• Created by Unknown User (kminder), last updated on May 09, 2014 1 minute read

This design is intended to address the following issues:

KNOX-195@jira: Simple way to introduce new service without requiring code

The basic issue is that the development and delivery of code is currently required to add a new Service into Knox.
This results in a barrier to entry for integrating new services with Knox.
The design below is intended to introduce a very simple configuration based mechanism to accomplish this.
Naturally this will only cover very simple use-cases.
More advanced requirements will still require the development of a ServiceDeploymentContributor.


A topology file sketch containing a use of the "default" service.

Topology
<topology>
  ...
  <service>
    <role>...</role>
    <name>generic</name>
    <url>...</url>  
    <param>
      <name>pattern</name>
      <value>custom/v1/**?**</value>
    </param>
    <param>
      <name>rewrite</name>
      <value>custom-rewrite-rules.xml</value>
    </param>
  </service>
</topology>

Note: Something isn't quite right with the above. Basically I'd prefer if there were a way to specify a chain per pattern but this doesn't support that.

 

DefaultServiceDeploymentContributor
public class DefaultServiceDeploymentContributor {

  String getRole() {
    return "*"; // The "*" will require special handling in the framework.

  String getName() {
    return "generic";
  }

  void initializeContribution( DeploymentContext context ) {
    // NoOp
  }

  void contributeService( DeploymentContext context, Service service ) throws Exception {
    ResourceDescriptor resource = context.getGatewayDescriptor().addResource();
    resource.role( service.getRole() );
    resource.pattern( service.getParam( "pattern" );

    UrlRewriteRulesDescriptor serviceRules = loadRules( service.getParam( "rewrite" ) );
    UrlRewriteRulesDescriptor clusterRules = context.getDescriptor( "rewrite" );
    clusterRules.addRules( serviceRules );
  }

  // Called after all contributors and before provider finalizeContribution methods.
  void finalizeContribution( DeploymentContext context )  {
    // NoOp
  }

}
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