feat(schema): add JSON marshaling for ModuleSchema (#21371)

schema/enum.go

@@ -12,16 +12,16 @@ type EnumType struct {
 	// Its name must be unique between all enum types and object types in the module.
 	// The same enum, however, can be used in multiple object types and fields as long as the
 	// definition is identical each time.
-	Name string
+	Name string `json:"name,omitempty"`
 
 	// Values is a list of distinct, non-empty values that are part of the enum type.
 	// Each value must conform to the NameFormat regular expression.
-	Values []EnumValueDefinition
+	Values []EnumValueDefinition `json:"values"`
 
 	// NumericKind is the numeric kind used to represent the enum values numerically.
 	// If it is left empty, Int32Kind is used by default.
 	// Valid values are Uint8Kind, Int8Kind, Uint16Kind, Int16Kind, and Int32Kind.
-	NumericKind Kind
+	NumericKind Kind `json:"numeric_kind,omitempty"`
 }
 
 // EnumValueDefinition represents a value in an enum type.
@@ -29,11 +29,11 @@ type EnumValueDefinition struct {
 	// Name is the name of the enum value.
 	// It must conform to the NameFormat regular expression.
 	// Its name must be unique between all values in the enum.
-	Name string
+	Name string `json:"name"`
 
 	// Value is the numeric value of the enum.
 	// It must be unique between all values in the enum.
-	Value int32
+	Value int32 `json:"value"`
 }
 
 // TypeName implements the Type interface.

schema/field.go

@@ -1,20 +1,22 @@
 package schema
 
-import "fmt"
+import (
+	"fmt"
+)
 
 // Field represents a field in an object type.
 type Field struct {
 	// Name is the name of the field. It must conform to the NameFormat regular expression.
-	Name string
+	Name string `json:"name"`
 
 	// Kind is the basic type of the field.
-	Kind Kind
+	Kind Kind `json:"kind"`
 
 	// Nullable indicates whether null values are accepted for the field. Key fields CANNOT be nullable.
-	Nullable bool
+	Nullable bool `json:"nullable,omitempty"`
 
 	// ReferencedType is the referenced type name when Kind is EnumKind.
-	ReferencedType string
+	ReferencedType string `json:"referenced_type,omitempty"`
 }
 
 // Validate validates the field.

schema/field_test.go

@@ -1,6 +1,8 @@
 package schema
 
 import (
+	"encoding/json"
+	"reflect"
 	"strings"
 	"testing"
 )
@@ -165,6 +167,64 @@ func TestField_ValidateValue(t *testing.T) {
 	}
 }
 
+func TestFieldJSON(t *testing.T) {
+	tt := []struct {
+		field     Field
+		json      string
+		expectErr bool
+	}{
+		{
+			field: Field{
+				Name: "field1",
+				Kind: StringKind,
+			},
+			json: `{"name":"field1","kind":"string"}`,
+		},
+		{
+			field: Field{
+				Name:     "field1",
+				Kind:     Int32Kind,
+				Nullable: true,
+			},
+			json: `{"name":"field1","kind":"int32","nullable":true}`,
+		},
+		{
+			field: Field{
+				Name:           "field1",
+				Kind:           EnumKind,
+				ReferencedType: "enum",
+			},
+			json: `{"name":"field1","kind":"enum","referenced_type":"enum"}`,
+		},
+	}
+
+	for _, tc := range tt {
+		t.Run(tc.json, func(t *testing.T) {
+			b, err := json.Marshal(tc.field)
+			if tc.expectErr {
+				if err == nil {
+					t.Fatalf("expected error, got nil")
+				}
+			} else {
+				if err != nil {
+					t.Fatalf("unexpected error: %v", err)
+				}
+				if string(b) != tc.json {
+					t.Fatalf("expected %s, got %s", tc.json, string(b))
+				}
+				var field Field
+				err = json.Unmarshal(b, &field)
+				if err != nil {
+					t.Fatalf("unexpected error: %v", err)
+				}
+				if !reflect.DeepEqual(field, tc.field) {
+					t.Fatalf("expected %v, got %v", tc.field, field)
+				}
+			}
+		})
+	}
+}
+
 var testEnumSchema = MustNewModuleSchema(EnumType{
 	Name:   "enum",
 	Values: []EnumValueDefinition{{Name: "a", Value: 1}, {Name: "b", Value: 2}},

schema/kind.go

@@ -431,3 +431,34 @@ func KindForGoValue(value interface{}) Kind {
 		return InvalidKind
 	}
 }
+
+// MarshalJSON marshals the kind to a JSON string and returns an error if the kind is invalid.
+func (t Kind) MarshalJSON() ([]byte, error) {
+	if err := t.Validate(); err != nil {
+		return nil, err
+	}
+	return json.Marshal(t.String())
+}
+
+// UnmarshalJSON unmarshals the kind from a JSON string and returns an error if the kind is invalid.
+func (t *Kind) UnmarshalJSON(data []byte) error {
+	var s string
+	err := json.Unmarshal(data, &s)
+	if err != nil {
+		return err
+	}
+	k, ok := kindStrings[s]
+	if !ok {
+		return fmt.Errorf("invalid kind: %s", s)
+	}
+	*t = k
+	return nil
+}
+
+var kindStrings = map[string]Kind{}
+
+func init() {
+	for i := InvalidKind + 1; i <= MAX_VALID_KIND; i++ {
+		kindStrings[i.String()] = i
+	}
+}

schema/kind_test.go

@@ -263,3 +263,58 @@ func TestKindForGoValue(t *testing.T) {
 		})
 	}
 }
+
+func TestKindJSON(t *testing.T) {
+	tt := []struct {
+		kind      Kind
+		want      string
+		expectErr bool
+	}{
+		{StringKind, `"string"`, false},
+		{BytesKind, `"bytes"`, false},
+		{Int8Kind, `"int8"`, false},
+		{Uint8Kind, `"uint8"`, false},
+		{Int16Kind, `"int16"`, false},
+		{Uint16Kind, `"uint16"`, false},
+		{Int32Kind, `"int32"`, false},
+		{Uint32Kind, `"uint32"`, false},
+		{Int64Kind, `"int64"`, false},
+		{Uint64Kind, `"uint64"`, false},
+		{IntegerStringKind, `"integer"`, false},
+		{DecimalStringKind, `"decimal"`, false},
+		{BoolKind, `"bool"`, false},
+		{TimeKind, `"time"`, false},
+		{DurationKind, `"duration"`, false},
+		{Float32Kind, `"float32"`, false},
+		{Float64Kind, `"float64"`, false},
+		{JSONKind, `"json"`, false},
+		{EnumKind, `"enum"`, false},
+		{AddressKind, `"address"`, false},
+		{InvalidKind, `""`, true},
+		{Kind(100), `""`, true},
+	}
+	for i, tc := range tt {
+		t.Run(fmt.Sprintf("test %d", i), func(t *testing.T) {
+			b, err := json.Marshal(tc.kind)
+			if tc.expectErr && err == nil {
+				t.Errorf("test %d: expected error, got nil", i)
+			}
+			if !tc.expectErr && err != nil {
+				t.Errorf("test %d: unexpected error: %v", i, err)
+			}
+			if !tc.expectErr {
+				if string(b) != tc.want {
+					t.Errorf("test %d: expected %s, got %s", i, tc.want, string(b))
+				}
+				var k Kind
+				err := json.Unmarshal(b, &k)
+				if err != nil {
+					t.Errorf("test %d: unexpected error: %v", i, err)
+				}
+				if k != tc.kind {
+					t.Errorf("test %d: expected %s, got %s", i, tc.kind, k)
+				}
+			}
+		})
+	}
+}

schema/module_schema.go

@@ -1,6 +1,7 @@
 package schema
 
 import (
+	"encoding/json"
 	"fmt"
 	"sort"
 )
@@ -113,4 +114,59 @@ func (s ModuleSchema) EnumTypes(f func(EnumType) bool) {
 	})
 }
 
+type moduleSchemaJson struct {
+	ObjectTypes []ObjectType `json:"object_types"`
+	EnumTypes   []EnumType   `json:"enum_types"`
+}
+
+// MarshalJSON implements the json.Marshaler interface for ModuleSchema.
+// It marshals the module schema into a JSON object with the object types and enum types
+// under the keys "object_types" and "enum_types" respectively.
+func (s ModuleSchema) MarshalJSON() ([]byte, error) {
+	asJson := moduleSchemaJson{}
+
+	s.ObjectTypes(func(objType ObjectType) bool {
+		asJson.ObjectTypes = append(asJson.ObjectTypes, objType)
+		return true
+	})
+
+	s.EnumTypes(func(enumType EnumType) bool {
+		asJson.EnumTypes = append(asJson.EnumTypes, enumType)
+		return true
+	})
+
+	return json.Marshal(asJson)
+}
+
+// UnmarshalJSON implements the json.Unmarshaler interface for ModuleSchema.
+// See MarshalJSON for the JSON format.
+func (s *ModuleSchema) UnmarshalJSON(data []byte) error {
+	asJson := moduleSchemaJson{}
+
+	err := json.Unmarshal(data, &asJson)
+	if err != nil {
+		return err
+	}
+
+	types := map[string]Type{}
+
+	for _, objType := range asJson.ObjectTypes {
+		types[objType.Name] = objType
+	}
+
+	for _, enumType := range asJson.EnumTypes {
+		types[enumType.Name] = enumType
+	}
+
+	s.types = types
+
+	// validate adds all enum types to the type map
+	err = s.Validate()
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
 var _ Schema = ModuleSchema{}

schema/module_schema_test.go

@@ -316,3 +316,27 @@ func TestModuleSchema_EnumTypes(t *testing.T) {
 		t.Fatalf("expected %v, got %v", expected, typeNames)
 	}
 }
+
+func TestModuleSchemaJSON(t *testing.T) {
+	moduleSchema := exampleSchema(t)
+
+	b, err := moduleSchema.MarshalJSON()
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	const expectedJson = `{"object_types":[{"name":"object1","key_fields":[{"name":"field1","kind":"enum","referenced_type":"enum2"}]},{"name":"object2","key_fields":[{"name":"field1","kind":"enum","referenced_type":"enum1"}]}],"enum_types":[{"name":"enum1","values":[{"name":"a","value":1},{"name":"b","value":2},{"name":"c","value":3}]},{"name":"enum2","values":[{"name":"d","value":4},{"name":"e","value":5},{"name":"f","value":6}]}]}`
+	if string(b) != expectedJson {
+		t.Fatalf("expected %s\n, got %s", expectedJson, string(b))
+	}
+
+	var moduleSchema2 ModuleSchema
+	err = moduleSchema2.UnmarshalJSON(b)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	if !reflect.DeepEqual(moduleSchema, moduleSchema2) {
+		t.Fatalf("expected %v, got %v", moduleSchema, moduleSchema2)
+	}
+}

schema/object_type.go

@@ -6,7 +6,7 @@ import "fmt"
 type ObjectType struct {
 	// Name is the name of the object type. It must be unique within the module schema amongst all object and enum
 	// types and conform to the NameFormat regular expression.
-	Name string
+	Name string `json:"name"`
 
 	// KeyFields is a list of fields that make up the primary key of the object.
 	// It can be empty in which case indexers should assume that this object is
@@ -14,19 +14,19 @@ type ObjectType struct {
 	// object between both key and value fields.
 	// Key fields CANNOT be nullable and Float32Kind, Float64Kind, and JSONKind types
 	// are not allowed.
-	KeyFields []Field
+	KeyFields []Field `json:"key_fields,omitempty"`
 
 	// ValueFields is a list of fields that are not part of the primary key of the object.
 	// It can be empty in the case where all fields are part of the primary key.
 	// Field names must be unique within the object between both key and value fields.
-	ValueFields []Field
+	ValueFields []Field `json:"value_fields,omitempty"`
 
 	// RetainDeletions is a flag that indicates whether the indexer should retain
 	// deleted rows in the database and flag them as deleted rather than actually
 	// deleting the row. For many types of data in state, the data is deleted even
 	// though it is still valid in order to save space. Indexers will want to have
 	// the option of retaining such data and distinguishing from other "true" deletions.
-	RetainDeletions bool
+	RetainDeletions bool `json:"retain_deletions,omitempty"`
 }
 
 // TypeName implements the Type interface.

schema/testing/appdatasim/testdata/app_sim_example_schema.txt

@@ -1,5 +1,5 @@
-InitializeModuleData: {"ModuleName":"all_kinds","Schema":{}}
-InitializeModuleData: {"ModuleName":"test_cases","Schema":{}}
+InitializeModuleData: {"ModuleName":"all_kinds","Schema":{"object_types":[{"name":"test_address","key_fields":[{"name":"key","kind":"address"}],"value_fields":[{"name":"valNotNull","kind":"address"},{"name":"valNullable","kind":"address","nullable":true}]},{"name":"test_bool","key_fields":[{"name":"key","kind":"bool"}],"value_fields":[{"name":"valNotNull","kind":"bool"},{"name":"valNullable","kind":"bool","nullable":true}]},{"name":"test_bytes","key_fields":[{"name":"key","kind":"bytes"}],"value_fields":[{"name":"valNotNull","kind":"bytes"},{"name":"valNullable","kind":"bytes","nullable":true}]},{"name":"test_decimal","key_fields":[{"name":"key","kind":"decimal"}],"value_fields":[{"name":"valNotNull","kind":"decimal"},{"name":"valNullable","kind":"decimal","nullable":true}]},{"name":"test_duration","key_fields":[{"name":"key","kind":"duration"}],"value_fields":[{"name":"valNotNull","kind":"duration"},{"name":"valNullable","kind":"duration","nullable":true}]},{"name":"test_enum","key_fields":[{"name":"key","kind":"enum","referenced_type":"test_enum_type"}],"value_fields":[{"name":"valNotNull","kind":"enum","referenced_type":"test_enum_type"},{"name":"valNullable","kind":"enum","nullable":true,"referenced_type":"test_enum_type"}]},{"name":"test_float32","key_fields":[{"name":"key","kind":"int32"}],"value_fields":[{"name":"valNotNull","kind":"float32"},{"name":"valNullable","kind":"float32","nullable":true}]},{"name":"test_float64","key_fields":[{"name":"key","kind":"int32"}],"value_fields":[{"name":"valNotNull","kind":"float64"},{"name":"valNullable","kind":"float64","nullable":true}]},{"name":"test_int16","key_fields":[{"name":"key","kind":"int16"}],"value_fields":[{"name":"valNotNull","kind":"int16"},{"name":"valNullable","kind":"int16","nullable":true}]},{"name":"test_int32","key_fields":[{"name":"key","kind":"int32"}],"value_fields":[{"name":"valNotNull","kind":"int32"},{"name":"valNullable","kind":"int32","nullable":true}]},{"name":"test_int64","key_fields":[{"name":"key","kind":"int64"}],"value_fields":[{"name":"valNotNull","kind":"int64"},{"name":"valNullable","kind":"int64","nullable":true}]},{"name":"test_int8","key_fields":[{"name":"key","kind":"int8"}],"value_fields":[{"name":"valNotNull","kind":"int8"},{"name":"valNullable","kind":"int8","nullable":true}]},{"name":"test_integer","key_fields":[{"name":"key","kind":"integer"}],"value_fields":[{"name":"valNotNull","kind":"integer"},{"name":"valNullable","kind":"integer","nullable":true}]},{"name":"test_string","key_fields":[{"name":"key","kind":"string"}],"value_fields":[{"name":"valNotNull","kind":"string"},{"name":"valNullable","kind":"string","nullable":true}]},{"name":"test_time","key_fields":[{"name":"key","kind":"time"}],"value_fields":[{"name":"valNotNull","kind":"time"},{"name":"valNullable","kind":"time","nullable":true}]},{"name":"test_uint16","key_fields":[{"name":"key","kind":"uint16"}],"value_fields":[{"name":"valNotNull","kind":"uint16"},{"name":"valNullable","kind":"uint16","nullable":true}]},{"name":"test_uint32","key_fields":[{"name":"key","kind":"uint32"}],"value_fields":[{"name":"valNotNull","kind":"uint32"},{"name":"valNullable","kind":"uint32","nullable":true}]},{"name":"test_uint64","key_fields":[{"name":"key","kind":"uint64"}],"value_fields":[{"name":"valNotNull","kind":"uint64"},{"name":"valNullable","kind":"uint64","nullable":true}]},{"name":"test_uint8","key_fields":[{"name":"key","kind":"uint8"}],"value_fields":[{"name":"valNotNull","kind":"uint8"},{"name":"valNullable","kind":"uint8","nullable":true}]}],"enum_types":[{"name":"test_enum_type","values":[{"name":"foo","value":1},{"name":"bar","value":2},{"name":"baz","value":3}]}]}}
+InitializeModuleData: {"ModuleName":"test_cases","Schema":{"object_types":[{"name":"ManyValues","key_fields":[{"name":"Key","kind":"string"}],"value_fields":[{"name":"Value1","kind":"int32"},{"name":"Value2","kind":"bytes"},{"name":"Value3","kind":"float64"},{"name":"Value4","kind":"uint64"}]},{"name":"RetainDeletions","key_fields":[{"name":"Key","kind":"string"}],"value_fields":[{"name":"Value1","kind":"int32"},{"name":"Value2","kind":"bytes"}],"retain_deletions":true},{"name":"Simple","key_fields":[{"name":"Key","kind":"string"}],"value_fields":[{"name":"Value1","kind":"int32"},{"name":"Value2","kind":"bytes"}]},{"name":"Singleton","value_fields":[{"name":"Value","kind":"string"},{"name":"Value2","kind":"bytes"}]},{"name":"ThreeKeys","key_fields":[{"name":"Key1","kind":"string"},{"name":"Key2","kind":"int32"},{"name":"Key3","kind":"uint64"}],"value_fields":[{"name":"Value1","kind":"int32"}]},{"name":"TwoKeys","key_fields":[{"name":"Key1","kind":"string"},{"name":"Key2","kind":"int32"}]}],"enum_types":null}}
 StartBlock: {1 <nil> <nil>}
 OnObjectUpdate: {"ModuleName":"test_cases","Updates":[{"TypeName":"RetainDeletions","Key":"","Value":[4602,"NwsAtcME5moByAKKwXU="],"Delete":false},{"TypeName":"Simple","Key":"","Value":[-89,"fgY="],"Delete":false}]}
 OnObjectUpdate: {"ModuleName":"test_cases","Updates":[{"TypeName":"Singleton","Key":null,"Value":["֑Ⱥ|@!`",""],"Delete":false}]}

schema/testing/json_test.go

@@ -0,0 +1,23 @@
+package schematesting
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"pgregory.net/rapid"
+
+	"cosmossdk.io/schema"
+)
+
+func TestModuleSchemaJSON(t *testing.T) {
+	rapid.Check(t, func(t *rapid.T) {
+		modSchema := ModuleSchemaGen().Draw(t, "moduleSchema")
+		bz, err := json.Marshal(modSchema)
+		require.NoError(t, err)
+		var modSchema2 schema.ModuleSchema
+		err = json.Unmarshal(bz, &modSchema2)
+		require.NoError(t, err)
+		require.Equal(t, modSchema, modSchema2)
+	})
+}