hcl/cmd/hcldec/spec.go
Martin Atkins 6c4344623b Unfold the "hcl" directory up into the root
The main HCL package is more visible this way, and so it's easier than
having to pick it out from dozens of other package directories.
2019-09-09 16:08:19 -07:00

646 lines
16 KiB
Go

package main
import (
"fmt"
"github.com/hashicorp/hcl/v2/ext/userfunc"
"github.com/hashicorp/hcl/v2/gohcl"
"github.com/hashicorp/hcl/v2"
"github.com/hashicorp/hcl/v2/hcldec"
"github.com/zclconf/go-cty/cty"
"github.com/zclconf/go-cty/cty/function"
)
type specFileContent struct {
Variables map[string]cty.Value
Functions map[string]function.Function
RootSpec hcldec.Spec
}
var specCtx = &hcl.EvalContext{
Functions: specFuncs,
}
func loadSpecFile(filename string) (specFileContent, hcl.Diagnostics) {
file, diags := parser.ParseHCLFile(filename)
if diags.HasErrors() {
return specFileContent{RootSpec: errSpec}, diags
}
vars, funcs, specBody, declDiags := decodeSpecDecls(file.Body)
diags = append(diags, declDiags...)
spec, specDiags := decodeSpecRoot(specBody)
diags = append(diags, specDiags...)
return specFileContent{
Variables: vars,
Functions: funcs,
RootSpec: spec,
}, diags
}
func decodeSpecDecls(body hcl.Body) (map[string]cty.Value, map[string]function.Function, hcl.Body, hcl.Diagnostics) {
funcs, body, diags := userfunc.DecodeUserFunctions(body, "function", func() *hcl.EvalContext {
return specCtx
})
content, body, moreDiags := body.PartialContent(&hcl.BodySchema{
Blocks: []hcl.BlockHeaderSchema{
{
Type: "variables",
},
},
})
diags = append(diags, moreDiags...)
vars := make(map[string]cty.Value)
for _, block := range content.Blocks {
// We only have one block type in our schema, so we can assume all
// blocks are of that type.
attrs, moreDiags := block.Body.JustAttributes()
diags = append(diags, moreDiags...)
for name, attr := range attrs {
val, moreDiags := attr.Expr.Value(specCtx)
diags = append(diags, moreDiags...)
vars[name] = val
}
}
return vars, funcs, body, diags
}
func decodeSpecRoot(body hcl.Body) (hcldec.Spec, hcl.Diagnostics) {
content, diags := body.Content(specSchemaUnlabelled)
if len(content.Blocks) == 0 {
if diags.HasErrors() {
// If we already have errors then they probably explain
// why we have no blocks, so we'll skip our additional
// error message added below.
return errSpec, diags
}
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Missing spec block",
Detail: "A spec file must have exactly one root block specifying how to map to a JSON value.",
Subject: body.MissingItemRange().Ptr(),
})
return errSpec, diags
}
if len(content.Blocks) > 1 {
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Extraneous spec block",
Detail: "A spec file must have exactly one root block specifying how to map to a JSON value.",
Subject: &content.Blocks[1].DefRange,
})
return errSpec, diags
}
spec, specDiags := decodeSpecBlock(content.Blocks[0])
diags = append(diags, specDiags...)
return spec, diags
}
func decodeSpecBlock(block *hcl.Block) (hcldec.Spec, hcl.Diagnostics) {
var impliedName string
if len(block.Labels) > 0 {
impliedName = block.Labels[0]
}
switch block.Type {
case "object":
return decodeObjectSpec(block.Body)
case "array":
return decodeArraySpec(block.Body)
case "attr":
return decodeAttrSpec(block.Body, impliedName)
case "block":
return decodeBlockSpec(block.Body, impliedName)
case "block_list":
return decodeBlockListSpec(block.Body, impliedName)
case "block_set":
return decodeBlockSetSpec(block.Body, impliedName)
case "block_map":
return decodeBlockMapSpec(block.Body, impliedName)
case "block_attrs":
return decodeBlockAttrsSpec(block.Body, impliedName)
case "default":
return decodeDefaultSpec(block.Body)
case "transform":
return decodeTransformSpec(block.Body)
case "literal":
return decodeLiteralSpec(block.Body)
default:
// Should never happen, because the above cases should be exhaustive
// for our schema.
var diags hcl.Diagnostics
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid spec block",
Detail: fmt.Sprintf("Blocks of type %q are not expected here.", block.Type),
Subject: &block.TypeRange,
})
return errSpec, diags
}
}
func decodeObjectSpec(body hcl.Body) (hcldec.Spec, hcl.Diagnostics) {
content, diags := body.Content(specSchemaLabelled)
spec := make(hcldec.ObjectSpec)
for _, block := range content.Blocks {
propSpec, propDiags := decodeSpecBlock(block)
diags = append(diags, propDiags...)
spec[block.Labels[0]] = propSpec
}
return spec, diags
}
func decodeArraySpec(body hcl.Body) (hcldec.Spec, hcl.Diagnostics) {
content, diags := body.Content(specSchemaUnlabelled)
spec := make(hcldec.TupleSpec, 0, len(content.Blocks))
for _, block := range content.Blocks {
elemSpec, elemDiags := decodeSpecBlock(block)
diags = append(diags, elemDiags...)
spec = append(spec, elemSpec)
}
return spec, diags
}
func decodeAttrSpec(body hcl.Body, impliedName string) (hcldec.Spec, hcl.Diagnostics) {
type content struct {
Name *string `hcl:"name"`
Type hcl.Expression `hcl:"type"`
Required *bool `hcl:"required"`
}
var args content
diags := gohcl.DecodeBody(body, nil, &args)
if diags.HasErrors() {
return errSpec, diags
}
spec := &hcldec.AttrSpec{
Name: impliedName,
}
if args.Required != nil {
spec.Required = *args.Required
}
if args.Name != nil {
spec.Name = *args.Name
}
var typeDiags hcl.Diagnostics
spec.Type, typeDiags = evalTypeExpr(args.Type)
diags = append(diags, typeDiags...)
if spec.Name == "" {
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Missing name in attribute spec",
Detail: "The name attribute is required, to specify the attribute name that is expected in an input HCL file.",
Subject: body.MissingItemRange().Ptr(),
})
return errSpec, diags
}
return spec, diags
}
func decodeBlockSpec(body hcl.Body, impliedName string) (hcldec.Spec, hcl.Diagnostics) {
type content struct {
TypeName *string `hcl:"block_type"`
Required *bool `hcl:"required"`
Nested hcl.Body `hcl:",remain"`
}
var args content
diags := gohcl.DecodeBody(body, nil, &args)
if diags.HasErrors() {
return errSpec, diags
}
spec := &hcldec.BlockSpec{
TypeName: impliedName,
}
if args.Required != nil {
spec.Required = *args.Required
}
if args.TypeName != nil {
spec.TypeName = *args.TypeName
}
nested, nestedDiags := decodeBlockNestedSpec(args.Nested)
diags = append(diags, nestedDiags...)
spec.Nested = nested
return spec, diags
}
func decodeBlockListSpec(body hcl.Body, impliedName string) (hcldec.Spec, hcl.Diagnostics) {
type content struct {
TypeName *string `hcl:"block_type"`
MinItems *int `hcl:"min_items"`
MaxItems *int `hcl:"max_items"`
Nested hcl.Body `hcl:",remain"`
}
var args content
diags := gohcl.DecodeBody(body, nil, &args)
if diags.HasErrors() {
return errSpec, diags
}
spec := &hcldec.BlockListSpec{
TypeName: impliedName,
}
if args.MinItems != nil {
spec.MinItems = *args.MinItems
}
if args.MaxItems != nil {
spec.MaxItems = *args.MaxItems
}
if args.TypeName != nil {
spec.TypeName = *args.TypeName
}
nested, nestedDiags := decodeBlockNestedSpec(args.Nested)
diags = append(diags, nestedDiags...)
spec.Nested = nested
if spec.TypeName == "" {
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Missing block_type in block_list spec",
Detail: "The block_type attribute is required, to specify the block type name that is expected in an input HCL file.",
Subject: body.MissingItemRange().Ptr(),
})
return errSpec, diags
}
return spec, diags
}
func decodeBlockSetSpec(body hcl.Body, impliedName string) (hcldec.Spec, hcl.Diagnostics) {
type content struct {
TypeName *string `hcl:"block_type"`
MinItems *int `hcl:"min_items"`
MaxItems *int `hcl:"max_items"`
Nested hcl.Body `hcl:",remain"`
}
var args content
diags := gohcl.DecodeBody(body, nil, &args)
if diags.HasErrors() {
return errSpec, diags
}
spec := &hcldec.BlockSetSpec{
TypeName: impliedName,
}
if args.MinItems != nil {
spec.MinItems = *args.MinItems
}
if args.MaxItems != nil {
spec.MaxItems = *args.MaxItems
}
if args.TypeName != nil {
spec.TypeName = *args.TypeName
}
nested, nestedDiags := decodeBlockNestedSpec(args.Nested)
diags = append(diags, nestedDiags...)
spec.Nested = nested
if spec.TypeName == "" {
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Missing block_type in block_set spec",
Detail: "The block_type attribute is required, to specify the block type name that is expected in an input HCL file.",
Subject: body.MissingItemRange().Ptr(),
})
return errSpec, diags
}
return spec, diags
}
func decodeBlockMapSpec(body hcl.Body, impliedName string) (hcldec.Spec, hcl.Diagnostics) {
type content struct {
TypeName *string `hcl:"block_type"`
Labels []string `hcl:"labels"`
Nested hcl.Body `hcl:",remain"`
}
var args content
diags := gohcl.DecodeBody(body, nil, &args)
if diags.HasErrors() {
return errSpec, diags
}
spec := &hcldec.BlockMapSpec{
TypeName: impliedName,
}
if args.TypeName != nil {
spec.TypeName = *args.TypeName
}
spec.LabelNames = args.Labels
nested, nestedDiags := decodeBlockNestedSpec(args.Nested)
diags = append(diags, nestedDiags...)
spec.Nested = nested
if spec.TypeName == "" {
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Missing block_type in block_map spec",
Detail: "The block_type attribute is required, to specify the block type name that is expected in an input HCL file.",
Subject: body.MissingItemRange().Ptr(),
})
return errSpec, diags
}
if len(spec.LabelNames) < 1 {
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid block label name list",
Detail: "A block_map must have at least one label specified.",
Subject: body.MissingItemRange().Ptr(),
})
return errSpec, diags
}
if hcldec.ImpliedType(spec).HasDynamicTypes() {
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid block_map spec",
Detail: "A block_map spec may not contain attributes with type 'any'.",
Subject: body.MissingItemRange().Ptr(),
})
}
return spec, diags
}
func decodeBlockNestedSpec(body hcl.Body) (hcldec.Spec, hcl.Diagnostics) {
content, diags := body.Content(specSchemaUnlabelled)
if len(content.Blocks) == 0 {
if diags.HasErrors() {
// If we already have errors then they probably explain
// why we have no blocks, so we'll skip our additional
// error message added below.
return errSpec, diags
}
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Missing spec block",
Detail: "A block spec must have exactly one child spec specifying how to decode block contents.",
Subject: body.MissingItemRange().Ptr(),
})
return errSpec, diags
}
if len(content.Blocks) > 1 {
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Extraneous spec block",
Detail: "A block spec must have exactly one child spec specifying how to decode block contents.",
Subject: &content.Blocks[1].DefRange,
})
return errSpec, diags
}
spec, specDiags := decodeSpecBlock(content.Blocks[0])
diags = append(diags, specDiags...)
return spec, diags
}
func decodeBlockAttrsSpec(body hcl.Body, impliedName string) (hcldec.Spec, hcl.Diagnostics) {
type content struct {
TypeName *string `hcl:"block_type"`
ElementType hcl.Expression `hcl:"element_type"`
Required *bool `hcl:"required"`
}
var args content
diags := gohcl.DecodeBody(body, nil, &args)
if diags.HasErrors() {
return errSpec, diags
}
spec := &hcldec.BlockAttrsSpec{
TypeName: impliedName,
}
if args.Required != nil {
spec.Required = *args.Required
}
if args.TypeName != nil {
spec.TypeName = *args.TypeName
}
var typeDiags hcl.Diagnostics
spec.ElementType, typeDiags = evalTypeExpr(args.ElementType)
diags = append(diags, typeDiags...)
if spec.TypeName == "" {
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Missing block_type in block_attrs spec",
Detail: "The block_type attribute is required, to specify the block type name that is expected in an input HCL file.",
Subject: body.MissingItemRange().Ptr(),
})
return errSpec, diags
}
return spec, diags
}
func decodeLiteralSpec(body hcl.Body) (hcldec.Spec, hcl.Diagnostics) {
type content struct {
Value cty.Value `hcl:"value"`
}
var args content
diags := gohcl.DecodeBody(body, specCtx, &args)
if diags.HasErrors() {
return errSpec, diags
}
return &hcldec.LiteralSpec{
Value: args.Value,
}, diags
}
func decodeDefaultSpec(body hcl.Body) (hcldec.Spec, hcl.Diagnostics) {
content, diags := body.Content(specSchemaUnlabelled)
if len(content.Blocks) == 0 {
if diags.HasErrors() {
// If we already have errors then they probably explain
// why we have no blocks, so we'll skip our additional
// error message added below.
return errSpec, diags
}
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Missing spec block",
Detail: "A default block must have at least one nested spec, each specifying a possible outcome.",
Subject: body.MissingItemRange().Ptr(),
})
return errSpec, diags
}
if len(content.Blocks) == 1 && !diags.HasErrors() {
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagWarning,
Summary: "Useless default block",
Detail: "A default block with only one spec is equivalent to using that spec alone.",
Subject: &content.Blocks[1].DefRange,
})
}
var spec hcldec.Spec
for _, block := range content.Blocks {
candidateSpec, candidateDiags := decodeSpecBlock(block)
diags = append(diags, candidateDiags...)
if candidateDiags.HasErrors() {
continue
}
if spec == nil {
spec = candidateSpec
} else {
spec = &hcldec.DefaultSpec{
Primary: spec,
Default: candidateSpec,
}
}
}
return spec, diags
}
func decodeTransformSpec(body hcl.Body) (hcldec.Spec, hcl.Diagnostics) {
type content struct {
Result hcl.Expression `hcl:"result"`
Nested hcl.Body `hcl:",remain"`
}
var args content
diags := gohcl.DecodeBody(body, nil, &args)
if diags.HasErrors() {
return errSpec, diags
}
spec := &hcldec.TransformExprSpec{
Expr: args.Result,
VarName: "nested",
TransformCtx: specCtx,
}
nestedContent, nestedDiags := args.Nested.Content(specSchemaUnlabelled)
diags = append(diags, nestedDiags...)
if len(nestedContent.Blocks) != 1 {
if nestedDiags.HasErrors() {
// If we already have errors then they probably explain
// why we have the wrong number of blocks, so we'll skip our
// additional error message added below.
return errSpec, diags
}
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid transform spec",
Detail: "A transform spec block must have exactly one nested spec block.",
Subject: body.MissingItemRange().Ptr(),
})
return errSpec, diags
}
nestedSpec, nestedDiags := decodeSpecBlock(nestedContent.Blocks[0])
diags = append(diags, nestedDiags...)
spec.Wrapped = nestedSpec
return spec, diags
}
var errSpec = &hcldec.LiteralSpec{
Value: cty.NullVal(cty.DynamicPseudoType),
}
var specBlockTypes = []string{
"object",
"array",
"literal",
"attr",
"block",
"block_list",
"block_map",
"block_set",
"default",
"transform",
}
var specSchemaUnlabelled *hcl.BodySchema
var specSchemaLabelled *hcl.BodySchema
var specSchemaLabelledLabels = []string{"key"}
func init() {
specSchemaLabelled = &hcl.BodySchema{
Blocks: make([]hcl.BlockHeaderSchema, 0, len(specBlockTypes)),
}
specSchemaUnlabelled = &hcl.BodySchema{
Blocks: make([]hcl.BlockHeaderSchema, 0, len(specBlockTypes)),
}
for _, name := range specBlockTypes {
specSchemaLabelled.Blocks = append(
specSchemaLabelled.Blocks,
hcl.BlockHeaderSchema{
Type: name,
LabelNames: specSchemaLabelledLabels,
},
)
specSchemaUnlabelled.Blocks = append(
specSchemaUnlabelled.Blocks,
hcl.BlockHeaderSchema{
Type: name,
},
)
}
}