tmpnet: Add a UUID to temporary networks to support metrics collection

Previously, tmpnet networks were only identified by their path on
disk. In anticipation of centralizing metrics collection for temporary
networks, tmpnet will now generate a UUID for each temporary network
to ensure a unique identifier across execution environments.

.github/workflows/ci.yml

@@ -21,7 +21,7 @@ concurrency:
 
 env:
   go_version: '~1.21.7'
-  tmpnet_data_path: ~/.tmpnet/networks/1000
+  tmpnet_data_path: ~/.tmpnet/networks
 
 jobs:
   Unit:

go.mod

@@ -18,6 +18,7 @@ require (
 	github.com/ethereum/go-ethereum v1.12.0
 	github.com/google/btree v1.1.2
 	github.com/google/renameio/v2 v2.0.0
+	github.com/google/uuid v1.3.0
 	github.com/gorilla/mux v1.8.0
 	github.com/gorilla/rpc v1.2.0
 	github.com/gorilla/websocket v1.4.2
@@ -100,7 +101,6 @@ require (
 	github.com/golang/snappy v0.0.5-0.20220116011046-fa5810519dcb // indirect
 	github.com/google/go-cmp v0.6.0 // indirect
 	github.com/google/pprof v0.0.0-20230207041349-798e818bf904 // indirect
-	github.com/google/uuid v1.3.0 // indirect
 	github.com/grpc-ecosystem/grpc-gateway/v2 v2.12.0 // indirect
 	github.com/hashicorp/go-bexpr v0.1.10 // indirect
 	github.com/hashicorp/golang-lru v0.5.5-0.20210104140557-80c98217689d // indirect

tests/fixture/tmpnet/network.go

@@ -9,17 +9,17 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/fs"
 	"os"
 	"path/filepath"
 	"strconv"
 	"strings"
 	"time"
 
+	"github.com/google/uuid"
+
 	"github.com/ava-labs/avalanchego/config"
 	"github.com/ava-labs/avalanchego/genesis"
 	"github.com/ava-labs/avalanchego/ids"
-	"github.com/ava-labs/avalanchego/utils/constants"
 	"github.com/ava-labs/avalanchego/utils/crypto/secp256k1"
 	"github.com/ava-labs/avalanchego/utils/perms"
 	"github.com/ava-labs/avalanchego/utils/set"
@@ -40,6 +40,9 @@ const (
 	// increase the time for a network's nodes to be seen as healthy.
 	networkHealthCheckInterval = 200 * time.Millisecond
 
+	// All temporary network will use this arbitrary default network ID by default.
+	defaultNetworkID = 88888
+
 	// eth address: 0x8db97C7cEcE249c2b98bDC0226Cc4C2A57BF52FC
 	HardHatKeyStr = "56289e99c94b6912bfc12adc093c9b51124f0dc54ac7a766b2bc5ccf558d8027"
 )
@@ -61,6 +64,13 @@ func init() {
 
 // Collects the configuration for running a temporary avalanchego network
 type Network struct {
+	// Uniquely identifies the temporary network for storage on disk and
+	// metrics collection. Distinct from avalanchego's concept of network ID
+	// since the utility of special network ID values (e.g. to trigger specific
+	// fork behavior in a given network) precludes requiring unique network ID
+	// values across all temporary networks.
+	UUID string
+
 	// Path where network configuration and data is stored
 	Dir string
 
@@ -208,6 +218,7 @@ func (n *Network) EnsureDefaultConfig(w io.Writer, avalancheGoPath string, plugi
 
 // Creates the network on disk, choosing its network id and generating its genesis in the process.
 func (n *Network) Create(rootDir string) error {
+	// Ensure creation of the root dir
 	if len(rootDir) == 0 {
 		// Use the default root dir
 		var err error
@@ -216,48 +227,30 @@ func (n *Network) Create(rootDir string) error {
 			return err
 		}
 	}
-
-	// Ensure creation of the root dir
 	if err := os.MkdirAll(rootDir, perms.ReadWriteExecute); err != nil {
 		return fmt.Errorf("failed to create root network dir: %w", err)
 	}
 
-	// Determine the network path and ID
-	var (
-		networkDir string
-		networkID  uint32
-	)
-	if n.Genesis != nil && n.Genesis.NetworkID > 0 {
-		// Use the network ID defined in the provided genesis
-		networkID = n.Genesis.NetworkID
+	// Ensure creation of the network dir
+	if len(n.UUID) == 0 {
+		n.UUID = uuid.NewString()
 	}
-	if networkID > 0 {
-		// Use a directory with a random suffix
-		var err error
-		networkDir, err = os.MkdirTemp(rootDir, fmt.Sprintf("%d.", n.Genesis.NetworkID))
-		if err != nil {
-			return fmt.Errorf("failed to create network dir: %w", err)
-		}
-	} else {
-		// Find the next available network ID based on the contents of the root dir
-		var err error
-		networkID, networkDir, err = findNextNetworkID(rootDir)
-		if err != nil {
-			return err
-		}
+	networkDir := filepath.Join(rootDir, n.UUID)
+	if err := os.MkdirAll(networkDir, perms.ReadWriteExecute); err != nil {
+		return fmt.Errorf("failed to create network dir: %w", err)
 	}
 	canonicalDir, err := toCanonicalDir(networkDir)
 	if err != nil {
 		return err
 	}
 	n.Dir = canonicalDir
 
+	// Ensure the existence of the plugin directory or nodes won't be able to start.
 	pluginDir, err := n.DefaultFlags.GetStringVal(config.PluginDirKey)
 	if err != nil {
 		return err
 	}
 	if len(pluginDir) > 0 {
-		// Ensure the existence of the plugin directory or nodes won't be able to start.
 		if err := os.MkdirAll(pluginDir, perms.ReadWriteExecute); err != nil {
 			return fmt.Errorf("failed to create plugin dir: %w", err)
 		}
@@ -275,7 +268,7 @@ func (n *Network) Create(rootDir string) error {
 		}
 		keysToFund = append(keysToFund, n.PreFundedKeys...)
 
-		genesis, err := NewTestGenesis(networkID, n.Nodes, keysToFund)
+		genesis, err := NewTestGenesis(defaultNetworkID, n.Nodes, keysToFund)
 		if err != nil {
 			return err
 		}
@@ -296,7 +289,7 @@ func (n *Network) Create(rootDir string) error {
 
 // Starts all nodes in the network
 func (n *Network) Start(ctx context.Context, w io.Writer) error {
-	if _, err := fmt.Fprintf(w, "Starting network %d @ %s\n", n.Genesis.NetworkID, n.Dir); err != nil {
+	if _, err := fmt.Fprintf(w, "Starting network %s\n", n.Dir); err != nil {
 		return err
 	}
 
@@ -313,7 +306,7 @@ func (n *Network) Start(ctx context.Context, w io.Writer) error {
 	if err := n.WaitForHealthy(ctx, w); err != nil {
 		return err
 	}
-	if _, err := fmt.Fprintf(w, "\nStarted network %d @ %s\n", n.Genesis.NetworkID, n.Dir); err != nil {
+	if _, err := fmt.Fprintf(w, "\nStarted network %s\n", n.Dir); err != nil {
 		return err
 	}
 
@@ -676,33 +669,3 @@ func getDefaultRootDir() (string, error) {
 	}
 	return filepath.Join(homeDir, ".tmpnet", "networks"), nil
 }
-
-// Finds the next available network ID by attempting to create a
-// directory numbered from 1000 until creation succeeds. Returns the
-// network id and the full path of the created directory.
-func findNextNetworkID(rootDir string) (uint32, string, error) {
-	var (
-		networkID uint32 = 1000
-		dirPath   string
-	)
-	for {
-		_, reserved := constants.NetworkIDToNetworkName[networkID]
-		if reserved {
-			networkID++
-			continue
-		}
-
-		dirPath = filepath.Join(rootDir, strconv.FormatUint(uint64(networkID), 10))
-		err := os.Mkdir(dirPath, perms.ReadWriteExecute)
-		if err == nil {
-			return networkID, dirPath, nil
-		}
-
-		if !errors.Is(err, fs.ErrExist) {
-			return 0, "", fmt.Errorf("failed to create network directory: %w", err)
-		}
-
-		// Directory already exists, keep iterating
-		networkID++
-	}
-}

tests/fixture/tmpnet/network_config.go

@@ -185,13 +185,15 @@ func (n *Network) readConfig() error {
 
 // The subset of network fields to store in the network config file.
 type serializedNetworkConfig struct {
+	UUID                 string
 	DefaultFlags         FlagsMap
 	DefaultRuntimeConfig NodeRuntimeConfig
 	PreFundedKeys        []*secp256k1.PrivateKey
 }
 
 func (n *Network) writeNetworkConfig() error {
 	config := &serializedNetworkConfig{
+		UUID:                 n.UUID,
 		DefaultFlags:         n.DefaultFlags,
 		DefaultRuntimeConfig: n.DefaultRuntimeConfig,
 		PreFundedKeys:        n.PreFundedKeys,