feat: Add Dockercompat Mode & DevContainer Support (#1100)

* Port changes from Shubham fork

Signed-off-by: Sam Chew <[email protected]>

* Add DevContainers functionality to Finch

Signed-off-by: Sam Chew <[email protected]>

---------

Signed-off-by: Sam Chew <[email protected]>

cmd/finch/main.go

@@ -44,5 +44,12 @@ func initializeNerdctlCommands(
 	for cmdName, cmdDescription := range nerdctlCmds {
 		allNerdctlCommands = append(allNerdctlCommands, nerdctlCommandCreator.create(cmdName, cmdDescription))
 	}
+
+	if fc.DockerCompat {
+		for cmdName, cmdDescription := range dockerCompatCmds {
+			allNerdctlCommands = append(allNerdctlCommands, nerdctlCommandCreator.create(cmdName, cmdDescription))
+		}
+	}
+
 	return allNerdctlCommands
 }

cmd/finch/nerdctl.go

@@ -6,10 +6,12 @@ package main
 import (
 	"encoding/json"
 	"fmt"
+	"strings"
 
 	"golang.org/x/exp/slices"
 
 	"github.com/aws/aws-sdk-go-v2/aws"
+	"github.com/sirupsen/logrus"
 	"github.com/spf13/afero"
 	"github.com/spf13/cobra"
 
@@ -41,6 +43,11 @@ type nerdctlCommandCreator struct {
 	fc         *config.Finch
 }
 
+type (
+	argHandler     func(systemDeps NerdctlCommandSystemDeps, fc *config.Finch, args []string, index int) error
+	commandHandler func(systemDeps NerdctlCommandSystemDeps, fc *config.Finch, cmdName *string, args *[]string) error
+)
+
 func newNerdctlCommandCreator(
 	ncc command.NerdctlCmdCreator,
 	ecc command.Creator,
@@ -192,12 +199,33 @@ var nerdctlCmds = map[string]string{
 	"wait":      "Block until one or more containers stop, then print their exit codes",
 }
 
+var dockerCompatCmds = map[string]string{
+	"buildx": "build version",
+}
+
+var aliasMap = map[string]string{
+	"build": "image build",
+	"run":   "container run",
+	"cp":    "container cp",
+}
+
+var commandHandlerMap = map[string]commandHandler{
+	"buildx":  handleBuildx,
+	"inspect": handleDockerCompatInspect,
+}
+
+var argHandlerMap = map[string]map[string]argHandler{
+	"image build": {
+		"--load": handleDockerBuildLoad,
+	},
+}
+
 var cmdFlagSetMap = map[string]map[string]sets.Set[string]{
 	"container run": {
 		"shortBoolFlags": sets.New[string]("-d", "-i", "-t"),
 		"longBoolFlags": sets.New[string](
 			"--detach", "--init", "--interactive", "--oom-kill-disable",
-			"--privileged", "--read-only", "--rm", "--rootfs", "--tty"),
+			"--privileged", "--read-only", "--rm", "--rootfs", "--tty", "--sig-proxy"),
 		"shortArgFlags": sets.New[string]("-e", "-h", "-m", "-u", "-w", "-p", "-l", "-v"),
 	},
 	"exec": {
@@ -215,3 +243,99 @@ var cmdFlagSetMap = map[string]map[string]sets.Set[string]{
 		"shortArgFlags": sets.New[string]("-e", "-h", "-m", "-u", "-w", "-p", "-l", "-v"),
 	},
 }
+
+// converts "docker build --load" flag to "nerdctl build --output=type=docker".
+func handleDockerBuildLoad(_ NerdctlCommandSystemDeps, fc *config.Finch, nerdctlCmdArgs []string, index int) error {
+	if fc.DockerCompat {
+		nerdctlCmdArgs[index] = "--output=type=docker"
+	}
+
+	return nil
+}
+
+func handleBuildx(_ NerdctlCommandSystemDeps, fc *config.Finch, cmdName *string, args *[]string) error {
+	if fc == nil || !fc.DockerCompat {
+		return nil
+	}
+
+	if cmdName != nil && *cmdName == "buildx" {
+		subCmd := (*args)[0]
+		buildxSubcommands := []string{"bake", "create", "debug", "du", "imagetools", "inspect", "ls", "prune", "rm", "stop", "use", "version"}
+
+		if slices.Contains(buildxSubcommands, subCmd) {
+			return fmt.Errorf("unsupported buildx command: %s", subCmd)
+		}
+
+		logrus.Warn("buildx is not supported. using standard buildkit instead...")
+		if subCmd == "build" {
+			*args = (*args)[1:]
+		}
+		*cmdName = "build"
+	}
+	// else, continue with the original command
+	return nil
+}
+
+func handleDockerCompatInspect(_ NerdctlCommandSystemDeps, fc *config.Finch, cmdName *string, args *[]string) error {
+	if !fc.DockerCompat {
+		return nil
+	}
+
+	if *args == nil {
+		return fmt.Errorf("invalid arguments: args (null pointer)")
+	}
+
+	modeDockerCompat := `--mode=dockercompat`
+	inspectType := ""
+	sizeArg := ""
+	savedArgs := []string{}
+	skip := false
+
+	for idx, arg := range *args {
+		if skip {
+			skip = false
+			continue
+		}
+
+		if (arg == "--type") && (idx < len(*args)-1) {
+			inspectType = (*args)[idx+1]
+			skip = true
+			continue
+		}
+
+		if strings.Contains(arg, "--type") && strings.Contains(arg, "=") {
+			inspectType = strings.Split(arg, "=")[1]
+			continue
+		}
+
+		if (arg == "--size") || (arg == "-s") {
+			sizeArg = "--size"
+			continue
+		}
+
+		savedArgs = append(savedArgs, arg)
+	}
+
+	switch inspectType {
+	case "image":
+		*cmdName = "image inspect"
+		*args = append([]string{modeDockerCompat}, savedArgs...)
+	case "volume":
+		*cmdName = "volume inspect"
+		if sizeArg != "" {
+			*args = append([]string{sizeArg}, savedArgs...)
+		} else {
+			*args = append([]string{}, savedArgs...)
+		}
+	case "container":
+		*cmdName = "inspect"
+		*args = append([]string{modeDockerCompat}, savedArgs...)
+	case "":
+		*cmdName = "inspect"
+		*args = append([]string{modeDockerCompat}, savedArgs...)
+	default:
+		return fmt.Errorf("unsupported inspect type: %s", inspectType)
+	}
+
+	return nil
+}

cmd/finch/nerdctl_darwin.go

@@ -13,20 +13,23 @@ import (
 	"github.com/lima-vm/lima/pkg/networks"
 
 	"github.com/runfinch/finch/pkg/command"
+	"github.com/runfinch/finch/pkg/config"
 	"github.com/runfinch/finch/pkg/flog"
 )
 
 func convertToWSLPath(_ NerdctlCommandSystemDeps, _ string) (string, error) {
 	return "", nil
 }
 
-var aliasMap = map[string]string{
-	"run": "container run",
-}
+var osAliasMap = map[string]string{}
 
-var argHandlerMap = map[string]map[string]argHandler{}
+var osArgHandlerMap = map[string]map[string]argHandler{
+	"container run": {
+		"--mount": handleBindMounts,
+	},
+}
 
-var commandHandlerMap = map[string]commandHandler{}
+var osCommandHandlerMap = map[string]commandHandler{}
 
 func (nc *nerdctlCommand) GetCmdArgs() []string {
 	return []string{"shell", limaInstanceName, "sudo", "-E"}
@@ -46,3 +49,73 @@ func resolveIP(host string, logger flog.Logger, _ command.Creator) (string, erro
 	}
 	return host, nil
 }
+
+// removes the consistency key-value entity from --mount.
+func handleBindMounts(_ NerdctlCommandSystemDeps, _ *config.Finch, nerdctlCmdArgs []string, index int) error {
+	prefix := nerdctlCmdArgs[index]
+	var (
+		v      string
+		found  bool
+		before string
+	)
+	if strings.Contains(nerdctlCmdArgs[index], "=") {
+		before, v, found = strings.Cut(prefix, "=")
+	} else {
+		if (index + 1) < len(nerdctlCmdArgs) {
+			v = nerdctlCmdArgs[index+1]
+		} else {
+			return fmt.Errorf("invalid positional parameter for %s", prefix)
+		}
+	}
+
+	// This is where the 'consistency=cached' strings should be removed....
+	//   "consistency will be one of the keys in the following map"
+
+	// eg --mount type=bind,source="$(pwd)"/target,target=/app,readonly
+	// eg --mount type=bind,
+	//            source=/Users/stchew/projs/arbtest_devcontainers_extensions,
+	//            target=/workspaces/arbtest_devcontainers_extensions,
+	//            consistency=cached
+	// https://docs.docker.com/storage/bind-mounts/#choose-the--v-or---mount-flag  order does not matter, so convert to a map
+	entries := strings.Split(v, ",")
+	m := make(map[string]string)
+	ro := []string{}
+	for _, e := range entries {
+		parts := strings.Split(e, "=")
+		if len(parts) < 2 {
+			ro = append(ro, parts...)
+		} else {
+			m[strings.TrimSpace(parts[0])] = strings.TrimSpace(parts[1])
+		}
+	}
+	// Check if type is bind mount, else return
+	if m["type"] != "bind" {
+		return nil
+	}
+
+	// Remove 'consistency' key-value pair
+	delete(m, "consistency")
+
+	// Convert to string representation
+	s := mapToString(m)
+	// append read-only key if present
+	if len(ro) > 0 {
+		s = s + "," + strings.Join(ro, ",")
+	}
+	if found {
+		nerdctlCmdArgs[index] = fmt.Sprintf("%s=%s", before, s)
+	} else {
+		nerdctlCmdArgs[index+1] = s
+	}
+
+	return nil
+}
+
+func mapToString(m map[string]string) string {
+	var parts []string
+	for k, v := range m {
+		part := fmt.Sprintf("%s=%s", k, v)
+		parts = append(parts, part)
+	}
+	return strings.Join(parts, ",")
+}