terraform/addrs/module.go

98 lines
3.0 KiB
Go

package addrs
import (
"strings"
)
// Module is an address for a module call within configuration. This is
// the static counterpart of ModuleInstance, representing a traversal through
// the static module call tree in configuration and does not take into account
// the potentially-multiple instances of a module that might be created by
// "count" and "for_each" arguments within those calls.
//
// This type should be used only in very specialized cases when working with
// the static module call tree. Type ModuleInstance is appropriate in more cases.
//
// Although Module is a slice, it should be treated as immutable after creation.
type Module []string
// RootModule is the module address representing the root of the static module
// call tree, which is also the zero value of Module.
//
// Note that this is not the root of the dynamic module tree, which is instead
// represented by RootModuleInstance.
var RootModule Module
// IsRoot returns true if the receiver is the address of the root module,
// or false otherwise.
func (m Module) IsRoot() bool {
return len(m) == 0
}
func (m Module) String() string {
if len(m) == 0 {
return ""
}
var steps []string
for _, s := range m {
steps = append(steps, "module", s)
}
return strings.Join(steps, ".")
}
func (m Module) Equal(other Module) bool {
return m.String() == other.String()
}
// Child returns the address of a child call in the receiver, identified by the
// given name.
func (m Module) Child(name string) Module {
ret := make(Module, 0, len(m)+1)
ret = append(ret, m...)
return append(ret, name)
}
// Parent returns the address of the parent module of the receiver, or the
// receiver itself if there is no parent (if it's the root module address).
func (m Module) Parent() Module {
if len(m) == 0 {
return m
}
return m[:len(m)-1]
}
// Call returns the module call address that corresponds to the given module
// instance, along with the address of the module that contains it.
//
// There is no call for the root module, so this method will panic if called
// on the root module address.
//
// In practice, this just turns the last element of the receiver into a
// ModuleCall and then returns a slice of the receiever that excludes that
// last part. This is just a convenience for situations where a call address
// is required, such as when dealing with *Reference and Referencable values.
func (m Module) Call() (Module, ModuleCall) {
if len(m) == 0 {
panic("cannot produce ModuleCall for root module")
}
caller, callName := m[:len(m)-1], m[len(m)-1]
return caller, ModuleCall{
Name: callName,
}
}
// Ancestors returns a slice containing the receiver and all of its ancestor
// modules, all the way up to (and including) the root module. The result is
// ordered by depth, with the root module always first.
//
// Since the result always includes the root module, a caller may choose to
// ignore it by slicing the result with [1:].
func (m Module) Ancestors() []Module {
ret := make([]Module, 0, len(m)+1)
for i := 0; i <= len(m); i++ {
ret = append(ret, m[:i])
}
return ret
}