This design is intended to address the following issues:
KNOX-179@jira: Simple way to introduce new servlet filters into the chains
KNOX-103@jira: Support multiple <pattern> children in <resource> for gateway.xml
KNOX-177@jira: Simplify service deployment contributor implementation
Each of these issues stem from what is currently expected of a ServiceDeploymentContributor in its contributeService method.
Basically each service deployment contributor is expected to build its own filter chain.
This is currently done by making calls to Deploymentcontext.contributeFilter.
While this provides a great deal of flexibility for each service to define a custom chain we have found that this isn't commonly necessary.
Furthermore it makes if very difficult if not impossible to introduce new filters in a chain without impacting all services.
This design will provide an abstraction to the service deployment contributors that can create either a default or specifically configured chain of filters.
The goal is to support a pattern in service deployment contributors that looks like this:
public void contributeService( DeploymentContext context, Service service ) throws Exception {
String chain = null; // Default if null, otherwise specific chain name defined in topoloy.xml
Map<String,Map<String,String>> params = null; // Default if null, otherwise map of per provider role map of name/value pairs.
ResourceDescriptor resource = context.addResource()
resource.role( "WEBHDFS" );
resource.pattern( "webhdfs/v1/?**" );
resource.pattern( "webhdfs/v1/**?**" );
context.contributeChain( service, resource, null, params );
}