/
named_values.go
330 lines (296 loc) · 11.3 KB
/
named_values.go
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package configs
import (
"fmt"
"github.com/hashicorp/hcl/v2"
"github.com/hashicorp/hcl/v2/ext/typeexpr"
"github.com/hashicorp/hcl/v2/gohcl"
"github.com/hashicorp/hcl/v2/hclsyntax"
"github.com/zclconf/go-cty/cty"
"github.com/zclconf/go-cty/cty/convert"
)
// A consistent detail message for all "not a valid identifier" diagnostics.
const badIdentifierDetail = "A name must start with a letter or underscore and may contain only letters, digits, underscores, and dashes."
// Variable represents a "variable" block in a module or file.
type Variable struct {
Name string
Description string
Default cty.Value
// Type is the concrete type of the variable value.
Type cty.Type
// ConstraintType is used for decoding and type conversions, and may
// contain nested ObjectWithOptionalAttr types.
ConstraintType cty.Type
TypeDefaults *typeexpr.Defaults
ParsingMode VariableParsingMode
Sensitive bool
DescriptionSet bool
SensitiveSet bool
// Nullable indicates that null is a valid value for this variable. Setting
// Nullable to false means that the module can expect this variable to
// never be null.
Nullable bool
NullableSet bool
DeclRange hcl.Range
}
func decodeVariableBlock(block *hcl.Block, override bool) (*Variable, hcl.Diagnostics) {
v := &Variable{
Name: block.Labels[0],
DeclRange: block.DefRange,
}
// Unless we're building an override, we'll set some defaults
// which we might override with attributes below. We leave these
// as zero-value in the override case so we can recognize whether
// or not they are set when we merge.
if !override {
v.Type = cty.DynamicPseudoType
v.ConstraintType = cty.DynamicPseudoType
v.ParsingMode = VariableParseLiteral
}
content, diags := block.Body.Content(variableBlockSchema)
if !hclsyntax.ValidIdentifier(v.Name) {
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid variable name",
Detail: badIdentifierDetail,
Subject: &block.LabelRanges[0],
})
}
// Don't allow declaration of variables that would conflict with the
// reserved attribute and block type names in a "module" block, since
// these won't be usable for child modules.
for _, attr := range moduleBlockSchema.Attributes {
if attr.Name == v.Name {
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid variable name",
Detail: fmt.Sprintf("The variable name %q is reserved due to its special meaning inside module blocks.", attr.Name),
Subject: &block.LabelRanges[0],
})
}
}
for _, blockS := range moduleBlockSchema.Blocks {
if blockS.Type == v.Name {
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid variable name",
Detail: fmt.Sprintf("The variable name %q is reserved due to its special meaning inside module blocks.", blockS.Type),
Subject: &block.LabelRanges[0],
})
}
}
if attr, exists := content.Attributes["description"]; exists {
valDiags := gohcl.DecodeExpression(attr.Expr, nil, &v.Description)
diags = append(diags, valDiags...)
v.DescriptionSet = true
}
if attr, exists := content.Attributes["type"]; exists {
ty, tyDefaults, parseMode, tyDiags := decodeVariableType(attr.Expr)
diags = append(diags, tyDiags...)
v.ConstraintType = ty
v.TypeDefaults = tyDefaults
v.Type = ty.WithoutOptionalAttributesDeep()
v.ParsingMode = parseMode
}
if attr, exists := content.Attributes["sensitive"]; exists {
valDiags := gohcl.DecodeExpression(attr.Expr, nil, &v.Sensitive)
diags = append(diags, valDiags...)
v.SensitiveSet = true
}
if attr, exists := content.Attributes["nullable"]; exists {
valDiags := gohcl.DecodeExpression(attr.Expr, nil, &v.Nullable)
diags = append(diags, valDiags...)
v.NullableSet = true
} else {
// The current default is true, which is subject to change in a future
// language edition.
v.Nullable = true
}
if attr, exists := content.Attributes["default"]; exists {
val, valDiags := attr.Expr.Value(nil)
diags = append(diags, valDiags...)
// Convert the default to the expected type so we can catch invalid
// defaults early and allow later code to assume validity.
// Note that this depends on us having already processed any "type"
// attribute above.
// However, we can't do this if we're in an override file where
// the type might not be set; we'll catch that during merge.
if v.ConstraintType != cty.NilType {
var err error
// If the type constraint has defaults, we must apply those
// defaults to the variable default value before type conversion,
// unless the default value is null. Null is excluded from the
// type default application process as a special case, to allow
// nullable variables to have a null default value.
if v.TypeDefaults != nil && !val.IsNull() {
val = v.TypeDefaults.Apply(val)
}
val, err = convert.Convert(val, v.ConstraintType)
if err != nil {
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid default value for variable",
Detail: fmt.Sprintf("This default value is not compatible with the variable's type constraint: %s.", err),
Subject: attr.Expr.Range().Ptr(),
})
val = cty.DynamicVal
}
}
if !v.Nullable && val.IsNull() {
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid default value for variable",
Detail: "A null default value is not valid when nullable=false.",
Subject: attr.Expr.Range().Ptr(),
})
}
v.Default = val
}
for _, block := range content.Blocks {
switch block.Type {
case "validation":
default:
// The above cases should be exhaustive for all block types
// defined in variableBlockSchema
panic(fmt.Sprintf("unhandled block type %q", block.Type))
}
}
return v, diags
}
func decodeVariableType(expr hcl.Expression) (cty.Type, *typeexpr.Defaults, VariableParsingMode, hcl.Diagnostics) {
if exprIsNativeQuotedString(expr) {
// If a user provides the pre-0.12 form of variable type argument where
// the string values "string", "list" and "map" are accepted, we
// provide an error to point the user towards using the type system
// correctly has a hint.
// Only the native syntax ends up in this codepath; we handle the
// JSON syntax (which is, of course, quoted within the type system)
// in the normal codepath below.
val, diags := expr.Value(nil)
if diags.HasErrors() {
return cty.DynamicPseudoType, nil, VariableParseHCL, diags
}
str := val.AsString()
switch str {
case "string":
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid quoted type constraints",
Detail: "Terraform 0.11 and earlier required type constraints to be given in quotes, but that form is now deprecated and will be removed in a future version of Terraform. Remove the quotes around \"string\".",
Subject: expr.Range().Ptr(),
})
return cty.DynamicPseudoType, nil, VariableParseLiteral, diags
case "list":
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid quoted type constraints",
Detail: "Terraform 0.11 and earlier required type constraints to be given in quotes, but that form is now deprecated and will be removed in a future version of Terraform. Remove the quotes around \"list\" and write list(string) instead to explicitly indicate that the list elements are strings.",
Subject: expr.Range().Ptr(),
})
return cty.DynamicPseudoType, nil, VariableParseHCL, diags
case "map":
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid quoted type constraints",
Detail: "Terraform 0.11 and earlier required type constraints to be given in quotes, but that form is now deprecated and will be removed in a future version of Terraform. Remove the quotes around \"map\" and write map(string) instead to explicitly indicate that the map elements are strings.",
Subject: expr.Range().Ptr(),
})
return cty.DynamicPseudoType, nil, VariableParseHCL, diags
default:
return cty.DynamicPseudoType, nil, VariableParseHCL, hcl.Diagnostics{{
Severity: hcl.DiagError,
Summary: "Invalid legacy variable type hint",
Detail: `To provide a full type expression, remove the surrounding quotes and give the type expression directly.`,
Subject: expr.Range().Ptr(),
}}
}
}
// First we'll deal with some shorthand forms that the HCL-level type
// expression parser doesn't include. These both emulate pre-0.12 behavior
// of allowing a list or map of any element type as long as all of the
// elements are consistent. This is the same as list(any) or map(any).
switch hcl.ExprAsKeyword(expr) {
case "list":
return cty.List(cty.DynamicPseudoType), nil, VariableParseHCL, nil
case "map":
return cty.Map(cty.DynamicPseudoType), nil, VariableParseHCL, nil
}
ty, typeDefaults, diags := typeexpr.TypeConstraintWithDefaults(expr)
if diags.HasErrors() {
return cty.DynamicPseudoType, nil, VariableParseHCL, diags
}
switch {
case ty.IsPrimitiveType():
// Primitive types use literal parsing.
return ty, typeDefaults, VariableParseLiteral, diags
default:
// Everything else uses HCL parsing
return ty, typeDefaults, VariableParseHCL, diags
}
}
// VariableParsingMode defines how values of a particular variable given by
// text-only mechanisms (command line arguments and environment variables)
// should be parsed to produce the final value.
type VariableParsingMode rune
// VariableParseLiteral is a variable parsing mode that just takes the given
// string directly as a cty.String value.
const VariableParseLiteral VariableParsingMode = 'L'
// VariableParseHCL is a variable parsing mode that attempts to parse the given
// string as an HCL expression and returns the result.
const VariableParseHCL VariableParsingMode = 'H'
// Parse uses the receiving parsing mode to process the given variable value
// string, returning the result along with any diagnostics.
//
// A VariableParsingMode does not know the expected type of the corresponding
// variable, so it's the caller's responsibility to attempt to convert the
// result to the appropriate type and return to the user any diagnostics that
// conversion may produce.
//
// The given name is used to create a synthetic filename in case any diagnostics
// must be generated about the given string value. This should be the name
// of the root module variable whose value will be populated from the given
// string.
//
// If the returned diagnostics has errors, the returned value may not be
// valid.
func (m VariableParsingMode) Parse(name, value string) (cty.Value, hcl.Diagnostics) {
switch m {
case VariableParseLiteral:
return cty.StringVal(value), nil
case VariableParseHCL:
fakeFilename := fmt.Sprintf("<value for var.%s>", name)
expr, diags := hclsyntax.ParseExpression([]byte(value), fakeFilename, hcl.Pos{Line: 1, Column: 1})
if diags.HasErrors() {
return cty.DynamicVal, diags
}
val, valDiags := expr.Value(nil)
diags = append(diags, valDiags...)
return val, diags
default:
// Should never happen
panic(fmt.Errorf("Parse called on invalid VariableParsingMode %#v", m))
}
}
var variableBlockSchema = &hcl.BodySchema{
Attributes: []hcl.AttributeSchema{
{
Name: "description",
},
{
Name: "default",
},
{
Name: "type",
},
{
Name: "sensitive",
},
{
Name: "nullable",
},
},
Blocks: []hcl.BlockHeaderSchema{
{
Type: "validation",
},
},
}