cmd/run: Implement the run command in Go

#318

Author: martymichal

src/cmd/run.go

@@ -17,10 +17,14 @@
 package cmd
 
 import (
+	"errors"
 	"fmt"
 	"os"
+	"strings"
+	"time"
 
 	"github.com/containers/toolbox/pkg/podman"
+	"github.com/containers/toolbox/pkg/shell"
 	"github.com/containers/toolbox/pkg/utils"
 	"github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
@@ -60,6 +64,265 @@ func init() {
 }
 
 func run(cmd *cobra.Command, args []string) error {
+	if utils.IsInsideContainer() {
+		if !utils.IsInsideToolboxContainer() {
+			return errors.New("this is not a toolbox container")
+		}
+
+		if _, err := utils.ForwardToHost(); err != nil {
+			return err
+		}
+
+		return nil
+	}
+
+	var nonDefaultContainer bool
+
+	if runFlags.container != "" {
+		nonDefaultContainer = true
+
+		if _, err := utils.IsContainerNameValid(runFlags.container); err != nil {
+			var builder strings.Builder
+			fmt.Fprintf(&builder, "invalid argument for '--container'\n")
+			fmt.Fprintf(&builder, "Container names must match '%s'\n", utils.ContainerNameRegexp)
+			fmt.Fprintf(&builder, "Run '%s --help' for usage.", executableBase)
+
+			errMsg := builder.String()
+			return errors.New(errMsg)
+		}
+	}
+
+	var release string
+	if runFlags.release != "" {
+		nonDefaultContainer = true
+
+		var err error
+		release, err = utils.ParseRelease(runFlags.release)
+		if err != nil {
+			err := utils.CreateErrorInvalidRelease(executableBase)
+			return err
+		}
+	}
+
+	if len(args) == 0 {
+		var builder strings.Builder
+		fmt.Fprintf(&builder, "missing argument for \"run\"\n")
+		fmt.Fprintf(&builder, "Run '%s --help' for usage.", executableBase)
+
+		errMsg := builder.String()
+		return errors.New(errMsg)
+	}
+
+	command := args
+
+	container, image, release, err := utils.ResolveContainerAndImageNames(runFlags.container, "", release)
+	if err != nil {
+		return err
+	}
+
+	if err := runCommand(container,
+		!nonDefaultContainer,
+		image,
+		release,
+		command,
+		false,
+		false,
+		true); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func runCommand(container string,
+	defaultContainer bool,
+	image, release string,
+	command []string,
+	emitEscapeSequence, fallbackToBash, pedantic bool) error {
+	if !pedantic {
+		if image == "" {
+			panic("image not specified")
+		}
+
+		if release == "" {
+			panic("release not specified")
+		}
+	}
+
+	logrus.Debugf("Checking if container %s exists", container)
+
+	if _, err := podman.ContainerExists(container); err != nil {
+		logrus.Debugf("Container %s not found", container)
+
+		if pedantic {
+			err := utils.CreateErrorContainerNotFound(container, executableBase)
+			return err
+		}
+
+		containers, err := listContainers()
+		if err != nil {
+			err := utils.CreateErrorContainerNotFound(container, executableBase)
+			return err
+		}
+
+		containersCount := len(containers)
+		logrus.Debugf("Found %d containers", containersCount)
+
+		if containersCount == 0 {
+			var shouldCreateContainer bool
+			promptForCreate := true
+
+			if rootFlags.assumeYes {
+				shouldCreateContainer = true
+				promptForCreate = false
+			}
+
+			if promptForCreate {
+				prompt := "No toolbox containers found. Create now? [y/N]"
+				shouldCreateContainer = utils.AskForConfirmation(prompt)
+			}
+
+			if !shouldCreateContainer {
+				fmt.Printf("A container can be created later with the 'create' command.\n")
+				fmt.Printf("Run '%s --help' for usage.\n", executableBase)
+				return nil
+			}
+
+			if err := createContainer(container, image, release, false); err != nil {
+				return err
+			}
+		} else if containersCount == 1 && defaultContainer {
+			fmt.Fprintf(os.Stderr, "Error: container %s not found\n", container)
+
+			container = containers[0]["Names"].(string)
+			fmt.Fprintf(os.Stderr, "Entering container %s instead.\n", container)
+			fmt.Fprintf(os.Stderr, "Use the 'create' command to create a different toolbox.\n")
+			fmt.Fprintf(os.Stderr, "Run '%s --help' for usage.\n", executableBase)
+		} else {
+			var builder strings.Builder
+			fmt.Fprintf(&builder, "container %s not found\n", container)
+			fmt.Fprintf(&builder, "Use the '--container' option to select a toolbox.\n")
+			fmt.Fprintf(&builder, "Run '%s --help' for usage.", executableBase)
+
+			errMsg := builder.String()
+			return errors.New(errMsg)
+		}
+	}
+
+	if _, err := utils.CallFlatpakSessionHelper(); err != nil {
+		return err
+	}
+
+	logrus.Debugf("Starting container %s", container)
+	if err := startContainer(container); err != nil {
+		return err
+	}
+
+	entryPoint, entryPointPID, err := getEntryPointAndPID(container)
+	if err != nil {
+		return err
+	}
+
+	if entryPoint != "toolbox" {
+		var builder strings.Builder
+		fmt.Fprintf(&builder, "container %s is too old and no longer supported \n", container)
+		fmt.Fprintf(&builder, "Recreate it with Toolbox version 0.0.17 or newer.\n")
+
+		errMsg := builder.String()
+		return errors.New(errMsg)
+	}
+
+	if entryPointPID <= 0 {
+		return fmt.Errorf("invalid entry point PID of container %s", container)
+	}
+
+	logrus.Debugf("Waiting for container %s to finish initializing", container)
+
+	runtimeDirectory := os.Getenv("XDG_RUNTIME_DIR")
+	toolboxRuntimeDirectory := runtimeDirectory + "/toolbox"
+	initializedStamp := fmt.Sprintf("%s/container-initialized-%d", toolboxRuntimeDirectory, entryPointPID)
+
+	logrus.Debugf("Checking if initialization stamp %s exists", initializedStamp)
+
+	initializedTimeout := 25 // seconds
+	for i := 0; !utils.PathExists(initializedStamp); i++ {
+		if i == initializedTimeout {
+			return fmt.Errorf("failed to initialize container %s", container)
+		}
+
+		time.Sleep(time.Second)
+	}
+
+	logrus.Debugf("Container %s is initialized", container)
+
+	if _, err := isCommandPresent(container, command[0]); err != nil {
+		if fallbackToBash {
+			logrus.Debugf("command %s not found in container %s; using /bin/bash instead",
+				command[0],
+				container)
+
+			command = []string{"/bin/bash"}
+		} else {
+			return fmt.Errorf("command %s not found in container %s", command[0], container)
+		}
+	}
+
+	envOptions := utils.GetEnvOptionsForPreservedVariables()
+	logLevelString := podman.LogLevel.String()
+
+	execArgs := []string{
+		"--log-level", logLevelString,
+		"exec",
+		"--interactive",
+		"--tty",
+		"--user", currentUser.Username,
+		"--workdir", workingDirectory,
+	}
+
+	execArgs = append(execArgs, envOptions...)
+
+	execArgs = append(execArgs, []string{
+		container,
+		"capsh", "--caps=", "--", "-c", "exec \"$@\"", "/bin/sh",
+	}...)
+
+	execArgs = append(execArgs, command...)
+
+	if emitEscapeSequence {
+		fmt.Printf("\033]777;container;push;%s;toolbox\033\\", container)
+	}
+
+	logrus.Debugf("Running in container %s:", container)
+	logrus.Debug("podman")
+	for _, arg := range execArgs {
+		logrus.Debugf("%s", arg)
+	}
+
+	exitCode, err := shell.RunWithExitCode("podman", os.Stdin, os.Stdout, nil, execArgs...)
+
+	if emitEscapeSequence {
+		fmt.Print("\033]777;container;pop;;\033\\")
+	}
+
+	switch exitCode {
+	case 0:
+		if err != nil {
+			panic("unexpected error: 'podman exec' finished successfully")
+		}
+	case 125:
+		err = fmt.Errorf("failed to invoke 'podman exec' in container %s", container)
+	case 126:
+		err = fmt.Errorf("failed to invoke command %s in container %s", command[0], container)
+	case 127:
+		err = fmt.Errorf("command %s not found in container %s", command[0], container)
+	default:
+		err = nil
+	}
+
+	if err != nil {
+		return err
+	}
+
 	return nil
 }
 
@@ -115,3 +378,79 @@ func getEntryPointAndPID(container string) (string, int, error) {
 
 	return entryPoint, entryPointPIDInt, nil
 }
+
+func isCommandPresent(container, command string) (bool, error) {
+	logrus.Debugf("Looking for command %s in container %s", command, container)
+
+	logLevelString := podman.LogLevel.String()
+	args := []string{
+		"--log-level", logLevelString,
+		"exec",
+		"--user", currentUser.Username,
+		container,
+		"sh", "-c", "command -v \"$1\"", "sh", command,
+	}
+
+	if err := shell.Run("podman", nil, nil, nil, args...); err != nil {
+		return false, err
+	}
+
+	return true, nil
+}
+
+func startContainer(container string) error {
+	var stderr strings.Builder
+	if err := podman.Start(container, &stderr); err == nil {
+		return nil
+	}
+
+	errString := stderr.String()
+	if !strings.Contains(errString, "use system migrate to mitigate") {
+		return fmt.Errorf("failed to start container %s", container)
+	}
+
+	logrus.Debug("Checking if 'podman system migrate' supports '--new-runtime'")
+
+	if !podman.CheckVersion("1.6.2") {
+		var builder strings.Builder
+
+		fmt.Fprintf(&builder,
+			"container %s doesn't support cgroups v%d\n",
+			container,
+			cgroupsVersion)
+
+		fmt.Fprintf(&builder, "Update Podman to version 1.6.2 or newer.\n")
+
+		errMsg := builder.String()
+		return errors.New(errMsg)
+	}
+
+	logrus.Debug("'podman system migrate' supports '--new-runtime'")
+
+	ociRuntimeRequired := "runc"
+	if cgroupsVersion == 2 {
+		ociRuntimeRequired = "crun"
+	}
+
+	logrus.Debugf("Migrating containers to OCI runtime %s", ociRuntimeRequired)
+
+	if err := podman.SystemMigrate(ociRuntimeRequired); err != nil {
+		var builder strings.Builder
+		fmt.Fprintf(&builder, "failed to migrate containers to OCI runtime %s\n", ociRuntimeRequired)
+		fmt.Fprintf(&builder, "Factory reset with: podman system reset")
+
+		errMsg := builder.String()
+		return errors.New(errMsg)
+	}
+
+	if err := podman.Start(container, nil); err != nil {
+		var builder strings.Builder
+		fmt.Fprintf(&builder, "container %s doesn't support cgroups v%d\n", container, cgroupsVersion)
+		fmt.Fprintf(&builder, "Factory reset with: podman system reset")
+
+		errMsg := builder.String()
+		return errors.New(errMsg)
+	}
+
+	return nil
+}