terraform/lang/blocktoattr/schema.go

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package blocktoattr
import (
"github.com/hashicorp/hcl2/hcl"
"github.com/hashicorp/terraform/configs/configschema"
"github.com/zclconf/go-cty/cty"
)
func ambiguousNames(schema *configschema.Block) map[string]struct{} {
if schema == nil {
return nil
}
ambiguousNames := make(map[string]struct{})
for name, attrS := range schema.Attributes {
aty := attrS.Type
if (aty.IsListType() || aty.IsSetType()) && aty.ElementType().IsObjectType() {
ambiguousNames[name] = struct{}{}
}
}
return ambiguousNames
}
func effectiveSchema(given *hcl.BodySchema, body hcl.Body, ambiguousNames map[string]struct{}, dynamicExpanded bool) *hcl.BodySchema {
ret := &hcl.BodySchema{}
appearsAsBlock := make(map[string]struct{})
{
// We'll construct some throwaway schemas here just to probe for
// whether each of our ambiguous names seems to be being used as
// an attribute or a block. We need to check both because in JSON
// syntax we rely on the schema to decide between attribute or block
// interpretation and so JSON will always answer yes to both of
// these questions and we want to prefer the attribute interpretation
// in that case.
var probeSchema hcl.BodySchema
for name := range ambiguousNames {
probeSchema = hcl.BodySchema{
Attributes: []hcl.AttributeSchema{
{
Name: name,
},
},
}
content, _, _ := body.PartialContent(&probeSchema)
if _, exists := content.Attributes[name]; exists {
// Can decode as an attribute, so we'll go with that.
continue
}
probeSchema = hcl.BodySchema{
Blocks: []hcl.BlockHeaderSchema{
{
Type: name,
},
},
}
content, _, _ = body.PartialContent(&probeSchema)
if len(content.Blocks) > 0 || dynamicExpanded {
// A dynamic block with an empty iterator returns nothing.
// If there's no attribute and we have either a block or a
// dynamic expansion, we need to rewrite this one as a
// block for a successful result.
appearsAsBlock[name] = struct{}{}
}
}
if !dynamicExpanded {
// If we're deciding for a context where dynamic blocks haven't
// been expanded yet then we need to probe for those too.
probeSchema = hcl.BodySchema{
Blocks: []hcl.BlockHeaderSchema{
{
Type: "dynamic",
LabelNames: []string{"type"},
},
},
}
content, _, _ := body.PartialContent(&probeSchema)
for _, block := range content.Blocks {
if _, exists := ambiguousNames[block.Labels[0]]; exists {
appearsAsBlock[block.Labels[0]] = struct{}{}
}
}
}
}
for _, attrS := range given.Attributes {
if _, exists := appearsAsBlock[attrS.Name]; exists {
ret.Blocks = append(ret.Blocks, hcl.BlockHeaderSchema{
Type: attrS.Name,
})
} else {
ret.Attributes = append(ret.Attributes, attrS)
}
}
// Anything that is specified as a block type in the input schema remains
// that way by just passing through verbatim.
ret.Blocks = append(ret.Blocks, given.Blocks...)
return ret
}
// SchemaForCtyElementType converts a cty object type into an
// approximately-equivalent configschema.Block representing the element of
// a list or set. If the given type is not an object type then this
// function will panic.
func SchemaForCtyElementType(ty cty.Type) *configschema.Block {
atys := ty.AttributeTypes()
ret := &configschema.Block{
Attributes: make(map[string]*configschema.Attribute, len(atys)),
}
for name, aty := range atys {
ret.Attributes[name] = &configschema.Attribute{
Type: aty,
Optional: true,
}
}
return ret
}
// SchemaForCtyContainerType converts a cty list-of-object or set-of-object type
// into an approximately-equivalent configschema.NestedBlock. If the given type
// is not of the expected kind then this function will panic.
func SchemaForCtyContainerType(ty cty.Type) *configschema.NestedBlock {
var nesting configschema.NestingMode
switch {
case ty.IsListType():
nesting = configschema.NestingList
case ty.IsSetType():
nesting = configschema.NestingSet
default:
panic("unsuitable type")
}
nested := SchemaForCtyElementType(ty.ElementType())
return &configschema.NestedBlock{
Nesting: nesting,
Block: *nested,
}
}
// TypeCanBeBlocks returns true if the given type is a list-of-object or
// set-of-object type, and would thus be subject to the blocktoattr fixup
// if used as an attribute type.
func TypeCanBeBlocks(ty cty.Type) bool {
return (ty.IsListType() || ty.IsSetType()) && ty.ElementType().IsObjectType()
}