basic 'zrok access stdio' (#1119)

cmd/zrok/accessStdio.go

@@ -0,0 +1,112 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"os/signal"
+	"syscall"
+
+	"github.com/openziti/zrok/environment"
+	"github.com/openziti/zrok/environment/env_core"
+	"github.com/openziti/zrok/sdk/golang/sdk"
+	"github.com/openziti/zrok/tui"
+	"github.com/spf13/cobra"
+)
+
+func init() {
+	accessCmd.AddCommand(newAccessStdioCommand().cmd)
+}
+
+type accessStdioCommand struct {
+	cmd *cobra.Command
+}
+
+func newAccessStdioCommand() *accessStdioCommand {
+	cmd := &cobra.Command{
+		Use:   "stdio <shareToken>",
+		Short: "Access a share using stdin/stdout",
+		Args:  cobra.ExactArgs(1),
+	}
+	command := &accessStdioCommand{cmd: cmd}
+	cmd.Run = command.run
+	return command
+}
+
+func (cmd *accessStdioCommand) run(_ *cobra.Command, args []string) {
+	shrToken := args[0]
+
+	root, err := environment.LoadRoot()
+	if err != nil {
+		cmd.error(err)
+	}
+
+	if !root.IsEnabled() {
+		cmd.error(fmt.Errorf("unable to load environment; did you 'zrok enable'?"))
+	}
+
+	acc, err := sdk.CreateAccess(root, &sdk.AccessRequest{ShareToken: shrToken})
+	if err != nil {
+		cmd.error(err)
+	}
+
+	// validate backend mode is compatible with stdio
+	switch acc.BackendMode {
+	case sdk.UdpTunnelBackendMode:
+		cmd.deleteAccess(root, acc)
+		cmd.error(fmt.Errorf("'udpTunnel' backend mode is not compatible with stdio access"))
+	case sdk.VpnBackendMode:
+		cmd.deleteAccess(root, acc)
+		cmd.error(fmt.Errorf("'vpn' backend mode is not compatible with stdio access"))
+	}
+
+	conn, err := sdk.NewDialer(shrToken, root)
+	if err != nil {
+		cmd.deleteAccess(root, acc)
+		cmd.error(err)
+	}
+
+	// signal handling for clean shutdown
+	c := make(chan os.Signal, 1)
+	signal.Notify(c, os.Interrupt, syscall.SIGTERM, syscall.SIGHUP)
+	go func() {
+		<-c
+		_ = conn.Close()
+		cmd.deleteAccess(root, acc)
+		os.Exit(0)
+	}()
+
+	// bidirectional copy
+	errc := make(chan error, 2)
+
+	// stdin -> connection
+	go func() {
+		_, err := io.Copy(conn, os.Stdin)
+		_ = conn.Close()
+		errc <- err
+	}()
+
+	// connection -> stdout
+	go func() {
+		_, err := io.Copy(os.Stdout, conn)
+		errc <- err
+	}()
+
+	// wait for either direction to complete
+	<-errc
+
+	cmd.deleteAccess(root, acc)
+}
+
+func (cmd *accessStdioCommand) deleteAccess(root env_core.Root, acc *sdk.Access) {
+	if err := sdk.DeleteAccess(root, acc); err != nil {
+		tui.Warning(fmt.Sprintf("error deleting access: %v", err))
+	}
+}
+
+func (cmd *accessStdioCommand) error(err error) {
+	if !panicInstead {
+		tui.Error("unable to create stdio access", err)
+	}
+	panic(err)
+}