vendor/github.com/hashicorp/terraform/terraform/transform_attach_state.go

   1 package terraform
   2
   3 import (
   4         "log"
   5
   6         "github.com/hashicorp/terraform/dag"
   7         "github.com/hashicorp/terraform/states"
   8 )
   9
  10 // GraphNodeAttachResourceState is an interface that can be implemented
  11 // to request that a ResourceState is attached to the node.
  12 //
  13 // Due to a historical naming inconsistency, the type ResourceState actually
  14 // represents the state for a particular _instance_, while InstanceState
  15 // represents the values for that instance during a particular phase
  16 // (e.g. primary vs. deposed). Consequently, GraphNodeAttachResourceState
  17 // is supported only for nodes that represent resource instances, even though
  18 // the name might suggest it is for containing resources.
  19 type GraphNodeAttachResourceState interface {
  20         GraphNodeResourceInstance
  21
  22         // Sets the state
  23         AttachResourceState(*states.Resource)
  24 }
  25
  26 // AttachStateTransformer goes through the graph and attaches
  27 // state to nodes that implement the interfaces above.
  28 type AttachStateTransformer struct {
  29         State *states.State // State is the root state
  30 }
  31
  32 func (t *AttachStateTransformer) Transform(g *Graph) error {
  33         // If no state, then nothing to do
  34         if t.State == nil {
  35                 log.Printf("[DEBUG] Not attaching any node states: overall state is nil")
  36                 return nil
  37         }
  38
  39         for _, v := range g.Vertices() {
  40                 // Nodes implement this interface to request state attachment.
  41                 an, ok := v.(GraphNodeAttachResourceState)
  42                 if !ok {
  43                         continue
  44                 }
  45                 addr := an.ResourceInstanceAddr()
  46
  47                 rs := t.State.Resource(addr.ContainingResource())
  48                 if rs == nil {
  49                         log.Printf("[DEBUG] Resource state not found for node %q, instance %s", dag.VertexName(v), addr)
  50                         continue
  51                 }
  52
  53                 is := rs.Instance(addr.Resource.Key)
  54                 if is == nil {
  55                         // We don't actually need this here, since we'll attach the whole
  56                         // resource state, but we still check because it'd be weird
  57                         // for the specific instance we're attaching to not to exist.
  58                         log.Printf("[DEBUG] Resource instance state not found for node %q, instance %s", dag.VertexName(v), addr)
  59                         continue
  60                 }
  61
  62                 // make sure to attach a copy of the state, so instances can modify the
  63                 // same ResourceState.
  64                 an.AttachResourceState(rs.DeepCopy())
  65         }
  66
  67         return nil
  68 }