringBoot

There is a lot of hype about PaaS and it appears to be the go to strategy where ever possible. I wont blame if people don’t want to deal with infrastructure and headache of following up with middleware to check if everything is installed as per instructions. I have noticed, one can write a very detailed installation instructions but, there is always possibility of human err. This human err could sometimes become nightmare to investigate. If you agree, say Hello!! PaaS.

With mule applications, there are couple of options with which you can declare victory of being on PaaS:

Mule CloudHub
Other Cloud solutions like Azure, Amazon, Heroku etc

If you need convenience, you may want to take the route of CloudHub. However, this may not be feasible if your organization is already using a different cloud solution. If you are using Microsoft Azure, you are in luck as so below are couple of ways you can achieve PaaS with Mule and Azure.

PaaSMS Welcome Spring Boot

Spring Boot makes it ridiculously easy to build any spring based stand alone applications. If you are not aware of Spring Boot, I would suggest to create a simple hello world application from here to see how you can build more than what you need in couple of minutes. One of the flashy features about using spring boot is the ability to provide health check metrics out of the box by including a single actuator dependency(as of 1/30/2015 this works only for MVC based applications)

So the idea is simple, build a spring boot application and start mule instance on the application start and boom, you have your application ready to be deployed on PaaS. Below is code snippet which is used to start Mule:

[java] //comma separated mule config files to be loaded
private final String mulefilestoload = "mule-config.xml";
@Override
public void run(String… arg0) throws Exception {
MuleContextFactory muleContextFactory = new DefaultMuleContextFactory();
MuleContextBuilder muleContextBuilder = new DefaultMuleContextBuilder();
try {
List&amp;amp;amp;lt;ConfigurationBuilder&amp;amp;amp;gt; configurationBuilders = Arrays
.&amp;amp;amp;lt;ConfigurationBuilder&amp;amp;amp;gt; asList(
new AnnotationsConfigurationBuilder(),
new SpringXmlConfigurationBuilder(mulefilestoload));
MuleContext muleContext = muleContextFactory.createMuleContext(configurationBuilders,muleContextBuilder);
muleContext.start();
} catch (Exception e) {
log.error(e.getMessage());
}
}
[/java]

If you have downloaded the code from GitHub, one thing you may want to notice is the application in packaged as JAR in pom.xml. This was done as we can directly run the spring boot application using java command and pass runtime parameters needed. Http port is passed as runtime parameter using server.port. There is hidden reason why the port is passed on runtime instead of hardcoding it, this is explained below.

Deploying to Azure

There are couple of ways you can deploy this application to Azure like using WebJob, WorkerRole, WebApp. Out of these, I found the easiest way to do is to use WebApp. If you are wondering why on earth you deploy a JAR as webapp, the answer is, you are using JAR as packaging type but when the JAR file is run, it is actually starting the whole instance of Mule and exposing endpoints and thus qualifying to receive http traffic. Below are the steps to run the “hello world” application as WebApp on Azure:

1. Create a WebApp by selecting the default one – IIS and not java specific such as tomcat
PaaS1

2. Create web.config with below spring configuration

[xml] <?xml version="1.0" encoding="UTF-8"?>
<configuration>
<system.webServer>
<handlers>
<add name="httpPlatformHandler" path="*" verb="*" modules="httpPlatformHandler" resourceType="Unspecified" />
</handlers>

<httpPlatform processPath="%JAVA_HOME%\bin\java.exe"
arguments="-Djava.net.preferIPv4Stack=true -Dserver.port=%HTTP_PLATFORM_PORT% -jar "%HOME%\site\wwwroot\mule-springboot-1.0.jar"">
</httpPlatform>
</system.webServer>
</configuration>
[/xml]

Notice that we are passing %HTTP_PLATFORM_PORT% for server.port. Azure opens a dynamic port for WebApps and is made available via HTTP_PLATFORM_PORT environment variable. Inorder for your http listener to use the same port opened, you need to use HTTP_PLATFORM_PORT in the port settings of http listener

3. Once the WebApp is up, ftp using any ftp tool like FileZilla using the ftp credentials on your Azure WebApp. After successful ftp connection, upload the web.config and mule-springboot-1.0.jar files to site/wwwroot location

PaaSFtp