Generate custom type and value types and to/from methods for primitives

[bendbennett]

Closes: #70

This PR extends the generation of custom type and value types for primitives that have an associated external type, and generates the methods for converting to/from the associated external type.

At this point, the implementation only covers BoolAttribute for data sources, but will be extended to encompass all primitive attributes (Bool, Float64, Int64, Number & String), if we're agreed on the approach.

For example, given the following spec:

{
  "version": "0.1",
  "datasources": [
    {
      "name": "datasource",
      "schema": {
        "attributes": [
          {
            "name": "bool_attribute",
            "bool": {
              "associated_external_type": {
                "import": {
                  "path": "github.com/api"
                },
                "type": "*api.BoolAttribute"
              },
              "computed_optional_required": "required"
            }
          }
        ]
      }
    }
  ],
  "provider": {
    "name": "provider"
  }
}

The generated code is as follows:

var _ basetypes.BoolTypable = BoolAttributeType{}

type BoolAttributeType struct {
	basetypes.BoolType
}

func (t BoolAttributeType) Equal(o attr.Type) bool {
	other, ok := o.(BoolAttributeType)

	if !ok {
		return false
	}

	return t.BoolType.Equal(other.BoolType)
}

func (t BoolAttributeType) String() string {
	return "BoolAttributeType"
}

func (t BoolAttributeType) ValueFromBool(ctx context.Context, in basetypes.BoolValue) (basetypes.BoolValuable, diag.Diagnostics) {
	return BoolAttributeValue{
		BoolValue: in,
	}, nil
}

func (t BoolAttributeType) ValueFromTerraform(ctx context.Context, in tftypes.Value) (attr.Value, error) {
	attrValue, err := t.BoolType.ValueFromTerraform(ctx, in)

	if err != nil {
		return nil, err
	}

	boolValue, ok := attrValue.(basetypes.BoolValue)

	if !ok {
		return nil, fmt.Errorf("unexpected value type of %T", attrValue)
	}

	boolValuable, diags := t.ValueFromBool(ctx, boolValue)

	if diags.HasError() {
		return nil, fmt.Errorf("unexpected error converting BoolValue to BoolValuable: %v", diags)
	}

	return boolValuable, nil
}

func (t BoolAttributeType) ValueType(ctx context.Context) attr.Value {
	return BoolAttributeValue{}
}

var _ basetypes.BoolValuable = BoolAttributeValue{}

type BoolAttributeValue struct {
	basetypes.BoolValue
}

func (v BoolAttributeValue) Equal(o attr.Value) bool {
	other, ok := o.(BoolAttributeValue)

	if !ok {
		return false
	}

	return v.BoolValue.Equal(other.BoolValue)
}

func (v BoolAttributeValue) Type(ctx context.Context) attr.Type {
	return BoolAttributeType{}
}

func (v BoolAttributeValue) ToApiBoolAttribute(ctx context.Context) (*api.BoolAttribute, diag.Diagnostics) {
	var diags diag.Diagnostics

	if v.IsNull() {
		return nil, diags
	}

	if v.IsUnknown() {
		diags.Append(diag.NewErrorDiagnostic(
			"BoolAttributeValue Value Is Unknown",
			`"BoolAttributeValue" is unknown.`,
		))

		return nil, diags
	}

	a := api.BoolAttribute(v.ValueBoolPointer())

	return &a, diags
}

func (v BoolAttributeValue) FromApiBoolAttribute(ctx context.Context, apiObject *api.BoolAttribute) (BoolAttributeValue, diag.Diagnostics) {
	var diags diag.Diagnostics

	if apiObject == nil {
		return BoolAttributeValue{
			types.BoolNull(),
		}, diags
	}

	return BoolAttributeValue{
		types.BoolPointerValue(*apiObject),
	}, diags
}

func DatasourceDataSourceSchema(ctx context.Context) schema.Schema {
	return schema.Schema{
		Attributes: map[string]schema.Attribute{
			"bool_attribute": schema.BoolAttribute{
				CustomType: BoolAttributeType{},
				Required: true,
			},
		},
	}
}

type DatasourceModel struct {
	BoolAttribute BoolAttributeValue `tfsdk:"bool_attribute"`
}

Outstanding Tasks

• The generation of the schema needs to be modified to use the generated custom type.
• The generation of the data model needs to be modified to use the generated custom value.
• Primitive attributes, with associated external types, that are nested within list, map, set, single nested attributes, or list, set single nested blocks need to be handled so that the generated custom type or value are used appropriately in this context. This can be managed by replacing the placeholder methods that are currently on GeneratorAttributes and GeneratorBlocks (i.e., AttributeTypes() / BlockTypes(), AttrTypes(), AttrValues(), FromFuncs(), and ToFuncs()), with calls that delegate to the individual attribute or block.
  • This will be deferred to the next PR.

Dependency

• Reinstating associate external type for primitives

[bendbennett]

This will be updated to v0.2.0 once hashicorp/terraform-plugin-codegen-spec#55 is merged and the v0.2.0 release is cut.

[austinvalle]

We chatted about this earlier, but maybe we can wait until codegen-framework needs a v0.2.0 release and then re-assess how we want to bump codegen-spec. SHAs are fine I'm sure 🧨

[bendbennett]

Ok, we'll stick with using SHAs until we want to release 👍

[austinvalle]

LGTM, would love to start looking at getting a more comprehensive e2e test once we get the rest of external types implemented 🚀 🚀

[austinvalle]

template.New("")

curious q: is there a reason to keep the template name empty? I don't fully grasp what it does, but never kept it empty lol

[bendbennett]

There is a detailed explanation of template naming on an SO post. TLDR: If you don't want/need to refer to the template, the name doesn't really matter.

[austinvalle]

awesome! thanks for sharing 👍🏻

[austinvalle]

Should the custom strings have tests as well?

[bendbennett]

Well spotted. Added

[austinvalle]

Same as above, does string get tests for this too? 🙂

[bendbennett]

Well spotted. Added

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