core: render variables, locals and outputs nicely in "terraform graph"

terraform/node_local.go

@@ -3,6 +3,7 @@ package terraform
 import (
 	"github.com/hashicorp/terraform/addrs"
 	"github.com/hashicorp/terraform/configs"
+	"github.com/hashicorp/terraform/dag"
 	"github.com/hashicorp/terraform/lang"
 )
 
@@ -21,6 +22,7 @@ var (
 	_ GraphNodeReferenceable = (*NodeLocal)(nil)
 	_ GraphNodeReferencer    = (*NodeLocal)(nil)
 	_ GraphNodeEvalable      = (*NodeLocal)(nil)
+	_ dag.GraphNodeDotter    = (*NodeLocal)(nil)
 )
 
 func (n *NodeLocal) Name() string {
@@ -55,3 +57,14 @@ func (n *NodeLocal) EvalTree() EvalNode {
 		Expr: n.Config.Expr,
 	}
 }
+
+// dag.GraphNodeDotter impl.
+func (n *NodeLocal) DotNode(name string, opts *dag.DotOpts) *dag.DotNode {
+	return &dag.DotNode{
+		Name: name,
+		Attrs: map[string]string{
+			"label": n.Name(),
+			"shape": "note",
+		},
+	}
+}

terraform/node_module_variable.go

@@ -4,6 +4,7 @@ import (
 	"github.com/hashicorp/hcl2/hcl"
 	"github.com/hashicorp/terraform/addrs"
 	"github.com/hashicorp/terraform/configs"
+	"github.com/hashicorp/terraform/dag"
 	"github.com/hashicorp/terraform/lang"
 	"github.com/zclconf/go-cty/cty"
 )
@@ -25,6 +26,7 @@ var (
 	_ GraphNodeReferenceable    = (*NodeApplyableModuleVariable)(nil)
 	_ GraphNodeReferencer       = (*NodeApplyableModuleVariable)(nil)
 	_ GraphNodeEvalable         = (*NodeApplyableModuleVariable)(nil)
+	_ dag.GraphNodeDotter       = (*NodeApplyableModuleVariable)(nil)
 )
 
 func (n *NodeApplyableModuleVariable) Name() string {
@@ -138,3 +140,14 @@ func (n *NodeApplyableModuleVariable) EvalTree() EvalNode {
 		},
 	}
 }
+
+// dag.GraphNodeDotter impl.
+func (n *NodeApplyableModuleVariable) DotNode(name string, opts *dag.DotOpts) *dag.DotNode {
+	return &dag.DotNode{
+		Name: name,
+		Attrs: map[string]string{
+			"label": n.Name(),
+			"shape": "note",
+		},
+	}
+}

terraform/node_output.go

@@ -24,6 +24,7 @@ var (
 	_ GraphNodeReferencer       = (*NodeApplyableOutput)(nil)
 	_ GraphNodeReferenceOutside = (*NodeApplyableOutput)(nil)
 	_ GraphNodeEvalable         = (*NodeApplyableOutput)(nil)
+	_ dag.GraphNodeDotter       = (*NodeApplyableOutput)(nil)
 )
 
 func (n *NodeApplyableOutput) Name() string {
@@ -137,6 +138,17 @@ func (n *NodeApplyableOutput) EvalTree() EvalNode {
 	}
 }
 
+// dag.GraphNodeDotter impl.
+func (n *NodeApplyableOutput) DotNode(name string, opts *dag.DotOpts) *dag.DotNode {
+	return &dag.DotNode{
+		Name: name,
+		Attrs: map[string]string{
+			"label": n.Name(),
+			"shape": "note",
+		},
+	}
+}
+
 // NodeDestroyableOutput represents an output that is "destroybale":
 // its application will remove the output from the state.
 type NodeDestroyableOutput struct {
@@ -150,6 +162,7 @@ var (
 	_ GraphNodeTargetDownstream = (*NodeDestroyableOutput)(nil)
 	_ GraphNodeReferencer       = (*NodeDestroyableOutput)(nil)
 	_ GraphNodeEvalable         = (*NodeDestroyableOutput)(nil)
+	_ dag.GraphNodeDotter       = (*NodeDestroyableOutput)(nil)
 )
 
 func (n *NodeDestroyableOutput) Name() string {
@@ -185,3 +198,14 @@ func (n *NodeDestroyableOutput) EvalTree() EvalNode {
 		Addr: n.Addr.OutputValue,
 	}
 }
+
+// dag.GraphNodeDotter impl.
+func (n *NodeDestroyableOutput) DotNode(name string, opts *dag.DotOpts) *dag.DotNode {
+	return &dag.DotNode{
+		Name: name,
+		Attrs: map[string]string{
+			"label": n.Name(),
+			"shape": "note",
+		},
+	}
+}

terraform/node_root_variable.go

@@ -3,6 +3,7 @@ package terraform
 import (
 	"github.com/hashicorp/terraform/addrs"
 	"github.com/hashicorp/terraform/configs"
+	"github.com/hashicorp/terraform/dag"
 )
 
 // NodeRootVariable represents a root variable input.
@@ -14,6 +15,7 @@ type NodeRootVariable struct {
 var (
 	_ GraphNodeSubPath       = (*NodeRootVariable)(nil)
 	_ GraphNodeReferenceable = (*NodeRootVariable)(nil)
+	_ dag.GraphNodeDotter    = (*NodeApplyableModuleVariable)(nil)
 )
 
 func (n *NodeRootVariable) Name() string {
@@ -29,3 +31,14 @@ func (n *NodeRootVariable) Path() addrs.ModuleInstance {
 func (n *NodeRootVariable) ReferenceableAddrs() []addrs.Referenceable {
 	return []addrs.Referenceable{n.Addr}
 }
+
+// dag.GraphNodeDotter impl.
+func (n *NodeRootVariable) DotNode(name string, opts *dag.DotOpts) *dag.DotNode {
+	return &dag.DotNode{
+		Name: name,
+		Attrs: map[string]string{
+			"label": n.Name(),
+			"shape": "note",
+		},
+	}
+}