cleanup and comments

cmd/consensusnode/testclient/consensustestclient.go

@@ -14,7 +14,7 @@ import (
 	"github.com/anytypeio/go-anytype-infrastructure-experiments/config"
 	"github.com/anytypeio/go-anytype-infrastructure-experiments/consensus/consensusclient"
 	"github.com/anytypeio/go-anytype-infrastructure-experiments/consensus/consensusproto"
-	"github.com/anytypeio/go-anytype-infrastructure-experiments/consensus/consensusproto/consensuserrs"
+	"github.com/anytypeio/go-anytype-infrastructure-experiments/consensus/consensusproto/consensuserr"
 	"github.com/anytypeio/go-anytype-infrastructure-experiments/node/account"
 	"go.uber.org/zap"
 	"gopkg.in/mgo.v2/bson"
@@ -154,7 +154,7 @@ func testCreateLogAndRecord(service consensusclient.Service) (err error) {
 			},
 		},
 	})
-	if err != consensuserrs.ErrLogExists {
+	if err != consensuserr.ErrLogExists {
 		return fmt.Errorf("unexpected error: '%v' want LogExists", zap.Error(err))
 	}
 	err = nil
@@ -181,7 +181,7 @@ func testCreateLogAndRecord(service consensusclient.Service) (err error) {
 		PrevId:      []byte(bson.NewObjectId()),
 		CreatedUnix: uint64(time.Now().Unix()),
 	})
-	if err != consensuserrs.ErrConflict {
+	if err != consensuserr.ErrConflict {
 		return fmt.Errorf("unexpected error: '%v' want Conflict", zap.Error(err))
 	}
 	err = nil

consensus/consensusproto/consensus.pb.go

@@ -59,7 +59,6 @@ func (ErrCodes) EnumDescriptor() ([]byte, []int) {
 type Log struct {
 	Id      []byte    `protobuf:"bytes,1,opt,name=id,proto3" json:"id,omitempty"`
 	Records []*Record `protobuf:"bytes,2,rep,name=records,proto3" json:"records,omitempty"`
-	CreatedUnix uint64    `protobuf:"varint,3,opt,name=createdUnix,proto3" json:"createdUnix,omitempty"`
 }
 
 func (m *Log) Reset()         { *m = Log{} }
@@ -109,13 +108,6 @@ func (m *Log) GetRecords() []*Record {
 	return nil
 }
 
-func (m *Log) GetCreatedUnix() uint64 {
-	if m != nil {
-		return m.CreatedUnix
-	}
-	return 0
-}
-
 type Record struct {
 	Id          []byte `protobuf:"bytes,1,opt,name=id,proto3" json:"id,omitempty"`
 	PrevId      []byte `protobuf:"bytes,2,opt,name=prevId,proto3" json:"prevId,omitempty"`
@@ -436,37 +428,37 @@ func init() {
 }
 
 var fileDescriptor_b8d7f1c16b400059 = []byte{
-	// 480 bytes of a gzipped FileDescriptorProto
+	// 474 bytes of a gzipped FileDescriptorProto
-	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0x94, 0x53, 0x41, 0x8b, 0xd3, 0x40,
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0x94, 0x53, 0x4f, 0x8b, 0xd3, 0x40,
-	0x14, 0xee, 0x24, 0x6b, 0xb7, 0x7d, 0x69, 0xbb, 0xf1, 0xb1, 0x48, 0xe8, 0x62, 0x08, 0xf1, 0x12,
+	0x14, 0xef, 0x24, 0xb5, 0xdb, 0xbe, 0xb4, 0xdd, 0xf8, 0x58, 0x24, 0x74, 0x31, 0x84, 0x78, 0x09,
-	0x44, 0xba, 0x52, 0x05, 0x4f, 0x1e, 0xd6, 0x52, 0xa1, 0x52, 0x2d, 0x04, 0xaa, 0xe0, 0xc9, 0x98,
+	0x22, 0x5d, 0xa9, 0x82, 0x27, 0x0f, 0x6b, 0xa9, 0x50, 0xa9, 0x16, 0x02, 0x55, 0xf0, 0x64, 0xcc,
-	0x99, 0xc6, 0xb0, 0x21, 0x53, 0x67, 0xd2, 0xb5, 0xfb, 0x2f, 0xfc, 0x21, 0xfe, 0x10, 0x6f, 0xee,
+	0x4c, 0x63, 0xd8, 0x90, 0xa9, 0x33, 0xe9, 0xda, 0xfd, 0x16, 0x7e, 0x10, 0x3f, 0x88, 0x37, 0xf7,
-	0xd1, 0xa3, 0xb4, 0x7f, 0x44, 0x3a, 0x69, 0x6a, 0xb2, 0xdd, 0x1e, 0xbc, 0x24, 0x79, 0xdf, 0x37,
+	0xe8, 0x51, 0xda, 0x2f, 0x22, 0x9d, 0x34, 0x35, 0x71, 0xb7, 0x87, 0xbd, 0x24, 0xf3, 0x7e, 0xbf,
-	0xef, 0x7d, 0xdf, 0xbc, 0x8f, 0xc0, 0x79, 0xc8, 0x53, 0xc9, 0x52, 0xb9, 0x90, 0xff, 0xbe, 0xe6,
+	0xf7, 0xe7, 0x37, 0xef, 0xc7, 0xc0, 0x59, 0xc8, 0x53, 0xc9, 0x52, 0xb9, 0x94, 0xff, 0x4e, 0x0b,
-	0x82, 0x67, 0xfc, 0x5c, 0x3d, 0x4b, 0x68, 0x4f, 0x01, 0xd8, 0x0a, 0xd2, 0xeb, 0x41, 0x81, 0xb9,
+	0xc1, 0x33, 0x7e, 0xa6, 0xbe, 0x25, 0xb4, 0xaf, 0x00, 0x6c, 0x07, 0xe9, 0xd5, 0xb0, 0xc0, 0xdc,
-	0x11, 0xe8, 0x63, 0x1e, 0x61, 0x07, 0xb4, 0x98, 0x5a, 0xc4, 0x21, 0x5e, 0xcb, 0xd7, 0x62, 0x8a,
+	0x11, 0xe8, 0x13, 0x1e, 0x61, 0x17, 0xb4, 0x98, 0x5a, 0xc4, 0x21, 0x5e, 0xdb, 0xd7, 0x62, 0x8a,
-	0x3d, 0x38, 0x16, 0x2c, 0xe4, 0x82, 0x4a, 0x4b, 0x73, 0x74, 0xcf, 0xe8, 0x9f, 0xf6, 0xca, 0x6d,
+	0x7d, 0x38, 0x12, 0x2c, 0xe4, 0x82, 0x4a, 0x4b, 0x73, 0x74, 0xcf, 0x18, 0x9c, 0xf4, 0xcb, 0x65,
-	0x3d, 0x5f, 0x91, 0x7e, 0x71, 0x08, 0x1d, 0x30, 0x42, 0xc1, 0x82, 0x8c, 0xd1, 0x69, 0x1a, 0x2f,
+	0x7d, 0x5f, 0x91, 0x7e, 0x91, 0xe4, 0x26, 0xd0, 0xc8, 0xa1, 0x1b, 0x9d, 0x1e, 0x40, 0x63, 0x21,
-	0x2d, 0xdd, 0x21, 0xde, 0x91, 0x5f, 0x86, 0xdc, 0x04, 0xea, 0x79, 0xd3, 0x9e, 0xd6, 0x03, 0xa8,
+	0xd8, 0xe5, 0x98, 0x5a, 0x9a, 0xc2, 0x76, 0x11, 0x5a, 0x70, 0xb4, 0x08, 0xae, 0x12, 0x1e, 0x50,
-	0xcf, 0x05, 0xbb, 0x1a, 0x51, 0x4b, 0x53, 0xd8, 0xb6, 0x42, 0x0b, 0x8e, 0xe7, 0xc1, 0x75, 0xc2,
+	0x4b, 0x57, 0x44, 0x11, 0xa2, 0x03, 0x46, 0x28, 0x58, 0x90, 0x31, 0x3a, 0x4b, 0xe3, 0x95, 0x55,
-	0x03, 0xaa, 0xe6, 0xb5, 0xfc, 0xa2, 0xbc, 0xad, 0x76, 0xb4, 0xaf, 0x76, 0x04, 0xda, 0xe4, 0xd2,
+	0x77, 0x88, 0x57, 0xf7, 0xcb, 0x90, 0x5b, 0x07, 0x6d, 0x7a, 0xe1, 0x3e, 0x87, 0xce, 0x39, 0xa5,
-	0x7d, 0x0e, 0xed, 0x0b, 0x4a, 0xc7, 0x3c, 0xf2, 0xd9, 0xd7, 0x05, 0x93, 0x19, 0x3e, 0x02, 0x3d,
+	0x13, 0x1e, 0xf9, 0xec, 0xeb, 0x92, 0xc9, 0x0c, 0x1f, 0x81, 0x9e, 0xf0, 0x48, 0xcd, 0x36, 0x06,
-	0xe1, 0x91, 0xd2, 0x36, 0xfa, 0xf7, 0xab, 0x57, 0xda, 0x1c, 0xdb, 0xb0, 0xee, 0x7b, 0x30, 0x2f,
+	0xf7, 0xab, 0x82, 0xb7, 0x69, 0x5b, 0xd6, 0x7d, 0x0f, 0xe6, 0x39, 0xa5, 0x3b, 0xfd, 0xbb, 0xc2,
-	0x28, 0xdd, 0xde, 0x70, 0xdb, 0x78, 0x0a, 0xf7, 0x12, 0x1e, 0x8d, 0x0a, 0xdb, 0x79, 0x81, 0x4f,
+	0x13, 0xb8, 0x97, 0xf0, 0x68, 0x5c, 0xc8, 0xce, 0x03, 0x7c, 0x02, 0x8d, 0xfc, 0x7a, 0x4a, 0xf9,
-	0xa0, 0x9e, 0x2f, 0x40, 0x39, 0x3f, 0xb4, 0xa4, 0xed, 0x19, 0xf7, 0x2d, 0x9c, 0x7c, 0x08, 0xb2,
+	0xa1, 0x15, 0xec, 0x72, 0xdc, 0xb7, 0x70, 0xfc, 0x21, 0xc8, 0xc2, 0x2f, 0x25, 0x3d, 0x3d, 0x68,
-	0xf0, 0x4b, 0xc9, 0x4f, 0x17, 0x1a, 0xdf, 0x36, 0xd0, 0x88, 0x4a, 0x8b, 0x38, 0xba, 0xd7, 0xf2,
+	0x7e, 0xdb, 0x42, 0x63, 0x2a, 0x2d, 0xe2, 0xe8, 0x5e, 0xdb, 0xdf, 0xc7, 0x68, 0x03, 0x2c, 0xd3,
-	0x77, 0x35, 0xda, 0x00, 0x8b, 0x74, 0xc7, 0x6a, 0x8a, 0x2d, 0x21, 0xee, 0x14, 0xda, 0xc5, 0xb8,
+	0x3d, 0xab, 0x29, 0xb6, 0x84, 0xb8, 0x33, 0xe8, 0x14, 0xed, 0x46, 0x97, 0x2c, 0x3d, 0xa4, 0xf1,
-	0xe1, 0x15, 0x4b, 0x0f, 0x79, 0xfc, 0xcf, 0x24, 0x1f, 0x7f, 0x82, 0xc6, 0x50, 0x88, 0x01, 0xa7,
+	0x8e, 0x3e, 0x3d, 0xfe, 0x04, 0xcd, 0x91, 0x10, 0x43, 0x4e, 0x99, 0xc4, 0x2e, 0xc0, 0x2c, 0x65,
-	0x4c, 0x62, 0x07, 0x60, 0x9a, 0xb2, 0xe5, 0x9c, 0x85, 0x19, 0xa3, 0x66, 0x0d, 0xdb, 0xd0, 0xdc,
+	0xab, 0x05, 0x0b, 0x33, 0x46, 0xcd, 0x1a, 0x76, 0xa0, 0xb5, 0x9d, 0xb6, 0x8a, 0x65, 0x26, 0x4d,
-	0xa8, 0x2d, 0x63, 0x99, 0x49, 0x93, 0xe0, 0x09, 0x18, 0x63, 0x1e, 0xbd, 0xe3, 0xd9, 0x6b, 0xbe,
+	0x82, 0xc7, 0x60, 0x4c, 0x78, 0xf4, 0x8e, 0x67, 0xaf, 0xf9, 0x32, 0xa5, 0xa6, 0x86, 0x08, 0xdd,
-	0x48, 0xa9, 0xa9, 0x21, 0x42, 0x27, 0x1f, 0x37, 0xe0, 0xe9, 0x2c, 0x89, 0xc3, 0xcc, 0xd4, 0xd1,
+	0xbc, 0xdd, 0x90, 0xa7, 0xf3, 0x24, 0x0e, 0x33, 0x53, 0x47, 0x13, 0x8c, 0x91, 0x10, 0x5c, 0x4c,
-	0x04, 0x63, 0x28, 0x04, 0x17, 0x93, 0xd9, 0x4c, 0xb2, 0xcc, 0xfc, 0xa1, 0xf5, 0x7f, 0x11, 0x68,
+	0xe7, 0x73, 0xc9, 0x32, 0xf3, 0x87, 0x36, 0xf8, 0x45, 0xa0, 0xb5, 0x9f, 0x8f, 0x2f, 0xa0, 0x91,
-	0xee, 0xf4, 0xf1, 0x05, 0xd4, 0xf3, 0x8c, 0xf0, 0xac, 0x6a, 0xac, 0x92, 0x5c, 0xd7, 0xac, 0x92,
+	0x7b, 0x84, 0xa7, 0x55, 0x61, 0x15, 0xe7, 0x7a, 0x66, 0x95, 0x9c, 0x5e, 0xe0, 0x4b, 0x68, 0xed,
-	0x93, 0x4b, 0x7c, 0x09, 0xcd, 0x5d, 0x4c, 0x68, 0xef, 0xf5, 0x56, 0xf2, 0xbb, 0xa3, 0xfd, 0x0d,
+	0x6d, 0x42, 0xfb, 0x46, 0x6d, 0xc5, 0xbf, 0x5b, 0xca, 0xdf, 0x40, 0xb3, 0x58, 0x1f, 0x3e, 0xac,
-	0x34, 0x8a, 0xf5, 0xe1, 0xc3, 0x2a, 0x7b, 0x2b, 0xa5, 0xee, 0xd9, 0xdd, 0xb4, 0xda, 0xba, 0x47,
+	0xb2, 0xff, 0xb9, 0xd4, 0x3b, 0xbd, 0x9d, 0x56, 0x5b, 0xf7, 0xc8, 0x53, 0xf2, 0x6a, 0xf0, 0x73,
-	0x9e, 0x92, 0x57, 0xfd, 0x9f, 0x2b, 0x9b, 0xdc, 0xac, 0x6c, 0xf2, 0x67, 0x65, 0x93, 0xef, 0x6b,
+	0x6d, 0x93, 0xeb, 0xb5, 0x4d, 0xfe, 0xac, 0x6d, 0xf2, 0x7d, 0x63, 0xd7, 0xae, 0x37, 0x76, 0xed,
-	0xbb, 0x76, 0xb3, 0xb6, 0x6b, 0xbf, 0xd7, 0x76, 0xed, 0xa3, 0x75, 0xe8, 0xef, 0xfc, 0x5c, 0x57,
+	0xf7, 0xc6, 0xae, 0x7d, 0xb4, 0x0e, 0xbd, 0xbd, 0xcf, 0x0d, 0xf5, 0x7b, 0xf6, 0x37, 0x00, 0x00,
-	0xaf, 0x67, 0x7f, 0x03, 0x00, 0x00, 0xff, 0xff, 0xf0, 0xc9, 0xa1, 0x1f, 0xc0, 0x03, 0x00, 0x00,
+	0xff, 0xff, 0x9f, 0x6e, 0xb2, 0xf8, 0x9e, 0x03, 0x00, 0x00,
 }
 
 func (m *Log) Marshal() (dAtA []byte, err error) {
@@ -489,11 +481,6 @@ func (m *Log) MarshalToSizedBuffer(dAtA []byte) (int, error) {
 	_ = i
 	var l int
 	_ = l
-	if m.CreatedUnix != 0 {
-		i = encodeVarintConsensus(dAtA, i, uint64(m.CreatedUnix))
-		i--
-		dAtA[i] = 0x18
-	}
 	if len(m.Records) > 0 {
 		for iNdEx := len(m.Records) - 1; iNdEx >= 0; iNdEx-- {
 			{
@@ -779,9 +766,6 @@ func (m *Log) Size() (n int) {
 			n += 1 + l + sovConsensus(uint64(l))
 		}
 	}
-	if m.CreatedUnix != 0 {
-		n += 1 + sovConsensus(uint64(m.CreatedUnix))
-	}
 	return n
 }
 
@@ -991,25 +975,6 @@ func (m *Log) Unmarshal(dAtA []byte) error {
 				return err
 			}
 			iNdEx = postIndex
-		case 3:
-			if wireType != 0 {
-				return fmt.Errorf("proto: wrong wireType = %d for field CreatedUnix", wireType)
-			}
-			m.CreatedUnix = 0
-			for shift := uint(0); ; shift += 7 {
-				if shift >= 64 {
-					return ErrIntOverflowConsensus
-				}
-				if iNdEx >= l {
-					return io.ErrUnexpectedEOF
-				}
-				b := dAtA[iNdEx]
-				iNdEx++
-				m.CreatedUnix |= uint64(b&0x7F) << shift
-				if b < 0x80 {
-					break
-				}
-			}
 		default:
 			iNdEx = preIndex
 			skippy, err := skipConsensus(dAtA[iNdEx:])

consensus/consensusproto/consensuserr/errors.go

@@ -1,4 +1,4 @@
-package consensuserrs
+package consensuserr
 
 import (
 	"fmt"

consensus/consensusproto/protos/consensus.proto

@@ -15,7 +15,6 @@ enum ErrCodes {
 message Log {
     bytes id = 1;
     repeated Record records = 2;
-    uint64 createdUnix = 3;
 }
 
 message Record {

consensus/consensusrpc/consensrpc.go

@@ -17,6 +17,7 @@ func New() app.Component {
 	return &consensusRpc{}
 }
 
+// consensusRpc implements consensus rpc server
 type consensusRpc struct {
 	db     db.Service
 	stream stream.Service

consensus/db/db.go

@@ -7,7 +7,7 @@ import (
 	"github.com/anytypeio/go-anytype-infrastructure-experiments/app/logger"
 	"github.com/anytypeio/go-anytype-infrastructure-experiments/consensus"
 	"github.com/anytypeio/go-anytype-infrastructure-experiments/consensus/config"
-	"github.com/anytypeio/go-anytype-infrastructure-experiments/consensus/consensusproto/consensuserrs"
+	"github.com/anytypeio/go-anytype-infrastructure-experiments/consensus/consensusproto/consensuserr"
 	"go.mongodb.org/mongo-driver/mongo"
 	"go.mongodb.org/mongo-driver/mongo/options"
 	"go.uber.org/zap"
@@ -24,9 +24,14 @@ func New() Service {
 type ChangeReceiver func(logId []byte, records []consensus.Record)
 
 type Service interface {
+	// AddLog adds new log db
 	AddLog(ctx context.Context, log consensus.Log) (err error)
+	// AddRecord adds new record to existing log
+	// returns consensuserr.ErrConflict if record didn't match or log not found
 	AddRecord(ctx context.Context, logId []byte, record consensus.Record) (err error)
+	// FetchLog gets log by id
 	FetchLog(ctx context.Context, logId []byte) (log consensus.Log, err error)
+	// SetChangeReceiver sets the receiver for updates, it must be called before app.Run stage
 	SetChangeReceiver(receiver ChangeReceiver) (err error)
 	app.ComponentRunnable
 }
@@ -69,7 +74,7 @@ func (s *service) Run(ctx context.Context) (err error) {
 func (s *service) AddLog(ctx context.Context, l consensus.Log) (err error) {
 	_, err = s.logColl.InsertOne(ctx, l)
 	if mongo.IsDuplicateKeyError(err) {
-		return consensuserrs.ErrLogExists
+		return consensuserr.ErrLogExists
 	}
 	return
 }
@@ -101,10 +106,10 @@ func (s *service) AddRecord(ctx context.Context, logId []byte, record consensus.
 	}, upd)
 	if err != nil {
 		log.Error("addRecord update error", zap.Error(err))
-		return consensuserrs.ErrUnexpected
+		return consensuserr.ErrUnexpected
 	}
 	if result.ModifiedCount == 0 {
-		return consensuserrs.ErrConflict
+		return consensuserr.ErrConflict
 	}
 	return
 }
@@ -112,7 +117,7 @@ func (s *service) AddRecord(ctx context.Context, logId []byte, record consensus.
 func (s *service) FetchLog(ctx context.Context, logId []byte) (l consensus.Log, err error) {
 	if err = s.logColl.FindOne(ctx, findLogQuery{Id: logId}).Decode(&l); err != nil {
 		if err == mongo.ErrNoDocuments {
-			err = consensuserrs.ErrLogNotFound
+			err = consensuserr.ErrLogNotFound
 		}
 		return
 	}
@@ -162,7 +167,9 @@ func (s *service) streamListener(stream *mongo.ChangeStream) {
 	for stream.Next(s.streamCtx) {
 		var res streamResult
 		if err := stream.Decode(&res); err != nil {
-			log.Error("stream decode error:", zap.Error(err))
+			// mongo driver maintains connections and handles reconnects so that the stream will work as usual in these cases
+			// here we have an unexpected error and should stop any operations to avoid an inconsistent state between db and cache
+			log.Fatal("stream decode error:", zap.Error(err))
 		}
 		s.changeReceiver(res.DocumentKey.Id, res.UpdateDescription.UpdateFields.Records)
 	}

consensus/db/db_test.go

@@ -5,7 +5,7 @@ import (
 	"github.com/anytypeio/go-anytype-infrastructure-experiments/app"
 	"github.com/anytypeio/go-anytype-infrastructure-experiments/consensus"
 	"github.com/anytypeio/go-anytype-infrastructure-experiments/consensus/config"
-	"github.com/anytypeio/go-anytype-infrastructure-experiments/consensus/consensusproto/consensuserrs"
+	"github.com/anytypeio/go-anytype-infrastructure-experiments/consensus/consensusproto/consensuserr"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"testing"
@@ -100,7 +100,7 @@ func TestService_FetchLog(t *testing.T) {
 		defer fx.Finish(t)
 		l, err := fx.FetchLog(ctx, []byte("not exists"))
 		assert.Empty(t, l)
-		assert.ErrorIs(t, err, consensuserrs.ErrLogNotFound)
+		assert.ErrorIs(t, err, consensuserr.ErrLogNotFound)
 	})
 }
 

consensus/stream/object.go

@@ -5,6 +5,7 @@ import (
 	"sync"
 )
 
+// object is a cache entry that holds the actual log state and maintains added streams
 type object struct {
 	logId   []byte
 	records []consensus.Record
@@ -14,6 +15,8 @@ type object struct {
 	mu sync.Mutex
 }
 
+// AddRecords adds new records to the log and sends new records to streams
+// The records source is db and called via stream.Service
 func (o *object) AddRecords(recs []consensus.Record) {
 	o.mu.Lock()
 	defer o.mu.Unlock()
@@ -28,12 +31,14 @@ func (o *object) AddRecords(recs []consensus.Record) {
 	}
 }
 
+// Records returns all log records
 func (o *object) Records() []consensus.Record {
 	o.mu.Lock()
 	defer o.mu.Unlock()
 	return o.records
 }
 
+// AddStream adds stream to the object
 func (o *object) AddStream(s *Stream) {
 	o.mu.Lock()
 	defer o.mu.Unlock()
@@ -42,18 +47,20 @@ func (o *object) AddStream(s *Stream) {
 	return
 }
 
-func (o *object) Locked() bool {
+// RemoveStream remove stream from object
-	o.mu.Lock()
-	defer o.mu.Unlock()
-	return len(o.streams) > 0
-}
-
 func (o *object) RemoveStream(id uint64) {
 	o.mu.Lock()
 	defer o.mu.Unlock()
 	delete(o.streams, id)
 }
 
+// Locked indicates that object can be garbage collected
+func (o *object) Locked() bool {
+	o.mu.Lock()
+	defer o.mu.Unlock()
+	return len(o.streams) > 0
+}
+
 func (o *object) Close() (err error) {
 	return nil
 }

consensus/stream/service.go

@@ -32,7 +32,9 @@ func New() Service {
 	return &service{}
 }
 
+// Service maintains a cache for logs (receive updates from db) and creates new stream objects with able to subscribe/unsubscribe to log ids
 type Service interface {
+	// NewStream creates new stream with able to watch and unwatch log ids
 	NewStream() *Stream
 	app.ComponentRunnable
 }
@@ -71,6 +73,7 @@ func (s *service) NewStream() *Stream {
 	}
 }
 
+// AddStream to object with given logId
 func (s *service) AddStream(ctx context.Context, logId []byte, stream *Stream) (err error) {
 	obj, err := s.getObject(ctx, logId)
 	if err != nil {
@@ -80,6 +83,7 @@ func (s *service) AddStream(ctx context.Context, logId []byte, stream *Stream) (
 	return
 }
 
+// RemoveStream from object with five logId
 func (s *service) RemoveStream(ctx context.Context, logId []byte, streamId uint64) (err error) {
 	obj, err := s.getObject(ctx, logId)
 	if err != nil {

consensus/stream/stream.go

@@ -8,6 +8,7 @@ import (
 	"sync"
 )
 
+// Stream is a buffer that receives updates from object and gives back to a client
 type Stream struct {
 	id     uint64
 	logIds map[string]struct{}
@@ -16,6 +17,7 @@ type Stream struct {
 	s      *service
 }
 
+// LogIds returns watched log ids
 func (s *Stream) LogIds() [][]byte {
 	s.mu.Lock()
 	defer s.mu.Unlock()
@@ -26,14 +28,18 @@ func (s *Stream) LogIds() [][]byte {
 	return logIds
 }
 
+// AddRecords adds new records to stream, called by objects
 func (s *Stream) AddRecords(logId []byte, records []consensus.Record) (err error) {
 	return s.mb.Add(consensus.Log{Id: logId, Records: records})
 }
 
+// WaitLogs wait for new log records
+// empty returned slice means that stream is closed
 func (s *Stream) WaitLogs() []consensus.Log {
 	return s.mb.Wait()
 }
 
+// WatchIds adds given ids to subscription
 func (s *Stream) WatchIds(ctx context.Context, logIds [][]byte) {
 	s.mu.Lock()
 	defer s.mu.Unlock()
@@ -49,6 +55,7 @@ func (s *Stream) WatchIds(ctx context.Context, logIds [][]byte) {
 	return
 }
 
+// UnwatchIds removes given ids from subscription
 func (s *Stream) UnwatchIds(ctx context.Context, logIds [][]byte) {
 	s.mu.Lock()
 	defer s.mu.Unlock()
@@ -64,6 +71,7 @@ func (s *Stream) UnwatchIds(ctx context.Context, logIds [][]byte) {
 	return
 }
 
+// Close closes stream and unsubscribes all ids
 func (s *Stream) Close() {
 	_ = s.mb.Close()
 	s.mu.Lock()