terraform/helper/plugin/unknown.go

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package plugin
import (
"fmt"
"github.com/hashicorp/terraform/configs/configschema"
"github.com/zclconf/go-cty/cty"
)
// SetUnknowns takes a cty.Value, and compares it to the schema setting any null
// values which are computed to unknown.
func SetUnknowns(val cty.Value, schema *configschema.Block) cty.Value {
if !val.IsKnown() {
return val
}
// If the object was null, we still need to handle the top level attributes
// which might be computed, but we don't need to expand the blocks.
if val.IsNull() {
objMap := map[string]cty.Value{}
allNull := true
for name, attr := range schema.Attributes {
switch {
case attr.Computed:
objMap[name] = cty.UnknownVal(attr.Type)
allNull = false
default:
objMap[name] = cty.NullVal(attr.Type)
}
}
// If this object has no unknown attributes, then we can leave it null.
if allNull {
return val
}
return cty.ObjectVal(objMap)
}
valMap := val.AsValueMap()
newVals := make(map[string]cty.Value)
for name, attr := range schema.Attributes {
v := valMap[name]
if attr.Computed && v.IsNull() {
newVals[name] = cty.UnknownVal(attr.Type)
continue
}
newVals[name] = v
}
for name, blockS := range schema.BlockTypes {
blockVal := valMap[name]
if blockVal.IsNull() || !blockVal.IsKnown() {
newVals[name] = blockVal
continue
}
blockValType := blockVal.Type()
blockElementType := blockS.Block.ImpliedType()
// This switches on the value type here, so we can correctly switch
// between Tuples/Lists and Maps/Objects.
switch {
case blockS.Nesting == configschema.NestingSingle:
// NestingSingle is the only exception here, where we treat the
// block directly as an object
newVals[name] = SetUnknowns(blockVal, &blockS.Block)
case blockValType.IsSetType(), blockValType.IsListType(), blockValType.IsTupleType():
listVals := blockVal.AsValueSlice()
newListVals := make([]cty.Value, 0, len(listVals))
for _, v := range listVals {
newListVals = append(newListVals, SetUnknowns(v, &blockS.Block))
}
switch {
case blockValType.IsSetType():
switch len(newListVals) {
case 0:
newVals[name] = cty.SetValEmpty(blockElementType)
default:
newVals[name] = cty.SetVal(newListVals)
}
case blockValType.IsListType():
switch len(newListVals) {
case 0:
newVals[name] = cty.ListValEmpty(blockElementType)
default:
newVals[name] = cty.ListVal(newListVals)
}
case blockValType.IsTupleType():
newVals[name] = cty.TupleVal(newListVals)
}
case blockValType.IsMapType(), blockValType.IsObjectType():
mapVals := blockVal.AsValueMap()
newMapVals := make(map[string]cty.Value)
for k, v := range mapVals {
newMapVals[k] = SetUnknowns(v, &blockS.Block)
}
switch {
case blockValType.IsMapType():
switch len(newMapVals) {
case 0:
newVals[name] = cty.MapValEmpty(blockElementType)
default:
newVals[name] = cty.MapVal(newMapVals)
}
case blockValType.IsObjectType():
if len(newMapVals) == 0 {
// We need to populate empty values to make a valid object.
for attr, ty := range blockElementType.AttributeTypes() {
newMapVals[attr] = cty.NullVal(ty)
}
}
newVals[name] = cty.ObjectVal(newMapVals)
}
default:
panic(fmt.Sprintf("failed to set unknown values for nested block %q:%#v", name, blockValType))
}
}
return cty.ObjectVal(newVals)
}