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package terraform
import (
"log"
"github.com/hashicorp/terraform/dag"
)
// GraphNodeTargetable is an interface for graph nodes to implement when they
// need to be told about incoming targets. This is useful for nodes that need
// to respect targets as they dynamically expand. Note that the list of targets
// provided will contain every target provided, and each implementing graph
// node must filter this list to targets considered relevant.
type GraphNodeTargetable interface {
SetTargets([]ResourceAddress)
}
// TargetsTransformer is a GraphTransformer that, when the user specifies a
// list of resources to target, limits the graph to only those resources and
// their dependencies.
type TargetsTransformer struct {
// List of targeted resource names specified by the user
Targets []string
// List of parsed targets, provided by callers like ResourceCountTransform
// that already have the targets parsed
ParsedTargets []ResourceAddress
// Set to true when we're in a `terraform destroy` or a
// `terraform plan -destroy`
Destroy bool
}
func (t *TargetsTransformer) Transform(g *Graph) error {
if len(t.Targets) > 0 && len(t.ParsedTargets) == 0 {
addrs, err := t.parseTargetAddresses()
if err != nil {
return err
}
t.ParsedTargets = addrs
}
if len(t.ParsedTargets) > 0 {
targetedNodes, err := t.selectTargetedNodes(g, t.ParsedTargets)
if err != nil {
return err
}
for _, v := range g.Vertices() {
removable := false
if _, ok := v.(GraphNodeResource); ok {
removable = true
}
if vr, ok := v.(RemovableIfNotTargeted); ok {
removable = vr.RemoveIfNotTargeted()
}
if removable && !targetedNodes.Include(v) {
log.Printf("[DEBUG] Removing %q, filtered by targeting.", dag.VertexName(v))
g.Remove(v)
}
}
}
return nil
}
func (t *TargetsTransformer) parseTargetAddresses() ([]ResourceAddress, error) {
addrs := make([]ResourceAddress, len(t.Targets))
for i, target := range t.Targets {
ta, err := ParseResourceAddress(target)
if err != nil {
return nil, err
}
addrs[i] = *ta
}
return addrs, nil
}
// Returns the list of targeted nodes. A targeted node is either addressed
// directly, or is an Ancestor of a targeted node. Destroy mode keeps
// Descendents instead of Ancestors.
func (t *TargetsTransformer) selectTargetedNodes(
g *Graph, addrs []ResourceAddress) (*dag.Set, error) {
targetedNodes := new(dag.Set)
for _, v := range g.Vertices() {
if t.nodeIsTarget(v, addrs) {
targetedNodes.Add(v)
// We inform nodes that ask about the list of targets - helps for nodes
// that need to dynamically expand. Note that this only occurs for nodes
// that are already directly targeted.
if tn, ok := v.(GraphNodeTargetable); ok {
tn.SetTargets(addrs)
}
var deps *dag.Set
var err error
if t.Destroy {
deps, err = g.Descendents(v)
} else {
deps, err = g.Ancestors(v)
}
if err != nil {
return nil, err
}
for _, d := range deps.List() {
targetedNodes.Add(d)
}
}
}
return targetedNodes, nil
}
func (t *TargetsTransformer) nodeIsTarget(
v dag.Vertex, addrs []ResourceAddress) bool {
r, ok := v.(GraphNodeResource)
if !ok {
return false
}
addr := r.ResourceAddr()
for _, targetAddr := range addrs {
if targetAddr.Equals(addr) {
return true
}
}
return false
}
// RemovableIfNotTargeted is a special interface for graph nodes that
// aren't directly addressable, but need to be removed from the graph when they
// are not targeted. (Nodes that are not directly targeted end up in the set of
// targeted nodes because something that _is_ targeted depends on them.) The
// initial use case for this interface is GraphNodeConfigVariable, which was
// having trouble interpolating for module variables in targeted scenarios that
// filtered out the resource node being referenced.
type RemovableIfNotTargeted interface {
RemoveIfNotTargeted() bool
}
|