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named_values.go
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named_values.go
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package configs
import (
"fmt"
"unicode"
"github.com/hashicorp/hcl/v2"
"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"
"github.com/hashicorp/terraform/addrs"
"github.com/hashicorp/terraform/internal/typeexpr"
)
// 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 cty.Type
ParsingMode VariableParsingMode
Validations []*VariableValidation
Sensitive bool
DescriptionSet bool
SensitiveSet 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.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, parseMode, tyDiags := decodeVariableType(attr.Expr)
diags = append(diags, tyDiags...)
v.Type = ty
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["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.Type != cty.NilType {
var err error
val, err = convert.Convert(val, v.Type)
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
}
}
v.Default = val
}
for _, block := range content.Blocks {
switch block.Type {
case "validation":
vv, moreDiags := decodeVariableValidationBlock(v.Name, block, override)
diags = append(diags, moreDiags...)
v.Validations = append(v.Validations, vv)
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, 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, 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, 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, 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, VariableParseHCL, diags
default:
return cty.DynamicPseudoType, 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), VariableParseHCL, nil
case "map":
return cty.Map(cty.DynamicPseudoType), VariableParseHCL, nil
}
ty, diags := typeexpr.TypeConstraint(expr)
if diags.HasErrors() {
return cty.DynamicPseudoType, VariableParseHCL, diags
}
switch {
case ty.IsPrimitiveType():
// Primitive types use literal parsing.
return ty, VariableParseLiteral, diags
default:
// Everything else uses HCL parsing
return ty, VariableParseHCL, diags
}
}
// Required returns true if this variable is required to be set by the caller,
// or false if there is a default value that will be used when it isn't set.
func (v *Variable) Required() bool {
return v.Default == cty.NilVal
}
// 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))
}
}
// VariableValidation represents a configuration-defined validation rule
// for a particular input variable, given as a "validation" block inside
// a "variable" block.
type VariableValidation struct {
// Condition is an expression that refers to the variable being tested
// and contains no other references. The expression must return true
// to indicate that the value is valid or false to indicate that it is
// invalid. If the expression produces an error, that's considered a bug
// in the module defining the validation rule, not an error in the caller.
Condition hcl.Expression
// ErrorMessage is one or more full sentences, which would need to be in
// English for consistency with the rest of the error message output but
// can in practice be in any language as long as it ends with a period.
// The message should describe what is required for the condition to return
// true in a way that would make sense to a caller of the module.
ErrorMessage string
DeclRange hcl.Range
}
func decodeVariableValidationBlock(varName string, block *hcl.Block, override bool) (*VariableValidation, hcl.Diagnostics) {
var diags hcl.Diagnostics
vv := &VariableValidation{
DeclRange: block.DefRange,
}
if override {
// For now we'll just forbid overriding validation blocks, to simplify
// the initial design. If we can find a clear use-case for overriding
// validations in override files and there's a way to define it that
// isn't confusing then we could relax this.
diags = diags.Append(&hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Can't override variable validation rules",
Detail: "Variable \"validation\" blocks cannot be used in override files.",
Subject: vv.DeclRange.Ptr(),
})
return vv, diags
}
content, moreDiags := block.Body.Content(variableValidationBlockSchema)
diags = append(diags, moreDiags...)
if attr, exists := content.Attributes["condition"]; exists {
vv.Condition = attr.Expr
// The validation condition can only refer to the variable itself,
// to ensure that the variable declaration can't create additional
// edges in the dependency graph.
goodRefs := 0
for _, traversal := range vv.Condition.Variables() {
ref, moreDiags := addrs.ParseRef(traversal)
if !moreDiags.HasErrors() {
if addr, ok := ref.Subject.(addrs.InputVariable); ok {
if addr.Name == varName {
goodRefs++
continue // Reference is valid
}
}
}
// If we fall out here then the reference is invalid.
diags = diags.Append(&hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid reference in variable validation",
Detail: fmt.Sprintf("The condition for variable %q can only refer to the variable itself, using var.%s.", varName, varName),
Subject: traversal.SourceRange().Ptr(),
})
}
if goodRefs < 1 {
diags = diags.Append(&hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid variable validation condition",
Detail: fmt.Sprintf("The condition for variable %q must refer to var.%s in order to test incoming values.", varName, varName),
Subject: attr.Expr.Range().Ptr(),
})
}
}
if attr, exists := content.Attributes["error_message"]; exists {
moreDiags := gohcl.DecodeExpression(attr.Expr, nil, &vv.ErrorMessage)
diags = append(diags, moreDiags...)
if !moreDiags.HasErrors() {
const errSummary = "Invalid validation error message"
switch {
case vv.ErrorMessage == "":
diags = diags.Append(&hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: errSummary,
Detail: "An empty string is not a valid nor useful error message.",
Subject: attr.Expr.Range().Ptr(),
})
case !looksLikeSentences(vv.ErrorMessage):
// Because we're going to include this string verbatim as part
// of a bigger error message written in our usual style in
// English, we'll require the given error message to conform
// to that. We might relax this in future if e.g. we start
// presenting these error messages in a different way, or if
// Terraform starts supporting producing error messages in
// other human languages, etc.
// For pragmatism we also allow sentences ending with
// exclamation points, but we don't mention it explicitly here
// because that's not really consistent with the Terraform UI
// writing style.
diags = diags.Append(&hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: errSummary,
Detail: "The validation error message must be at least one full sentence starting with an uppercase letter and ending with a period or question mark.\n\nYour given message will be included as part of a larger Terraform error message, written as English prose. For broadly-shared modules we suggest using a similar writing style so that the overall result will be consistent.",
Subject: attr.Expr.Range().Ptr(),
})
}
}
}
return vv, diags
}
// looksLikeSentence is a simple heuristic that encourages writing error
// messages that will be presentable when included as part of a larger
// Terraform error diagnostic whose other text is written in the Terraform
// UI writing style.
//
// This is intentionally not a very strong validation since we're assuming
// that module authors want to write good messages and might just need a nudge
// about Terraform's specific style, rather than that they are going to try
// to work around these rules to write a lower-quality message.
func looksLikeSentences(s string) bool {
if len(s) < 1 {
return false
}
runes := []rune(s) // HCL guarantees that all strings are valid UTF-8
first := runes[0]
last := runes[len(runes)-1]
// If the first rune is a letter then it must be an uppercase letter.
// (This will only see the first rune in a multi-rune combining sequence,
// but the first rune is generally the letter if any are, and if not then
// we'll just ignore it because we're primarily expecting English messages
// right now anyway, for consistency with all of Terraform's other output.)
if unicode.IsLetter(first) && !unicode.IsUpper(first) {
return false
}
// The string must be at least one full sentence, which implies having
// sentence-ending punctuation.
// (This assumes that if a sentence ends with quotes then the period
// will be outside the quotes, which is consistent with Terraform's UI
// writing style.)
return last == '.' || last == '?' || last == '!'
}
// Output represents an "output" block in a module or file.
type Output struct {
Name string
Description string
Expr hcl.Expression
DependsOn []hcl.Traversal
Sensitive bool
DescriptionSet bool
SensitiveSet bool
DeclRange hcl.Range
}
func decodeOutputBlock(block *hcl.Block, override bool) (*Output, hcl.Diagnostics) {
var diags hcl.Diagnostics
o := &Output{
Name: block.Labels[0],
DeclRange: block.DefRange,
}
schema := outputBlockSchema
if override {
schema = schemaForOverrides(schema)
}
content, moreDiags := block.Body.Content(schema)
diags = append(diags, moreDiags...)
if !hclsyntax.ValidIdentifier(o.Name) {
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid output name",
Detail: badIdentifierDetail,
Subject: &block.LabelRanges[0],
})
}
if attr, exists := content.Attributes["description"]; exists {
valDiags := gohcl.DecodeExpression(attr.Expr, nil, &o.Description)
diags = append(diags, valDiags...)
o.DescriptionSet = true
}
if attr, exists := content.Attributes["value"]; exists {
o.Expr = attr.Expr
}
if attr, exists := content.Attributes["sensitive"]; exists {
valDiags := gohcl.DecodeExpression(attr.Expr, nil, &o.Sensitive)
diags = append(diags, valDiags...)
o.SensitiveSet = true
}
if attr, exists := content.Attributes["depends_on"]; exists {
deps, depsDiags := decodeDependsOn(attr)
diags = append(diags, depsDiags...)
o.DependsOn = append(o.DependsOn, deps...)
}
return o, diags
}
// Local represents a single entry from a "locals" block in a module or file.
// The "locals" block itself is not represented, because it serves only to
// provide context for us to interpret its contents.
type Local struct {
Name string
Expr hcl.Expression
DeclRange hcl.Range
}
func decodeLocalsBlock(block *hcl.Block) ([]*Local, hcl.Diagnostics) {
attrs, diags := block.Body.JustAttributes()
if len(attrs) == 0 {
return nil, diags
}
locals := make([]*Local, 0, len(attrs))
for name, attr := range attrs {
if !hclsyntax.ValidIdentifier(name) {
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid local value name",
Detail: badIdentifierDetail,
Subject: &attr.NameRange,
})
}
locals = append(locals, &Local{
Name: name,
Expr: attr.Expr,
DeclRange: attr.Range,
})
}
return locals, diags
}
// Addr returns the address of the local value declared by the receiver,
// relative to its containing module.
func (l *Local) Addr() addrs.LocalValue {
return addrs.LocalValue{
Name: l.Name,
}
}
var variableBlockSchema = &hcl.BodySchema{
Attributes: []hcl.AttributeSchema{
{
Name: "description",
},
{
Name: "default",
},
{
Name: "type",
},
{
Name: "sensitive",
},
},
Blocks: []hcl.BlockHeaderSchema{
{
Type: "validation",
},
},
}
var variableValidationBlockSchema = &hcl.BodySchema{
Attributes: []hcl.AttributeSchema{
{
Name: "condition",
Required: true,
},
{
Name: "error_message",
Required: true,
},
},
}
var outputBlockSchema = &hcl.BodySchema{
Attributes: []hcl.AttributeSchema{
{
Name: "description",
},
{
Name: "value",
Required: true,
},
{
Name: "depends_on",
},
{
Name: "sensitive",
},
},
}