STRATEGY: Detect abnormal volume increases using isolation forest

config/sentinel.yaml

@@ -0,0 +1,19 @@
+sessions:
+  max:
+    exchange: &exchange max
+    envVarPrefix: max
+
+persistence:
+  json:
+    directory: var/data
+  redis:
+    host: 127.0.0.1
+    port: 6379
+    db: 0
+
+exchangeStrategies:
+- on: *exchange
+  sentinel:
+    symbol: BTCUSDT
+    interval: 1m
+    scoreThreshold: 0.6

go.mod

@@ -125,6 +125,7 @@ require (
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/modern-go/reflect2 v1.0.2 // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
+	github.com/narumiruna/go-iforest v0.2.2 // indirect
 	github.com/pelletier/go-toml/v2 v2.2.3 // indirect
 	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
 	github.com/prometheus/client_model v0.6.1 // indirect

go.sum

@@ -446,6 +446,8 @@ github.com/muesli/kmeans v0.3.0/go.mod h1:eNyybq0tX9/iBEP6EMU4Y7dpmGK0uEhODdZpnG
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 h1:C3w9PqII01/Oq1c1nUAm88MOHcQC9l5mIlSMApZMrHA=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
 github.com/mwitkow/go-conntrack v0.0.0-20161129095857-cc309e4a2223/go.mod h1:qRWi+5nqEBWmkhHvq77mSJWrCKwh8bxhgT7d/eI7P4U=
+github.com/narumiruna/go-iforest v0.2.2 h1:48GGRVLSlgtV3vGr+eedXODn5RT3WvYroqpMNEoQvkk=
+github.com/narumiruna/go-iforest v0.2.2/go.mod h1:2pumoiqKf0Lr+KvLECMC8uNrbRkxtSvUwMJC/6AW7DM=
 github.com/nxadm/tail v1.4.8 h1:nPr65rt6Y5JFSKQO7qToXr7pePgD6Gwiw05lkbyAQTE=
 github.com/nxadm/tail v1.4.8/go.mod h1:+ncqLTQzXmGhMZNUePPaPqPvBxHAIsmXswZKocGu+AU=
 github.com/oklog/ulid v1.3.1/go.mod h1:CirwcVhetQ6Lv90oh/F+FBtV6XMibvdAFo93nm5qn4U=

pkg/cmd/strategy/builtin.go

@@ -40,6 +40,7 @@ import (
 	_ "github.com/c9s/bbgo/pkg/strategy/rsmaker"
 	_ "github.com/c9s/bbgo/pkg/strategy/schedule"
 	_ "github.com/c9s/bbgo/pkg/strategy/scmaker"
+	_ "github.com/c9s/bbgo/pkg/strategy/sentinel"
 	_ "github.com/c9s/bbgo/pkg/strategy/supertrend"
 	_ "github.com/c9s/bbgo/pkg/strategy/support"
 	_ "github.com/c9s/bbgo/pkg/strategy/swing"

pkg/datatype/floats/slice.go

@@ -87,6 +87,24 @@ func (s Slice) Mean() (mean float64) {
 	return s.Sum() / float64(length)
 }
 
+func (s Slice) Var() float64 {
+	length := len(s)
+	if length == 0 {
+		panic("zero length slice")
+	}
+
+	mean := s.Mean()
+	variance := 0.0
+	for _, v := range s {
+		variance += (v - mean) * (v - mean)
+	}
+	return variance / float64(length)
+}
+
+func (s Slice) Std() float64 {
+	return math.Sqrt(s.Var())
+}
+
 func (s Slice) Tail(size int) Slice {
 	length := len(s)
 	if length <= size {

pkg/strategy/sentinel/strategy.go

@@ -0,0 +1,161 @@
+package sentinel
+
+import (
+	"context"
+	"time"
+
+	"github.com/c9s/bbgo/pkg/bbgo"
+	"github.com/c9s/bbgo/pkg/datatype/floats"
+	"github.com/c9s/bbgo/pkg/types"
+	"github.com/narumiruna/go-iforest/pkg/iforest"
+	log "github.com/sirupsen/logrus"
+	"golang.org/x/time/rate"
+)
+
+const ID = "sentinel"
+
+func init() {
+	bbgo.RegisterStrategy(ID, &Strategy{})
+}
+
+type Strategy struct {
+	Symbol         string         `json:"symbol"`
+	Interval       types.Interval `json:"interval"`
+	ScoreThreshold float64        `json:"scoreThreshold"`
+	KLineLimit     int            `json:"klineLimit"`
+	Window         int            `json:"window"`
+
+	IsolationForest      *iforest.IsolationForest `json:"isolationForest"`
+	NotificationInterval time.Duration            `json:"notificationInterval"`
+	RetrainingInterval   time.Duration            `json:"retrainingInterval"`
+
+	notificationRateLimiter *rate.Limiter
+	retrainingRateLimiter   *rate.Limiter
+}
+
+func (s *Strategy) ID() string {
+	return ID
+}
+
+func (s *Strategy) Defaults() error {
+	if s.ScoreThreshold == 0 {
+		s.ScoreThreshold = 0.6
+	}
+
+	if s.KLineLimit == 0 {
+		s.KLineLimit = 1440
+	}
+
+	if s.Window == 0 {
+		s.Window = 60
+	}
+
+	if s.NotificationInterval == 0 {
+		s.NotificationInterval = 10 * time.Minute
+	}
+
+	if s.RetrainingInterval == 0 {
+		s.RetrainingInterval = 1 * time.Hour
+	}
+
+	s.notificationRateLimiter = rate.NewLimiter(rate.Every(s.NotificationInterval), 1)
+	s.retrainingRateLimiter = rate.NewLimiter(rate.Every(s.RetrainingInterval), 1)
+	return nil
+}
+
+func (s *Strategy) Subscribe(session *bbgo.ExchangeSession) {
+	session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: s.Interval})
+}
+
+func (s *Strategy) Run(ctx context.Context, orderExecutor bbgo.OrderExecutor, session *bbgo.ExchangeSession) error {
+	session.MarketDataStream.OnKLine(types.KLineWith(s.Symbol, s.Interval, func(kline types.KLine) {
+		if !s.isMarketAvailable(session, s.Symbol) {
+			return
+		}
+
+		klines, err := s.queryKLines(ctx, session)
+		if err != nil {
+			log.Errorf("Unable to query klines: %v", err)
+			return
+		}
+
+		volumes := s.extractVolumes(klines)
+		samples := s.generateSamples(volumes)
+
+		if s.shouldSkipIsolationForest(volumes, samples) {
+			s.logSkipIsolationForest(samples, volumes, kline)
+			return
+		}
+
+		s.fitIsolationForest(samples)
+		scores := s.IsolationForest.Score(samples)
+		s.notifyOnIsolationForestScore(scores, kline)
+	}))
+	return nil
+}
+
+func (s *Strategy) isMarketAvailable(session *bbgo.ExchangeSession, symbol string) bool {
+	_, ok := session.Market(symbol)
+	return ok
+}
+
+func (s *Strategy) queryKLines(ctx context.Context, session *bbgo.ExchangeSession) ([]types.KLine, error) {
+	endTime := time.Now()
+	options := types.KLineQueryOptions{
+		Limit:   s.KLineLimit,
+		EndTime: &endTime,
+	}
+	return session.Exchange.QueryKLines(ctx, s.Symbol, s.Interval, options)
+}
+
+func (s *Strategy) extractVolumes(klines []types.KLine) floats.Slice {
+	volumes := floats.Slice{}
+	for _, kline := range klines {
+		volumes.Push(kline.Volume.Float64())
+	}
+	return volumes
+}
+
+func (s *Strategy) generateSamples(volumes floats.Slice) [][]float64 {
+	samples := make([][]float64, 0, len(volumes))
+	for i := range volumes {
+		if i < s.Window {
+			continue
+		}
+
+		subset := volumes.Tail(s.Window)
+
+		mean := subset.Mean()
+		std := subset.Std()
+		samples = append(samples, []float64{mean, std})
+	}
+	return samples
+}
+
+func (s *Strategy) shouldSkipIsolationForest(volumes floats.Slice, samples [][]float64) bool {
+	volumeMean := volumes.Mean()
+	lastMovingMean := samples[len(samples)-1][0]
+	return lastMovingMean < volumeMean
+}
+
+func (s *Strategy) logSkipIsolationForest(samples [][]float64, volumes floats.Slice, kline types.KLine) {
+	log.Infof("Skipping isolation forest calculation for symbol: %s, last moving mean: %f, average volume: %f, kline: %s", s.Symbol, samples[len(samples)-1][0], volumes.Mean(), kline.String())
+}
+
+func (s *Strategy) fitIsolationForest(samples [][]float64) {
+	if s.retrainingRateLimiter.Allow() {
+		s.IsolationForest = iforest.New()
+		s.IsolationForest.Fit(samples)
+		log.Infof("Isolation forest fitted with %d samples and %d/%d trees", len(samples), len(s.IsolationForest.Trees), s.IsolationForest.NumTrees)
+	}
+}
+
+func (s *Strategy) notifyOnIsolationForestScore(scores []float64, kline types.KLine) {
+	lastScore := scores[len(scores)-1]
+	log.Warnf("Symbol: %s, isolation forest score: %f, threshold: %f, kline: %s", s.Symbol, lastScore, s.ScoreThreshold, kline.String())
+	if lastScore > s.ScoreThreshold {
+		if s.notificationRateLimiter.Allow() {
+			bbgo.Notify("symbol: %s isolation forest score: %f", s.Symbol, lastScore)
+		}
+	}
+}