Adding List validation for SizeAtLeast, SizeAtMost and SizeBetween

.changelog/37.txt

@@ -0,0 +1,3 @@
+```release-note:feature
+Introduced `listvalidator` package with `ValuesAre()` validation functions
+```

.changelog/41.txt

@@ -0,0 +1,3 @@
+```release-note:feature
+Added `SizeAtLeast()`, `SizeAtMost()` and `SizeBetween` validation functions to `listvalidator` package
+```

listvalidator/doc.go

@@ -0,0 +1,2 @@
+// Package listvalidator provides validators for types.List attributes.
+package listvalidator

listvalidator/size_at_least.go

@@ -0,0 +1,58 @@
+package listvalidator
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/hashicorp/terraform-plugin-framework/tfsdk"
+
+	"github.com/hashicorp/terraform-plugin-framework-validators/validatordiag"
+)
+
+var _ tfsdk.AttributeValidator = sizeAtLeastValidator{}
+
+// sizeAtLeastValidator validates that list contains at least min elements.
+type sizeAtLeastValidator struct {
+	min int
+}
+
+// Description describes the validation in plain text formatting.
+func (v sizeAtLeastValidator) Description(ctx context.Context) string {
+	return fmt.Sprintf("list must contain at least %d elements", v.min)
+}
+
+// MarkdownDescription describes the validation in Markdown formatting.
+func (v sizeAtLeastValidator) MarkdownDescription(ctx context.Context) string {
+	return v.Description(ctx)
+}
+
+// Validate performs the validation.
+func (v sizeAtLeastValidator) Validate(ctx context.Context, req tfsdk.ValidateAttributeRequest, resp *tfsdk.ValidateAttributeResponse) {
+	elems, ok := validateList(ctx, req, resp)
+	if !ok {
+		return
+	}
+
+	if len(elems) < v.min {
+		resp.Diagnostics.Append(validatordiag.AttributeValueDiagnostic(
+			req.AttributePath,
+			v.Description(ctx),
+			fmt.Sprintf("%d", len(elems)),
+		))
+
+		return
+	}
+}
+
+// SizeAtLeast returns an AttributeValidator which ensures that any configured
+// attribute value:
+//
+//     - Is a List.
+//     - Contains at least min elements.
+//
+// Null (unconfigured) and unknown (known after apply) values are skipped.
+func SizeAtLeast(min int) tfsdk.AttributeValidator {
+	return sizeAtLeastValidator{
+		min: min,
+	}
+}

listvalidator/size_at_least_test.go

@@ -0,0 +1,90 @@
+package listvalidator
+
+import (
+	"context"
+	"testing"
+
+	"github.com/hashicorp/terraform-plugin-framework/attr"
+	"github.com/hashicorp/terraform-plugin-framework/tfsdk"
+	"github.com/hashicorp/terraform-plugin-framework/types"
+	"github.com/hashicorp/terraform-plugin-go/tftypes"
+)
+
+func TestSizeAtLeastValidator(t *testing.T) {
+	t.Parallel()
+
+	type testCase struct {
+		val         attr.Value
+		min         int
+		expectError bool
+	}
+	tests := map[string]testCase{
+		"not a List": {
+			val:         types.Bool{Value: true},
+			expectError: true,
+		},
+		"List unknown": {
+			val: types.List{
+				Unknown:  true,
+				ElemType: types.StringType,
+			},
+			expectError: false,
+		},
+		"List null": {
+			val: types.List{
+				Null:     true,
+				ElemType: types.StringType,
+			},
+			expectError: false,
+		},
+		"List size greater than min": {
+			val: types.List{
+				ElemType: types.StringType,
+				Elems: []attr.Value{
+					types.String{Value: "first"},
+					types.String{Value: "second"},
+				},
+			},
+			min:         1,
+			expectError: false,
+		},
+		"List size equal to min": {
+			val: types.List{
+				ElemType: types.StringType,
+				Elems: []attr.Value{
+					types.String{Value: "first"},
+				},
+			},
+			min:         1,
+			expectError: false,
+		},
+		"List size less than min": {
+			val: types.List{
+				ElemType: types.StringType,
+				Elems:    []attr.Value{},
+			},
+			min:         1,
+			expectError: true,
+		},
+	}
+
+	for name, test := range tests {
+		name, test := name, test
+		t.Run(name, func(t *testing.T) {
+			request := tfsdk.ValidateAttributeRequest{
+				AttributePath:   tftypes.NewAttributePath().WithAttributeName("test"),
+				AttributeConfig: test.val,
+			}
+			response := tfsdk.ValidateAttributeResponse{}
+			SizeAtLeast(test.min).Validate(context.TODO(), request, &response)
+
+			if !response.Diagnostics.HasError() && test.expectError {
+				t.Fatal("expected error, got no error")
+			}
+
+			if response.Diagnostics.HasError() && !test.expectError {
+				t.Fatalf("got unexpected error: %s", response.Diagnostics)
+			}
+		})
+	}
+}

listvalidator/size_at_most.go

@@ -0,0 +1,58 @@
+package listvalidator
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/hashicorp/terraform-plugin-framework/tfsdk"
+
+	"github.com/hashicorp/terraform-plugin-framework-validators/validatordiag"
+)
+
+var _ tfsdk.AttributeValidator = sizeAtMostValidator{}
+
+// sizeAtMostValidator validates that list contains at most max elements.
+type sizeAtMostValidator struct {
+	max int
+}
+
+// Description describes the validation in plain text formatting.
+func (v sizeAtMostValidator) Description(ctx context.Context) string {
+	return fmt.Sprintf("list must contain at most %d elements", v.max)
+}
+
+// MarkdownDescription describes the validation in Markdown formatting.
+func (v sizeAtMostValidator) MarkdownDescription(ctx context.Context) string {
+	return v.Description(ctx)
+}
+
+// Validate performs the validation.
+func (v sizeAtMostValidator) Validate(ctx context.Context, req tfsdk.ValidateAttributeRequest, resp *tfsdk.ValidateAttributeResponse) {
+	elems, ok := validateList(ctx, req, resp)
+	if !ok {
+		return
+	}
+
+	if len(elems) > v.max {
+		resp.Diagnostics.Append(validatordiag.AttributeValueDiagnostic(
+			req.AttributePath,
+			v.Description(ctx),
+			fmt.Sprintf("%d", len(elems)),
+		))
+
+		return
+	}
+}
+
+// SizeAtMost returns an AttributeValidator which ensures that any configured
+// attribute value:
+//
+//     - Is a List.
+//     - Contains at most max elements.
+//
+// Null (unconfigured) and unknown (known after apply) values are skipped.
+func SizeAtMost(max int) tfsdk.AttributeValidator {
+	return sizeAtMostValidator{
+		max: max,
+	}
+}

listvalidator/size_at_most_test.go

@@ -0,0 +1,93 @@
+package listvalidator
+
+import (
+	"context"
+	"testing"
+
+	"github.com/hashicorp/terraform-plugin-framework/attr"
+	"github.com/hashicorp/terraform-plugin-framework/tfsdk"
+	"github.com/hashicorp/terraform-plugin-framework/types"
+	"github.com/hashicorp/terraform-plugin-go/tftypes"
+)
+
+func TestSizeAtMostValidator(t *testing.T) {
+	t.Parallel()
+
+	type testCase struct {
+		val         attr.Value
+		max         int
+		expectError bool
+	}
+	tests := map[string]testCase{
+		"not a List": {
+			val:         types.Bool{Value: true},
+			expectError: true,
+		},
+		"List unknown": {
+			val: types.List{
+				Unknown:  true,
+				ElemType: types.StringType,
+			},
+			expectError: false,
+		},
+		"List null": {
+			val: types.List{
+				Null:     true,
+				ElemType: types.StringType,
+			},
+			expectError: false,
+		},
+		"List size less than max": {
+			val: types.List{
+				ElemType: types.StringType,
+				Elems: []attr.Value{
+					types.String{Value: "first"},
+				},
+			},
+			max:         2,
+			expectError: false,
+		},
+		"List size equal to max": {
+			val: types.List{
+				ElemType: types.StringType,
+				Elems: []attr.Value{
+					types.String{Value: "first"},
+					types.String{Value: "second"},
+				},
+			},
+			max:         2,
+			expectError: false,
+		},
+		"List size greater than max": {
+			val: types.List{
+				ElemType: types.StringType,
+				Elems: []attr.Value{
+					types.String{Value: "first"},
+					types.String{Value: "second"},
+					types.String{Value: "third"},
+				}},
+			max:         2,
+			expectError: true,
+		},
+	}
+
+	for name, test := range tests {
+		name, test := name, test
+		t.Run(name, func(t *testing.T) {
+			request := tfsdk.ValidateAttributeRequest{
+				AttributePath:   tftypes.NewAttributePath().WithAttributeName("test"),
+				AttributeConfig: test.val,
+			}
+			response := tfsdk.ValidateAttributeResponse{}
+			SizeAtMost(test.max).Validate(context.TODO(), request, &response)
+
+			if !response.Diagnostics.HasError() && test.expectError {
+				t.Fatal("expected error, got no error")
+			}
+
+			if response.Diagnostics.HasError() && !test.expectError {
+				t.Fatalf("got unexpected error: %s", response.Diagnostics)
+			}
+		})
+	}
+}

listvalidator/size_between.go

@@ -0,0 +1,61 @@
+package listvalidator
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/hashicorp/terraform-plugin-framework/tfsdk"
+
+	"github.com/hashicorp/terraform-plugin-framework-validators/validatordiag"
+)
+
+var _ tfsdk.AttributeValidator = sizeBetweenValidator{}
+
+// sizeBetweenValidator validates that list contains at least min elements
+// and at most max elements.
+type sizeBetweenValidator struct {
+	min int
+	max int
+}
+
+// Description describes the validation in plain text formatting.
+func (v sizeBetweenValidator) Description(ctx context.Context) string {
+	return fmt.Sprintf("list must contain at least %d elements and at most %d elements", v.min, v.max)
+}
+
+// MarkdownDescription describes the validation in Markdown formatting.
+func (v sizeBetweenValidator) MarkdownDescription(ctx context.Context) string {
+	return v.Description(ctx)
+}
+
+// Validate performs the validation.
+func (v sizeBetweenValidator) Validate(ctx context.Context, req tfsdk.ValidateAttributeRequest, resp *tfsdk.ValidateAttributeResponse) {
+	elems, ok := validateList(ctx, req, resp)
+	if !ok {
+		return
+	}
+
+	if len(elems) < v.min || len(elems) > v.max {
+		resp.Diagnostics.Append(validatordiag.AttributeValueDiagnostic(
+			req.AttributePath,
+			v.Description(ctx),
+			fmt.Sprintf("%d", len(elems)),
+		))
+
+		return
+	}
+}
+
+// SizeBetween returns an AttributeValidator which ensures that any configured
+// attribute value:
+//
+//     - Is a List.
+//     - Contains at least min elements and at most max elements.
+//
+// Null (unconfigured) and unknown (known after apply) values are skipped.
+func SizeBetween(min, max int) tfsdk.AttributeValidator {
+	return sizeBetweenValidator{
+		min: min,
+		max: max,
+	}
+}