terraform/config/hcl2shim/paths.go

277 lines
6.2 KiB
Go

package hcl2shim
import (
"fmt"
"reflect"
"strconv"
"strings"
"github.com/zclconf/go-cty/cty"
)
// RequiresReplace takes a list of flatmapped paths from a
// InstanceDiff.Attributes along with the corresponding cty.Type, and returns
// the list of the cty.Paths that are flagged as causing the resource
// replacement (RequiresNew).
// This will filter out redundant paths, paths that refer to flatmapped indexes
// (e.g. "#", "%"), and will return any changes within a set as the path to the
// set itself.
func RequiresReplace(attrs []string, ty cty.Type) ([]cty.Path, error) {
var paths []cty.Path
for _, attr := range attrs {
p, err := requiresReplacePath(attr, ty)
if err != nil {
return nil, err
}
paths = append(paths, p)
}
// now trim off any trailing paths that aren't GetAttrSteps, since only an
// attribute itself can require replacement
paths = trimPaths(paths)
// There may be redundant paths due to set elements or index attributes
// Do some ugly n^2 filtering, but these are always fairly small sets.
for i := 0; i < len(paths)-1; i++ {
for j := i + 1; j < len(paths); j++ {
if reflect.DeepEqual(paths[i], paths[j]) {
// swap the tail and slice it off
paths[j], paths[len(paths)-1] = paths[len(paths)-1], paths[j]
paths = paths[:len(paths)-1]
j--
}
}
}
return paths, nil
}
// trimPaths removes any trailing steps that aren't of type GetAttrSet, since
// only an attribute itself can require replacement
func trimPaths(paths []cty.Path) []cty.Path {
var trimmed []cty.Path
for _, path := range paths {
path = trimPath(path)
if len(path) > 0 {
trimmed = append(trimmed, path)
}
}
return trimmed
}
func trimPath(path cty.Path) cty.Path {
for len(path) > 0 {
_, isGetAttr := path[len(path)-1].(cty.GetAttrStep)
if isGetAttr {
break
}
path = path[:len(path)-1]
}
return path
}
// requiresReplacePath takes a key from a flatmap along with the cty.Type
// describing the structure, and returns the cty.Path that would be used to
// reference the nested value in the data structure.
// This is used specifically to record the RequiresReplace attributes from a
// ResourceInstanceDiff.
func requiresReplacePath(k string, ty cty.Type) (cty.Path, error) {
if k == "" {
return nil, nil
}
if !ty.IsObjectType() {
panic(fmt.Sprintf("requires replace path on non-object type: %#v", ty))
}
path, err := pathFromFlatmapKeyObject(k, ty.AttributeTypes())
if err != nil {
return path, fmt.Errorf("[%s] %s", k, err)
}
return path, nil
}
func pathSplit(p string) (string, string) {
parts := strings.SplitN(p, ".", 2)
head := parts[0]
rest := ""
if len(parts) > 1 {
rest = parts[1]
}
return head, rest
}
func pathFromFlatmapKeyObject(key string, atys map[string]cty.Type) (cty.Path, error) {
k, rest := pathSplit(key)
path := cty.Path{cty.GetAttrStep{Name: k}}
ty, ok := atys[k]
if !ok {
return path, fmt.Errorf("attribute %q not found", k)
}
if rest == "" {
return path, nil
}
p, err := pathFromFlatmapKeyValue(rest, ty)
if err != nil {
return path, err
}
return append(path, p...), nil
}
func pathFromFlatmapKeyValue(key string, ty cty.Type) (cty.Path, error) {
var path cty.Path
var err error
switch {
case ty.IsPrimitiveType():
err = fmt.Errorf("invalid step %q with type %#v", key, ty)
case ty.IsObjectType():
path, err = pathFromFlatmapKeyObject(key, ty.AttributeTypes())
case ty.IsTupleType():
path, err = pathFromFlatmapKeyTuple(key, ty.TupleElementTypes())
case ty.IsMapType():
path, err = pathFromFlatmapKeyMap(key, ty)
case ty.IsListType():
path, err = pathFromFlatmapKeyList(key, ty)
case ty.IsSetType():
path, err = pathFromFlatmapKeySet(key, ty)
default:
err = fmt.Errorf("unrecognized type: %s", ty.FriendlyName())
}
if err != nil {
return path, err
}
return path, nil
}
func pathFromFlatmapKeyTuple(key string, etys []cty.Type) (cty.Path, error) {
var path cty.Path
var err error
k, rest := pathSplit(key)
// we don't need to convert the index keys to paths
if k == "#" {
return path, nil
}
idx, err := strconv.Atoi(k)
if err != nil {
return path, err
}
path = cty.Path{cty.IndexStep{Key: cty.NumberIntVal(int64(idx))}}
if idx >= len(etys) {
return path, fmt.Errorf("index %s out of range in %#v", key, etys)
}
if rest == "" {
return path, nil
}
ty := etys[idx]
p, err := pathFromFlatmapKeyValue(rest, ty.ElementType())
if err != nil {
return path, err
}
return append(path, p...), nil
}
func pathFromFlatmapKeyMap(key string, ty cty.Type) (cty.Path, error) {
var path cty.Path
var err error
k, rest := key, ""
if !ty.ElementType().IsPrimitiveType() {
k, rest = pathSplit(key)
}
// we don't need to convert the index keys to paths
if k == "%" {
return path, nil
}
path = cty.Path{cty.IndexStep{Key: cty.StringVal(k)}}
if rest == "" {
return path, nil
}
p, err := pathFromFlatmapKeyValue(rest, ty.ElementType())
if err != nil {
return path, err
}
return append(path, p...), nil
}
func pathFromFlatmapKeyList(key string, ty cty.Type) (cty.Path, error) {
var path cty.Path
var err error
k, rest := pathSplit(key)
// we don't need to convert the index keys to paths
if key == "#" {
return path, nil
}
idx, err := strconv.Atoi(k)
if err != nil {
return path, err
}
path = cty.Path{cty.IndexStep{Key: cty.NumberIntVal(int64(idx))}}
if rest == "" {
return path, nil
}
p, err := pathFromFlatmapKeyValue(rest, ty.ElementType())
if err != nil {
return path, err
}
return append(path, p...), nil
}
func pathFromFlatmapKeySet(key string, ty cty.Type) (cty.Path, error) {
// once we hit a set, we can't return consistent paths, so just mark the
// set as a whole changed.
return nil, nil
}
// FlatmapKeyFromPath returns the flatmap equivalent of the given cty.Path for
// use in generating legacy style diffs.
func FlatmapKeyFromPath(path cty.Path) string {
var parts []string
for _, step := range path {
switch step := step.(type) {
case cty.GetAttrStep:
parts = append(parts, step.Name)
case cty.IndexStep:
switch ty := step.Key.Type(); {
case ty == cty.String:
parts = append(parts, step.Key.AsString())
case ty == cty.Number:
i, _ := step.Key.AsBigFloat().Int64()
parts = append(parts, strconv.Itoa(int(i)))
}
}
}
return strings.Join(parts, ".")
}