command/jsonprovider: export providers schemas to json (#20446)

* command/jsonprovider: a new package for exporting providers schemas as JSON

command/jsonprovider/attribute.go

@@ -0,0 +1,31 @@
+package jsonprovider
+
+import (
+	"encoding/json"
+
+	"github.com/hashicorp/terraform/configs/configschema"
+)
+
+type attribute struct {
+	AttributeType json.RawMessage `json:"type,omitempty"`
+	Description   string          `json:"description,omitempty"`
+	Required      bool            `json:"required,omitempty"`
+	Optional      bool            `json:"optional,omitempty"`
+	Computed      bool            `json:"computed,omitempty"`
+	Sensitive     bool            `json:"sensitive,omitempty"`
+}
+
+func marshalAttribute(attr *configschema.Attribute) *attribute {
+	// we're not concerned about errors because at this point the schema has
+	// already been checked and re-checked.
+	attrTy, _ := attr.Type.MarshalJSON()
+
+	return &attribute{
+		AttributeType: attrTy,
+		Description:   attr.Description,
+		Required:      attr.Required,
+		Optional:      attr.Optional,
+		Computed:      attr.Computed,
+		Sensitive:     attr.Sensitive,
+	}
+}

command/jsonprovider/attribute_test.go

@@ -0,0 +1,42 @@
+package jsonprovider
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+	"github.com/zclconf/go-cty/cty"
+
+	"github.com/hashicorp/terraform/configs/configschema"
+)
+
+func TestMarshalAttribute(t *testing.T) {
+	tests := []struct {
+		Input *configschema.Attribute
+		Want  *attribute
+	}{
+		{
+			&configschema.Attribute{Type: cty.String, Optional: true, Computed: true},
+			&attribute{
+				AttributeType: json.RawMessage(`"string"`),
+				Optional:      true,
+				Computed:      true,
+			},
+		},
+		{ // collection types look a little odd.
+			&configschema.Attribute{Type: cty.Map(cty.String), Optional: true, Computed: true},
+			&attribute{
+				AttributeType: json.RawMessage(`["map","string"]`),
+				Optional:      true,
+				Computed:      true,
+			},
+		},
+	}
+
+	for _, test := range tests {
+		got := marshalAttribute(test.Input)
+		if !cmp.Equal(got, test.Want) {
+			t.Fatalf("wrong result:\n %v\n", cmp.Diff(got, test.Want))
+		}
+	}
+}

command/jsonprovider/block.go

@@ -0,0 +1,67 @@
+package jsonprovider
+
+import (
+	"github.com/hashicorp/terraform/configs/configschema"
+)
+
+type block struct {
+	Attributes map[string]*attribute `json:"attributes,omitempty"`
+	BlockTypes map[string]*blockType `json:"block_types,omitempty"`
+}
+
+type blockType struct {
+	NestingMode string `json:"nesting_mode,omitempty"`
+	Block       *block `json:"block,omitempty"`
+	MinItems    uint64 `json:"min_items,omitempty"`
+	MaxItems    uint64 `json:"max_items,omitempty"`
+}
+
+func marshalBlockTypes(nestedBlock *configschema.NestedBlock) *blockType {
+	if nestedBlock == nil {
+		return &blockType{}
+	}
+	ret := &blockType{
+		Block:    marshalBlock(&nestedBlock.Block),
+		MinItems: uint64(nestedBlock.MinItems),
+		MaxItems: uint64(nestedBlock.MaxItems),
+	}
+
+	switch nestedBlock.Nesting {
+	case configschema.NestingSingle:
+		ret.NestingMode = "single"
+	case configschema.NestingList:
+		ret.NestingMode = "list"
+	case configschema.NestingSet:
+		ret.NestingMode = "set"
+	case configschema.NestingMap:
+		ret.NestingMode = "map"
+	default:
+		ret.NestingMode = "invalid"
+	}
+	return ret
+}
+
+func marshalBlock(configBlock *configschema.Block) *block {
+	if configBlock == nil {
+		return &block{}
+	}
+
+	var ret block
+	if len(configBlock.Attributes) > 0 {
+		attrs := make(map[string]*attribute, len(configBlock.Attributes))
+		for k, attr := range configBlock.Attributes {
+			attrs[k] = marshalAttribute(attr)
+		}
+		ret.Attributes = attrs
+	}
+
+	if len(configBlock.BlockTypes) > 0 {
+		blockTypes := make(map[string]*blockType, len(configBlock.BlockTypes))
+		for k, bt := range configBlock.BlockTypes {
+			blockTypes[k] = marshalBlockTypes(bt)
+		}
+		ret.BlockTypes = blockTypes
+	}
+
+	return &ret
+}

command/jsonprovider/block_test.go

@@ -0,0 +1,66 @@
+package jsonprovider
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+	"github.com/zclconf/go-cty/cty"
+
+	"github.com/hashicorp/terraform/configs/configschema"
+)
+
+func TestMarshalBlock(t *testing.T) {
+	tests := []struct {
+		Input *configschema.Block
+		Want  *block
+	}{
+		{
+			nil,
+			&block{},
+		},
+		{
+			Input: &configschema.Block{
+				Attributes: map[string]*configschema.Attribute{
+					"id":  {Type: cty.String, Optional: true, Computed: true},
+					"ami": {Type: cty.String, Optional: true},
+				},
+				BlockTypes: map[string]*configschema.NestedBlock{
+					"network_interface": {
+						Nesting: configschema.NestingList,
+						Block: configschema.Block{
+							Attributes: map[string]*configschema.Attribute{
+								"device_index": {Type: cty.String, Optional: true},
+								"description":  {Type: cty.String, Optional: true},
+							},
+						},
+					},
+				},
+			},
+			Want: &block{
+				Attributes: map[string]*attribute{
+					"ami": {AttributeType: json.RawMessage(`"string"`), Optional: true},
+					"id":  {AttributeType: json.RawMessage(`"string"`), Optional: true, Computed: true},
+				},
+				BlockTypes: map[string]*blockType{
+					"network_interface": {
+						NestingMode: "list",
+						Block: &block{
+							Attributes: map[string]*attribute{
+								"description":  {AttributeType: json.RawMessage(`"string"`), Optional: true},
+								"device_index": {AttributeType: json.RawMessage(`"string"`), Optional: true},
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	for _, test := range tests {
+		got := marshalBlock(test.Input)
+		if !cmp.Equal(got, test.Want) {
+			t.Fatalf("wrong result:\n %v\n", cmp.Diff(got, test.Want))
+		}
+	}
+}

command/jsonprovider/doc.go

@@ -0,0 +1,3 @@
+// Package jsonprovider contains types and functions to marshal terraform
+// provider schemas into a json formatted output.
+package jsonprovider

command/jsonprovider/provider.go

@@ -0,0 +1,75 @@
+package jsonprovider
+
+import (
+	"encoding/json"
+
+	"github.com/hashicorp/terraform/terraform"
+)
+
+// FormatVersion represents the version of the json format and will be
+// incremented for any change to this format that requires changes to a
+// consuming parser.
+const FormatVersion = "0.1"
+
+// providers is the top-level object returned when exporting provider schemas
+type providers struct {
+	FormatVersion string              `json:"format_version"`
+	Schemas       map[string]Provider `json:"provider_schemas"`
+}
+
+type Provider struct {
+	Provider          *schema            `json:"provider,omitempty"`
+	ResourceSchemas   map[string]*schema `json:"resource_schemas,omitempty"`
+	DataSourceSchemas map[string]*schema `json:"data_source_schemas,omitempty"`
+}
+
+func newProviders() *providers {
+	schemas := make(map[string]Provider)
+	return &providers{
+		FormatVersion: FormatVersion,
+		Schemas:       schemas,
+	}
+}
+
+func Marshal(s *terraform.Schemas) ([]byte, error) {
+	if len(s.Providers) == 0 {
+		return nil, nil
+	}
+
+	providers := newProviders()
+
+	for k, v := range s.Providers {
+		providers.Schemas[k] = marshalProvider(v)
+	}
+
+	// add some polish for the human consumers
+	ret, err := json.MarshalIndent(providers, "", "  ")
+	return ret, err
+}
+
+func marshalProvider(tps *terraform.ProviderSchema) Provider {
+	if tps == nil {
+		return Provider{}
+	}
+
+	var ps *schema
+	var rs, ds map[string]*schema
+
+	if tps.Provider != nil {
+		ps = marshalSchema(tps.Provider)
+	}
+
+	if tps.ResourceTypes != nil {
+		rs = marshalSchemas(tps.ResourceTypes, tps.ResourceTypeSchemaVersions)
+	}
+
+	if tps.DataSources != nil {
+		ds = marshalSchemas(tps.DataSources, tps.ResourceTypeSchemaVersions)
+	}
+
+	return Provider{
+		Provider:          ps,
+		ResourceSchemas:   rs,
+		DataSourceSchemas: ds,
+	}
+}