[#705] innerring/governance: Hide fetching ir keys behind interface

Add to governance processor IRFetcher interface.
Implementation must deduct if notary enabled or not.

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

pkg/innerring/innerring.go

@@ -547,6 +547,7 @@ func New(ctx context.Context, log *zap.Logger, cfg *viper.Viper) (*Server, error
 			AlphabetState:  server,
 			EpochState:     server,
 			Voter:          server,
+			IRFetcher:      irf,
 			MorphClient:    server.morphClient,
 			MainnetClient:  server.mainnetClient,
 			NotaryDisabled: server.sideNotaryConfig.disabled,

pkg/innerring/processors/governance/process_update.go

@@ -54,7 +54,7 @@ func (gp *Processor) processAlphabetSync() {
 	}
 
 	// 2. Update NeoFSAlphabet role in side chain.
-	innerRing, err := gp.morphClient.NeoFSAlphabetList()
+	innerRing, err := gp.irFetcher.InnerRingKeys()
 	if err != nil {
 		gp.log.Error("can't fetch inner ring list from side chain",
 			zap.String("error", err.Error()))

pkg/innerring/processors/governance/processor.go

@@ -36,6 +36,13 @@ type (
 		EpochCounter() uint64
 	}
 
+	// IRFetcher is a callback interface for innerring keys.
+	// Implementation must take into account availability of
+	// the notary contract.
+	IRFetcher interface {
+		InnerRingKeys() (keys.PublicKeys, error)
+	}
+
 	// Processor of events related to governance in the network.
 	Processor struct {
 		log          *zap.Logger
@@ -46,6 +53,7 @@ type (
 		alphabetState AlphabetState
 		epochState    EpochState
 		voter         Voter
+		irFetcher     IRFetcher
 
 		mainnetClient *client.Client
 		morphClient   *client.Client
@@ -60,6 +68,7 @@ type (
 		AlphabetState AlphabetState
 		EpochState    EpochState
 		Voter         Voter
+		IRFetcher     IRFetcher
 
 		MorphClient   *client.Client
 		MainnetClient *client.Client
@@ -85,6 +94,8 @@ func New(p *Params) (*Processor, error) {
 		return nil, errors.New("ir/governance: global state is not set")
 	case p.Voter == nil:
 		return nil, errors.New("ir/governance: global state is not set")
+	case p.IRFetcher == nil:
+		return nil, errors.New("ir/governance: innerring keys fetcher is not set")
 	}
 
 	pool, err := ants.NewPool(ProcessorPoolSize, ants.WithNonblocking(true))
@@ -100,6 +111,7 @@ func New(p *Params) (*Processor, error) {
 		alphabetState:  p.AlphabetState,
 		epochState:     p.EpochState,
 		voter:          p.Voter,
+		irFetcher:      p.IRFetcher,
 		mainnetClient:  p.MainnetClient,
 		morphClient:    p.MorphClient,
 		notaryDisabled: p.NotaryDisabled,