rename machine config to state

internal/machine/state.go

@@ -0,0 +1,139 @@
+package machine
+
+import (
+	"crypto/rand"
+	"encoding/json"
+	"fmt"
+	"math/big"
+	"net/netip"
+	"os"
+	"path/filepath"
+	"uncloud/internal/machine/network"
+	"uncloud/internal/secret"
+)
+
+const (
+	DefaultDataDir = "/var/lib/uncloud"
+	StateFileName  = "machine.json"
+	APIPort        = 51000
+)
+
+// State defines the machine-specific configuration within a cluster. It encapsulates essential identifiers
+// and settings required to establish an overlay network and operate as a member of a cluster.
+type State struct {
+	// ID uniquely identifies this machine in the cluster.
+	ID string
+	// Name provides a human-readable identifier for the machine.
+	Name string
+	// Network specifies the network configuration for this machine.
+	Network *network.Config
+
+	// path is the file path config is read from and saved to.
+	path string
+}
+
+// StatePath returns the path to the machine state file within the given data directory.
+func StatePath(dataDir string) string {
+	return filepath.Join(dataDir, StateFileName)
+}
+
+// ParseState reads and decodes a state from the file at the given path.
+func ParseState(path string) (*State, error) {
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return nil, fmt.Errorf("read config file: %w", err)
+	}
+	var config State
+	if err = json.Unmarshal(data, &config); err != nil {
+		return nil, fmt.Errorf("parse config file %q: %w", path, err)
+	}
+
+	if config.Network == nil {
+		return nil, fmt.Errorf("missing network configuration in config file %q", path)
+	}
+	return &config, nil
+}
+
+// SetPath sets the file path the state can be saved to.
+func (c *State) SetPath(path string) {
+	c.path = path
+}
+
+// Encode returns the JSON encoded state data.
+func (c *State) Encode() ([]byte, error) {
+	data, err := json.MarshalIndent(c, "", "  ")
+	if err != nil {
+		return nil, fmt.Errorf("marshal config: %w", err)
+	}
+	return data, nil
+}
+
+// Save writes the state data to the file at the given path.
+func (c *State) Save() error {
+	if c.path == "" {
+		return fmt.Errorf("config path not set")
+	}
+	dir, _ := filepath.Split(c.path)
+	if err := os.MkdirAll(dir, 0700); err != nil {
+		return fmt.Errorf("create config directory %q: %w", dir, err)
+	}
+
+	data, err := c.Encode()
+	if err != nil {
+		return err
+	}
+	return os.WriteFile(c.path, data, 0600)
+}
+
+// NewID generates a new unique machine ID.
+func NewID() (string, error) {
+	return secret.NewID()
+}
+
+// NewRandomName generates a random machine name in the format "machine-xxxx".
+func NewRandomName() (string, error) {
+	const charset = "abcdefghijklmnopqrstuvwxyz0123456789"
+	suffix := make([]byte, 4)
+	for i := range suffix {
+		randIdx, err := rand.Int(rand.Reader, big.NewInt(int64(len(charset))))
+		if err != nil {
+			return "", fmt.Errorf("get random number: %w", err)
+		}
+		suffix[i] = charset[randIdx.Int64()]
+	}
+	return "machine-" + string(suffix), nil
+}
+
+// NewBootstrapConfig returns a new machine configuration that should be applied to the first machine in a cluster.
+func NewBootstrapConfig(name string, subnet netip.Prefix, peers ...network.PeerConfig) (*State, error) {
+	mid, err := NewID()
+	if err != nil {
+		return nil, fmt.Errorf("generate machine ID: %w", err)
+	}
+	if name == "" {
+		name, err = NewRandomName()
+		if err != nil {
+			return nil, fmt.Errorf("generate machine name: %w", err)
+		}
+	}
+	privKey, pubKey, err := network.NewMachineKeys()
+	if err != nil {
+		return nil, fmt.Errorf("generate machine keys: %w", err)
+	}
+	if subnet == (netip.Prefix{}) {
+		// Use the first /24 subnet in the default network.
+		subnet = netip.PrefixFrom(network.DefaultNetwork.Addr(), network.DefaultSubnetBits)
+	}
+
+	return &State{
+		ID:   mid,
+		Name: name,
+		Network: &network.Config{
+			Subnet:       subnet,
+			ManagementIP: network.ManagementIP(pubKey),
+			PrivateKey:   privKey,
+			PublicKey:    pubKey,
+			Peers:        peers,
+		},
+	}, nil
+}