restful_resource - Introduce force_new_attrs to support condition…

…al replace resource (#37)

* Surface

* `restful_resource` - Introduce `force_new_attrs` to mark resoruce to be replaced once any of these attributes in `body` got changed

docs/resources/resource.md

@@ -50,6 +50,7 @@ resource "restful_resource" "rg" {
 - `create_selector` (String) A selector in [gjson query syntax](https://github.com/tidwall/gjson/blob/master/SYNTAX.md#queries) query syntax, that is used when create returns a collection of resources, to select exactly one member resource of from it. By default, the whole response body is used as the body.
 - `delete_method` (String) The method used to delete the resource. Possible values are `DELETE` and `POST`. This overrides the `delete_method` set in the provider block (defaults to DELETE).
 - `delete_path` (String) The API path used to delete the resource. The `id` is used instead if `delete_path` is absent. The path can be string literal, or combined by followings: `$(path)` expanded to `path`, `$(body.x.y.z)` expands to the `x.y.z` property (urlencoded) in API body, `#(body.id)` expands to the `id` property, with `base_url` prefix trimmed.
+- `force_new_attrs` (Set of String) A set of `body` attribute paths (in [gjson syntax](https://github.com/tidwall/gjson/blob/master/SYNTAX.md)) whose value once changed, will trigger a replace of this resource. Note this only take effects when the `body` is a unknown before apply. Technically, we do a JSON merge patch and check whether the attribute path appear in the merge patch.
 - `header` (Map of String) The header parameters that are applied to each request. This overrides the `header` set in the provider block.
 - `merge_patch_disabled` (Boolean) Whether to use a JSON Merge Patch as the request body in the PATCH update? This is only effective when `update_method` is set to `PATCH`. This overrides the `merge_patch_disabled` set in the provider block (defaults to `false`).
 - `poll_create` (Attributes) The polling option for the "Create" operation (see [below for nested schema](#nestedatt--poll_create))

internal/provider/resource.go

@@ -64,7 +64,9 @@ type resourceData struct {
 	MergePatchDisabled types.Bool `tfsdk:"merge_patch_disabled"`
 	Query              types.Map  `tfsdk:"query"`
 	Header             types.Map  `tfsdk:"header"`
-	CheckExistance     types.Bool `tfsdk:"check_existance"`
+
+	CheckExistance types.Bool `tfsdk:"check_existance"`
+	ForceNewAttrs  types.Set  `tfsdk:"force_new_attrs"`
 
 	Output types.String `tfsdk:"output"`
 }
@@ -366,6 +368,12 @@ func (r *Resource) Schema(ctx context.Context, req resource.SchemaRequest, resp
 				MarkdownDescription: "Whether to check resource already existed? Defaults to `false`.",
 				Optional:            true,
 			},
+			"force_new_attrs": schema.SetAttribute{
+				Description:         "A set of `body` attribute paths (in gjson syntax) whose value once changed, will trigger a replace of this resource. Note this only take effects when the `body` is a unknown before apply. Technically, we do a JSON merge patch and check whether the attribute path appear in the merge patch.",
+				MarkdownDescription: "A set of `body` attribute paths (in [gjson syntax](https://github.com/tidwall/gjson/blob/master/SYNTAX.md)) whose value once changed, will trigger a replace of this resource. Note this only take effects when the `body` is a unknown before apply. Technically, we do a JSON merge patch and check whether the attribute path appear in the merge patch.",
+				Optional:            true,
+				ElementType:         types.StringType,
+			},
 			"output": schema.StringAttribute{
 				Description:         "The response body after reading the resource.",
 				MarkdownDescription: "The response body after reading the resource.",
@@ -400,6 +408,69 @@ func (r *Resource) ValidateConfig(ctx context.Context, req resource.ValidateConf
 	}
 }
 
+func (r *Resource) ModifyPlan(ctx context.Context, req resource.ModifyPlanRequest, resp *resource.ModifyPlanResponse) {
+	if req.Plan.Raw.IsNull() {
+		// // If the entire plan is null, the resource is planned for destruction.
+		return
+	}
+
+	if req.State.Raw.IsNull() {
+		// // If the entire state is null, the resource is planned for creation.
+		return
+	}
+	var plan resourceData
+	if diags := req.Plan.Get(ctx, &plan); diags.HasError() {
+		resp.Diagnostics.Append(diags...)
+		return
+	}
+
+	if !plan.ForceNewAttrs.IsUnknown() && !plan.Body.IsUnknown() {
+		var forceNewAttrs []types.String
+		if diags := plan.ForceNewAttrs.ElementsAs(ctx, &forceNewAttrs, false); diags != nil {
+			resp.Diagnostics.Append(diags...)
+			return
+		}
+		var knownForceNewAttrs []string
+		for _, attr := range forceNewAttrs {
+			if attr.IsUnknown() {
+				continue
+			}
+			knownForceNewAttrs = append(knownForceNewAttrs, attr.ValueString())
+		}
+
+		if len(knownForceNewAttrs) != 0 {
+			var state resourceData
+			if diags := req.State.Get(ctx, &state); diags.HasError() {
+				resp.Diagnostics.Append(diags...)
+				return
+			}
+
+			originJson := state.Body.ValueString()
+			if originJson == "" {
+				originJson = "{}"
+			}
+
+			modifiedJson := plan.Body.ValueString()
+			if modifiedJson == "" {
+				modifiedJson = "{}"
+			}
+			patch, err := jsonpatch.CreateMergePatch([]byte(originJson), []byte(modifiedJson))
+			if err != nil {
+				resp.Diagnostics.AddError("failed to create merge patch", err.Error())
+				return
+			}
+
+			for _, attr := range knownForceNewAttrs {
+				result := gjson.Get(string(patch), attr)
+				if result.Exists() {
+					resp.RequiresReplace = []tfpath.Path{tfpath.Root("body")}
+					break
+				}
+			}
+		}
+	}
+}
+
 func (r *Resource) Configure(ctx context.Context, req resource.ConfigureRequest, resp *resource.ConfigureResponse) {
 	r.p = &Provider{}
 	if req.ProviderData != nil {