Profile Selection

Requires Merlin 3.1

In the Profile tutorial we covered the mechanisms used to establish a pre-configured deployment profile. In this tutorial we update the <classname>.xprofile to include multiple named profiles and show how you can select a specific profile when declaring a component in block descriptor.

Component deployment profiles are co-located with the component implementation class under an .xprofile resource.

Adding multiple profiles

The RandomGeneratorProvider.xprofile is updated to include multiple profiles.

RandomGeneratorProvider.xprofile

<?xml version="1.0"?>
<profiles>

  <profile name="primary">
    <configuration>
      <seed>1024</seed>
    </configuration>
  </profile>

  <profile name="secondary">
    <configuration>
      <seed>2048</seed>
    </configuration>
  </profile>

</profiles>

Component declaration using a named profile

A <component> element may contain the profile attribute. The value of the profile attribute is the name of a profile declared under the .xprofile resource. If a component directive uses the profile attribute content of the element will be ignored.

Extract from block.xml

   <component name="randomizer" 
     class="tutorial.RandomGeneratorProvider" 
     profile="secondary"/>

Executing the tutorial

Build and run the tutorial.

$ maven jar
$ merlin -execute target\classes
        

In the logging output we see that Merlin has selected the "secondary" profile and as a consequence the random seed declared in the secondary profile is different to our earlier examples.

[INFO   ] (kernel): installing: file:/${user.dir}/target/classes/
[INFO   ] (tutorial.randomizer): configuration stage
[INFO   ] (tutorial.randomizer): seed: 2048
[INFO   ] (tutorial.hello): supplied random: 1998430032
[INFO   ] (kernel): dissassembly phase
[INFO   ] (kernel): disposal phase