The argList Child Element

The <argList> element is a child of the <call>, <install>, <uninstall>, <execSubplan>, and <addSnapshot> steps. It specifies a list of variables to be passed as arguments to the called service. The called service declares the variables that it expects using a <paramList> element. The variables within the <argList> and the called <paramList> need not be the same. However, for any variable in the called <paramList> that does not have a default value, there must be a variable with the same name in the <argList>, or a preflight error is raised at plan runtime. For each variable in the called <paramList> for which there is a corresponding variable in the <argList>, the value of the variable in <paramList> will obtain the value of corresponding variable in <argList> for the duration of the execution of the called service.

Variables in <argList> that do not correspond to a variable in the called <paramList> will be silently ignored. This permits services to be redefined with additional parameters, while still allowing for backward compatibility such that one plan can call both old and new versions of the service.

The arguments of the <argList> element are expressed as attributes. For example, the following <argList> declares two arguments, “password” and “path”:

<argList password=”:[password]”
path=”/tmp”/> 

Order is not important.