r/aws_iam_group_policy_attachments_exclusive: new resource

This resource will allow practitioners to retain exclusive ownership of customer managed policy attachments to IAM groups via Terraform.

```console
% make testacc PKG=iam TESTS=TestAccIAMGroupPolicyAttachmentsExclusive_
make: Verifying source code with gofmt...
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go1.23.2 test ./internal/service/iam/... -v -count 1 -parallel 20 -run='TestAccIAMGroupPolicyAttachmentsExclusive_'  -timeout 360m
2024/10/15 15:41:33 Initializing Terraform AWS Provider...

--- PASS: TestAccIAMGroupPolicyAttachmentsExclusive_empty (14.72s)
--- PASS: TestAccIAMGroupPolicyAttachmentsExclusive_disappears_Policy (15.88s)
--- PASS: TestAccIAMGroupPolicyAttachmentsExclusive_disappears_Group (15.92s)
--- PASS: TestAccIAMGroupPolicyAttachmentsExclusive_basic (16.48s)
--- PASS: TestAccIAMGroupPolicyAttachmentsExclusive_outOfBandRemoval (23.58s)
--- PASS: TestAccIAMGroupPolicyAttachmentsExclusive_outOfBandAddition (24.17s)
--- PASS: TestAccIAMGroupPolicyAttachmentsExclusive_multiple (24.29s)
PASS
ok      github.com/hashicorp/terraform-provider-aws/internal/service/iam        30.887s
```

internal/service/iam/exports_test.go

@@ -42,6 +42,7 @@ var (
 	FindEntitiesForPolicyByARN          = findEntitiesForPolicyByARN
 	FindGroupByName                     = findGroupByName
 	FindGroupPoliciesByName             = findGroupPoliciesByName
+	FindGroupPolicyAttachmentsByName    = findGroupPolicyAttachmentsByName
 	FindInstanceProfileByName           = findInstanceProfileByName
 	FindOpenIDConnectProviderByARN      = findOpenIDConnectProviderByARN
 	FindPolicyByARN                     = findPolicyByARN

internal/service/iam/group_policy_attachments_exclusive.go

@@ -0,0 +1,211 @@
+// Copyright (c) HashiCorp, Inc.
+// SPDX-License-Identifier: MPL-2.0
+
+package iam
+
+import (
+	"context"
+
+	"github.com/aws/aws-sdk-go-v2/aws"
+	"github.com/aws/aws-sdk-go-v2/service/iam"
+	awstypes "github.com/aws/aws-sdk-go-v2/service/iam/types"
+	"github.com/hashicorp/terraform-plugin-framework/path"
+	"github.com/hashicorp/terraform-plugin-framework/resource"
+	"github.com/hashicorp/terraform-plugin-framework/resource/schema"
+	"github.com/hashicorp/terraform-plugin-framework/resource/schema/planmodifier"
+	"github.com/hashicorp/terraform-plugin-framework/resource/schema/stringplanmodifier"
+	"github.com/hashicorp/terraform-plugin-framework/types"
+	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/retry"
+	"github.com/hashicorp/terraform-provider-aws/internal/create"
+	"github.com/hashicorp/terraform-provider-aws/internal/errs"
+	intflex "github.com/hashicorp/terraform-provider-aws/internal/flex"
+	"github.com/hashicorp/terraform-provider-aws/internal/framework"
+	"github.com/hashicorp/terraform-provider-aws/internal/framework/flex"
+	"github.com/hashicorp/terraform-provider-aws/internal/tfresource"
+	"github.com/hashicorp/terraform-provider-aws/names"
+)
+
+// @FrameworkResource("aws_iam_group_policy_attachments_exclusive", name="Group Policy Attachments Exclusive")
+func newResourceGroupPolicyAttachmentsExclusive(_ context.Context) (resource.ResourceWithConfigure, error) {
+	return &resourceGroupPolicyAttachmentsExclusive{}, nil
+}
+
+const (
+	ResNameGroupPolicyAttachmentsExclusive = "Group Policy Attachments Exclusive"
+)
+
+type resourceGroupPolicyAttachmentsExclusive struct {
+	framework.ResourceWithConfigure
+	framework.WithNoOpDelete
+}
+
+func (r *resourceGroupPolicyAttachmentsExclusive) Metadata(_ context.Context, req resource.MetadataRequest, resp *resource.MetadataResponse) {
+	resp.TypeName = "aws_iam_group_policy_attachments_exclusive"
+}
+
+func (r *resourceGroupPolicyAttachmentsExclusive) Schema(ctx context.Context, req resource.SchemaRequest, resp *resource.SchemaResponse) {
+	resp.Schema = schema.Schema{
+		Attributes: map[string]schema.Attribute{
+			names.AttrGroupName: schema.StringAttribute{
+				Required: true,
+				PlanModifiers: []planmodifier.String{
+					stringplanmodifier.RequiresReplace(),
+				},
+			},
+			"policy_arns": schema.SetAttribute{
+				ElementType: types.StringType,
+				Required:    true,
+			},
+		},
+	}
+}
+
+func (r *resourceGroupPolicyAttachmentsExclusive) Create(ctx context.Context, req resource.CreateRequest, resp *resource.CreateResponse) {
+	var plan resourceGroupPolicyAttachmentsExclusiveData
+	resp.Diagnostics.Append(req.Plan.Get(ctx, &plan)...)
+	if resp.Diagnostics.HasError() {
+		return
+	}
+
+	var policyARNs []string
+	resp.Diagnostics.Append(plan.PolicyARNs.ElementsAs(ctx, &policyARNs, false)...)
+	if resp.Diagnostics.HasError() {
+		return
+	}
+
+	err := r.syncAttachments(ctx, plan.GroupName.ValueString(), policyARNs)
+	if err != nil {
+		resp.Diagnostics.AddError(
+			create.ProblemStandardMessage(names.IAM, create.ErrActionCreating, ResNameGroupPolicyAttachmentsExclusive, plan.GroupName.String(), err),
+			err.Error(),
+		)
+		return
+	}
+
+	resp.Diagnostics.Append(resp.State.Set(ctx, plan)...)
+}
+
+func (r *resourceGroupPolicyAttachmentsExclusive) Read(ctx context.Context, req resource.ReadRequest, resp *resource.ReadResponse) {
+	conn := r.Meta().IAMClient(ctx)
+
+	var state resourceGroupPolicyAttachmentsExclusiveData
+	resp.Diagnostics.Append(req.State.Get(ctx, &state)...)
+	if resp.Diagnostics.HasError() {
+		return
+	}
+
+	out, err := findGroupPolicyAttachmentsByName(ctx, conn, state.GroupName.ValueString())
+	if tfresource.NotFound(err) {
+		resp.State.RemoveResource(ctx)
+		return
+	}
+	if err != nil {
+		resp.Diagnostics.AddError(
+			create.ProblemStandardMessage(names.IAM, create.ErrActionReading, ResNameGroupPolicyAttachmentsExclusive, state.GroupName.String(), err),
+			err.Error(),
+		)
+		return
+	}
+
+	state.PolicyARNs = flex.FlattenFrameworkStringValueSetLegacy(ctx, out)
+	resp.Diagnostics.Append(resp.State.Set(ctx, &state)...)
+}
+
+func (r *resourceGroupPolicyAttachmentsExclusive) Update(ctx context.Context, req resource.UpdateRequest, resp *resource.UpdateResponse) {
+	var plan, state resourceGroupPolicyAttachmentsExclusiveData
+	resp.Diagnostics.Append(req.Plan.Get(ctx, &plan)...)
+	resp.Diagnostics.Append(req.State.Get(ctx, &state)...)
+	if resp.Diagnostics.HasError() {
+		return
+	}
+
+	if !plan.PolicyARNs.Equal(state.PolicyARNs) {
+		var policyARNs []string
+		resp.Diagnostics.Append(plan.PolicyARNs.ElementsAs(ctx, &policyARNs, false)...)
+		if resp.Diagnostics.HasError() {
+			return
+		}
+
+		err := r.syncAttachments(ctx, plan.GroupName.ValueString(), policyARNs)
+		if err != nil {
+			resp.Diagnostics.AddError(
+				create.ProblemStandardMessage(names.IAM, create.ErrActionUpdating, ResNameGroupPolicyAttachmentsExclusive, plan.GroupName.String(), err),
+				err.Error(),
+			)
+			return
+		}
+	}
+
+	resp.Diagnostics.Append(resp.State.Set(ctx, &plan)...)
+}
+
+// syncAttachments handles keeping the configured customer managed policy
+// attachments in sync with the remote resource.
+//
+// Customer managed policies defined on this resource but not attached to
+// the group will be added. Policies attached to the group but not configured
+// on this resource will be removed.
+func (r *resourceGroupPolicyAttachmentsExclusive) syncAttachments(ctx context.Context, groupName string, want []string) error {
+	conn := r.Meta().IAMClient(ctx)
+
+	have, err := findGroupPolicyAttachmentsByName(ctx, conn, groupName)
+	if err != nil {
+		return err
+	}
+
+	create, remove, _ := intflex.DiffSlices(have, want, func(s1, s2 string) bool { return s1 == s2 })
+
+	for _, arn := range create {
+		err := attachPolicyToGroup(ctx, conn, groupName, arn)
+		if err != nil {
+			return err
+		}
+	}
+
+	for _, arn := range remove {
+		err := detachPolicyFromGroup(ctx, conn, groupName, arn)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (r *resourceGroupPolicyAttachmentsExclusive) ImportState(ctx context.Context, req resource.ImportStateRequest, resp *resource.ImportStateResponse) {
+	resource.ImportStatePassthroughID(ctx, path.Root(names.AttrGroupName), req, resp)
+}
+
+func findGroupPolicyAttachmentsByName(ctx context.Context, conn *iam.Client, groupName string) ([]string, error) {
+	in := &iam.ListAttachedGroupPoliciesInput{
+		GroupName: aws.String(groupName),
+	}
+
+	var policyARNs []string
+	paginator := iam.NewListAttachedGroupPoliciesPaginator(conn, in)
+	for paginator.HasMorePages() {
+		page, err := paginator.NextPage(ctx)
+		if err != nil {
+			if errs.IsA[*awstypes.NoSuchEntityException](err) {
+				return nil, &retry.NotFoundError{
+					LastError:   err,
+					LastRequest: in,
+				}
+			}
+			return policyARNs, err
+		}
+
+		for _, p := range page.AttachedPolicies {
+			if p.PolicyArn != nil {
+				policyARNs = append(policyARNs, aws.ToString(p.PolicyArn))
+			}
+		}
+	}
+
+	return policyARNs, nil
+}
+
+type resourceGroupPolicyAttachmentsExclusiveData struct {
+	GroupName  types.String `tfsdk:"group_name"`
+	PolicyARNs types.Set    `tfsdk:"policy_arns"`
+}