Remove loop detection

backend.go

@@ -74,10 +74,6 @@ type Backend interface {
 	// a message is being forced in being resent by a user
 	ClearMsgSent(context.Context, MsgID) error
 
-	// IsMsgLoop returns whether the passed in message is part of a message loop, possibly with another bot. Backends should
-	// implement their own logic to implement this.
-	IsMsgLoop(ctx context.Context, msg Msg) (bool, error)
-
 	// MarkOutgoingMsgComplete marks the passed in message as having been processed. Note this should be called even in the case
 	// of errors during sending as it will manage the number of active workers per channel. The optional status parameter can be
 	// used to determine any sort of deduping of msg sends

backends/rapidpro/backend.go

@@ -35,9 +35,6 @@ const sentSetName = "msgs_sent_%s"
 // our timeout for backend operations
 const backendTimeout = time.Second * 20
 
-// number of messages for loop detection
-const msgLoopThreshold = 20
-
 func init() {
 	courier.RegisterBackend("rapidpro", newBackend)
 }
@@ -202,63 +199,6 @@ func (b *backend) ClearMsgSent(ctx context.Context, id courier.MsgID) error {
 	return err
 }
 
-var luaMsgLoop = redis.NewScript(3, `-- KEYS: [key, contact_id, text]
-	local key = KEYS[1]
-	local contact_id = KEYS[2]
-	local text = KEYS[3]
-	local count = 1
-
-    -- try to look up in window
-	local record = redis.call("hget", key, contact_id)
-	if record then
-		local record_count = tonumber(string.sub(record, 1, 2))
-		local record_text = string.sub(record, 4, -1)
-
-		if record_text == text then 
-			count = math.min(record_count + 1, 99)
-		else
-			count = 1
-		end		
-	end
-
-	-- create our new record with our updated count
-	record = string.format("%02d:%s", count, text)
-
-	-- write our new record with updated count
-	redis.call("hset", key, contact_id, record)
-
-	-- sets its expiration
-	redis.call("expire", key, 300)
-
-	return count
-`)
-
-// IsMsgLoop checks whether the passed in message is part of a loop
-func (b *backend) IsMsgLoop(ctx context.Context, msg courier.Msg) (bool, error) {
-	m := msg.(*DBMsg)
-
-	// things that aren't replies can't be loops, neither do we count retries
-	if m.ResponseToExternalID_ == "" || m.ErrorCount_ > 0 {
-		return false, nil
-	}
-
-	// otherwise run our script to check whether this is a loop in the past 5 minutes
-	rc := b.redisPool.Get()
-	defer rc.Close()
-
-	keyTime := time.Now().UTC().Round(time.Minute * 5)
-	key := fmt.Sprintf(sentSetName, fmt.Sprintf("loop_msgs:%s", keyTime.Format("2006-01-02-15:04")))
-	count, err := redis.Int(luaMsgLoop.Do(rc, key, m.ContactID_, m.Text_))
-	if err != nil {
-		return false, errors.Wrapf(err, "error while checking for msg loop")
-	}
-
-	if count >= msgLoopThreshold {
-		return true, nil
-	}
-	return false, nil
-}
-
 // MarkOutgoingMsgComplete marks the passed in message as having completed processing, freeing up a worker for that channel
 func (b *backend) MarkOutgoingMsgComplete(ctx context.Context, msg courier.Msg, status courier.MsgStatus) {
 	rc := b.redisPool.Get()

backends/rapidpro/backend_test.go

@@ -748,36 +748,6 @@ func (ts *BackendTestSuite) TestExternalIDDupes() {
 	ts.True(m2.alreadyWritten)
 }
 
-func (ts *BackendTestSuite) TestLoop() {
-	ctx := context.Background()
-	dbMsg := readMsgFromDB(ts.b, courier.NewMsgID(10000))
-
-	dbMsg.ResponseToExternalID_ = "65474"
-
-	loop, err := ts.b.IsMsgLoop(ctx, dbMsg)
-	ts.NoError(err)
-	ts.False(loop)
-
-	// call it 18 times more, no loop still
-	for i := 0; i < 18; i++ {
-		loop, err = ts.b.IsMsgLoop(ctx, dbMsg)
-		ts.NoError(err)
-		ts.False(loop)
-	}
-
-	// last one should make us a loop
-	loop, err = ts.b.IsMsgLoop(ctx, dbMsg)
-	ts.NoError(err)
-	ts.True(loop)
-
-	// make sure this keeps working even in hundreds of loops
-	for i := 0; i < 100; i++ {
-		loop, err = ts.b.IsMsgLoop(ctx, dbMsg)
-		ts.NoError(err)
-		ts.True(loop)
-	}
-}
-
 func (ts *BackendTestSuite) TestStatus() {
 	// our health should just contain the header
 	ts.True(strings.Contains(ts.b.Status(), "Channel"), ts.b.Status())

sender.go

@@ -189,23 +189,10 @@ func (w *Sender) sendMessage(msg Msg) {
 		log.WithError(err).Error("error looking up msg was sent")
 	}
 
-	// is this msg in a loop?
-	loop, err := backend.IsMsgLoop(sendCTX, msg)
-
-	// failing on loop lookup isn't permanent, but log
-	if err != nil {
-		log.WithError(err).Error("error looking up msg loop")
-	}
-
 	if sent {
 		// if this message was already sent, create a wired status for it
 		status = backend.NewMsgStatusForID(msg.Channel(), msg.ID(), MsgWired)
 		log.Warning("duplicate send, marking as wired")
-	} else if loop {
-		// if this contact is in a loop, fail the message immediately without sending
-		status = backend.NewMsgStatusForID(msg.Channel(), msg.ID(), MsgFailed)
-		status.AddLog(NewChannelLogFromError("Message Loop", msg.Channel(), msg.ID(), 0, fmt.Errorf("message loop detected, failing message without send")))
-		log.Error("message loop detected, failing message")
 	} else {
 		// send our message
 		status, err = server.SendMsg(sendCTX, msg)

test.go

@@ -161,11 +161,6 @@ func (mb *MockBackend) ClearMsgSent(ctx context.Context, id MsgID) error {
 	return nil
 }
 
-// IsMsgLoop returns whether the passed in msg is a loop
-func (mb *MockBackend) IsMsgLoop(ctx context.Context, msg Msg) (bool, error) {
-	return false, nil
-}
-
 // MarkOutgoingMsgComplete marks the passed msg as having been dealt with
 func (mb *MockBackend) MarkOutgoingMsgComplete(ctx context.Context, msg Msg, s MsgStatus) {
 	mb.mutex.Lock()