implement CLI init cluster, add SSH and WireGuard cluster connectors

internal/cli/client/connector/wireguard.go

@@ -0,0 +1,83 @@
+package connector
+
+import (
+	"context"
+	"fmt"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials/insecure"
+	"net"
+	"net/netip"
+	"strconv"
+	"uncloud/internal/cli/client"
+	"uncloud/internal/cli/config"
+	machine2 "uncloud/internal/machine"
+	"uncloud/internal/machine/network"
+	"uncloud/internal/machine/network/tunnel"
+)
+
+// WireGuardConnector establishes a connection to the cluster API through a WireGuard tunnel
+// to one of the cluster machines.
+type WireGuardConnector struct {
+	user     *client.User
+	machines []config.MachineConnection
+	tun      *tunnel.Tunnel
+}
+
+func NewWireGuardConnector(user *client.User, machines []config.MachineConnection) *WireGuardConnector {
+	return &WireGuardConnector{
+		user:     user,
+		machines: machines,
+	}
+}
+
+// TODO: handle context cancelation.
+func (c *WireGuardConnector) Connect(ctx context.Context) (*grpc.ClientConn, error) {
+	if len(c.machines) == 0 {
+		return nil, fmt.Errorf("no machines to connect to")
+	}
+	// TODO: iterate over machines and try to connect to each one until successful.
+	//  For now, try to connect to only the first machine.
+	machine := c.machines[0]
+	endpointIPs, err := net.LookupIP(machine.Host)
+	if err != nil {
+		return nil, fmt.Errorf("resolve IP for %q: %w", machine.Host, err)
+	}
+	endpointAddr, err := netip.ParseAddr(endpointIPs[0].String())
+	if err != nil {
+		return nil, fmt.Errorf("parse IP address %q: %w", endpointIPs[0].String(), err)
+	}
+	endpoint := netip.AddrPortFrom(endpointAddr, tunnel.DefaultEndpointPort)
+	machineManagementIP := network.ManagementIP(machine.PublicKey)
+	machineAPIAddr := net.JoinHostPort(machineManagementIP.String(), strconv.Itoa(machine2.APIPort))
+
+	tunCfg := &tunnel.Config{
+		LocalAddress:    c.user.ManagementIP(),
+		LocalPrivateKey: c.user.PrivateKey(),
+		RemotePublicKey: machine.PublicKey,
+		RemoteNetwork:   netip.PrefixFrom(machineManagementIP, 128),
+		Endpoint:        endpoint,
+	}
+	if c.tun, err = tunnel.Connect(tunCfg); err != nil {
+		return nil, fmt.Errorf("establish WireGuard tunnel to %q: %w", endpoint, err)
+	}
+
+	conn, err := grpc.NewClient(
+		machineAPIAddr,
+		grpc.WithTransportCredentials(insecure.NewCredentials()),
+		grpc.WithContextDialer(func(ctx context.Context, addr string) (net.Conn, error) {
+			return c.tun.DialContext(ctx, "tcp", addr)
+		}),
+	)
+	if err != nil {
+		return nil, fmt.Errorf("connect to machine API through WireGuard tunnel: %w", err)
+	}
+	return conn, nil
+}
+
+func (c *WireGuardConnector) Close() error {
+	if c.tun != nil {
+		c.tun.Close()
+		c.tun = nil
+	}
+	return nil
+}