Fix datasync retry

This commit fixes a bug on the mvds library where the nextEpoch would be
incorrectly summed to the retry time, resulting in messages not being
retried, or retried much less frequently the longer the app was running.
It also updates the retry timing to backoff exponentially at multiple of
30 seconds.

go.mod

@@ -48,7 +48,6 @@ require (
 	github.com/pborman/uuid v1.2.0
 	github.com/pkg/errors v0.9.1
 	github.com/prometheus/client_golang v1.5.0
-	github.com/prometheus/common v0.9.1
 	github.com/russolsen/ohyeah v0.0.0-20160324131710-f4938c005315 // indirect
 	github.com/russolsen/same v0.0.0-20160222130632-f089df61f51d // indirect
 	github.com/russolsen/transit v0.0.0-20180705123435-0794b4c4505a
@@ -63,7 +62,7 @@ require (
 	github.com/stretchr/testify v1.5.1
 	github.com/syndtr/goleveldb v1.0.0
 	github.com/tsenart/tb v0.0.0-20181025101425-0d2499c8b6e9
-	github.com/vacp2p/mvds v0.0.23
+	github.com/vacp2p/mvds v0.0.24-0.20201124060106-26d8e94130d8
 	github.com/wealdtech/go-ens/v3 v3.3.0
 	go.uber.org/multierr v1.4.0 // indirect
 	go.uber.org/zap v1.13.0

go.sum

@@ -701,8 +701,8 @@ github.com/tyler-smith/go-bip39 v1.0.2/go.mod h1:sJ5fKU0s6JVwZjjcUEX2zFOnvq0ASQ2
 github.com/uber/jaeger-client-go v0.0.0-20180607151842-f7e0d4744fa6/go.mod h1:WVhlPFC8FDjOFMMWRy2pZqQJSXxYSwNYOkTr/Z6d3Kk=
 github.com/uber/jaeger-lib v0.0.0-20180615202729-a51202d6f4a7/go.mod h1:ComeNDZlWwrWnDv8aPp0Ba6+uUTzImX/AauajbLI56U=
 github.com/ugorji/go/codec v0.0.0-20181204163529-d75b2dcb6bc8/go.mod h1:VFNgLljTbGfSG7qAOspJ7OScBnGdDN/yBr0sguwnwf0=
-github.com/vacp2p/mvds v0.0.23 h1:BKdn7tyGvl/J/Pwv6FlcW6Xbzm+17jv141GB1mFXyOU=
+github.com/vacp2p/mvds v0.0.24-0.20201124060106-26d8e94130d8 h1:aSQuY64yglPb7I6lZRXt/xWD4ExM1DZo8Gpb7xCz6zk=
-github.com/vacp2p/mvds v0.0.23/go.mod h1:uUmtiahU7efOVl/5w5yk9jOze5xYpDZDrSrT8TvHXjQ=
+github.com/vacp2p/mvds v0.0.24-0.20201124060106-26d8e94130d8/go.mod h1:uUmtiahU7efOVl/5w5yk9jOze5xYpDZDrSrT8TvHXjQ=
 github.com/wealdtech/go-ens/v3 v3.3.0 h1:xJJlFLEbdnzU7dLFwyg5fXlZVprwoLPlAPVZdpYCCrY=
 github.com/wealdtech/go-ens/v3 v3.3.0/go.mod h1:P2OEBvgkhXLrPzPN+eR5z2/wFIGwHyijTDvpuC1xLlo=
 github.com/wealdtech/go-multicodec v1.2.0 h1:9AHSxcSE9F9r6ZvQLAO0EXCdM08QfYohaXmW3k6sSh4=

protocol/common/message_processor.go

@@ -108,7 +108,7 @@ func NewMessageProcessor(
 		// Messages will be tried to send in any case, even if they exceed this
 		// value
 		ds.Init(p.sendDataSync, transport.MaxMessageSize()/4*3, logger)
-		ds.Start(300 * time.Millisecond)
+		ds.Start(datasync.DatasyncTicker)
 	}
 
 	return p, nil

protocol/datasync/transport.go

@@ -4,6 +4,8 @@ import (
 	"context"
 	"crypto/ecdsa"
 	"errors"
+	"math"
+	"time"
 
 	"github.com/golang/protobuf/proto"
 	"github.com/vacp2p/mvds/protobuf"
@@ -14,7 +16,14 @@ import (
 	datasyncpeer "github.com/status-im/status-go/protocol/datasync/peer"
 )
 
+const backoffInterval = 30
+
 var errNotInitialized = errors.New("Datasync transport not initialized")
+var DatasyncTicker = 300 * time.Millisecond
+
+// It's easier to calculate nextEpoch if we consider seconds as a unit rather than
+// 300 ms, so we multiply the result by the ratio
+var offsetToSecond = uint64(time.Second / DatasyncTicker)
 
 // payloadTagSize is the tag size for the protobuf.Payload message which is number of fields * 2 bytes
 var payloadTagSize = 14
@@ -149,5 +158,5 @@ func splitPayloadInBatches(payload *protobuf.Payload, maxSizeBytes int) []*proto
 // CalculateSendTime calculates the next epoch
 // at which a message should be sent.
 func CalculateSendTime(count uint64, time int64) int64 {
-	return time + int64(count*2) // @todo this should match that time is increased by whisper periods, aka we only retransmit the first time when a message has expired.
+	return time + int64(uint64(math.Exp2(float64(count-1)))*backoffInterval*offsetToSecond)
 }

vendor/github.com/vacp2p/mvds/node/node.go

@@ -545,7 +545,7 @@ func (n *Node) insertSyncState(groupID *state.GroupID, messageID state.MessageID
 
 func (n *Node) updateSendEpoch(s state.State) state.State {
 	s.SendCount += 1
-	s.SendEpoch += n.nextEpoch(s.SendCount, n.epoch)
+	s.SendEpoch = n.nextEpoch(s.SendCount, n.epoch)
 	return s
 }
 

vendor/modules.txt

@@ -426,7 +426,7 @@ github.com/tsenart/tb
 # github.com/tyler-smith/go-bip39 v1.0.2
 github.com/tyler-smith/go-bip39
 github.com/tyler-smith/go-bip39/wordlists
-# github.com/vacp2p/mvds v0.0.23
+# github.com/vacp2p/mvds v0.0.24-0.20201124060106-26d8e94130d8
 github.com/vacp2p/mvds/node
 github.com/vacp2p/mvds/node/migrations
 github.com/vacp2p/mvds/peers