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core: Support explicit variable type declaration 

This commit adds support for declaring variable types in Terraform
configuration. Historically, the type has been inferred from the default
value, defaulting to string if no default was supplied. This has caused
users to devise workarounds if they wanted to declare a map but provide
values from a .tfvars file (for example).

The new syntax adds the "type" key to variable blocks:

```
variable "i_am_a_string" {
    type = "string"
}

variable "i_am_a_map" {
    type = "map"
}
```

This commit does _not_ extend the type system to include bools, integers
or floats - the only two types available are maps and strings.

Validation is performed if a default value is provided in order to
ensure that the default value type matches the declared type.

In the case that a type is not declared, the old logic is used for
determining the type. This allows backwards compatiblity with previous
Terraform configuration.
This commit is contained in:
James Nugent 2016-01-21 14:33:16 -05:00
parent 1e99ff6c44
commit cb6cb8b96a
11 changed files with 186 additions and 30 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

74
config/config.go
View File

@ -99,6 +99,7 @@ type Provisioner struct {
// Variable is a variable defined within the configuration.
type Variable struct {
Name string
DeclaredType string `mapstructure:"type"`
Default interface{}
Description string
}
@ -177,7 +178,7 @@ func (c *Config) Validate() error {
for _, v := range c.Variables {
if v.Type() == VariableTypeUnknown {
errs = append(errs, fmt.Errorf(
"Variable '%s': must be string or mapping",
"Variable '%s': must be a string or a map",
v.Name))
continue
}
@ -780,8 +781,64 @@ func (v *Variable) Merge(v2 *Variable) *Variable {
return &result
}
// Type returns the type of varialbe this is.
var typeStringMap = map[string]VariableType{
"string": VariableTypeString,
"map": VariableTypeMap,
}
// Type returns the type of variable this is.
func (v *Variable) Type() VariableType {
if v.DeclaredType != "" {
declaredType, ok := typeStringMap[v.DeclaredType]
if !ok {
return VariableTypeUnknown
}
return declaredType
}
return v.inferTypeFromDefault()
}
// ValidateTypeAndDefault ensures that default variable value is compatible
// with the declared type (if one exists), and that the type is one which is
// known to Terraform
func (v *Variable) ValidateTypeAndDefault() error {
// If an explicit type is declared, ensure it is valid
if v.DeclaredType != "" {
if _, ok := typeStringMap[v.DeclaredType]; !ok {
return fmt.Errorf("Variable '%s' must be of type string or map", v.Name)
}
}
if v.DeclaredType == "" || v.Default == nil {
return nil
}
if v.inferTypeFromDefault() != v.Type() {
return fmt.Errorf("'%s' has a default value which is not of type '%s'", v.Name, v.DeclaredType)
}
return nil
}
func (v *Variable) mergerName() string {
return v.Name
}
func (v *Variable) mergerMerge(m merger) merger {
return v.Merge(m.(*Variable))
}
// Required tests whether a variable is required or not.
func (v *Variable) Required() bool {
return v.Default == nil
}
// inferTypeFromDefault contains the logic for the old method of inferring
// variable types - we can also use this for validating that the declared
// type matches the type of the default value
func (v *Variable) inferTypeFromDefault() VariableType {
if v.Default == nil {
return VariableTypeString
}
@ -800,16 +857,3 @@ func (v *Variable) Type() VariableType {
return VariableTypeUnknown
}
func (v *Variable) mergerName() string {
return v.Name
}
func (v *Variable) mergerMerge(m merger) merger {
return v.Merge(m.(*Variable))
}
// Required tests whether a variable is required or not.
func (v *Variable) Required() bool {
return v.Default == nil
}

8
config/config_string.go
View File

@ -278,6 +278,11 @@ func variablesStr(vs []*Variable) string {
required = " (required)"
}
declaredType := ""
if v.DeclaredType != "" {
declaredType = fmt.Sprintf(" (%s)", v.DeclaredType)
}
if v.Default == nil || v.Default == "" {
v.Default = "<>"
}
@ -286,9 +291,10 @@ func variablesStr(vs []*Variable) string {
}
result += fmt.Sprintf(
"%s%s\n %v\n %s\n",
"%s%s%s\n %v\n %s\n",
k,
required,
declaredType,
v.Default,
v.Description)
}

6
config/loader_hcl.go
View File

@ -30,6 +30,7 @@ func (t *hclConfigurable) Config() (*Config, error) {
type hclVariable struct {
Default interface{}
Description string
DeclaredType string `hcl:"type"`
Fields []string `hcl:",decodedFields"`
}
@ -71,10 +72,15 @@ func (t *hclConfigurable) Config() (*Config, error) {
newVar := &Variable{
Name: k,
DeclaredType: v.DeclaredType,
Default: v.Default,
Description: v.Description,
}
if err := newVar.ValidateTypeAndDefault(); err != nil {
return nil, err
}
config.Variables = append(config.Variables, newVar)
}
}

30
config/loader_test.go
View File

@ -444,6 +444,30 @@ func TestLoadDir_override(t *testing.T) {
}
}
func TestLoadFile_mismatchedVariableTypes(t *testing.T) {
_, err := LoadFile(filepath.Join(fixtureDir, "variable-mismatched-type.tf"))
if err == nil {
t.Fatalf("bad: expected error")
}
errorStr := err.Error()
if !strings.Contains(errorStr, "'not_a_map' has a default value which is not of type 'string'") {
t.Fatalf("bad: expected error has wrong text: %s", errorStr)
}
}
func TestLoadFile_badVariableTypes(t *testing.T) {
_, err := LoadFile(filepath.Join(fixtureDir, "bad-variable-type.tf"))
if err == nil {
t.Fatalf("bad: expected error")
}
errorStr := err.Error()
if !strings.Contains(errorStr, "'bad_type' must be of type string") {
t.Fatalf("bad: expected error has wrong text: %s", errorStr)
}
}
func TestLoadFile_provisioners(t *testing.T) {
c, err := LoadFile(filepath.Join(fixtureDir, "provisioners.tf"))
if err != nil {
@ -802,6 +826,12 @@ aws_security_group[firewall] (x5)
`
const basicVariablesStr = `
bar (required) (string)
<>
<>
baz (map)
map[key:value]
<>
foo
bar
bar

3
config/test-fixtures/bad-variable-type.tf Normal file
View File

@ -0,0 +1,3 @@
variable "bad_type" {
type = "notatype"
}

12
config/test-fixtures/basic.tf
View File

@ -3,6 +3,18 @@ variable "foo" {
description = "bar"
}
variable "bar" {
type = "string"
}
variable "baz" {
type = "map"
default = {
key = "value"
}
}
provider "aws" {
access_key = "foo"
secret_key = "bar"

9
config/test-fixtures/basic.tf.json
View File

@ -3,6 +3,15 @@
"foo": {
"default": "bar",
"description": "bar"
},
"bar": {
"type": "string"
},
"baz": {
"type": "map",
"default": {
"key": "value"
}
}
},

7
config/test-fixtures/variable-mismatched-type.tf Normal file
View File

@ -0,0 +1,7 @@
variable "not_a_map" {
type = "string"
default = {
i_am_not = "a string"
}
}

15
terraform/context_validate_test.go
View File

@ -25,6 +25,21 @@ func TestContext2Validate_badVar(t *testing.T) {
}
}
func TestContext2Validate_varNoDefaultExplicitType(t *testing.T) {
m := testModule(t, "validate-var-no-default-explicit-type")
c := testContext2(t, &ContextOpts{
Module: m,
})
w, e := c.Validate()
if len(w) > 0 {
t.Fatalf("bad: %#v", w)
}
if len(e) == 0 {
t.Fatalf("bad: %#v", e)
}
}
func TestContext2Validate_computedVar(t *testing.T) {
p := testProvider("aws")
m := testModule(t, "validate-computed-var")

5
terraform/test-fixtures/validate-var-no-default-explicit-type/main.tf Normal file
View File

@ -0,0 +1,5 @@
variable "maybe_a_map" {
type = "map"
// No default
}

29
website/source/docs/configuration/variables.html.md
View File

@ -23,9 +23,13 @@ already.
A variable configuration looks like the following:
```
variable "key" {}
variable "key" {
type = "string"
}
variable "images" {
type = "map"
default = {
us-east-1 = "image-1234"
us-west-2 = "image-4567"
@ -39,13 +43,22 @@ The `variable` block configures a single input variable for
a Terraform configuration. Multiple variables blocks can be used to
add multiple variables.
The `NAME` given to the variable block is the name used to
The `name` given to the variable block is the name used to
set the variable via the CLI as well as reference the variable
throughout the Terraform configuration.
Within the block (the `{ }`) is configuration for the variable.
These are the parameters that can be set:
* `type` (optional) - If set this defines the type of the variable.
Valid values are `string` and `map`. In older versions of Terraform
this parameter did not exist, and the type was inferred from the
default value, defaulting to `string` if no default was set. If a
type is not specified, the previous behavior is maintained. It is
recommended to set variable types explicitly in preference to relying
on inferrence - this allows variables of type `map` to be set in the
`terraform.tfvars` file without requiring a default value to be set.
* `default` (optional) - If set, this sets a default value
for the variable. If this isn't set, the variable is required
and Terraform will error if not set. The default value can be
@ -59,15 +72,18 @@ These are the parameters that can be set:
------
**Default values** can be either strings or maps. If a default
value is omitted and the variable is required, the value assigned
via the CLI must be a string.
**Default values** can be either strings or maps, and if specified
must match the declared type of the variable. If no value is supplied
for a variable of type `map`, the values must be supplied in a
`terraform.tfvars` file - they cannot be input via the console.
String values are simple and represent a basic key to value
mapping where the key is the variable name. An example is:
```
variable "key" {
type = "string"
default = "value"
}
```
@ -79,6 +95,8 @@ An example:
```
variable "images" {
type = "map"
default = {
us-east-1 = "image-1234"
us-west-2 = "image-4567"
@ -115,6 +133,7 @@ The full syntax is:
```
variable NAME {
[type = TYPE]
[default = DEFAULT]
[description = DESCRIPTION]
}