258 lines
8.4 KiB
Go
258 lines
8.4 KiB
Go
package terraform
|
|
|
|
import (
|
|
"log"
|
|
|
|
"github.com/hashicorp/terraform/internal/addrs"
|
|
"github.com/hashicorp/terraform/internal/states"
|
|
|
|
"github.com/hashicorp/terraform/internal/configs"
|
|
"github.com/hashicorp/terraform/internal/dag"
|
|
)
|
|
|
|
// GraphNodeDestroyer must be implemented by nodes that destroy resources.
|
|
type GraphNodeDestroyer interface {
|
|
dag.Vertex
|
|
|
|
// DestroyAddr 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() *addrs.AbsResourceInstance
|
|
}
|
|
|
|
// GraphNodeCreator must be implemented by nodes that create OR update resources.
|
|
type GraphNodeCreator interface {
|
|
// CreateAddr is the address of the resource being created or updated
|
|
CreateAddr() *addrs.AbsResourceInstance
|
|
}
|
|
|
|
// 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.
|
|
Config *configs.Config
|
|
State *states.State
|
|
}
|
|
|
|
func (t *DestroyEdgeTransformer) Transform(g *Graph) error {
|
|
// Build a map of what is being destroyed (by address string) to
|
|
// the list of destroyers.
|
|
destroyers := make(map[string][]GraphNodeDestroyer)
|
|
|
|
// Record the creators, which will need to depend on the destroyers if they
|
|
// are only being updated.
|
|
creators := make(map[string][]GraphNodeCreator)
|
|
|
|
// destroyersByResource records each destroyer by the ConfigResource
|
|
// address. We use this because dependencies are only referenced as
|
|
// resources and have no index or module instance information, but we will
|
|
// want to connect all the individual instances for correct ordering.
|
|
destroyersByResource := make(map[string][]GraphNodeDestroyer)
|
|
for _, v := range g.Vertices() {
|
|
switch n := v.(type) {
|
|
case GraphNodeDestroyer:
|
|
addrP := n.DestroyAddr()
|
|
if addrP == nil {
|
|
log.Printf("[WARN] DestroyEdgeTransformer: %q (%T) has no destroy address", dag.VertexName(n), v)
|
|
continue
|
|
}
|
|
addr := *addrP
|
|
|
|
key := addr.String()
|
|
log.Printf("[TRACE] DestroyEdgeTransformer: %q (%T) destroys %s", dag.VertexName(n), v, key)
|
|
destroyers[key] = append(destroyers[key], n)
|
|
|
|
resAddr := addr.ContainingResource().Config().String()
|
|
destroyersByResource[resAddr] = append(destroyersByResource[resAddr], n)
|
|
case GraphNodeCreator:
|
|
addr := n.CreateAddr().ContainingResource().Config().String()
|
|
creators[addr] = append(creators[addr], n)
|
|
}
|
|
}
|
|
|
|
// 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
|
|
}
|
|
|
|
// Connect destroy despendencies as stored in the state
|
|
for _, ds := range destroyers {
|
|
for _, des := range ds {
|
|
ri, ok := des.(GraphNodeResourceInstance)
|
|
if !ok {
|
|
continue
|
|
}
|
|
|
|
for _, resAddr := range ri.StateDependencies() {
|
|
for _, desDep := range destroyersByResource[resAddr.String()] {
|
|
if !graphNodesAreResourceInstancesInDifferentInstancesOfSameModule(desDep, des) {
|
|
log.Printf("[TRACE] DestroyEdgeTransformer: %s has stored dependency of %s\n", dag.VertexName(desDep), dag.VertexName(des))
|
|
g.Connect(dag.BasicEdge(desDep, des))
|
|
} else {
|
|
log.Printf("[TRACE] DestroyEdgeTransformer: skipping %s => %s inter-module-instance dependency\n", dag.VertexName(desDep), dag.VertexName(des))
|
|
}
|
|
}
|
|
|
|
// We can have some create or update nodes which were
|
|
// dependents of the destroy node. If they have no destroyer
|
|
// themselves, make the connection directly from the creator.
|
|
for _, createDep := range creators[resAddr.String()] {
|
|
if !graphNodesAreResourceInstancesInDifferentInstancesOfSameModule(createDep, des) {
|
|
log.Printf("[DEBUG] DestroyEdgeTransformer: %s has stored dependency of %s\n", dag.VertexName(createDep), dag.VertexName(des))
|
|
g.Connect(dag.BasicEdge(createDep, des))
|
|
} else {
|
|
log.Printf("[TRACE] DestroyEdgeTransformer: skipping %s => %s inter-module-instance dependency\n", dag.VertexName(createDep), dag.VertexName(des))
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// connect creators to any destroyers on which they may depend
|
|
for _, cs := range creators {
|
|
for _, c := range cs {
|
|
ri, ok := c.(GraphNodeResourceInstance)
|
|
if !ok {
|
|
continue
|
|
}
|
|
|
|
for _, resAddr := range ri.StateDependencies() {
|
|
for _, desDep := range destroyersByResource[resAddr.String()] {
|
|
if !graphNodesAreResourceInstancesInDifferentInstancesOfSameModule(c, desDep) {
|
|
log.Printf("[TRACE] DestroyEdgeTransformer: %s has stored dependency of %s\n", dag.VertexName(c), dag.VertexName(desDep))
|
|
g.Connect(dag.BasicEdge(c, desDep))
|
|
} else {
|
|
log.Printf("[TRACE] DestroyEdgeTransformer: skipping %s => %s inter-module-instance dependency\n", dag.VertexName(c), dag.VertexName(desDep))
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// 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
|
|
}
|
|
|
|
for _, d := range destroyers[addr.String()] {
|
|
// For illustrating our example
|
|
a_d := d.(dag.Vertex)
|
|
a := v
|
|
|
|
log.Printf(
|
|
"[TRACE] DestroyEdgeTransformer: connecting creator %q with destroyer %q",
|
|
dag.VertexName(a), dag.VertexName(a_d))
|
|
|
|
g.Connect(dag.BasicEdge(a, a_d))
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// Remove any nodes that aren't needed when destroying modules.
|
|
// Variables, outputs, locals, and expanders may not be able to evaluate
|
|
// correctly, so we can remove these if nothing depends on them. The module
|
|
// closers also need to disable their use of expansion if the module itself is
|
|
// no longer present.
|
|
type pruneUnusedNodesTransformer struct {
|
|
}
|
|
|
|
func (t *pruneUnusedNodesTransformer) Transform(g *Graph) error {
|
|
// We need a reverse depth first walk of modules, processing them in order
|
|
// from the leaf modules to the root. This allows us to remove unneeded
|
|
// dependencies from child modules, freeing up nodes in the parent module
|
|
// to also be removed.
|
|
|
|
nodes := g.Vertices()
|
|
|
|
for removed := true; removed; {
|
|
removed = false
|
|
|
|
for i := 0; i < len(nodes); i++ {
|
|
// run this in a closure, so we can return early rather than
|
|
// dealing with complex looping and labels
|
|
func() {
|
|
n := nodes[i]
|
|
switch n := n.(type) {
|
|
case graphNodeTemporaryValue:
|
|
// root module outputs indicate they are not temporary by
|
|
// returning false here.
|
|
if !n.temporaryValue() {
|
|
return
|
|
}
|
|
|
|
// temporary values, which consist of variables, locals,
|
|
// and outputs, must be kept if anything refers to them.
|
|
for _, v := range g.UpEdges(n) {
|
|
// keep any value which is connected through a
|
|
// reference
|
|
if _, ok := v.(GraphNodeReferencer); ok {
|
|
return
|
|
}
|
|
}
|
|
|
|
case graphNodeExpandsInstances:
|
|
// Any nodes that expand instances are kept when their
|
|
// instances may need to be evaluated.
|
|
for _, v := range g.UpEdges(n) {
|
|
switch v.(type) {
|
|
case graphNodeExpandsInstances:
|
|
// expanders can always depend on module expansion
|
|
// themselves
|
|
return
|
|
case GraphNodeResourceInstance:
|
|
// resource instances always depend on their
|
|
// resource node, which is an expander
|
|
return
|
|
}
|
|
}
|
|
|
|
case GraphNodeProvider:
|
|
// Providers that may have been required by expansion nodes
|
|
// that we no longer need can also be removed.
|
|
if g.UpEdges(n).Len() > 0 {
|
|
return
|
|
}
|
|
|
|
default:
|
|
return
|
|
}
|
|
|
|
log.Printf("[DEBUG] pruneUnusedNodes: %s is no longer needed, removing", dag.VertexName(n))
|
|
g.Remove(n)
|
|
removed = true
|
|
|
|
// remove the node from our iteration as well
|
|
last := len(nodes) - 1
|
|
nodes[i], nodes[last] = nodes[last], nodes[i]
|
|
nodes = nodes[:last]
|
|
}()
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|