buildkit/frontend/dockerfile/dockerfile2llb/convert.go

554 lines
14 KiB
Go

package dockerfile2llb
import (
"bytes"
"context"
"encoding/json"
"fmt"
"net/url"
"path"
"path/filepath"
"strconv"
"strings"
"github.com/docker/distribution/reference"
"github.com/docker/docker/builder/dockerfile/instructions"
"github.com/docker/docker/builder/dockerfile/parser"
"github.com/docker/docker/pkg/signal"
"github.com/docker/docker/pkg/urlutil"
"github.com/docker/go-connections/nat"
"github.com/moby/buildkit/client/llb"
"github.com/moby/buildkit/client/llb/imagemetaresolver"
"github.com/pkg/errors"
"golang.org/x/sync/errgroup"
)
const (
emptyImageName = "scratch"
localNameContext = "context"
)
type ConvertOpt struct {
Target string
MetaResolver llb.ImageMetaResolver
BuildArgs map[string]string
SessionID string
BuildContext *llb.State
}
func Dockerfile2LLB(ctx context.Context, dt []byte, opt ConvertOpt) (*llb.State, *Image, error) {
if len(dt) == 0 {
return nil, nil, errors.Errorf("the Dockerfile cannot be empty")
}
dockerfile, err := parser.Parse(bytes.NewReader(dt))
if err != nil {
return nil, nil, err
}
stages, metaArgs, err := instructions.Parse(dockerfile.AST)
if err != nil {
return nil, nil, err
}
for i := range metaArgs {
metaArgs[i] = setBuildArgValue(metaArgs[i], opt.BuildArgs)
}
shlex := NewShellLex(dockerfile.EscapeToken)
metaResolver := opt.MetaResolver
if metaResolver == nil {
metaResolver = imagemetaresolver.Default()
}
var allDispatchStates []*dispatchState
dispatchStatesByName := map[string]*dispatchState{}
// set base state for every image
for _, st := range stages {
name, err := shlex.ProcessWord(st.BaseName, toEnvList(metaArgs, nil))
if err != nil {
return nil, nil, err
}
st.BaseName = name
ds := &dispatchState{
stage: st,
}
if d, ok := dispatchStatesByName[st.BaseName]; ok {
ds.base = d
}
allDispatchStates = append(allDispatchStates, ds)
if st.Name != "" {
dispatchStatesByName[strings.ToLower(st.Name)] = ds
}
}
eg, ctx := errgroup.WithContext(ctx)
for i, d := range allDispatchStates {
// resolve image config for every stage
if d.base == nil {
if d.stage.BaseName == emptyImageName {
d.state = llb.Scratch()
d.image = emptyImage()
continue
}
func(i int, d *dispatchState) {
eg.Go(func() error {
ref, err := reference.ParseNormalizedNamed(d.stage.BaseName)
if err != nil {
return err
}
d.stage.BaseName = reference.TagNameOnly(ref).String()
if metaResolver != nil {
dgst, dt, err := metaResolver.ResolveImageConfig(ctx, d.stage.BaseName)
if err == nil { // handle the error while builder is actually running
// TODO: detect unreachable stages so config is not pulled for them
var img Image
if err := json.Unmarshal(dt, &img); err != nil {
return err
}
d.image = img
ref, err := reference.WithDigest(ref, dgst)
if err != nil {
return err
}
d.stage.BaseName = ref.String()
_ = ref
}
}
d.state = llb.Image(d.stage.BaseName)
return nil
})
}(i, d)
}
}
if err := eg.Wait(); err != nil {
return nil, nil, err
}
buildContext := llb.Local(localNameContext, llb.SessionID(opt.SessionID))
if opt.BuildContext != nil {
buildContext = *opt.BuildContext
}
for _, d := range allDispatchStates {
if d.base != nil {
d.state = d.base.state
d.image = clone(d.base.image)
}
// initialize base metadata from image conf
for _, env := range d.image.Config.Env {
parts := strings.SplitN(env, "=", 2)
v := ""
if len(parts) > 1 {
v = parts[1]
}
if err := dispatchEnv(d, &instructions.EnvCommand{Env: []instructions.KeyValuePair{{Key: parts[0], Value: v}}}); err != nil {
return nil, nil, err
}
}
if d.image.Config.WorkingDir != "" {
if err = dispatchWorkdir(d, &instructions.WorkdirCommand{Path: d.image.Config.WorkingDir}); err != nil {
return nil, nil, err
}
}
if d.image.Config.User != "" {
if err = dispatchUser(d, &instructions.UserCommand{User: d.image.Config.User}); err != nil {
return nil, nil, err
}
}
opt := dispatchOpt{
allDispatchStates: allDispatchStates,
dispatchStatesByName: dispatchStatesByName,
metaArgs: metaArgs,
buildArgValues: opt.BuildArgs,
shlex: shlex,
sessionID: opt.SessionID,
buildContext: buildContext,
}
if err = dispatchOnBuild(d, d.image.Config.OnBuild, opt); err != nil {
return nil, nil, err
}
for _, cmd := range d.stage.Commands {
if err := dispatch(d, cmd, opt); err != nil {
return nil, nil, err
}
}
}
if opt.Target == "" {
return &allDispatchStates[len(allDispatchStates)-1].state, &allDispatchStates[len(allDispatchStates)-1].image, nil
}
state, ok := dispatchStatesByName[strings.ToLower(opt.Target)]
if !ok {
return nil, nil, errors.Errorf("target stage %s could not be found", opt.Target)
}
return &state.state, &state.image, nil
}
type dispatchOpt struct {
allDispatchStates []*dispatchState
dispatchStatesByName map[string]*dispatchState
metaArgs []instructions.ArgCommand
buildArgValues map[string]string
shlex *ShellLex
sessionID string
buildContext llb.State
}
func dispatch(d *dispatchState, cmd instructions.Command, opt dispatchOpt) error {
if ex, ok := cmd.(instructions.SupportsSingleWordExpansion); ok {
err := ex.Expand(func(word string) (string, error) {
return opt.shlex.ProcessWord(word, toEnvList(d.buildArgs, d.image.Config.Env))
})
if err != nil {
return err
}
}
var err error
switch c := cmd.(type) {
case *instructions.EnvCommand:
err = dispatchEnv(d, c)
case *instructions.RunCommand:
err = dispatchRun(d, c)
case *instructions.WorkdirCommand:
err = dispatchWorkdir(d, c)
case *instructions.AddCommand:
err = dispatchCopy(d, c.SourcesAndDest, opt.buildContext, true)
case *instructions.LabelCommand:
err = dispatchLabel(d, c)
case *instructions.OnbuildCommand:
err = dispatchOnbuild(d, c)
case *instructions.CmdCommand:
err = dispatchCmd(d, c)
case *instructions.EntrypointCommand:
err = dispatchEntrypoint(d, c)
case *instructions.HealthCheckCommand:
err = dispatchHealthcheck(d, c)
case *instructions.ExposeCommand:
err = dispatchExpose(d, c)
case *instructions.UserCommand:
err = dispatchUser(d, c)
case *instructions.VolumeCommand:
err = dispatchVolume(d, c)
case *instructions.StopSignalCommand:
err = dispatchStopSignal(d, c)
case *instructions.ShellCommand:
err = dispatchShell(d, c)
case *instructions.ArgCommand:
err = dispatchArg(d, c, opt.metaArgs, opt.buildArgValues)
case *instructions.CopyCommand:
l := opt.buildContext
if c.From != "" {
index, err := strconv.Atoi(c.From)
if err != nil {
stn, ok := opt.dispatchStatesByName[strings.ToLower(c.From)]
if !ok {
return errors.Errorf("stage %s not found", c.From)
}
l = stn.state
} else {
if index >= len(opt.allDispatchStates) {
return errors.Errorf("invalid stage index %d", index)
}
l = opt.allDispatchStates[index].state
}
}
err = dispatchCopy(d, c.SourcesAndDest, l, false)
default:
}
return err
}
type dispatchState struct {
state llb.State
image Image
stage instructions.Stage
base *dispatchState
buildArgs []instructions.ArgCommand
}
func dispatchOnBuild(d *dispatchState, triggers []string, opt dispatchOpt) error {
for _, trigger := range triggers {
ast, err := parser.Parse(strings.NewReader(trigger))
if err != nil {
return err
}
if len(ast.AST.Children) != 1 {
return errors.New("onbuild trigger should be a single expression")
}
cmd, err := instructions.ParseCommand(ast.AST.Children[0])
if err != nil {
return err
}
if err := dispatch(d, cmd, opt); err != nil {
return err
}
}
return nil
}
func dispatchEnv(d *dispatchState, c *instructions.EnvCommand) error {
for _, e := range c.Env {
d.state = d.state.AddEnv(e.Key, e.Value)
d.image.Config.Env = addEnv(d.image.Config.Env, e.Key, e.Value, true)
}
return nil
}
func dispatchRun(d *dispatchState, c *instructions.RunCommand) error {
var args []string = c.CmdLine
if c.PrependShell {
args = append(defaultShell(), strings.Join(args, " "))
} else if d.image.Config.Entrypoint != nil {
args = append(d.image.Config.Entrypoint, args...)
}
opt := []llb.RunOption{llb.Args(args)}
for _, arg := range d.buildArgs {
opt = append(opt, llb.AddEnv(arg.Key, getArgValue(arg)))
}
d.state = d.state.Run(opt...).Root()
return nil
}
func dispatchWorkdir(d *dispatchState, c *instructions.WorkdirCommand) error {
d.state = d.state.Dir(c.Path)
wd := c.Path
if !path.IsAbs(c.Path) {
wd = path.Join("/", d.image.Config.WorkingDir, wd)
}
d.image.Config.WorkingDir = wd
return nil
}
func dispatchCopy(d *dispatchState, c instructions.SourcesAndDest, sourceState llb.State, isAddCommand bool) error {
// TODO: this should use CopyOp instead. Current implementation is inefficient
img := llb.Image("tonistiigi/copy@sha256:ca6620946b2db7ad92f80cc5834f5d0724e6ede1f00004c965f6ded61592553a")
dest := path.Join("/dest", pathRelativeToWorkingDir(d.state, c.Dest()))
if c.Dest() == "." || c.Dest()[len(c.Dest())-1] == filepath.Separator {
dest += string(filepath.Separator)
}
args := []string{"copy"}
if isAddCommand {
args = append(args, "--unpack")
}
mounts := make([]llb.RunOption, 0, len(c.Sources()))
for i, src := range c.Sources() {
if isAddCommand && urlutil.IsURL(src) {
u, err := url.Parse(src)
f := "__unnamed__"
if err == nil {
if base := path.Base(u.Path); base != "." && base != "/" {
f = base
}
}
target := path.Join(fmt.Sprintf("/src-%d", i), f)
args = append(args, target)
mounts = append(mounts, llb.AddMount(target, llb.HTTP(src, llb.Filename(f)), llb.Readonly))
} else {
d, f := splitWildcards(src)
if f == "" {
f = path.Base(src)
}
target := path.Join(fmt.Sprintf("/src-%d", i), f)
args = append(args, target)
mounts = append(mounts, llb.AddMount(target, sourceState, llb.SourcePath(d), llb.Readonly))
}
}
args = append(args, dest)
run := img.Run(append([]llb.RunOption{llb.Args(args)}, mounts...)...)
d.state = run.AddMount("/dest", d.state)
return nil
}
func dispatchMaintainer(d *dispatchState, c instructions.MaintainerCommand) error {
d.image.Author = c.Maintainer
return nil
}
func dispatchLabel(d *dispatchState, c *instructions.LabelCommand) error {
if d.image.Config.Labels == nil {
d.image.Config.Labels = make(map[string]string)
}
for _, v := range c.Labels {
d.image.Config.Labels[v.Key] = v.Value
}
return nil
}
func dispatchOnbuild(d *dispatchState, c *instructions.OnbuildCommand) error {
d.image.Config.OnBuild = append(d.image.Config.OnBuild, c.Expression)
return nil
}
func dispatchCmd(d *dispatchState, c *instructions.CmdCommand) error {
var args []string = c.CmdLine
if c.PrependShell {
args = append(defaultShell(), strings.Join(args, " "))
}
d.image.Config.Cmd = args
d.image.Config.ArgsEscaped = true
return nil
}
func dispatchEntrypoint(d *dispatchState, c *instructions.EntrypointCommand) error {
var args []string = c.CmdLine
if c.PrependShell {
args = append(defaultShell(), strings.Join(args, " "))
}
d.image.Config.Entrypoint = args
return nil
}
func dispatchHealthcheck(d *dispatchState, c *instructions.HealthCheckCommand) error {
d.image.Config.Healthcheck = &HealthConfig{
Test: c.Health.Test,
Interval: c.Health.Interval,
Timeout: c.Health.Timeout,
StartPeriod: c.Health.StartPeriod,
Retries: c.Health.Retries,
}
return nil
}
func dispatchExpose(d *dispatchState, c *instructions.ExposeCommand) error {
// TODO: custom multi word expansion
ps, _, err := nat.ParsePortSpecs(c.Ports)
if err != nil {
return err
}
if d.image.Config.ExposedPorts == nil {
d.image.Config.ExposedPorts = make(map[string]struct{})
}
for p := range ps {
d.image.Config.ExposedPorts[string(p)] = struct{}{}
}
return nil
}
func dispatchUser(d *dispatchState, c *instructions.UserCommand) error {
d.image.Config.User = c.User
return nil
}
func dispatchVolume(d *dispatchState, c *instructions.VolumeCommand) error {
if d.image.Config.Volumes == nil {
d.image.Config.Volumes = map[string]struct{}{}
}
for _, v := range c.Volumes {
if v == "" {
return errors.New("VOLUME specified can not be an empty string")
}
d.image.Config.Volumes[v] = struct{}{}
}
return nil
}
func dispatchStopSignal(d *dispatchState, c *instructions.StopSignalCommand) error {
if _, err := signal.ParseSignal(c.Signal); err != nil {
return err
}
d.image.Config.StopSignal = c.Signal
return nil
}
func dispatchShell(d *dispatchState, c *instructions.ShellCommand) error {
d.image.Config.Shell = c.Shell
return nil
}
func dispatchArg(d *dispatchState, c *instructions.ArgCommand, metaArgs []instructions.ArgCommand, buildArgValues map[string]string) error {
if c.Value == nil {
for _, ma := range metaArgs {
if ma.Key == c.Key {
c.Value = ma.Value
}
}
}
d.buildArgs = append(d.buildArgs, setBuildArgValue(*c, buildArgValues))
return nil
}
func pathRelativeToWorkingDir(s llb.State, p string) string {
if path.IsAbs(p) {
return p
}
return path.Join(s.GetDir(), p)
}
func splitWildcards(name string) (string, string) {
i := 0
for ; i < len(name); i++ {
ch := name[i]
if ch == '\\' {
i++
} else if ch == '*' || ch == '?' || ch == '[' {
break
}
}
if i == len(name) {
return name, ""
}
return path.Dir(name[:i]), path.Base(name[:i]) + name[i:]
}
func addEnv(env []string, k, v string, override bool) []string {
gotOne := false
for i, envVar := range env {
envParts := strings.SplitN(envVar, "=", 2)
compareFrom := envParts[0]
if equalEnvKeys(compareFrom, k) {
if override {
env[i] = k + "=" + v
}
gotOne = true
break
}
}
if !gotOne {
env = append(env, k+"="+v)
}
return env
}
func equalEnvKeys(from, to string) bool {
return from == to
}
func setBuildArgValue(c instructions.ArgCommand, values map[string]string) instructions.ArgCommand {
if v, ok := values[c.Key]; ok {
c.Value = &v
}
return c
}
func toEnvList(args []instructions.ArgCommand, env []string) []string {
for _, arg := range args {
env = addEnv(env, arg.Key, getArgValue(arg), false)
}
return env
}
func getArgValue(arg instructions.ArgCommand) string {
v := ""
if arg.Value != nil {
v = *arg.Value
}
return v
}