<call> Step

Use the <call> step to execute a control block associated with a component installed on the target host.

The <call> step has the following child elements:

• <argList> – An optional element that is a list of arguments to pass to the control block. If you specify this element, it can only appear one time.

• Installed component targeter – An optional element that identifies the component containing the control block to execute. This element is optional if the <call> step appears in a component, but not if the step appears in a plan. If this element is omitted, <thisComponent> is used. If you specify this element, it can only appear one time. See Installed Component Targeters.

Attributes for the <call> Step

The <call> element has one required attribute of type entityName, blockName, which is the name of the control block to execute on the installed component.

<argList> Element

The <argList> element is a child of the <call>, <install>, <uninstall>, <execSubplan>, and <addSnapshot> steps. This element specifies a list of variables to be passed as arguments to the called service.

The called service declares the variables that it expects by using a <paramList> element. The variables within the <argList> and the called <paramList> need not be the same. However, for each variable in the called <paramList> that does not have a default value, a variable with the same name must be present 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 the 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> are silently ignored. Thus, services can be redefined with additional parameters, while still ensuring backward compatibility. So, one plan could call both old and new versions of the service.

The arguments of the <argList> element are expressed as attributes. The order in which the attributes appear is not significant. The following <argList> declares two arguments, password and path:

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

Attributes for the <argList> Element

The <argList> element must have at least one attribute. Each attribute is treated as a named variable to be passed to the called service. The name of each attribute must be an identifier without substitution variable references. The attribute name should correspond to the name of a parameter in the called service. The value of each attribute is an arbitrary string that can include references to variables in the enclosing scope, but not other arguments within the <argList>.