terraform/terraform/eval_ignore_changes.go

88 lines
2.4 KiB
Go

package terraform
import (
"log"
"strings"
"github.com/hashicorp/terraform/config"
)
// EvalIgnoreChanges is an EvalNode implementation that removes diff
// attributes if their name matches names provided by the resource's
// IgnoreChanges lifecycle.
type EvalIgnoreChanges struct {
Resource *config.Resource
Diff **InstanceDiff
WasChangeType *DiffChangeType
}
func (n *EvalIgnoreChanges) Eval(ctx EvalContext) (interface{}, error) {
if n.Diff == nil || *n.Diff == nil || n.Resource == nil || n.Resource.Id() == "" {
return nil, nil
}
diff := *n.Diff
ignoreChanges := n.Resource.Lifecycle.IgnoreChanges
if len(ignoreChanges) == 0 {
return nil, nil
}
changeType := diff.ChangeType()
// Let the passed in change type pointer override what the diff currently has.
if n.WasChangeType != nil && *n.WasChangeType != DiffInvalid {
changeType = *n.WasChangeType
}
// If we're just creating the resource, we shouldn't alter the
// Diff at all
if changeType == DiffCreate {
return nil, nil
}
for _, ignoredName := range ignoreChanges {
for name := range diff.Attributes {
if strings.HasPrefix(name, ignoredName) {
delete(diff.Attributes, name)
}
}
}
// If we are replacing the resource, then we expect there to be a bunch of
// extraneous attribute diffs we need to filter out for the other
// non-requires-new attributes going from "" -> "configval" or "" ->
// "<computed>". Filtering these out allows us to see if we might be able to
// skip this diff altogether.
if changeType == DiffDestroyCreate {
for k, v := range diff.Attributes {
if v.Empty() || v.NewComputed {
delete(diff.Attributes, k)
}
}
// Here we emulate the implementation of diff.RequiresNew() with one small
// tweak, we ignore the "id" attribute diff that gets added by EvalDiff,
// since that was added in reaction to RequiresNew being true.
requiresNewAfterIgnores := false
for k, v := range diff.Attributes {
if k == "id" {
continue
}
if v.RequiresNew == true {
requiresNewAfterIgnores = true
}
}
// Here we undo the two reactions to RequireNew in EvalDiff - the "id"
// attribute diff and the Destroy boolean field
if !requiresNewAfterIgnores {
log.Printf("[DEBUG] Removing 'id' diff and setting Destroy to false " +
"because after ignore_changes, this diff no longer requires replacement")
delete(diff.Attributes, "id")
diff.Destroy = false
}
}
return nil, nil
}