github.com/cmalfait/terraform@v0.11.12-beta1/helper/schema/data_source_resource_shim.go (about)

     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  }