vendor/github.com/hashicorp/terraform/helper/schema/data_source_resource_shim.go

   1 package schema
   2
   3 import (
   4         "fmt"
   5 )
   6
   7 // DataSourceResourceShim takes a Resource instance describing a data source
   8 // (with a Read implementation and a Schema, at least) and returns a new
   9 // Resource instance with additional Create and Delete implementations that
  10 // allow the data source to be used as a resource.
  11 //
  12 // This is a backward-compatibility layer for data sources that were formerly
  13 // read-only resources before the data source concept was added. It should not
  14 // be used for any *new* data sources.
  15 //
  16 // The Read function for the data source *must* call d.SetId with a non-empty
  17 // id in order for this shim to function as expected.
  18 //
  19 // The provided Resource instance, and its schema, will be modified in-place
  20 // to make it suitable for use as a full resource.
  21 func DataSourceResourceShim(name string, dataSource *Resource) *Resource {
  22         // Recursively, in-place adjust the schema so that it has ForceNew
  23         // on any user-settable resource.
  24         dataSourceResourceShimAdjustSchema(dataSource.Schema)
  25
  26         dataSource.Create = CreateFunc(dataSource.Read)
  27         dataSource.Delete = func(d *ResourceData, meta interface{}) error {
  28                 d.SetId("")
  29                 return nil
  30         }
  31         dataSource.Update = nil // should already be nil, but let's make sure
  32
  33         // FIXME: Link to some further docs either on the website or in the
  34         // changelog, once such a thing exists.
  35         dataSource.DeprecationMessage = fmt.Sprintf(
  36                 "using %s as a resource is deprecated; consider using the data source instead",
  37                 name,
  38         )
  39
  40         return dataSource
  41 }
  42
  43 func dataSourceResourceShimAdjustSchema(schema map[string]*Schema) {
  44         for _, s := range schema {
  45                 // If the attribute is configurable then it must be ForceNew,
  46                 // since we have no Update implementation.
  47                 if s.Required || s.Optional {
  48                         s.ForceNew = true
  49                 }
  50
  51                 // If the attribute is a nested resource, we need to recursively
  52                 // apply these same adjustments to it.
  53                 if s.Elem != nil {
  54                         if r, ok := s.Elem.(*Resource); ok {
  55                                 dataSourceResourceShimAdjustSchema(r.Schema)
  56                         }
  57                 }
  58         }
  59 }