github.com/vtorhonen/terraform@v0.9.0-beta2.0.20170307220345-5d894e4ffda7/terraform/transform_state.go (about)

     1  package terraform
     2  
     3  import (
     4  	"fmt"
     5  	"log"
     6  
     7  	"github.com/hashicorp/terraform/dag"
     8  )
     9  
    10  // StateTransformer is a GraphTransformer that adds the elements of
    11  // the state to the graph.
    12  //
    13  // This transform is used for example by the DestroyPlanGraphBuilder to ensure
    14  // that only resources that are in the state are represented in the graph.
    15  type StateTransformer struct {
    16  	Concrete ConcreteResourceNodeFunc
    17  
    18  	State *State
    19  }
    20  
    21  func (t *StateTransformer) Transform(g *Graph) error {
    22  	// If the state is nil or empty (nil is empty) then do nothing
    23  	if t.State.Empty() {
    24  		return nil
    25  	}
    26  
    27  	// Go through all the modules in the diff.
    28  	log.Printf("[TRACE] StateTransformer: starting")
    29  	var nodes []dag.Vertex
    30  	for _, ms := range t.State.Modules {
    31  		log.Printf("[TRACE] StateTransformer: Module: %v", ms.Path)
    32  
    33  		// Go through all the resources in this module.
    34  		for name, rs := range ms.Resources {
    35  			log.Printf("[TRACE] StateTransformer: Resource %q: %#v", name, rs)
    36  
    37  			// Add the resource to the graph
    38  			addr, err := parseResourceAddressInternal(name)
    39  			if err != nil {
    40  				panic(fmt.Sprintf(
    41  					"Error parsing internal name, this is a bug: %q", name))
    42  			}
    43  
    44  			// Very important: add the module path for this resource to
    45  			// the address. Remove "root" from it.
    46  			addr.Path = ms.Path[1:]
    47  
    48  			// Add the resource to the graph
    49  			abstract := &NodeAbstractResource{Addr: addr}
    50  			var node dag.Vertex = abstract
    51  			if f := t.Concrete; f != nil {
    52  				node = f(abstract)
    53  			}
    54  
    55  			nodes = append(nodes, node)
    56  		}
    57  	}
    58  
    59  	// Add all the nodes to the graph
    60  	for _, n := range nodes {
    61  		g.Add(n)
    62  	}
    63  
    64  	return nil
    65  }