Improve error handling using pkg/errors

In the case of zap currently in use, the place where the log is
output is shown as the error occurrence point in the stack
trace. Introduced pkg/errors to allow log output to be processed
at the end of the logic.

api/converter/from_bytes.go

@@ -17,9 +17,8 @@
 package converter
 
 import (
-	"fmt"
-
 	"github.com/gogo/protobuf/proto"
+	"github.com/pkg/errors"
 
 	"github.com/yorkie-team/yorkie/api"
 	"github.com/yorkie-team/yorkie/internal/log"
@@ -35,7 +34,7 @@ func BytesToObject(snapshot []byte) (*json.Object, error) {
 
 	pbElem := &api.JSONElement{}
 	if err := proto.Unmarshal(snapshot, pbElem); err != nil {
-		return nil, err
+		return nil, errors.WithStack(err)
 	}
 
 	obj, err := fromJSONObject(pbElem.GetJsonObject())
@@ -61,7 +60,7 @@ func fromJSONElement(pbElem *api.JSONElement) (json.Element, error) {
 	case *api.JSONElement_Counter_:
 		return fromJSONCounter(decoded.Counter)
 	default:
-		return nil, fmt.Errorf("%s: %w", decoded, ErrUnsupportedElement)
+		return nil, errors.Wrapf(ErrUnsupportedElement, "decoded: %s", decoded)
 	}
 }
 

api/converter/from_pb.go

@@ -17,7 +17,7 @@
 package converter
 
 import (
-	"fmt"
+	"github.com/pkg/errors"
 
 	"github.com/yorkie-team/yorkie/api"
 	"github.com/yorkie-team/yorkie/pkg/document/change"
@@ -46,10 +46,10 @@ func FromClient(pbClient *api.Client) (*types.Client, error) {
 // FromChangePack converts the given Protobuf format to model format.
 func FromChangePack(pbPack *api.ChangePack) (*change.Pack, error) {
 	if pbPack == nil {
-		return nil, ErrPackRequired
+		return nil, errors.WithStack(ErrPackRequired)
 	}
 	if pbPack.Checkpoint == nil {
-		return nil, ErrCheckpointRequired
+		return nil, errors.WithStack(ErrCheckpointRequired)
 	}
 
 	changes, err := fromChanges(pbPack.Changes)
@@ -137,7 +137,7 @@ func FromEventType(pbDocEventType api.DocEventType) (types.DocEventType, error)
 	case api.DocEventType_DOCUMENTS_UNWATCHED:
 		return types.DocumentsUnwatchedEvent, nil
 	}
-	return "", fmt.Errorf("%v: %w", pbDocEventType, ErrUnsupportedEventType)
+	return "", errors.Wrapf(ErrUnsupportedEventType, "document event type: %v", pbDocEventType)
 }
 
 // FromDocEvent converts the given Protobuf format to model format.
@@ -185,7 +185,7 @@ func FromOperations(pbOps []*api.Operation) ([]operation.Operation, error) {
 		case *api.Operation_Increase_:
 			op, err = fromIncrease(decoded.Increase)
 		default:
-			return nil, ErrUnsupportedOperation
+			return nil, errors.WithStack(ErrUnsupportedOperation)
 		}
 		if err != nil {
 			return nil, err
@@ -553,7 +553,7 @@ func fromElement(pbElement *api.JSONElementSimple) (json.Element, error) {
 		), nil
 	}
 
-	return nil, fmt.Errorf("%d, %w", pbElement.Type, ErrUnsupportedElement)
+	return nil, errors.Wrapf(ErrUnsupportedElement, "element type: %d", pbElement.Type)
 }
 
 func fromPrimitiveValueType(valueType api.ValueType) (json.ValueType, error) {
@@ -576,7 +576,7 @@ func fromPrimitiveValueType(valueType api.ValueType) (json.ValueType, error) {
 		return json.Date, nil
 	}
 
-	return 0, fmt.Errorf("%d, %w", valueType, ErrUnsupportedValueType)
+	return 0, errors.Wrapf(ErrUnsupportedValueType, "value type: %d", valueType)
 }
 
 func fromCounterType(valueType api.ValueType) (json.CounterType, error) {
@@ -589,5 +589,5 @@ func fromCounterType(valueType api.ValueType) (json.CounterType, error) {
 		return json.DoubleCnt, nil
 	}
 
-	return 0, fmt.Errorf("%d, %w", valueType, ErrUnsupportedCounterType)
+	return 0, errors.Wrapf(ErrUnsupportedCounterType, "value type: %d", valueType)
 }

api/converter/to_bytes.go

@@ -17,13 +17,12 @@
 package converter
 
 import (
-	"fmt"
 	"reflect"
 
 	"github.com/gogo/protobuf/proto"
+	"github.com/pkg/errors"
 
 	"github.com/yorkie-team/yorkie/api"
-	"github.com/yorkie-team/yorkie/internal/log"
 	"github.com/yorkie-team/yorkie/pkg/document/json"
 )
 
@@ -36,8 +35,7 @@ func ObjectToBytes(obj *json.Object) ([]byte, error) {
 
 	bytes, err := proto.Marshal(pbElem)
 	if err != nil {
-		log.Logger.Error(err)
-		return nil, err
+		return nil, errors.WithStack(err)
 	}
 	return bytes, nil
 }
@@ -57,7 +55,7 @@ func toJSONElement(elem json.Element) (*api.JSONElement, error) {
 	case *json.Counter:
 		return toCounter(elem)
 	default:
-		return nil, fmt.Errorf("%v: %w", reflect.TypeOf(elem), ErrUnsupportedElement)
+		return nil, errors.Wrapf(ErrUnsupportedElement, "element type: %v", reflect.TypeOf(elem))
 	}
 }
 

api/converter/to_pb.go

@@ -17,9 +17,10 @@
 package converter
 
 import (
-	"fmt"
 	"reflect"
 
+	"github.com/pkg/errors"
+
 	"github.com/yorkie-team/yorkie/api"
 	"github.com/yorkie-team/yorkie/pkg/document/change"
 	"github.com/yorkie-team/yorkie/pkg/document/checkpoint"
@@ -133,7 +134,7 @@ func ToDocEventType(eventType types.DocEventType) (api.DocEventType, error) {
 	case types.DocumentsUnwatchedEvent:
 		return api.DocEventType_DOCUMENTS_UNWATCHED, nil
 	default:
-		return 0, fmt.Errorf("%s: %w", eventType, ErrUnsupportedEventType)
+		return 0, errors.Wrapf(ErrUnsupportedEventType, "document event type: %s", eventType)
 	}
 }
 
@@ -178,7 +179,7 @@ func ToOperations(operations []operation.Operation) ([]*api.Operation, error) {
 		case *operation.Increase:
 			pbOperation.Body, err = toIncrease(op)
 		default:
-			return nil, ErrUnsupportedOperation
+			return nil, errors.WithStack(ErrUnsupportedOperation)
 		}
 		if err != nil {
 			return nil, err
@@ -353,7 +354,7 @@ func toJSONElementSimple(elem json.Element) (*api.JSONElementSimple, error) {
 		}, nil
 	}
 
-	return nil, fmt.Errorf("%v, %w", reflect.TypeOf(elem), ErrUnsupportedElement)
+	return nil, errors.Wrapf(ErrUnsupportedElement, "element type: %v", reflect.TypeOf(elem))
 }
 
 func toTextNodePos(pos *json.RGATreeSplitNodePos) *api.TextNodePos {
@@ -406,7 +407,7 @@ func toValueType(valueType json.ValueType) (api.ValueType, error) {
 		return api.ValueType_DATE, nil
 	}
 
-	return 0, fmt.Errorf("%d, %w", valueType, ErrUnsupportedValueType)
+	return 0, errors.Wrapf(ErrUnsupportedValueType, "value type: %d", valueType)
 }
 
 func toCounterType(valueType json.CounterType) (api.ValueType, error) {
@@ -419,5 +420,5 @@ func toCounterType(valueType json.CounterType) (api.ValueType, error) {
 		return api.ValueType_DOUBLE_CNT, nil
 	}
 
-	return 0, fmt.Errorf("%d, %w", valueType, ErrUnsupportedCounterType)
+	return 0, errors.Wrapf(ErrUnsupportedCounterType, "value type: %d", valueType)
 }

client/client.go

@@ -18,9 +18,10 @@ package client
 
 import (
 	"context"
-	"errors"
+	goerrors "errors"
 
 	"github.com/google/uuid"
+	"github.com/pkg/errors"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/credentials"
 
@@ -43,11 +44,11 @@ const (
 var (
 	// ErrClientNotActivated occurs when an inactive client executes a function
 	// that can only be executed when activated.
-	ErrClientNotActivated = errors.New("client is not activated")
+	ErrClientNotActivated = goerrors.New("client is not activated")
 
 	// ErrDocumentNotAttached occurs when the given document is not attached to
 	// this client.
-	ErrDocumentNotAttached = errors.New("document is not attached")
+	ErrDocumentNotAttached = goerrors.New("document is not attached")
 )
 
 // Client is a normal client that can communicate with the agent.
@@ -105,8 +106,7 @@ func NewClient(opts ...Option) (*Client, error) {
 			serverNameOverride,
 		)
 		if err != nil {
-			log.Logger.Error(err)
-			return nil, err
+			return nil, errors.WithStack(err)
 		}
 		dialOptions = append(dialOptions, grpc.WithTransportCredentials(creds))
 	} else {
@@ -150,8 +150,7 @@ func Dial(rpcAddr string, opts ...Option) (*Client, error) {
 func (c *Client) Dial(rpcAddr string) error {
 	conn, err := grpc.Dial(rpcAddr, c.dialOptions...)
 	if err != nil {
-		log.Logger.Error(err)
-		return err
+		return errors.WithStack(err)
 	}
 
 	c.conn = conn
@@ -163,6 +162,7 @@ func (c *Client) Dial(rpcAddr string) error {
 // Close closes all resources of this client.
 func (c *Client) Close() error {
 	if err := c.Deactivate(context.Background()); err != nil {
+		log.Logger.Errorf("%+v", err)
 		return err
 	}
 
@@ -185,14 +185,14 @@ func (c *Client) Activate(ctx context.Context) error {
 	response, err := c.client.ActivateClient(ctx, &api.ActivateClientRequest{
 		ClientKey: c.key,
 	})
-
 	if err != nil {
 		log.Logger.Error(err)
 		return err
 	}
 
 	clientID, err := time.ActorIDFromBytes(response.ClientId)
 	if err != nil {
+		log.Logger.Errorf("%+v", err)
 		return err
 	}
 
@@ -212,8 +212,7 @@ func (c *Client) Deactivate(ctx context.Context) error {
 		ClientId: c.id.Bytes(),
 	})
 	if err != nil {
-		log.Logger.Error(err)
-		return err
+		return errors.WithStack(err)
 	}
 
 	c.status = deactivated
@@ -232,6 +231,7 @@ func (c *Client) Attach(ctx context.Context, doc *document.Document) error {
 
 	pbChangePack, err := converter.ToChangePack(doc.CreateChangePack())
 	if err != nil {
+		log.Logger.Errorf("%+v", err)
 		return err
 	}
 
@@ -246,11 +246,12 @@ func (c *Client) Attach(ctx context.Context, doc *document.Document) error {
 
 	pack, err := converter.FromChangePack(res.ChangePack)
 	if err != nil {
+		log.Logger.Errorf("%+v", err)
 		return err
 	}
 
 	if err := doc.ApplyChangePack(pack); err != nil {
-		log.Logger.Error(err)
+		log.Logger.Errorf("%+v", err)
 		return err
 	}
 
@@ -268,15 +269,18 @@ func (c *Client) Attach(ctx context.Context, doc *document.Document) error {
 // document is no longer used by this client, it should be detached.
 func (c *Client) Detach(ctx context.Context, doc *document.Document) error {
 	if c.status != activated {
+		log.Logger.Error(ErrClientNotActivated)
 		return ErrClientNotActivated
 	}
 
 	if _, ok := c.attachedDocs[doc.Key().BSONKey()]; !ok {
+		log.Logger.Error(ErrClientNotActivated)
 		return ErrDocumentNotAttached
 	}
 
 	pbChangePack, err := converter.ToChangePack(doc.CreateChangePack())
 	if err != nil {
+		log.Logger.Errorf("%+v", err)
 		return err
 	}
 
@@ -291,11 +295,12 @@ func (c *Client) Detach(ctx context.Context, doc *document.Document) error {
 
 	pack, err := converter.FromChangePack(res.ChangePack)
 	if err != nil {
+		log.Logger.Errorf("%+v", err)
 		return err
 	}
 
 	if err := doc.ApplyChangePack(pack); err != nil {
-		log.Logger.Error(err)
+		log.Logger.Errorf("%+v", err)
 		return err
 	}
 
@@ -317,6 +322,7 @@ func (c *Client) Sync(ctx context.Context, keys ...*key.Key) error {
 
 	for _, k := range keys {
 		if err := c.sync(ctx, k); err != nil {
+			log.Logger.Errorf("%+v", err)
 			return err
 		}
 	}
@@ -423,12 +429,12 @@ func (c *Client) IsActive() bool {
 
 func (c *Client) sync(ctx context.Context, key *key.Key) error {
 	if c.status != activated {
-		return ErrClientNotActivated
+		return errors.WithStack(ErrClientNotActivated)
 	}
 
 	doc, ok := c.attachedDocs[key.BSONKey()]
 	if !ok {
-		return ErrDocumentNotAttached
+		return errors.WithStack(ErrDocumentNotAttached)
 	}
 
 	pbChangePack, err := converter.ToChangePack(doc.CreateChangePack())
@@ -441,8 +447,7 @@ func (c *Client) sync(ctx context.Context, key *key.Key) error {
 		ChangePack: pbChangePack,
 	})
 	if err != nil {
-		log.Logger.Error(err)
-		return err
+		return errors.WithStack(err)
 	}
 
 	pack, err := converter.FromChangePack(res.ChangePack)
@@ -451,7 +456,6 @@ func (c *Client) sync(ctx context.Context, key *key.Key) error {
 	}
 
 	if err := doc.ApplyChangePack(pack); err != nil {
-		log.Logger.Error(err)
 		return err
 	}
 

go.mod

@@ -11,6 +11,7 @@ require (
 	github.com/grpc-ecosystem/go-grpc-middleware v1.0.1-0.20190118093823-f849b5445de4
 	github.com/grpc-ecosystem/go-grpc-prometheus v1.2.0
 	github.com/moby/locker v1.0.1
+	github.com/pkg/errors v0.9.1 // indirect
 	github.com/prometheus/client_golang v1.10.0
 	github.com/rs/xid v1.2.1
 	github.com/spf13/cobra v1.1.1

internal/cli/agent.go

@@ -68,10 +68,12 @@ func newAgentCmd() *cobra.Command {
 
 			r, err := yorkie.New(conf)
 			if err != nil {
+				log.Logger.Errorf("%+v", err)
 				return err
 			}
 
 			if err := r.Start(); err != nil {
+				log.Logger.Errorf("%+v", err)
 				return err
 			}
 

internal/log/log.go

@@ -58,7 +58,7 @@ func init() {
 			zapcore.AddSync(os.Stdout),
 			zap.InfoLevel,
 		),
-	), zap.AddStacktrace(zap.ErrorLevel))
+	))
 
 	Logger = rawLogger.Sugar()
 }