Merge pull request #9517 from hashicorp/f-disable-shadow

command/meta: add -shadow flag to disable shadow graph

command/meta.go

@@ -63,10 +63,13 @@ type Meta struct {
 	//
 	// parallelism is used to control the number of concurrent operations
 	// allowed when walking the graph
+	//
+	// shadow is used to enable/disable the shadow graph
 	statePath    string
 	stateOutPath string
 	backupPath   string
 	parallelism  int
+	shadow       bool
 }
 
 // initStatePaths is used to initialize the default values for
@@ -312,6 +315,7 @@ func (m *Meta) contextOpts() *terraform.ContextOpts {
 	opts.Variables = vs
 	opts.Targets = m.targets
 	opts.UIInput = m.UIInput()
+	opts.Shadow = m.shadow
 
 	return &opts
 }
@@ -328,6 +332,9 @@ func (m *Meta) flagSet(n string) *flag.FlagSet {
 		f.Var((*FlagKVFile)(&m.autoVariables), m.autoKey, "variable file")
 	}
 
+	// Advanced (don't need documentation, or unlikely to be set)
+	f.BoolVar(&m.shadow, "shadow", true, "shadow graph")
+
 	// Experimental features
 	f.BoolVar(&terraform.X_newApply, "Xnew-apply", false, "experiment: new apply")
 

terraform/context.go

@@ -70,6 +70,7 @@ type ContextOpts struct {
 	StateFutureAllowed bool
 	Providers          map[string]ResourceProviderFactory
 	Provisioners       map[string]ResourceProvisionerFactory
+	Shadow             bool
 	Targets            []string
 	Variables          map[string]interface{}
 
@@ -93,6 +94,7 @@ type Context struct {
 	hooks      []Hook
 	module     *module.Tree
 	sh         *stopHook
+	shadow     bool
 	state      *State
 	stateLock  sync.RWMutex
 	targets    []string
@@ -174,6 +176,7 @@ func NewContext(opts *ContextOpts) (*Context, error) {
 		diff:      opts.Diff,
 		hooks:     hooks,
 		module:    opts.Module,
+		shadow:    opts.Shadow,
 		state:     state,
 		targets:   opts.Targets,
 		uiInput:   opts.UIInput,
@@ -695,13 +698,18 @@ func (c *Context) walk(
 	// If we have a shadow graph, walk that as well
 	var shadowCtx *Context
 	var shadowCloser Shadow
-	if shadow != nil {
+	if c.shadow && shadow != nil {
 		// Build the shadow context. In the process, override the real context
 		// with the one that is wrapped so that the shadow context can verify
 		// the results of the real.
 		realCtx, shadowCtx, shadowCloser = newShadowContext(c)
 	}
 
+	// Just log this so we can see it in a debug log
+	if !c.shadow {
+		log.Printf("[WARN] terraform: shadow graph disabled")
+	}
+
 	// Build the real graph walker
 	log.Printf("[DEBUG] Starting graph walk: %s", operation.String())
 	walker := &ContextGraphWalker{Context: realCtx, Operation: operation}

terraform/context_test.go

@@ -68,6 +68,9 @@ func TestNewContextState(t *testing.T) {
 }
 
 func testContext2(t *testing.T, opts *ContextOpts) *Context {
+	// Enable the shadow graph
+	opts.Shadow = true
+
 	ctx, err := NewContext(opts)
 	if err != nil {
 		t.Fatalf("err: %s", err)