crud: support schema

Support `crud.schema` request [1] and response parsing.

1. tarantool/crud#380

CHANGELOG.md

@@ -19,6 +19,7 @@ Versioning](http://semver.org/spec/v2.0.0.html) except to the first release.
 - Support `operation_data` in `crud.Error` (#330) 
 - Support `fetch_latest_metadata` option for crud requests with metadata (#335)
 - Support `noreturn` option for data change crud requests (#335)
+- Support `crud.schema` request (#336)
 
 ### Changed
 

Makefile

@@ -27,7 +27,7 @@ clean:
 .PHONY: deps
 deps: clean
 	( cd ./queue/testdata; $(TTCTL) rocks install queue 1.3.0 )
-	( cd ./crud/testdata; $(TTCTL) rocks install crud 1.3.0 )
+	( cd ./crud/testdata; $(TTCTL) rocks install crud 1.4.0 )
 
 .PHONY: datetime-timezones
 datetime-timezones:

crud/example_test.go

@@ -299,3 +299,32 @@ func ExampleSelectRequest_pagination() {
 	// [{id unsigned false} {bucket_id unsigned true} {name string false}]
 	// [[3006 32 bla] [3007 33 bla]]
 }
+
+func ExampleSchema() {
+	conn := exampleConnect()
+
+	req := crud.MakeSchemaRequest()
+	var result crud.SchemaResult
+
+	if err := conn.Do(req).GetTyped(&result); err != nil {
+		fmt.Printf("Failed to execute request: %s", err)
+		return
+	}
+
+	// Schema may differ between different Tarantool versions.
+	// https://github.com/tarantool/tarantool/issues/4091
+	// https://github.com/tarantool/tarantool/commit/17c9c034933d726925910ce5bf8b20e8e388f6e3
+	for spaceName, spaceSchema := range result.Value {
+		fmt.Printf("Space format for '%s' is as follows:\n", spaceName)
+
+		for _, field := range spaceSchema.Format {
+			fmt.Printf("    - field '%s' with type '%s'\n", field.Name, field.Type)
+		}
+	}
+
+	// Output:
+	// Space format for 'test' is as follows:
+	//     - field 'id' with type 'unsigned'
+	//     - field 'bucket_id' with type 'unsigned'
+	//     - field 'name' with type 'string'
+}

crud/schema.go

@@ -0,0 +1,214 @@
+package crud
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/vmihailenco/msgpack/v5"
+	"github.com/vmihailenco/msgpack/v5/msgpcode"
+
+	"github.com/tarantool/go-tarantool/v2"
+)
+
+func msgpackIsMap(code byte) bool {
+	return code == msgpcode.Map16 || code == msgpcode.Map32 || msgpcode.IsFixedMap(code)
+}
+
+// SchemaRequest helps you to create request object to call `crud.schema`
+// for execution by a Connection.
+type SchemaRequest struct {
+	baseRequest
+	space OptString
+}
+
+// MakeSchemaRequest returns a new empty StatsRequest.
+func MakeSchemaRequest() SchemaRequest {
+	req := SchemaRequest{}
+	req.impl = newCall("crud.schema")
+	return req
+}
+
+// Space sets the space name for the StatsRequest request.
+// Note: default value is nil.
+func (req SchemaRequest) Space(space string) SchemaRequest {
+	req.space = MakeOptString(space)
+	return req
+}
+
+// Body fills an encoder with the call request body.
+func (req SchemaRequest) Body(res tarantool.SchemaResolver, enc *msgpack.Encoder) error {
+	if value, ok := req.space.Get(); ok {
+		req.impl = req.impl.Args([]interface{}{value})
+	} else {
+		req.impl = req.impl.Args([]interface{}{})
+	}
+
+	return req.impl.Body(res, enc)
+}
+
+// Context sets a passed context to CRUD request.
+func (req SchemaRequest) Context(ctx context.Context) SchemaRequest {
+	req.impl = req.impl.Context(ctx)
+
+	return req
+}
+
+// Schema contains CRUD cluster schema definition.
+type Schema map[string]SpaceSchema
+
+// DecodeMsgpack provides custom msgpack decoder.
+func (schema *Schema) DecodeMsgpack(d *msgpack.Decoder) error {
+	var l int
+
+	code, err := d.PeekCode()
+	if err != nil {
+		return err
+	}
+
+	if msgpackIsArray(code) {
+		// Process empty schema case.
+		l, err = d.DecodeArrayLen()
+		if err != nil {
+			return err
+		}
+		if l != 0 {
+			return fmt.Errorf("expected map or empty array, got non-empty array")
+		}
+		*schema = make(map[string]SpaceSchema, l)
+	} else if msgpackIsMap(code) {
+		l, err := d.DecodeMapLen()
+		if err != nil {
+			return err
+		}
+		*schema = make(map[string]SpaceSchema, l)
+
+		for i := 0; i < l; i++ {
+			key, err := d.DecodeString()
+			if err != nil {
+				return err
+			}
+
+			var spaceSchema SpaceSchema
+			if err := d.Decode(&spaceSchema); err != nil {
+				return err
+			}
+
+			(*schema)[key] = spaceSchema
+		}
+	} else {
+		return fmt.Errorf("unexpected code=%d decoding map or empty array", code)
+	}
+
+	return nil
+}
+
+// SpaceSchema contains a single CRUD space schema definition.
+type SpaceSchema struct {
+	Format  []FieldFormat    `msgpack:"format"`
+	Indexes map[uint32]Index `msgpack:"indexes"`
+}
+
+// Index contains a CRUD space index definition.
+type Index struct {
+	Id     uint32      `msgpack:"id"`
+	Name   string      `msgpack:"name"`
+	Type   string      `msgpack:"type"`
+	Unique bool        `msgpack:"unique"`
+	Parts  []IndexPart `msgpack:"parts"`
+}
+
+// IndexField contains a CRUD space index part definition.
+type IndexPart struct {
+	Fieldno     uint32 `msgpack:"fieldno"`
+	Type        string `msgpack:"type"`
+	ExcludeNull bool   `msgpack:"exclude_null"`
+	IsNullable  bool   `msgpack:"is_nullable"`
+}
+
+// SchemaResult contains a schema request result for all spaces.
+type SchemaResult struct {
+	Value Schema
+}
+
+// DecodeMsgpack provides custom msgpack decoder.
+func (result *SchemaResult) DecodeMsgpack(d *msgpack.Decoder) error {
+	arrLen, err := d.DecodeArrayLen()
+	if err != nil {
+		return err
+	}
+
+	if arrLen == 0 {
+		return fmt.Errorf("unexpected empty response array")
+	}
+
+	// DecodeMapLen inside Schema decode processes `nil` as zero length map,
+	// so in `return nil, err` case we don't miss error info.
+	// https://github.com/vmihailenco/msgpack/blob/3f7bd806fea698e7a9fe80979aa3512dea0a7368/decode_map.go#L79-L81
+	if err = d.Decode(&result.Value); err != nil {
+		return err
+	}
+
+	if arrLen > 1 {
+		var crudErr *Error = nil
+
+		if err := d.Decode(&crudErr); err != nil {
+			return err
+		}
+
+		if crudErr != nil {
+			return crudErr
+		}
+	}
+
+	for i := 2; i < arrLen; i++ {
+		if err := d.Skip(); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// SchemaResult contains a schema request result for a single space.
+type SpaceSchemaResult struct {
+	Value SpaceSchema
+}
+
+// DecodeMsgpack provides custom msgpack decoder.
+func (result *SpaceSchemaResult) DecodeMsgpack(d *msgpack.Decoder) error {
+	arrLen, err := d.DecodeArrayLen()
+	if err != nil {
+		return err
+	}
+
+	if arrLen == 0 {
+		return fmt.Errorf("unexpected empty response array")
+	}
+
+	// DecodeMapLen inside SpaceSchema decode processes `nil` as zero length map,
+	// so in `return nil, err` case we don't miss error info.
+	// https://github.com/vmihailenco/msgpack/blob/3f7bd806fea698e7a9fe80979aa3512dea0a7368/decode_map.go#L79-L81
+	if err = d.Decode(&result.Value); err != nil {
+		return err
+	}
+
+	if arrLen > 1 {
+		var crudErr *Error = nil
+
+		if err := d.Decode(&crudErr); err != nil {
+			return err
+		}
+
+		if crudErr != nil {
+			return crudErr
+		}
+	}
+
+	for i := 2; i < arrLen; i++ {
+		if err := d.Skip(); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}

crud/tarantool_test.go

@@ -1207,6 +1207,130 @@ func TestNoreturnOptionTyped(t *testing.T) {
 	}
 }
 
+func getTestSchema(t *testing.T) crud.Schema {
+	schema := crud.Schema{
+		"test": crud.SpaceSchema{
+			Format: []crud.FieldFormat{
+				crud.FieldFormat{
+					Name:       "id",
+					Type:       "unsigned",
+					IsNullable: false,
+				},
+				{
+					Name:       "bucket_id",
+					Type:       "unsigned",
+					IsNullable: true,
+				},
+				{
+					Name:       "name",
+					Type:       "string",
+					IsNullable: false,
+				},
+			},
+			Indexes: map[uint32]crud.Index{
+				0: {
+					Id:     0,
+					Name:   "primary_index",
+					Type:   "TREE",
+					Unique: true,
+					Parts: []crud.IndexPart{
+						{
+							Fieldno:     1,
+							Type:        "unsigned",
+							ExcludeNull: false,
+							IsNullable:  false,
+						},
+					},
+				},
+			},
+		},
+	}
+
+	// https://github.com/tarantool/tarantool/issues/4091
+	uniqueIssue, err := test_helpers.IsTarantoolVersionLess(2, 2, 1)
+	require.Equal(t, err, nil, "expected version check to succeed")
+
+	if uniqueIssue {
+		for sk, sv := range schema {
+			for ik, iv := range sv.Indexes {
+				iv.Unique = false
+				sv.Indexes[ik] = iv
+			}
+			schema[sk] = sv
+		}
+	}
+
+	// https://github.com/tarantool/tarantool/commit/17c9c034933d726925910ce5bf8b20e8e388f6e3
+	excludeNullUnsupported, err := test_helpers.IsTarantoolVersionLess(2, 8, 1)
+	require.Equal(t, err, nil, "expected version check to succeed")
+
+	if excludeNullUnsupported {
+		for sk, sv := range schema {
+			for ik, iv := range sv.Indexes {
+				for pk, pv := range iv.Parts {
+					// Struct default value.
+					pv.ExcludeNull = false
+					iv.Parts[pk] = pv
+				}
+				sv.Indexes[ik] = iv
+			}
+			schema[sk] = sv
+		}
+	}
+
+	return schema
+}
+
+func TestSchemaTyped(t *testing.T) {
+	conn := connect(t)
+	defer conn.Close()
+
+	req := crud.MakeSchemaRequest()
+	var result crud.SchemaResult
+
+	err := conn.Do(req).GetTyped(&result)
+	require.Equal(t, err, nil, "Expected CRUD request to succeed")
+	require.Equal(t, result.Value, getTestSchema(t), "map with \"test\" schema expected")
+}
+
+func TestSpaceSchemaTyped(t *testing.T) {
+	conn := connect(t)
+	defer conn.Close()
+
+	req := crud.MakeSchemaRequest().Space("test")
+	var result crud.SpaceSchemaResult
+
+	err := conn.Do(req).GetTyped(&result)
+	require.Equal(t, err, nil, "Expected CRUD request to succeed")
+	require.Equal(t, result.Value, getTestSchema(t)["test"], "map with \"test\" schema expected")
+}
+
+func TestSpaceSchemaTypedError(t *testing.T) {
+	conn := connect(t)
+	defer conn.Close()
+
+	req := crud.MakeSchemaRequest().Space("not_exist")
+	var result crud.SpaceSchemaResult
+
+	err := conn.Do(req).GetTyped(&result)
+	require.NotEqual(t, err, nil, "Expected CRUD request to fail")
+	require.Regexp(t, "Space \"not_exist\" doesn't exist", err.Error())
+}
+
+func TestUnitEmptySchema(t *testing.T) {
+	// We need to create another cluster with no spaces
+	// to test `{}` schema, so let's at least add a unit test.
+	conn := connect(t)
+	defer conn.Close()
+
+	req := tarantool.NewEvalRequest("return {}")
+	var result crud.SchemaResult
+
+	err := conn.Do(req).GetTyped(&result)
+	require.Equal(t, err, nil, "Expected CRUD request to succeed")
+	require.Equal(t, result.Value, crud.Schema{}, "empty schema expected")
+}
+
 // runTestMain is a body of TestMain function
 // (see https://pkg.go.dev/testing#hdr-Main).
 // Using defer + os.Exit is not works so TestMain body