String Length Validation (LengthAtLeast / LengthAtMost / LengthBetween)

[bflad]

Terraform CLI and Framework Versions

Any Terraform CLI version; terraform-plugin-framework v0.8.0

Use Cases or Problem Statement

Provider developers should be able to generically validate types.String values for their length. For example:

• Whether a known value is equal or more than a certain length, but not constrained
• Whether a known value is equal or less than a certain length, but not constrained
• Whether a value is equal or more than a certain length and equal or less than another length

Proposal

Inside a stringvalidator package, create three new unexported types that satisfy the tfsdk.AttributeValidator interface:

var _ lengthAtLeastValidator = tfsdk.AttributeValidator

type lengthAtLeastValidator struct {
  min int
}

func (v lengthAtLeastValidator) Description(ctx context.Context) string {/*...*/}
func (v lengthAtLeastValidator) MarkdownDescription(ctx context.Context) string {/*...*/}
func (v lengthAtLeastValidator) Validate(ctx context.Context, req tfsdk.ValidateAttributeRequest, resp *tfsdk.ValidateAttributeResponse) {/*...*/}

var _ lengthAtMostValidator = tfsdk.AttributeValidator

type lengthAtMostValidator struct {
  max int
}

func (v lengthAtMostValidator) Description(ctx context.Context) string {/*...*/}
func (v lengthAtMostValidator) MarkdownDescription(ctx context.Context) string {/*...*/}
func (v lengthAtMostValidator) Validate(ctx context.Context, req tfsdk.ValidateAttributeRequest, resp *tfsdk.ValidateAttributeResponse) {/*...*/}

var _ lengthBetweenValidator = tfsdk.AttributeValidator

type lengthBetweenValidator struct {
  max int
  min int
}

func (v lengthBetweenValidator) Description(ctx context.Context) string {/*...*/}
func (v lengthBetweenValidator) MarkdownDescription(ctx context.Context) string {/*...*/}
func (v lengthBetweenValidator) Validate(ctx context.Context, req tfsdk.ValidateAttributeRequest, resp *tfsdk.ValidateAttributeResponse) {/*...*/}

Then, create exported functions that return these:

func LengthAtLeast(min int) AttributeValidator {/*...*/}
func LengthAtMost(max int) AttributeValidator {/*...*/}
func LengthBetween(min int, max int) AttributeValidator {/*...*/}

This would allow provider developers to declare attributes such as:

tfsdk.Attribute{
  // ... other fields ...
  Type: types.String,
  Validators: tfsdk.AttributeValidators{
    stringvalidator.AtLeast(123),
  },
},

Additional Information

No response

Code of Conduct

• I agree to follow this project's Code of Conduct

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