opentofu/terraform/transform_diff.go
Martin Atkins c937c06a03 terraform: ugly huge change to weave in new HCL2-oriented types
Due to how deeply the configuration types go into Terraform Core, there
isn't a great way to switch out to HCL2 gradually. As a consequence, this
huge commit gets us from the old state to a _compilable_ new state, but
does not yet attempt to fix any tests and has a number of known missing
parts and bugs. We will continue to iterate on this in forthcoming
commits, heading back towards passing tests and making Terraform
fully-functional again.

The three main goals here are:
- Use the configuration models from the "configs" package instead of the
  older models in the "config" package, which is now deprecated and
  preserved only to help us write our migration tool.
- Do expression inspection and evaluation using the functionality of the
  new "lang" package, instead of the Interpolator type and related
  functionality in the main "terraform" package.
- Represent addresses of various objects using types in the addrs package,
  rather than hand-constructed strings. This is not critical to support
  the above, but was a big help during the implementation of these other
  points since it made it much more explicit what kind of address is
  expected in each context.

Since our new packages are built to accommodate some future planned
features that are not yet implemented (e.g. the "for_each" argument on
resources, "count"/"for_each" on modules), and since there's still a fair
amount of functionality still using old-style APIs, there is a moderate
amount of shimming here to connect new assumptions with old, hopefully in
a way that makes it easier to find and eliminate these shims later.

I apologize in advance to the person who inevitably just found this huge
commit while spelunking through the commit history.
2018-10-16 18:46:46 -07:00

74 lines
2.0 KiB
Go

package terraform
import (
"fmt"
"log"
"github.com/hashicorp/terraform/dag"
)
// DiffTransformer is a GraphTransformer that adds the elements of
// the diff to the graph.
//
// This transform is used for example by the ApplyGraphBuilder to ensure
// that only resources that are being modified are represented in the graph.
type DiffTransformer struct {
Concrete ConcreteResourceInstanceNodeFunc
Diff *Diff
}
func (t *DiffTransformer) Transform(g *Graph) error {
// If the diff is nil or empty (nil is empty) then do nothing
if t.Diff.Empty() {
return nil
}
// Go through all the modules in the diff.
log.Printf("[TRACE] DiffTransformer: starting")
var nodes []dag.Vertex
for _, m := range t.Diff.Modules {
log.Printf("[TRACE] DiffTransformer: Module: %s", m)
// TODO: If this is a destroy diff then add a module destroy node
// Go through all the resources in this module.
for name, inst := range m.Resources {
log.Printf("[TRACE] DiffTransformer: Resource %q: %#v", name, inst)
// We have changes! This is a create or update operation.
// First grab the address so we have a unique way to
// reference this resource.
legacyAddr, err := parseResourceAddressInternal(name)
if err != nil {
panic(fmt.Sprintf(
"Error parsing internal name, this is a bug: %q", name))
}
addr := legacyAddr.AbsResourceInstanceAddr()
// If we're destroying, add the destroy node
if inst.Destroy || inst.GetDestroyDeposed() {
abstract := NewNodeAbstractResourceInstance(addr)
g.Add(&NodeDestroyResourceInstance{NodeAbstractResourceInstance: abstract})
}
// If we have changes, then add the applyable version
if len(inst.Attributes) > 0 {
// Add the resource to the graph
abstract := NewNodeAbstractResourceInstance(addr)
var node dag.Vertex = abstract
if f := t.Concrete; f != nil {
node = f(abstract)
}
nodes = append(nodes, node)
}
}
}
// Add all the nodes to the graph
for _, n := range nodes {
g.Add(n)
}
return nil
}