1 files changed, 269 insertions, 0 deletions
diff --git a/vendor/github.com/hashicorp/terraform/terraform/transform_destroy_edge.go b/vendor/github.com/hashicorp/terraform/terraform/transform_destroy_edge.go
new file mode 100644
index 00000000..22be1ab6
--- /dev/null
+++ b/vendor/github.com/hashicorp/terraform/terraform/transform_destroy_edge.go
@@ -0,0 +1,269 @@
+package terraform
+
+import (
+	"log"
+
+	"github.com/hashicorp/terraform/config/module"
+	"github.com/hashicorp/terraform/dag"
+)
+
+// GraphNodeDestroyer must be implemented by nodes that destroy resources.
+type GraphNodeDestroyer interface {
+	dag.Vertex
+
+	// ResourceAddr is the address of the resource that is being
+	// destroyed by this node. If this returns nil, then this node
+	// is not destroying anything.
+	DestroyAddr() *ResourceAddress
+}
+
+// GraphNodeCreator must be implemented by nodes that create OR update resources.
+type GraphNodeCreator interface {
+	// ResourceAddr is the address of the resource being created or updated
+	CreateAddr() *ResourceAddress
+}
+
+// DestroyEdgeTransformer is a GraphTransformer that creates the proper
+// references for destroy resources. Destroy resources are more complex
+// in that they must be depend on the destruction of resources that
+// in turn depend on the CREATION of the node being destroy.
+//
+// That is complicated. Visually:
+//
+//   B_d -> A_d -> A -> B
+//
+// Notice that A destroy depends on B destroy, while B create depends on
+// A create. They're inverted. This must be done for example because often
+// dependent resources will block parent resources from deleting. Concrete
+// example: VPC with subnets, the VPC can't be deleted while there are
+// still subnets.
+type DestroyEdgeTransformer struct {
+	// These are needed to properly build the graph of dependencies
+	// to determine what a destroy node depends on. Any of these can be nil.
+	Module *module.Tree
+	State  *State
+}
+
+func (t *DestroyEdgeTransformer) Transform(g *Graph) error {
+	log.Printf("[TRACE] DestroyEdgeTransformer: Beginning destroy edge transformation...")
+
+	// Build a map of what is being destroyed (by address string) to
+	// the list of destroyers. In general there will only be one destroyer
+	// but to make it more robust we support multiple.
+	destroyers := make(map[string][]GraphNodeDestroyer)
+	for _, v := range g.Vertices() {
+		dn, ok := v.(GraphNodeDestroyer)
+		if !ok {
+			continue
+		}
+
+		addr := dn.DestroyAddr()
+		if addr == nil {
+			continue
+		}
+
+		key := addr.String()
+		log.Printf(
+			"[TRACE] DestroyEdgeTransformer: %s destroying %q",
+			dag.VertexName(dn), key)
+		destroyers[key] = append(destroyers[key], dn)
+	}
+
+	// If we aren't destroying anything, there will be no edges to make
+	// so just exit early and avoid future work.
+	if len(destroyers) == 0 {
+		return nil
+	}
+
+	// Go through and connect creators to destroyers. Going along with
+	// our example, this makes: A_d => A
+	for _, v := range g.Vertices() {
+		cn, ok := v.(GraphNodeCreator)
+		if !ok {
+			continue
+		}
+
+		addr := cn.CreateAddr()
+		if addr == nil {
+			continue
+		}
+
+		key := addr.String()
+		ds := destroyers[key]
+		if len(ds) == 0 {
+			continue
+		}
+
+		for _, d := range ds {
+			// For illustrating our example
+			a_d := d.(dag.Vertex)
+			a := v
+
+			log.Printf(
+				"[TRACE] DestroyEdgeTransformer: connecting creator/destroyer: %s, %s",
+				dag.VertexName(a), dag.VertexName(a_d))
+
+			g.Connect(&DestroyEdge{S: a, T: a_d})
+		}
+	}
+
+	// This is strange but is the easiest way to get the dependencies
+	// of a node that is being destroyed. We use another graph to make sure
+	// the resource is in the graph and ask for references. We have to do this
+	// because the node that is being destroyed may NOT be in the graph.
+	//
+	// Example: resource A is force new, then destroy A AND create A are
+	// in the graph. BUT if resource A is just pure destroy, then only
+	// destroy A is in the graph, and create A is not.
+	providerFn := func(a *NodeAbstractProvider) dag.Vertex {
+		return &NodeApplyableProvider{NodeAbstractProvider: a}
+	}
+	steps := []GraphTransformer{
+		// Add outputs and metadata
+		&OutputTransformer{Module: t.Module},
+		&AttachResourceConfigTransformer{Module: t.Module},
+		&AttachStateTransformer{State: t.State},
+
+		// Add providers since they can affect destroy order as well
+		&MissingProviderTransformer{AllowAny: true, Concrete: providerFn},
+		&ProviderTransformer{},
+		&DisableProviderTransformer{},
+		&ParentProviderTransformer{},
+		&AttachProviderConfigTransformer{Module: t.Module},
+
+		// Add all the variables. We can depend on resources through
+		// variables due to module parameters, and we need to properly
+		// determine that.
+		&RootVariableTransformer{Module: t.Module},
+		&ModuleVariableTransformer{Module: t.Module},
+
+		&ReferenceTransformer{},
+	}
+
+	// Go through all the nodes being destroyed and create a graph.
+	// The resulting graph is only of things being CREATED. For example,
+	// following our example, the resulting graph would be:
+	//
+	//   A, B (with no edges)
+	//
+	var tempG Graph
+	var tempDestroyed []dag.Vertex
+	for d, _ := range destroyers {
+		// d is what is being destroyed. We parse the resource address
+		// which it came from it is a panic if this fails.
+		addr, err := ParseResourceAddress(d)
+		if err != nil {
+			panic(err)
+		}
+
+		// This part is a little bit weird but is the best way to
+		// find the dependencies we need to: build a graph and use the
+		// attach config and state transformers then ask for references.
+		abstract := &NodeAbstractResource{Addr: addr}
+		tempG.Add(abstract)
+		tempDestroyed = append(tempDestroyed, abstract)
+
+		// We also add the destroy version here since the destroy can
+		// depend on things that the creation doesn't (destroy provisioners).
+		destroy := &NodeDestroyResource{NodeAbstractResource: abstract}
+		tempG.Add(destroy)
+		tempDestroyed = append(tempDestroyed, destroy)
+	}
+
+	// Run the graph transforms so we have the information we need to
+	// build references.
+	for _, s := range steps {
+		if err := s.Transform(&tempG); err != nil {
+			return err
+		}
+	}
+
+	log.Printf("[TRACE] DestroyEdgeTransformer: reference graph: %s", tempG.String())
+
+	// Go through all the nodes in the graph and determine what they
+	// depend on.
+	for _, v := range tempDestroyed {
+		// Find all ancestors of this to determine the edges we'll depend on
+		vs, err := tempG.Ancestors(v)
+		if err != nil {
+			return err
+		}
+
+		refs := make([]dag.Vertex, 0, vs.Len())
+		for _, raw := range vs.List() {
+			refs = append(refs, raw.(dag.Vertex))
+		}
+
+		refNames := make([]string, len(refs))
+		for i, ref := range refs {
+			refNames[i] = dag.VertexName(ref)
+		}
+		log.Printf(
+			"[TRACE] DestroyEdgeTransformer: creation node %q references %s",
+			dag.VertexName(v), refNames)
+
+		// If we have no references, then we won't need to do anything
+		if len(refs) == 0 {
+			continue
+		}
+
+		// Get the destroy node for this. In the example of our struct,
+		// we are currently at B and we're looking for B_d.
+		rn, ok := v.(GraphNodeResource)
+		if !ok {
+			continue
+		}
+
+		addr := rn.ResourceAddr()
+		if addr == nil {
+			continue
+		}
+
+		dns := destroyers[addr.String()]
+
+		// We have dependencies, check if any are being destroyed
+		// to build the list of things that we must depend on!
+		//
+		// In the example of the struct, if we have:
+		//
+		//   B_d => A_d => A => B
+		//
+		// Then at this point in the algorithm we started with B_d,
+		// we built B (to get dependencies), and we found A. We're now looking
+		// to see if A_d exists.
+		var depDestroyers []dag.Vertex
+		for _, v := range refs {
+			rn, ok := v.(GraphNodeResource)
+			if !ok {
+				continue
+			}
+
+			addr := rn.ResourceAddr()
+			if addr == nil {
+				continue
+			}
+
+			key := addr.String()
+			if ds, ok := destroyers[key]; ok {
+				for _, d := range ds {
+					depDestroyers = append(depDestroyers, d.(dag.Vertex))
+					log.Printf(
+						"[TRACE] DestroyEdgeTransformer: destruction of %q depends on %s",
+						key, dag.VertexName(d))
+				}
+			}
+		}
+
+		// Go through and make the connections. Use the variable
+		// names "a_d" and "b_d" to reference our example.
+		for _, a_d := range dns {
+			for _, b_d := range depDestroyers {
+				if b_d != a_d {
+					g.Connect(dag.BasicEdge(b_d, a_d))
+				}
+			}
+		}
+	}
+
+	return nil
+}