vendor/github.com/hashicorp/terraform/terraform/graph_builder.go

   1 package terraform
   2
   3 import (
   4         "fmt"
   5         "log"
   6         "strings"
   7 )
   8
   9 // GraphBuilder is an interface that can be implemented and used with
  10 // Terraform to build the graph that Terraform walks.
  11 type GraphBuilder interface {
  12         // Build builds the graph for the given module path. It is up to
  13         // the interface implementation whether this build should expand
  14         // the graph or not.
  15         Build(path []string) (*Graph, error)
  16 }
  17
  18 // BasicGraphBuilder is a GraphBuilder that builds a graph out of a
  19 // series of transforms and (optionally) validates the graph is a valid
  20 // structure.
  21 type BasicGraphBuilder struct {
  22         Steps    []GraphTransformer
  23         Validate bool
  24         // Optional name to add to the graph debug log
  25         Name string
  26 }
  27
  28 func (b *BasicGraphBuilder) Build(path []string) (*Graph, error) {
  29         g := &Graph{Path: path}
  30
  31         debugName := "graph.json"
  32         if b.Name != "" {
  33                 debugName = b.Name + "-" + debugName
  34         }
  35         debugBuf := dbug.NewFileWriter(debugName)
  36         g.SetDebugWriter(debugBuf)
  37         defer debugBuf.Close()
  38
  39         for _, step := range b.Steps {
  40                 if step == nil {
  41                         continue
  42                 }
  43
  44                 stepName := fmt.Sprintf("%T", step)
  45                 dot := strings.LastIndex(stepName, ".")
  46                 if dot >= 0 {
  47                         stepName = stepName[dot+1:]
  48                 }
  49
  50                 debugOp := g.DebugOperation(stepName, "")
  51                 err := step.Transform(g)
  52
  53                 errMsg := ""
  54                 if err != nil {
  55                         errMsg = err.Error()
  56                 }
  57                 debugOp.End(errMsg)
  58
  59                 log.Printf(
  60                         "[TRACE] Graph after step %T:\n\n%s",
  61                         step, g.StringWithNodeTypes())
  62
  63                 if err != nil {
  64                         return g, err
  65                 }
  66         }
  67
  68         // Validate the graph structure
  69         if b.Validate {
  70                 if err := g.Validate(); err != nil {
  71                         log.Printf("[ERROR] Graph validation failed. Graph:\n\n%s", g.String())
  72                         return nil, err
  73                 }
  74         }
  75
  76         return g, nil
  77 }