terraform: Handle module depedency inversion

This commit is contained in:
Armon Dadgar 2014-11-24 14:38:06 -08:00
parent d5fd4dabe8
commit afef564108
1 changed files with 82 additions and 67 deletions

View File

@ -274,7 +274,7 @@ func Graph(opts *GraphOpts) (*depgraph.Graph, error) {
// If we have a diff, then make sure to add that in
if modDiff != nil {
if err := graphAddDiff(g, modDiff); err != nil {
if err := graphAddDiff(g, opts.Diff, modDiff); err != nil {
return nil, err
}
}
@ -544,10 +544,22 @@ func graphAddConfigResources(
// destroying the VPC's subnets first, whereas creating a VPC requires
// doing it before the subnets are created. This function handles inserting
// these nodes for you.
func graphAddDiff(g *depgraph.Graph, d *ModuleDiff) error {
func graphAddDiff(g *depgraph.Graph, gDiff *Diff, d *ModuleDiff) error {
var nlist []*depgraph.Noun
var modules []*depgraph.Noun
injected := make(map[*depgraph.Dependency]struct{})
for _, n := range g.Nouns {
// A module is being destroyed if all it's resources are being
// destroyed (via a destroy plan) or if it is orphaned. Only in
// those cases do we need to handle depedency inversion.
if mod, ok := n.Meta.(*GraphNodeModule); ok {
md := gDiff.ModuleByPath(mod.Path)
if mod.Flags&FlagOrphan != 0 || (md != nil && md.Destroy) {
modules = append(modules, n)
}
continue
}
rn, ok := n.Meta.(*GraphNodeResource)
if !ok {
continue
@ -693,78 +705,81 @@ func graphAddDiff(g *depgraph.Graph, d *ModuleDiff) error {
rn.Resource.Diff = rd
}
// Go through each noun and make sure we calculate all the dependencies
// properly.
for _, n := range nlist {
deps := n.Deps
num := len(deps)
for i := 0; i < num; i++ {
dep := deps[i]
// Go through each resource and module and make sure we
// calculate all the dependencies properly.
invertDeps := [][]*depgraph.Noun{nlist, modules}
for _, list := range invertDeps {
for _, n := range list {
deps := n.Deps
num := len(deps)
for i := 0; i < num; i++ {
dep := deps[i]
// Check if this dependency was just injected, otherwise
// we will incorrectly flip the depedency twice.
if _, ok := injected[dep]; ok {
continue
}
// Check if this dependency was just injected, otherwise
// we will incorrectly flip the depedency twice.
if _, ok := injected[dep]; ok {
continue
}
switch target := dep.Target.Meta.(type) {
case *GraphNodeResource:
// If the other node is also being deleted,
// we must be deleted first. E.g. if A -> B,
// then when we create, B is created first then A.
// On teardown, A is destroyed first, then B.
// Thus we must flip our depedency and instead inject
// it on B.
for _, n2 := range nlist {
rn2 := n2.Meta.(*GraphNodeResource)
if target.Resource.Id == rn2.Resource.Id {
newDep := &depgraph.Dependency{
Name: n.Name,
Source: n2,
Target: n,
switch target := dep.Target.Meta.(type) {
case *GraphNodeResource:
// If the other node is also being deleted,
// we must be deleted first. E.g. if A -> B,
// then when we create, B is created first then A.
// On teardown, A is destroyed first, then B.
// Thus we must flip our depedency and instead inject
// it on B.
for _, n2 := range nlist {
rn2 := n2.Meta.(*GraphNodeResource)
if target.Resource.Id == rn2.Resource.Id {
newDep := &depgraph.Dependency{
Name: n.Name,
Source: n2,
Target: n,
}
injected[newDep] = struct{}{}
n2.Deps = append(n2.Deps, newDep)
break
}
injected[newDep] = struct{}{}
n2.Deps = append(n2.Deps, newDep)
break
}
// Drop the dependency. We may have created
// an inverse depedency if the dependent resource
// is also being deleted, but this dependence is
// no longer required.
deps[i], deps[num-1] = deps[num-1], nil
num--
i--
case *GraphNodeModule:
// We invert any module dependencies so we're destroyed
// first, before any modules are applied.
newDep := &depgraph.Dependency{
Name: n.Name,
Source: dep.Target,
Target: n,
}
dep.Target.Deps = append(dep.Target.Deps, newDep)
// Drop the dependency. We may have created
// an inverse depedency if the dependent resource
// is also being deleted, but this dependence is
// no longer required.
deps[i], deps[num-1] = deps[num-1], nil
num--
i--
case *GraphNodeResourceProvider:
// Keep these around, but fix up the source to be ourselves
// rather than the old node.
newDep := *dep
newDep.Source = n
deps[i] = &newDep
default:
panic(fmt.Errorf("Unhandled depedency type: %#v", dep.Target.Meta))
}
// Drop the dependency. We may have created
// an inverse depedency if the dependent resource
// is also being deleted, but this dependence is
// no longer required.
deps[i], deps[num-1] = deps[num-1], nil
num--
i--
case *GraphNodeModule:
// We invert any module dependencies so we're destroyed
// first, before any modules are applied.
newDep := &depgraph.Dependency{
Name: n.Name,
Source: dep.Target,
Target: n,
}
dep.Target.Deps = append(dep.Target.Deps, newDep)
// Drop the dependency. We may have created
// an inverse depedency if the dependent resource
// is also being deleted, but this dependence is
// no longer required.
deps[i], deps[num-1] = deps[num-1], nil
num--
i--
case *GraphNodeResourceProvider:
// Keep these around, but fix up the source to be ourselves
// rather than the old node.
newDep := *dep
newDep.Source = n
deps[i] = &newDep
default:
panic(fmt.Errorf("Unhandled depedency type: %#v", dep.Target.Meta))
}
n.Deps = deps[:num]
}
n.Deps = deps[:num]
}
// Add the nouns to the graph