Files
opentf/terraform/transform_diff.go
2016-10-19 13:38:51 -07:00

131 lines
3.5 KiB
Go

package terraform
import (
"fmt"
"log"
"github.com/hashicorp/terraform/config/module"
)
// 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.
//
// Module and State is still required for the DiffTransformer for annotations
// since the Diff doesn't contain all the information required to build the
// complete graph (such as create-before-destroy information). The graph
// is built based on the diff first, though, ensuring that only resources
// that are being modified are present in the graph.
type DiffTransformer struct {
Diff *Diff
Module *module.Tree
State *State
}
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 []*NodeApplyableResource
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)
// TODO: destroy
if inst.Destroy {
}
// If this diff has no attribute changes, then we have
// nothing to do and therefore won't add it to the graph.
if len(inst.Attributes) == 0 {
continue
}
// We have changes! This is a create or update operation.
// First grab the address so we have a unique way to
// reference this resource.
addr, err := parseResourceAddressInternal(name)
if err != nil {
panic(fmt.Sprintf(
"Error parsing internal name, this is a bug: %q", name))
}
// Very important: add the module path for this resource to
// the address. Remove "root" from it.
addr.Path = m.Path[1:]
// Add the resource to the graph
nodes = append(nodes, &NodeApplyableResource{
Addr: addr,
})
}
}
// NOTE: Lots of room for performance optimizations below. For
// resource-heavy diffs this part alone is probably pretty slow.
// Annotate all nodes with their config and state
for _, n := range nodes {
// Grab the configuration at this path.
if t := t.Module.Child(n.Addr.Path); t != nil {
for _, r := range t.Config().Resources {
// Get a resource address so we can compare
addr, err := parseResourceAddressConfig(r)
if err != nil {
panic(fmt.Sprintf(
"Error parsing config address, this is a bug: %#v", r))
}
addr.Path = n.Addr.Path
// If this is not the same resource, then continue
if !addr.Equals(n.Addr) {
continue
}
// Same resource! Mark it and exit
n.Config = r
break
}
}
// Grab the state at this path
if ms := t.State.ModuleByPath(normalizeModulePath(n.Addr.Path)); ms != nil {
for name, rs := range ms.Resources {
// Parse the name for comparison
addr, err := parseResourceAddressInternal(name)
if err != nil {
panic(fmt.Sprintf(
"Error parsing internal name, this is a bug: %q", name))
}
addr.Path = n.Addr.Path
// If this is not the same resource, then continue
if !addr.Equals(n.Addr) {
continue
}
// Same resource!
n.ResourceState = rs
break
}
}
}
// Add all the nodes to the graph
for _, n := range nodes {
g.Add(n)
}
return nil
}