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

   1 package terraform
   2
   3 import (
   4         "github.com/hashicorp/terraform/config"
   5 )
   6
   7 // EvalCountFixZeroOneBoundary is an EvalNode that fixes up the state
   8 // when there is a resource count with zero/one boundary, i.e. fixing
   9 // a resource named "aws_instance.foo" to "aws_instance.foo.0" and vice-versa.
  10 type EvalCountFixZeroOneBoundary struct {
  11         Resource *config.Resource
  12 }
  13
  14 // TODO: test
  15 func (n *EvalCountFixZeroOneBoundary) Eval(ctx EvalContext) (interface{}, error) {
  16         // Get the count, important for knowing whether we're supposed to
  17         // be adding the zero, or trimming it.
  18         count, err := n.Resource.Count()
  19         if err != nil {
  20                 return nil, err
  21         }
  22
  23         // Figure what to look for and what to replace it with
  24         hunt := n.Resource.Id()
  25         replace := hunt + ".0"
  26         if count < 2 {
  27                 hunt, replace = replace, hunt
  28         }
  29
  30         state, lock := ctx.State()
  31
  32         // Get a lock so we can access this instance and potentially make
  33         // changes to it.
  34         lock.Lock()
  35         defer lock.Unlock()
  36
  37         // Look for the module state. If we don't have one, then it doesn't matter.
  38         mod := state.ModuleByPath(ctx.Path())
  39         if mod == nil {
  40                 return nil, nil
  41         }
  42
  43         // Look for the resource state. If we don't have one, then it is okay.
  44         rs, ok := mod.Resources[hunt]
  45         if !ok {
  46                 return nil, nil
  47         }
  48
  49         // If the replacement key exists, we just keep both
  50         if _, ok := mod.Resources[replace]; ok {
  51                 return nil, nil
  52         }
  53
  54         mod.Resources[replace] = rs
  55         delete(mod.Resources, hunt)
  56
  57         return nil, nil
  58 }