// Apply creates, updates, and/or deletes a resource.
func (r *Resource) Apply(
s *terraform.InstanceState,
d *terraform.InstanceDiff,
meta interface{}) (*terraform.InstanceState, error) {
data, err := schemaMap(r.Schema).Data(s, d)
if err != nil {
return s, err
}
if s == nil {
// The Terraform API dictates that this should never happen, but
// it doesn't hurt to be safe in this case.
s = new(terraform.InstanceState)
}
if d.Destroy || d.RequiresNew() {
if s.ID != "" {
// Destroy the resource since it is created
if err := r.Delete(data, meta); err != nil {
return data.State(), err
}
// Make sure the ID is gone.
data.SetId("")
}
// If we're only destroying, and not creating, then return
// now since we're done!
if !d.RequiresNew() {
return nil, nil
}
// Reset the data to be stateless since we just destroyed
data, err = schemaMap(r.Schema).Data(nil, d)
if err != nil {
return nil, err
}
}
err = nil
if data.Id() == "" {
// We're creating, it is a new resource.
err = r.Create(data, meta)
} else {
if r.Update == nil {
return s, fmt.Errorf("doesn't support update")
}
err = r.Update(data, meta)
}
return r.recordCurrentSchemaVersion(data.State()), err
}
// Diff returns the diff for a resource given the schema map,
// state, and configuration.
func (m schemaMap) Diff(
s *terraform.InstanceState,
c *terraform.ResourceConfig) (*terraform.InstanceDiff, error) {
result := new(terraform.InstanceDiff)
result.Attributes = make(map[string]*terraform.ResourceAttrDiff)
d := &ResourceData{
schema: m,
state: s,
config: c,
}
for k, schema := range m {
err := m.diff(k, schema, result, d, false)
if err != nil {
return nil, err
}
}
// If the diff requires a new resource, then we recompute the diff
// so we have the complete new resource diff, and preserve the
// RequiresNew fields where necessary so the user knows exactly what
// caused that.
if result.RequiresNew() {
// Create the new diff
result2 := new(terraform.InstanceDiff)
result2.Attributes = make(map[string]*terraform.ResourceAttrDiff)
// Reset the data to not contain state. We have to call init()
// again in order to reset the FieldReaders.
d.state = nil
d.init()
// Perform the diff again
for k, schema := range m {
err := m.diff(k, schema, result2, d, false)
if err != nil {
return nil, err
}
}
// Force all the fields to not force a new since we know what we
// want to force new.
for k, attr := range result2.Attributes {
if attr == nil {
continue
}
if attr.RequiresNew {
attr.RequiresNew = false
}
if s != nil {
attr.Old = s.Attributes[k]
}
}
// Now copy in all the requires new diffs...
for k, attr := range result.Attributes {
if attr == nil {
continue
}
newAttr, ok := result2.Attributes[k]
if !ok {
newAttr = attr
}
if attr.RequiresNew {
newAttr.RequiresNew = true
}
result2.Attributes[k] = newAttr
}
// And set the diff!
result = result2
}
// Remove any nil diffs just to keep things clean
for k, v := range result.Attributes {
if v == nil {
delete(result.Attributes, k)
}
}
// Go through and detect all of the ComputedWhens now that we've
// finished the diff.
// TODO
if result.Empty() {
// If we don't have any diff elements, just return nil
return nil, nil
}
return result, nil
}