Your provider can modify the Terraform plan to match the expected end state. This can include replacing unknown values
with expected known values or marking a resource that must be replaced. Refer to
Plan Modification in the Framework documentation for details.
This page explains how to migrate resource CustomizeDiff functions in SDKv2 to PlanModifiers in the plugin
Framework.
In SDKv2, plan modification is implemented with the CustomizeDiff field on the schema.Resource struct. The following
code shows a basic implementation of plan modification with SDKv2.
In the Framework, you implement plan modification either by implementing the ResourceWithModifyPlan interface on your
resource type, or by implementing PlanModifiers on individual attributes. This page demonstrates how to implement the
plan modifiers on individual attributes. Refer to
Attributes - Default Values and
Attributes - Force New in this guide for further information on how
to implement a plan modifier on an attribute.
The ResourceWithModifyPlan interface requires a ModifyPlan function.
The following code shows how you can implement the ModifyPlan function on your resource.Resource type.
Remember the following differences between SDKv2 and the Framework when completing the migration.
In SDKv2, you implement plan modification with the CustomizeDiff field on the schema.Resource struct. In the
Framework, you can either implement plan modification for the entire resource by implementing the
ResourceWithModifyPlan interface, or on individual attributes by adding PlanModifiers to your resource attributes.
Many existing CustomizeDiff implementations may be better suited to implementation as attribute plan modifiers in the
Framework.
In SDKv2, the CustomizeDiff field on the schema.Resource struct refers to a function or set of functions that
implement plan modification.
The following example from the resource_password.go files shows the use of CustomizeDiff to keep two attributes
synchronized (i.e., ensure that they contain the same value) with SDKv2.
Many existing CustomizeDiff implementations would be better suited to migration to attribute plan modifiers in the
Framework. This code shows the implementation using attribute plan modifiers with the Framework.
The following shows an implementation of NumberNumericAttributePlanModifier in the Framework.
funcNumberNumericAttributePlanModifier() tfsdk.AttributePlanModifier {return&numberNumericAttributePlanModifier{}}type numberNumericAttributePlanModifier struct{}func(d *numberNumericAttributePlanModifier)Description(ctx context.Context)string{return"Ensures that number and numeric attributes are kept synchronised."}func(d *numberNumericAttributePlanModifier)MarkdownDescription(ctx context.Context)string{return d.Description(ctx)}func(d *numberNumericAttributePlanModifier)Modify(ctx context.Context, req tfsdk.ModifyAttributePlanRequest, resp *tfsdk.ModifyAttributePlanResponse){
numberConfig := types.Bool{}
diags := req.Config.GetAttribute(ctx, path.Root("number"),&numberConfig)
resp.Diagnostics.Append(diags...)if resp.Diagnostics.HasError(){return}
numericConfig := types.Bool{}
req.Config.GetAttribute(ctx, path.Root("numeric"),&numericConfig)
resp.Diagnostics.Append(diags...)if resp.Diagnostics.HasError(){return}if!numberConfig.Null &&!numericConfig.Null &&(numberConfig.Value != numericConfig.Value){
resp.Diagnostics.AddError("Number and numeric are both configured with different values","Number is deprecated, use numeric instead",)return}// Default to true for both number and numeric when both are null.if numberConfig.Null && numericConfig.Null {
resp.AttributePlan = types.Bool{Value:true}return}// Default to using value for numeric if number is nullif numberConfig.Null &&!numericConfig.Null {
resp.AttributePlan = numericConfig
return}// Default to using value for number if numeric is nullif!numberConfig.Null && numericConfig.Null {
resp.AttributePlan = numberConfig
return}}
funcNumberNumericAttributePlanModifier() tfsdk.AttributePlanModifier {return&numberNumericAttributePlanModifier{}}type numberNumericAttributePlanModifier struct{}func(d *numberNumericAttributePlanModifier)Description(ctx context.Context)string{return"Ensures that number and numeric attributes are kept synchronised."}func(d *numberNumericAttributePlanModifier)MarkdownDescription(ctx context.Context)string{return d.Description(ctx)}func(d *numberNumericAttributePlanModifier)Modify(ctx context.Context, req tfsdk.ModifyAttributePlanRequest, resp *tfsdk.ModifyAttributePlanResponse){ numberConfig := types.Bool{} diags := req.Config.GetAttribute(ctx, path.Root("number"),&numberConfig) resp.Diagnostics.Append(diags...)if resp.Diagnostics.HasError(){return} numericConfig := types.Bool{} req.Config.GetAttribute(ctx, path.Root("numeric"),&numericConfig) resp.Diagnostics.Append(diags...)if resp.Diagnostics.HasError(){return}if!numberConfig.Null &&!numericConfig.Null &&(numberConfig.Value != numericConfig.Value){ resp.Diagnostics.AddError("Number and numeric are both configured with different values","Number is deprecated, use numeric instead",)return}// Default to true for both number and numeric when both are null.if numberConfig.Null && numericConfig.Null { resp.AttributePlan = types.Bool{Value:true}return}// Default to using value for numeric if number is nullif numberConfig.Null &&!numericConfig.Null { resp.AttributePlan = numericConfig
return}// Default to using value for number if numeric is nullif!numberConfig.Null && numericConfig.Null { resp.AttributePlan = numberConfig
return}}