chore: Remove running multiple fp instances support (#86)

This PR partly addresses
#34 by
disallowing running multiple fp instances within the fp manager. Keyring
level improvement will be done in a separate PR to address #63. Notable
changes in this PR:

1. Remove `MaxNumFinalityProviders` from config as it is not applicable
2. If `--eots-pk` is not specified in `fpd start`, fp app will start
without any fp instances. To run a fp instance, `--eots-pk` must be
given
3. fp manager only keeps a single fp instance instead of a map

finality-provider/cmd/fpd/daemon/start.go

@@ -120,35 +120,31 @@ func startApp(
 	fpApp *service.FinalityProviderApp,
 	fpPkStr, passphrase string,
 ) error {
-	// only start the app without starting any finality-provider instance
-	// as there might be no finality-provider registered yet
+	// only start the app without starting any finality provider instance
+	// this is needed for new finality provider registration or unjailing
+	// finality providers
 	if err := fpApp.Start(); err != nil {
-		return fmt.Errorf("failed to start the finality-provider app: %w", err)
+		return fmt.Errorf("failed to start the finality provider app: %w", err)
 	}
 
-	if fpPkStr != "" {
-		// start the finality-provider instance with the given public key
-		fpPk, err := types.NewBIP340PubKeyFromHex(fpPkStr)
-		if err != nil {
-			return fmt.Errorf("invalid finality-provider public key %s: %w", fpPkStr, err)
-		}
+	// no fp instance will be started if public key is not specified
+	if fpPkStr == "" {
+		return nil
+	}
 
-		if err := fpApp.StartHandlingFinalityProvider(fpPk, passphrase); err != nil {
-			if errors.Is(err, service.ErrFinalityProviderJailed) {
-				fpApp.Logger().Error("failed to start finality provider", zap.Error(err))
-				// do not return error as we still want the service to start
-				return nil
-			}
-			return fmt.Errorf("failed to start the finality-provider instance %s: %w", fpPkStr, err)
-		}
+	// start the finality-provider instance with the given public key
+	fpPk, err := types.NewBIP340PubKeyFromHex(fpPkStr)
+	if err != nil {
+		return fmt.Errorf("invalid finality provider public key %s: %w", fpPkStr, err)
 	}
 
-	if err := fpApp.StartHandlingAll(); err != nil {
+	if err := fpApp.StartHandlingFinalityProvider(fpPk, passphrase); err != nil {
 		if errors.Is(err, service.ErrFinalityProviderJailed) {
 			fpApp.Logger().Error("failed to start finality provider", zap.Error(err))
 			// do not return error as we still want the service to start
 			return nil
 		}
+		return fmt.Errorf("failed to start the finality-provider instance %s: %w", fpPkStr, err)
 	}
 
 	return nil

finality-provider/config/config.go

@@ -38,7 +38,6 @@ const (
 	defaultMaxSubmissionRetries    = 20
 	defaultBitcoinNetwork          = "signet"
 	defaultDataDirname             = "data"
-	defaultMaxNumFinalityProviders = 3
 )
 
 var (
@@ -69,7 +68,6 @@ type Config struct {
 	FastSyncLimit            uint32        `long:"fastsynclimit" description:"The maximum number of blocks to catch up for each fast sync"`
 	FastSyncGap              uint64        `long:"fastsyncgap" description:"The block gap that will trigger the fast sync"`
 	EOTSManagerAddress       string        `long:"eotsmanageraddress" description:"The address of the remote EOTS manager; Empty if the EOTS manager is running locally"`
-	MaxNumFinalityProviders  uint32        `long:"maxnumfinalityproviders" description:"The maximum number of finality-provider instances running concurrently within the daemon"`
 	SyncFpStatusInterval     time.Duration `long:"syncfpstatusinterval" description:"The duration of time that it should sync FP status with the client blockchain"`
 
 	BitcoinNetwork string `long:"bitcoinnetwork" description:"Bitcoin network to run on" choise:"mainnet" choice:"regtest" choice:"testnet" choice:"simnet" choice:"signet"`
@@ -112,7 +110,6 @@ func DefaultConfigWithHome(homePath string) Config {
 		BTCNetParams:             defaultBTCNetParams,
 		EOTSManagerAddress:       defaultEOTSManagerAddress,
 		RpcListener:              DefaultRpcListener,
-		MaxNumFinalityProviders:  defaultMaxNumFinalityProviders,
 		Metrics:                  metrics.DefaultFpConfig(),
 		SyncFpStatusInterval:     defaultSyncFpStatusInterval,
 	}

finality-provider/service/app.go

@@ -151,10 +151,6 @@ func (app *FinalityProviderApp) Logger() *zap.Logger {
 	return app.logger
 }
 
-func (app *FinalityProviderApp) ListFinalityProviderInstances() []*FinalityProviderInstance {
-	return app.fpManager.ListFinalityProviderInstances()
-}
-
 func (app *FinalityProviderApp) ListAllFinalityProvidersInfo() ([]*proto.FinalityProviderInfo, error) {
 	return app.fpManager.AllFinalityProviders()
 }
@@ -164,8 +160,8 @@ func (app *FinalityProviderApp) GetFinalityProviderInfo(fpPk *bbntypes.BIP340Pub
 }
 
 // GetFinalityProviderInstance returns the finality-provider instance with the given Babylon public key
-func (app *FinalityProviderApp) GetFinalityProviderInstance(fpPk *bbntypes.BIP340PubKey) (*FinalityProviderInstance, error) {
-	return app.fpManager.GetFinalityProviderInstance(fpPk)
+func (app *FinalityProviderApp) GetFinalityProviderInstance() (*FinalityProviderInstance, error) {
+	return app.fpManager.GetFinalityProviderInstance()
 }
 
 func (app *FinalityProviderApp) RegisterFinalityProvider(fpPkStr string) (*RegisterFinalityProviderResponse, error) {
@@ -220,16 +216,12 @@ func (app *FinalityProviderApp) RegisterFinalityProvider(fpPkStr string) (*Regis
 	}
 }
 
-// StartHandlingFinalityProvider starts a finality-provider instance with the given Babylon public key
+// StartHandlingFinalityProvider starts a finality provider instance with the given EOTS public key
 // Note: this should be called right after the finality-provider is registered
 func (app *FinalityProviderApp) StartHandlingFinalityProvider(fpPk *bbntypes.BIP340PubKey, passphrase string) error {
 	return app.fpManager.StartFinalityProvider(fpPk, passphrase)
 }
 
-func (app *FinalityProviderApp) StartHandlingAll() error {
-	return app.fpManager.StartAll()
-}
-
 // NOTE: this is not safe in production, so only used for testing purpose
 func (app *FinalityProviderApp) getFpPrivKey(fpPk []byte) (*btcec.PrivateKey, error) {
 	record, err := app.eotsManager.KeyRecord(fpPk, "")

finality-provider/service/app_test.go

@@ -133,7 +133,7 @@ func FuzzRegisterFinalityProvider(f *testing.F) {
 		err = app.StartHandlingFinalityProvider(fp.GetBIP340BTCPK(), passphrase)
 		require.NoError(t, err)
 
-		fpAfterReg, err := app.GetFinalityProviderInstance(fp.GetBIP340BTCPK())
+		fpAfterReg, err := app.GetFinalityProviderInstance()
 		require.NoError(t, err)
 		require.Equal(t, proto.FinalityProviderStatus_REGISTERED, fpAfterReg.GetStoreFinalityProvider().Status)
 
@@ -210,7 +210,7 @@ func FuzzSyncFinalityProviderStatus(f *testing.F) {
 			if noVotingPowerTable {
 				expectedStatus = proto.FinalityProviderStatus_REGISTERED
 			}
-			fpInstance, err := app.GetFinalityProviderInstance(fpPk)
+			fpInstance, err := app.GetFinalityProviderInstance()
 			if err != nil {
 				return false
 			}

finality-provider/service/fp_instance.go

@@ -68,12 +68,11 @@ func NewFinalityProviderInstance(
 ) (*FinalityProviderInstance, error) {
 	sfp, err := s.GetFinalityProvider(fpPk.MustToBTCPK())
 	if err != nil {
-		return nil, fmt.Errorf("failed to retrive the finality-provider %s from DB: %w", fpPk.MarshalHex(), err)
+		return nil, fmt.Errorf("failed to retrive the finality provider %s from DB: %w", fpPk.MarshalHex(), err)
 	}
 
-	// ensure the finality-provider has been registered
-	if sfp.Status < proto.FinalityProviderStatus_REGISTERED {
-		return nil, fmt.Errorf("the finality-provider %s has not been registered", sfp.KeyName)
+	if !sfp.ShouldStart() {
+		return nil, fmt.Errorf("the finality provider instance cannot be initiated with status %s", sfp.Status.String())
 	}
 
 	return &FinalityProviderInstance{

finality-provider/service/fp_instance_test.go

@@ -12,6 +12,7 @@ import (
 
 	"github.com/babylonlabs-io/babylon/testutil/datagen"
 	ftypes "github.com/babylonlabs-io/babylon/x/finality/types"
+
 	"github.com/babylonlabs-io/finality-provider/clientcontroller"
 	"github.com/babylonlabs-io/finality-provider/eotsmanager"
 	eotscfg "github.com/babylonlabs-io/finality-provider/eotsmanager/config"
@@ -120,8 +121,6 @@ func startFinalityProviderAppWithRegisteredFp(t *testing.T, r *rand.Rand, cc cli
 	require.NoError(t, err)
 	err = app.Start()
 	require.NoError(t, err)
-	err = app.StartHandlingAll()
-	require.NoError(t, err)
 
 	// create registered finality-provider
 	fp := testutil.GenStoredFinalityProvider(r, t, app, passphrase, hdPath, nil)