[#352] Add explicit max number of alphabet nodes

Signed-off-by: Alejandro Lopez <a.lopez@yadro.com>

cmd/frostfs-adm/docs/deploy.md

@@ -18,6 +18,7 @@ To start a network, you need a set of consensus nodes, the same number of
 Alphabet nodes and any number of Storage nodes. While the number of Storage
 nodes can be scaled almost infinitely, the number of consensus and Alphabet
 nodes can't be changed so easily right now. Consider this before going any further.
+Note also that there is an upper limit on the number of alphabet nodes (currently 22).
 
 It is easier to use`frostfs-adm` with a predefined configuration. First, create
 a network configuration file. In this example, there is going to be only one

cmd/frostfs-adm/internal/modules/morph/generate.go

@@ -39,6 +39,9 @@ func generateAlphabetCreds(cmd *cobra.Command, _ []string) error {
 	if size == 0 {
 		return errors.New("size must be > 0")
 	}
+	if size > maxAlphabetNodes {
+		return ErrTooManyAlphabetNodes
+	}
 
 	v := viper.GetViper()
 	walletDir := config.ResolveHomePath(viper.GetString(alphabetWalletsFlag))

cmd/frostfs-adm/internal/modules/morph/initialize.go

@@ -23,6 +23,13 @@ import (
 	"github.com/spf13/viper"
 )
 
+const (
+	// maxAlphabetNodes is the maximum number of candidates allowed, which is currently limited by the size
+	// of the invocation script.
+	// See: https://github.com/nspcc-dev/neo-go/blob/740488f7f35e367eaa99a71c0a609c315fe2b0fc/pkg/core/transaction/witness.go#L10
+	maxAlphabetNodes = 22
+)
+
 type cache struct {
 	nnsCs    *state.Contract
 	groupKey *keys.PublicKey
@@ -45,6 +52,8 @@ type initializeContext struct {
 	ContractPath string
 }
 
+var ErrTooManyAlphabetNodes = fmt.Errorf("too many alphabet nodes (maximum allowed is %d)", maxAlphabetNodes)
+
 func initializeSideChainCmd(cmd *cobra.Command, _ []string) error {
 	initCtx, err := newInitializeContext(cmd, viper.GetViper())
 	if err != nil {
@@ -111,6 +120,10 @@ func newInitializeContext(cmd *cobra.Command, v *viper.Viper) (*initializeContex
 		return nil, err
 	}
 
+	if len(wallets) > maxAlphabetNodes {
+		return nil, ErrTooManyAlphabetNodes
+	}
+
 	needContracts := cmd.Name() == "update-contracts" || cmd.Name() == "init"
 
 	var w *wallet.Wallet

cmd/frostfs-adm/internal/modules/morph/initialize_test.go

@@ -2,6 +2,7 @@ package morph
 
 import (
 	"encoding/hex"
+	"fmt"
 	"os"
 	"path/filepath"
 	"strconv"
@@ -40,8 +41,11 @@ func TestInitialize(t *testing.T) {
 	t.Run("16 nodes", func(t *testing.T) {
 		testInitialize(t, 16)
 	})
-	t.Run("22 nodes", func(t *testing.T) {
-		testInitialize(t, 22)
+	t.Run("max nodes", func(t *testing.T) {
+		testInitialize(t, maxAlphabetNodes)
+	})
+	t.Run("too many nodes", func(t *testing.T) {
+		require.ErrorIs(t, generateTestData(t, t.TempDir(), maxAlphabetNodes+1), ErrTooManyAlphabetNodes)
 	})
 }
 
@@ -49,7 +53,7 @@ func testInitialize(t *testing.T, committeeSize int) {
 	testdataDir := t.TempDir()
 	v := viper.GetViper()
 
-	generateTestData(t, testdataDir, committeeSize)
+	require.NoError(t, generateTestData(t, testdataDir, committeeSize))
 	v.Set(protoConfigPath, filepath.Join(testdataDir, protoFileName))
 
 	// Set to the path or remove the next statement to download from the network.
@@ -80,25 +84,33 @@ func testInitialize(t *testing.T, committeeSize int) {
 	})
 }
 
-func generateTestData(t *testing.T, dir string, size int) {
+func generateTestData(t *testing.T, dir string, size int) error {
 	v := viper.GetViper()
 	v.Set(alphabetWalletsFlag, dir)
 
 	sizeStr := strconv.FormatUint(uint64(size), 10)
-	require.NoError(t, generateAlphabetCmd.Flags().Set(alphabetSizeFlag, sizeStr))
+	if err := generateAlphabetCmd.Flags().Set(alphabetSizeFlag, sizeStr); err != nil {
+		return err
+	}
 
 	setTestCredentials(v, size)
-	require.NoError(t, generateAlphabetCreds(generateAlphabetCmd, nil))
+	if err := generateAlphabetCreds(generateAlphabetCmd, nil); err != nil {
+		return err
+	}
 
 	var pubs []string
 	for i := 0; i < size; i++ {
 		p := filepath.Join(dir, innerring.GlagoliticLetter(i).String()+".json")
 		w, err := wallet.NewWalletFromFile(p)
-		require.NoError(t, err, "wallet doesn't exist")
+		if err != nil {
+			return fmt.Errorf("wallet doesn't exist: %w", err)
+		}
 		for _, acc := range w.Accounts {
 			if acc.Label == singleAccountName {
 				pub, ok := vm.ParseSignatureContract(acc.Contract.Script)
-				require.True(t, ok)
+				if !ok {
+					return fmt.Errorf("could not parse signature script for %s", acc.Address)
+				}
 				pubs = append(pubs, hex.EncodeToString(pub))
 				continue
 			}
@@ -113,10 +125,12 @@ func generateTestData(t *testing.T, dir string, size int) {
 	cfg.ProtocolConfiguration.P2PSigExtensions = true
 	cfg.ProtocolConfiguration.VerifyTransactions = true
 	data, err := yaml.Marshal(cfg)
-	require.NoError(t, err)
+	if err != nil {
+		return err
+	}
 
 	protoPath := filepath.Join(dir, protoFileName)
-	require.NoError(t, os.WriteFile(protoPath, data, os.ModePerm))
+	return os.WriteFile(protoPath, data, os.ModePerm)
 }
 
 func setTestCredentials(v *viper.Viper, size int) {