terraform/states/instance_object.go

121 lines
4.8 KiB
Go

package states
import (
"github.com/zclconf/go-cty/cty"
ctyjson "github.com/zclconf/go-cty/cty/json"
"github.com/hashicorp/terraform/addrs"
)
// ResourceInstanceObject is the local representation of a specific remote
// object associated with a resource instance. In practice not all remote
// objects are actually remote in the sense of being accessed over the network,
// but this is the most common case.
//
// It is not valid to mutate a ResourceInstanceObject once it has been created.
// Instead, create a new object and replace the existing one.
type ResourceInstanceObject struct {
// Value is the object-typed value representing the remote object within
// Terraform.
Value cty.Value
// Private is an opaque value set by the provider when this object was
// last created or updated. Terraform Core does not use this value in
// any way and it is not exposed anywhere in the user interface, so
// a provider can use it for retaining any necessary private state.
Private []byte
// Status represents the "readiness" of the object as of the last time
// it was updated.
Status ObjectStatus
// Dependencies is a set of other addresses in the same module which
// this instance depended on when the given attributes were evaluated.
// This is used to construct the dependency relationships for an object
// whose configuration is no longer available, such as if it has been
// removed from configuration altogether, or is now deposed.
Dependencies []addrs.Referenceable
}
// ObjectStatus represents the status of a RemoteObject.
type ObjectStatus rune
//go:generate go run golang.org/x/tools/cmd/stringer -type ObjectStatus
const (
// ObjectReady is an object status for an object that is ready to use.
ObjectReady ObjectStatus = 'R'
// ObjectTainted is an object status representing an object that is in
// an unrecoverable bad state due to a partial failure during a create,
// update, or delete operation. Since it cannot be moved into the
// ObjectRead state, a tainted object must be replaced.
ObjectTainted ObjectStatus = 'T'
// ObjectPlanned is a special object status used only for the transient
// placeholder objects we place into state during the refresh and plan
// walks to stand in for objects that will be created during apply.
//
// Any object of this status must have a corresponding change recorded
// in the current plan, whose value must then be used in preference to
// the value stored in state when evaluating expressions. A planned
// object stored in state will be incomplete if any of its attributes are
// not yet known, and the plan must be consulted in order to "see" those
// unknown values, because the state is not able to represent them.
ObjectPlanned ObjectStatus = 'P'
)
// Encode marshals the value within the receiver to produce a
// ResourceInstanceObjectSrc ready to be written to a state file.
//
// The given type must be the implied type of the resource type schema, and
// the given value must conform to it. It is important to pass the schema
// type and not the object's own type so that dynamically-typed attributes
// will be stored correctly. The caller must also provide the version number
// of the schema that the given type was derived from, which will be recorded
// in the source object so it can be used to detect when schema migration is
// required on read.
//
// The returned object may share internal references with the receiver and
// so the caller must not mutate the receiver any further once once this
// method is called.
func (o *ResourceInstanceObject) Encode(ty cty.Type, schemaVersion uint64) (*ResourceInstanceObjectSrc, error) {
// Our state serialization can't represent unknown values, so we convert
// them to nulls here. This is lossy, but nobody should be writing unknown
// values here and expecting to get them out again later.
//
// We get unknown values here while we're building out a "planned state"
// during the plan phase, but the value stored in the plan takes precedence
// for expression evaluation. The apply step should never produce unknown
// values, but if it does it's the responsibility of the caller to detect
// and raise an error about that.
val := cty.UnknownAsNull(o.Value)
src, err := ctyjson.Marshal(val, ty)
if err != nil {
return nil, err
}
return &ResourceInstanceObjectSrc{
SchemaVersion: schemaVersion,
AttrsJSON: src,
Private: o.Private,
Status: o.Status,
Dependencies: o.Dependencies,
}, nil
}
// AsTainted returns a deep copy of the receiver with the status updated to
// ObjectTainted.
func (o *ResourceInstanceObject) AsTainted() *ResourceInstanceObject {
if o == nil {
// A nil object can't be tainted, but we'll allow this anyway to
// avoid a crash, since we presumably intend to eventually record
// the object has having been deleted anyway.
return nil
}
ret := o.DeepCopy()
ret.Status = ObjectTainted
return ret
}