opentofu/internal/addrs/resource_phase.go
Martin Atkins f3a57db293 addrs: UniqueKey and UniqueKeyer
Many times now we've seen situations where we need to use addresses
as map keys, but not all of our address types are comparable and thus
we tend to end up using string representations as keys instead.

That's problematic because conversion to string uses type information
and some of the address types have string representations that are
ambiguous with one another.

UniqueKey therefore represents an opaque key that is unique for each
functionally-distinct address across all types that implement
UniqueKeyer.

For this initial commit I've implemented UniqueKeyer only for the
Referenceable family of types. These are an easy case because they
were all already comparable (intentionally) anyway. Later commits
can implement UniqueKeyer for other types that are not naturally
comparable, such as any which include a ModuleInstance.

This also includes a new type addrs.Set which wraps a map as a set
of addresses, using the unique keys to ensure that there can be only
one element for each distinct address.
2021-07-14 17:37:48 -07:00

118 lines
4.2 KiB
Go

package addrs
import "fmt"
// ResourceInstancePhase is a special kind of reference used only internally
// during graph building to represent resource instances that are in a
// non-primary state.
//
// Graph nodes can declare themselves referenceable via an instance phase
// or can declare that they reference an instance phase in order to accomodate
// secondary graph nodes dealing with, for example, destroy actions.
//
// This special reference type cannot be accessed directly by end-users, and
// should never be shown in the UI.
type ResourceInstancePhase struct {
referenceable
ResourceInstance ResourceInstance
Phase ResourceInstancePhaseType
}
var _ Referenceable = ResourceInstancePhase{}
// Phase returns a special "phase address" for the receving instance. See the
// documentation of ResourceInstancePhase for the limited situations where this
// is intended to be used.
func (r ResourceInstance) Phase(rpt ResourceInstancePhaseType) ResourceInstancePhase {
return ResourceInstancePhase{
ResourceInstance: r,
Phase: rpt,
}
}
// ContainingResource returns an address for the same phase of the resource
// that this instance belongs to.
func (rp ResourceInstancePhase) ContainingResource() ResourcePhase {
return rp.ResourceInstance.Resource.Phase(rp.Phase)
}
func (rp ResourceInstancePhase) String() string {
// We use a different separator here than usual to ensure that we'll
// never conflict with any non-phased resource instance string. This
// is intentionally something that would fail parsing with ParseRef,
// because this special address type should never be exposed in the UI.
return fmt.Sprintf("%s#%s", rp.ResourceInstance, rp.Phase)
}
func (rp ResourceInstancePhase) UniqueKey() UniqueKey {
return rp // A ResourceInstancePhase is its own UniqueKey
}
func (rp ResourceInstancePhase) uniqueKeySigil() {}
// ResourceInstancePhaseType is an enumeration used with ResourceInstancePhase.
type ResourceInstancePhaseType string
const (
// ResourceInstancePhaseDestroy represents the "destroy" phase of a
// resource instance.
ResourceInstancePhaseDestroy ResourceInstancePhaseType = "destroy"
// ResourceInstancePhaseDestroyCBD is similar to ResourceInstancePhaseDestroy
// but is used for resources that have "create_before_destroy" set, thus
// requiring a different dependency ordering.
ResourceInstancePhaseDestroyCBD ResourceInstancePhaseType = "destroy-cbd"
)
func (rpt ResourceInstancePhaseType) String() string {
return string(rpt)
}
// ResourcePhase is a special kind of reference used only internally
// during graph building to represent resources that are in a
// non-primary state.
//
// Graph nodes can declare themselves referenceable via a resource phase
// or can declare that they reference a resource phase in order to accomodate
// secondary graph nodes dealing with, for example, destroy actions.
//
// Since resources (as opposed to instances) aren't actually phased, this
// address type is used only as an approximation during initial construction
// of the resource-oriented plan graph, under the assumption that resource
// instances with ResourceInstancePhase addresses will be created in dynamic
// subgraphs during the graph walk.
//
// This special reference type cannot be accessed directly by end-users, and
// should never be shown in the UI.
type ResourcePhase struct {
referenceable
Resource Resource
Phase ResourceInstancePhaseType
}
var _ Referenceable = ResourcePhase{}
// Phase returns a special "phase address" for the receving instance. See the
// documentation of ResourceInstancePhase for the limited situations where this
// is intended to be used.
func (r Resource) Phase(rpt ResourceInstancePhaseType) ResourcePhase {
return ResourcePhase{
Resource: r,
Phase: rpt,
}
}
func (rp ResourcePhase) String() string {
// We use a different separator here than usual to ensure that we'll
// never conflict with any non-phased resource instance string. This
// is intentionally something that would fail parsing with ParseRef,
// because this special address type should never be exposed in the UI.
return fmt.Sprintf("%s#%s", rp.Resource, rp.Phase)
}
func (rp ResourcePhase) UniqueKey() UniqueKey {
return rp // A ResourcePhase is its own UniqueKey
}
func (rp ResourcePhase) uniqueKeySigil() {}