package configschema
import (
"fmt"
"github.com/zclconf/go-cty/cty"
"github.com/zclconf/go-cty/cty/convert"
)
// CoerceValue attempts to force the given value to conform to the type
// implied by the receiever, while also applying the same validation and
// transformation rules that would be applied by the decoder specification
// returned by method DecoderSpec.
//
// This is useful in situations where a configuration must be derived from
// an already-decoded value. It is always better to decode directly from
// configuration where possible since then source location information is
// still available to produce diagnostics, but in special situations this
// function allows a compatible result to be obtained even if the
// configuration objects are not available.
//
// If the given value cannot be converted to conform to the receiving schema
// then an error is returned describing one of possibly many problems. This
// error may be a cty.PathError indicating a position within the nested
// data structure where the problem applies.
func (b *Block) CoerceValue(in cty.Value) (cty.Value, error) {
var path cty.Path
return b.coerceValue(in, path)
}
func (b *Block) coerceValue(in cty.Value, path cty.Path) (cty.Value, error) {
switch {
case in.IsNull():
return cty.NullVal(b.ImpliedType()), nil
case !in.IsKnown():
return cty.UnknownVal(b.ImpliedType()), nil
}
ty := in.Type()
if !ty.IsObjectType() {
return cty.UnknownVal(b.ImpliedType()), path.NewErrorf("an object is required")
}
for name := range ty.AttributeTypes() {
if _, defined := b.Attributes[name]; defined {
continue
}
if _, defined := b.BlockTypes[name]; defined {
continue
}
return cty.UnknownVal(b.ImpliedType()), path.NewErrorf("unexpected attribute %q", name)
}
attrs := make(map[string]cty.Value)
for name, attrS := range b.Attributes {
var val cty.Value
switch {
case ty.HasAttribute(name):
val = in.GetAttr(name)
case attrS.Computed || attrS.Optional:
val = cty.NullVal(attrS.Type)
default:
return cty.UnknownVal(b.ImpliedType()), path.NewErrorf("attribute %q is required", name)
}
val, err := attrS.coerceValue(val, append(path, cty.GetAttrStep{Name: name}))
if err != nil {
return cty.UnknownVal(b.ImpliedType()), err
}
attrs[name] = val
}
for typeName, blockS := range b.BlockTypes {
switch blockS.Nesting {
case NestingSingle, NestingGroup:
switch {
case ty.HasAttribute(typeName):
var err error
val := in.GetAttr(typeName)
attrs[typeName], err = blockS.coerceValue(val, append(path, cty.GetAttrStep{Name: typeName}))
if err != nil {
return cty.UnknownVal(b.ImpliedType()), err
}
case blockS.MinItems != 1 && blockS.MaxItems != 1:
if blockS.Nesting == NestingGroup {
attrs[typeName] = blockS.EmptyValue()
} else {
attrs[typeName] = cty.NullVal(blockS.ImpliedType())
}
default:
// We use the word "attribute" here because we're talking about
// the cty sense of that word rather than the HCL sense.
return cty.UnknownVal(b.ImpliedType()), path.NewErrorf("attribute %q is required", typeName)
}
case NestingList:
switch {
case ty.HasAttribute(typeName):
coll := in.GetAttr(typeName)
switch {
case coll.IsNull():
attrs[typeName] = cty.NullVal(cty.List(blockS.ImpliedType()))
continue
case !coll.IsKnown():
attrs[typeName] = cty.UnknownVal(cty.List(blockS.ImpliedType()))
continue
}
if !coll.CanIterateElements() {
return cty.UnknownVal(b.ImpliedType()), path.NewErrorf("must be a list")
}
l := coll.LengthInt()
// Assume that if there are unknowns this could have come from
// a dynamic block, and we can't validate MinItems yet.
if l < blockS.MinItems && coll.IsWhollyKnown() {
return cty.UnknownVal(b.ImpliedType()), path.NewErrorf("insufficient items for attribute %q; must have at least %d", typeName, blockS.MinItems)
}
if l > blockS.MaxItems && blockS.MaxItems > 0 {
return cty.UnknownVal(b.ImpliedType()), path.NewErrorf("too many items for attribute %q; cannot have more than %d", typeName, blockS.MaxItems)
}
if l == 0 {
attrs[typeName] = cty.ListValEmpty(blockS.ImpliedType())
continue
}
elems := make([]cty.Value, 0, l)
{
path = append(path, cty.GetAttrStep{Name: typeName})
for it := coll.ElementIterator(); it.Next(); {
var err error
idx, val := it.Element()
val, err = blockS.coerceValue(val, append(path, cty.IndexStep{Key: idx}))
if err != nil {
return cty.UnknownVal(b.ImpliedType()), err
}
elems = append(elems, val)
}
}
attrs[typeName] = cty.ListVal(elems)
case blockS.MinItems == 0:
attrs[typeName] = cty.ListValEmpty(blockS.ImpliedType())
default:
return cty.UnknownVal(b.ImpliedType()), path.NewErrorf("attribute %q is required", typeName)
}
case NestingSet:
switch {
case ty.HasAttribute(typeName):
coll := in.GetAttr(typeName)
switch {
case coll.IsNull():
attrs[typeName] = cty.NullVal(cty.Set(blockS.ImpliedType()))
continue
case !coll.IsKnown():
attrs[typeName] = cty.UnknownVal(cty.Set(blockS.ImpliedType()))
continue
}
if !coll.CanIterateElements() {
return cty.UnknownVal(b.ImpliedType()), path.NewErrorf("must be a set")
}
l := coll.LengthInt()
// Assume that if there are unknowns this could have come from
// a dynamic block, and we can't validate MinItems yet.
if l < blockS.MinItems && coll.IsWhollyKnown() {
return cty.UnknownVal(b.ImpliedType()), path.NewErrorf("insufficient items for attribute %q; must have at least %d", typeName, blockS.MinItems)
}
if l > blockS.MaxItems && blockS.MaxItems > 0 {
return cty.UnknownVal(b.ImpliedType()), path.NewErrorf("too many items for attribute %q; cannot have more than %d", typeName, blockS.MaxItems)
}
if l == 0 {
attrs[typeName] = cty.SetValEmpty(blockS.ImpliedType())
continue
}
elems := make([]cty.Value, 0, l)
{
path = append(path, cty.GetAttrStep{Name: typeName})
for it := coll.ElementIterator(); it.Next(); {
var err error
idx, val := it.Element()
val, err = blockS.coerceValue(val, append(path, cty.IndexStep{Key: idx}))
if err != nil {
return cty.UnknownVal(b.ImpliedType()), err
}
elems = append(elems, val)
}
}
attrs[typeName] = cty.SetVal(elems)
case blockS.MinItems == 0:
attrs[typeName] = cty.SetValEmpty(blockS.ImpliedType())
default:
return cty.UnknownVal(b.ImpliedType()), path.NewErrorf("attribute %q is required", typeName)
}
case NestingMap:
switch {
case ty.HasAttribute(typeName):
coll := in.GetAttr(typeName)
switch {
case coll.IsNull():
attrs[typeName] = cty.NullVal(cty.Map(blockS.ImpliedType()))
continue
case !coll.IsKnown():
attrs[typeName] = cty.UnknownVal(cty.Map(blockS.ImpliedType()))
continue
}
if !coll.CanIterateElements() {
return cty.UnknownVal(b.ImpliedType()), path.NewErrorf("must be a map")
}
l := coll.LengthInt()
if l == 0 {
attrs[typeName] = cty.MapValEmpty(blockS.ImpliedType())
continue
}
elems := make(map[string]cty.Value)
{
path = append(path, cty.GetAttrStep{Name: typeName})
for it := coll.ElementIterator(); it.Next(); {
var err error
key, val := it.Element()
if key.Type() != cty.String || key.IsNull() || !key.IsKnown() {
return cty.UnknownVal(b.ImpliedType()), path.NewErrorf("must be a map")
}
val, err = blockS.coerceValue(val, append(path, cty.IndexStep{Key: key}))
if err != nil {
return cty.UnknownVal(b.ImpliedType()), err
}
elems[key.AsString()] = val
}
}
// If the attribute values here contain any DynamicPseudoTypes,
// the concrete type must be an object.
useObject := false
switch {
case coll.Type().IsObjectType():
useObject = true
default:
// It's possible that we were given a map, and need to coerce it to an object
ety := coll.Type().ElementType()
for _, v := range elems {
if !v.Type().Equals(ety) {
useObject = true
break
}
}
}
if useObject {
attrs[typeName] = cty.ObjectVal(elems)
} else {
attrs[typeName] = cty.MapVal(elems)
}
default:
attrs[typeName] = cty.MapValEmpty(blockS.ImpliedType())
}
default:
// should never happen because above is exhaustive
panic(fmt.Errorf("unsupported nesting mode %#v", blockS.Nesting))
}
}
return cty.ObjectVal(attrs), nil
}
func (a *Attribute) coerceValue(in cty.Value, path cty.Path) (cty.Value, error) {
val, err := convert.Convert(in, a.Type)
if err != nil {
return cty.UnknownVal(a.Type), path.NewError(err)
}
return val, nil
}
