Mechanism for Parameter Passing compatible with v1.0

As an action item accepted on the 2013-07-25 TOSCA TC call, I am opening up this JIRA issue.

It is recognized that via interop. activities and discussions such as plan portability API that TOSCA would benefit from a single mechanism to pass parameters between nodes. It is also believed that this can be done in a way to preserve compatibility with the v1.0 spec. and work with a declarative modeling approach.

Of note at this point in time are the facts that the TOSCA v1.0 spec. (and schema):

• defines input and output parameters for service templates
• the concept that abstract node (types) can be replaced by service templates

however there is no described mechanism for how parameter passing would occur given the schema and modeling concepts.

This problem was also encountered at the TOSCA Interop. SC where when attempting to interop. on the SugarCRM CSAR file. To get past this an informal (non-normative) agreement was reached to assume the "environment" would preserve whatever variables (i.e. including parameters) are left over by one node and assume they are available to another (essentially within the same terminal session, since bash scripts were assumed for interop). However, each company could implement this in any way they saw fit leaving the issue still unresolved (for spec. purposes).

It is also recognized that his topic/concept has come up when developing other template formats and TOSCA would likely need a mechanism and to address this topic as well.