[#488] storage/calculator: Make alpha dynamic

Delete reading `alpha` from env var. Cover
retrieving `alpha` behind interface in
intermediate calculator. Add TODO to decide
if it is necessary to receive that param from
global config or not.

Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>

cmd/neofs-node/config.go

@@ -102,7 +102,6 @@ const (
 
 	// config keys for cfgReputation
 	cfgReputationContract          = "reputation.scripthash"
-	cfgReputationAlpha             = "reputation.alpha"
 	cfgReputationWorkerPoolEnabled = "reputation.async_worker.enabled"
 	cfgReputationWorkerPoolSize    = "reputation.async_worker.size"
 
@@ -320,9 +319,6 @@ type cfgControlService struct {
 }
 
 type cfgReputation struct {
-	// Alpha parameter from origin EigenTrust algorithm
-	// http://ilpubs.stanford.edu:8090/562/1/2002-56.pdf Ch.5.1.
-	alpha      float64
 	workerPool util2.WorkerPool // pool for EigenTrust algorithm's iterations
 
 	localTrustStorage *truststorage.Storage
@@ -430,7 +426,6 @@ func initCfg(path string) *cfg {
 		healthStatus: atomic.NewInt32(int32(control.HealthStatus_HEALTH_STATUS_UNDEFINED)),
 		cfgReputation: cfgReputation{
 			scriptHash: u160Reputation,
-			alpha:      viper.GetFloat64(cfgReputationAlpha),
 			workerPool: reputationWorkerPool,
 		},
 	}
@@ -486,7 +481,6 @@ func defaultConfiguration(v *viper.Viper) {
 	v.SetDefault(cfgContainerWorkerPoolEnabled, true)
 	v.SetDefault(cfgContainerWorkerPoolSize, 10)
 
-	v.SetDefault(cfgReputationAlpha, 0.5)
 	v.SetDefault(cfgReputationWorkerPoolEnabled, true)
 	v.SetDefault(cfgReputationWorkerPoolSize, 10)
 

cmd/neofs-node/reputation/intermediate/calculator.go

@@ -25,3 +25,13 @@ func (c *DaughtersTrustCalculator) Calculate(ctx eigentrustctrl.IterationContext
 
 	c.Calculator.Calculate(calcPrm)
 }
+
+// AlphaProvider provides required alpha parameter of eigen trust algorithm.
+// TODO: decide if `Alpha` should be dynamically read from global config. #497
+type AlphaProvider struct {
+	Alpha float64
+}
+
+func (ap AlphaProvider) EigenTrustAlpha() (float64, error) {
+	return ap.Alpha, nil
+}

pkg/services/reputation/eigentrust/calculator/calculator.go

@@ -18,7 +18,7 @@ type Prm struct {
 	// http://ilpubs.stanford.edu:8090/562/1/2002-56.pdf Ch.5.1.
 	//
 	// Must be in range (0, 1).
-	Alpha float64
+	AlphaProvider AlphaProvider
 
 	// Source of initial node trust values
 	//
@@ -63,8 +63,8 @@ func panicOnPrmValue(n string, v interface{}) {
 // initialization and is completely ready for work.
 func New(prm Prm, opts ...Option) *Calculator {
 	switch {
-	case prm.Alpha <= 0 || prm.Alpha >= 1:
-		panicOnPrmValue("Alpha", prm.Alpha)
+	case prm.AlphaProvider == nil:
+		panicOnPrmValue("AlphaProvider", prm.AlphaProvider)
 	case prm.InitialTrustSource == nil:
 		panicOnPrmValue("InitialTrustSource", prm.InitialTrustSource)
 	case prm.DaughterTrustSource == nil:
@@ -84,9 +84,7 @@ func New(prm Prm, opts ...Option) *Calculator {
 	}
 
 	return &Calculator{
-		alpha: reputation.TrustValueFromFloat64(prm.Alpha),
-		beta:  reputation.TrustValueFromFloat64(1 - prm.Alpha),
-		prm:   prm,
-		opts:  o,
+		prm:  prm,
+		opts: o,
 	}
 }

pkg/services/reputation/eigentrust/calculator/calls.go

@@ -24,6 +24,18 @@ func (p *CalculatePrm) SetEpochIteration(ei eigentrust.EpochIteration) {
 }
 
 func (c *Calculator) Calculate(prm CalculatePrm) {
+	alpha, err := c.prm.AlphaProvider.EigenTrustAlpha()
+	if err != nil {
+		c.opts.log.Debug(
+			"failed to get alpha param",
+			zap.Error(err),
+		)
+		return
+	}
+
+	c.alpha = reputation.TrustValueFromFloat64(alpha)
+	c.beta = reputation.TrustValueFromFloat64(1 - alpha)
+
 	ctx := eigentrust.IterContext{
 		Context:        context.Background(),
 		EpochIteration: prm.ei,

pkg/services/reputation/eigentrust/calculator/deps.go

@@ -59,3 +59,9 @@ type IntermediateWriter interface {
 type IntermediateWriterProvider interface {
 	InitIntermediateWriter(Context) (IntermediateWriter, error)
 }
+
+// AlphaProvider must provide information about required
+// alpha parameter for eigen trust algorithm.
+type AlphaProvider interface {
+	EigenTrustAlpha() (float64, error)
+}

pkg/services/reputation/eigentrust/controller/deps.go

@@ -34,7 +34,7 @@ type DaughtersTrustCalculator interface {
 	Calculate(ctx IterationContext)
 }
 
-// IterationsProvider must provides information about numbers
+// IterationsProvider must provide information about numbers
 // of iterations for algorithm.
 type IterationsProvider interface {
 	EigenTrustIterations() (uint64, error)