1
0
Fork 0
mirror of https://github.com/moby/moby.git synced 2022-11-09 12:21:53 -05:00
moby--moby/builder/dockerfile/dispatchers.go
Tibor Vass e0ef11a4c2 Abstract builder and implement server-side dockerfile builder
This patch creates interfaces in builder/ for building Docker images.
It is a first step in a series of patches to remove the daemon
dependency on builder and later allow a client-side Dockerfile builder
as well as potential builder plugins.

It is needed because we cannot remove the /build API endpoint, so we
need to keep the server-side Dockerfile builder, but we also want to
reuse the same Dockerfile parser and evaluator for both server-side and
client-side.

builder/dockerfile/ and api/server/builder.go contain implementations
of those interfaces as a refactoring of the current code.

Signed-off-by: Tibor Vass <tibor@docker.com>
2015-10-06 19:10:19 -04:00

647 lines
18 KiB
Go

package dockerfile
// This file contains the dispatchers for each command. Note that
// `nullDispatch` is not actually a command, but support for commands we parse
// but do nothing with.
//
// See evaluator.go for a higher level discussion of the whole evaluator
// package.
import (
"fmt"
"io/ioutil"
"os"
"path/filepath"
"regexp"
"runtime"
"sort"
"strings"
"github.com/Sirupsen/logrus"
derr "github.com/docker/docker/errors"
"github.com/docker/docker/image"
flag "github.com/docker/docker/pkg/mflag"
"github.com/docker/docker/pkg/nat"
"github.com/docker/docker/pkg/signal"
"github.com/docker/docker/pkg/stringutils"
"github.com/docker/docker/pkg/system"
"github.com/docker/docker/runconfig"
)
const (
// NoBaseImageSpecifier is the symbol used by the FROM
// command to specify that no base image is to be used.
NoBaseImageSpecifier string = "scratch"
)
// dispatch with no layer / parsing. This is effectively not a command.
func nullDispatch(b *Builder, args []string, attributes map[string]bool, original string) error {
return nil
}
// ENV foo bar
//
// Sets the environment variable foo to bar, also makes interpolation
// in the dockerfile available from the next statement on via ${foo}.
//
func env(b *Builder, args []string, attributes map[string]bool, original string) error {
if len(args) == 0 {
return derr.ErrorCodeAtLeastOneArg.WithArgs("ENV")
}
if len(args)%2 != 0 {
// should never get here, but just in case
return derr.ErrorCodeTooManyArgs.WithArgs("ENV")
}
if err := b.flags.Parse(); err != nil {
return err
}
// TODO/FIXME/NOT USED
// Just here to show how to use the builder flags stuff within the
// context of a builder command. Will remove once we actually add
// a builder command to something!
/*
flBool1 := b.flags.AddBool("bool1", false)
flStr1 := b.flags.AddString("str1", "HI")
if err := b.flags.Parse(); err != nil {
return err
}
fmt.Printf("Bool1:%v\n", flBool1)
fmt.Printf("Str1:%v\n", flStr1)
*/
commitStr := "ENV"
for j := 0; j < len(args); j++ {
// name ==> args[j]
// value ==> args[j+1]
newVar := args[j] + "=" + args[j+1] + ""
commitStr += " " + newVar
gotOne := false
for i, envVar := range b.runConfig.Env {
envParts := strings.SplitN(envVar, "=", 2)
if envParts[0] == args[j] {
b.runConfig.Env[i] = newVar
gotOne = true
break
}
}
if !gotOne {
b.runConfig.Env = append(b.runConfig.Env, newVar)
}
j++
}
return b.commit("", b.runConfig.Cmd, commitStr)
}
// MAINTAINER some text <maybe@an.email.address>
//
// Sets the maintainer metadata.
func maintainer(b *Builder, args []string, attributes map[string]bool, original string) error {
if len(args) != 1 {
return derr.ErrorCodeExactlyOneArg.WithArgs("MAINTAINER")
}
if err := b.flags.Parse(); err != nil {
return err
}
b.maintainer = args[0]
return b.commit("", b.runConfig.Cmd, fmt.Sprintf("MAINTAINER %s", b.maintainer))
}
// LABEL some json data describing the image
//
// Sets the Label variable foo to bar,
//
func label(b *Builder, args []string, attributes map[string]bool, original string) error {
if len(args) == 0 {
return derr.ErrorCodeAtLeastOneArg.WithArgs("LABEL")
}
if len(args)%2 != 0 {
// should never get here, but just in case
return derr.ErrorCodeTooManyArgs.WithArgs("LABEL")
}
if err := b.flags.Parse(); err != nil {
return err
}
commitStr := "LABEL"
if b.runConfig.Labels == nil {
b.runConfig.Labels = map[string]string{}
}
for j := 0; j < len(args); j++ {
// name ==> args[j]
// value ==> args[j+1]
newVar := args[j] + "=" + args[j+1] + ""
commitStr += " " + newVar
b.runConfig.Labels[args[j]] = args[j+1]
j++
}
return b.commit("", b.runConfig.Cmd, commitStr)
}
// ADD foo /path
//
// Add the file 'foo' to '/path'. Tarball and Remote URL (git, http) handling
// exist here. If you do not wish to have this automatic handling, use COPY.
//
func add(b *Builder, args []string, attributes map[string]bool, original string) error {
if len(args) < 2 {
return derr.ErrorCodeAtLeastTwoArgs.WithArgs("ADD")
}
if err := b.flags.Parse(); err != nil {
return err
}
return b.runContextCommand(args, true, true, "ADD")
}
// COPY foo /path
//
// Same as 'ADD' but without the tar and remote url handling.
//
func dispatchCopy(b *Builder, args []string, attributes map[string]bool, original string) error {
if len(args) < 2 {
return derr.ErrorCodeAtLeastTwoArgs.WithArgs("COPY")
}
if err := b.flags.Parse(); err != nil {
return err
}
return b.runContextCommand(args, false, false, "COPY")
}
// FROM imagename
//
// This sets the image the dockerfile will build on top of.
//
func from(b *Builder, args []string, attributes map[string]bool, original string) error {
if len(args) != 1 {
return derr.ErrorCodeExactlyOneArg.WithArgs("FROM")
}
if err := b.flags.Parse(); err != nil {
return err
}
name := args[0]
// Windows cannot support a container with no base image.
if name == NoBaseImageSpecifier {
if runtime.GOOS == "windows" {
return fmt.Errorf("Windows does not support FROM scratch")
}
b.image = ""
b.noBaseImage = true
return nil
}
var (
image *image.Image
err error
)
// TODO: don't use `name`, instead resolve it to a digest
if !b.Pull {
image, err = b.docker.LookupImage(name)
// TODO: shouldn't we error out if error is different from "not found" ?
}
if image == nil {
image, err = b.docker.Pull(name)
if err != nil {
return err
}
}
return b.processImageFrom(image)
}
// ONBUILD RUN echo yo
//
// ONBUILD triggers run when the image is used in a FROM statement.
//
// ONBUILD handling has a lot of special-case functionality, the heading in
// evaluator.go and comments around dispatch() in the same file explain the
// special cases. search for 'OnBuild' in internals.go for additional special
// cases.
//
func onbuild(b *Builder, args []string, attributes map[string]bool, original string) error {
if len(args) == 0 {
return derr.ErrorCodeAtLeastOneArg.WithArgs("ONBUILD")
}
if err := b.flags.Parse(); err != nil {
return err
}
triggerInstruction := strings.ToUpper(strings.TrimSpace(args[0]))
switch triggerInstruction {
case "ONBUILD":
return derr.ErrorCodeChainOnBuild
case "MAINTAINER", "FROM":
return derr.ErrorCodeBadOnBuildCmd.WithArgs(triggerInstruction)
}
original = regexp.MustCompile(`(?i)^\s*ONBUILD\s*`).ReplaceAllString(original, "")
b.runConfig.OnBuild = append(b.runConfig.OnBuild, original)
return b.commit("", b.runConfig.Cmd, fmt.Sprintf("ONBUILD %s", original))
}
// WORKDIR /tmp
//
// Set the working directory for future RUN/CMD/etc statements.
//
func workdir(b *Builder, args []string, attributes map[string]bool, original string) error {
if len(args) != 1 {
return derr.ErrorCodeExactlyOneArg.WithArgs("WORKDIR")
}
if err := b.flags.Parse(); err != nil {
return err
}
// This is from the Dockerfile and will not necessarily be in platform
// specific semantics, hence ensure it is converted.
workdir := filepath.FromSlash(args[0])
if !system.IsAbs(workdir) {
current := filepath.FromSlash(b.runConfig.WorkingDir)
workdir = filepath.Join(string(os.PathSeparator), current, workdir)
}
b.runConfig.WorkingDir = workdir
return b.commit("", b.runConfig.Cmd, fmt.Sprintf("WORKDIR %v", workdir))
}
// RUN some command yo
//
// run a command and commit the image. Args are automatically prepended with
// 'sh -c' under linux or 'cmd /S /C' under Windows, in the event there is
// only one argument. The difference in processing:
//
// RUN echo hi # sh -c echo hi (Linux)
// RUN echo hi # cmd /S /C echo hi (Windows)
// RUN [ "echo", "hi" ] # echo hi
//
func run(b *Builder, args []string, attributes map[string]bool, original string) error {
if b.image == "" && !b.noBaseImage {
return derr.ErrorCodeMissingFrom
}
if err := b.flags.Parse(); err != nil {
return err
}
args = handleJSONArgs(args, attributes)
if !attributes["json"] {
if runtime.GOOS != "windows" {
args = append([]string{"/bin/sh", "-c"}, args...)
} else {
args = append([]string{"cmd", "/S", "/C"}, args...)
}
}
runCmd := flag.NewFlagSet("run", flag.ContinueOnError)
runCmd.SetOutput(ioutil.Discard)
runCmd.Usage = nil
config, _, _, err := runconfig.Parse(runCmd, append([]string{b.image}, args...))
if err != nil {
return err
}
// stash the cmd
cmd := b.runConfig.Cmd
runconfig.Merge(b.runConfig, config)
// stash the config environment
env := b.runConfig.Env
defer func(cmd *stringutils.StrSlice) { b.runConfig.Cmd = cmd }(cmd)
defer func(env []string) { b.runConfig.Env = env }(env)
// derive the net build-time environment for this run. We let config
// environment override the build time environment.
// This means that we take the b.buildArgs list of env vars and remove
// any of those variables that are defined as part of the container. In other
// words, anything in b.Config.Env. What's left is the list of build-time env
// vars that we need to add to each RUN command - note the list could be empty.
//
// We don't persist the build time environment with container's config
// environment, but just sort and prepend it to the command string at time
// of commit.
// This helps with tracing back the image's actual environment at the time
// of RUN, without leaking it to the final image. It also aids cache
// lookup for same image built with same build time environment.
cmdBuildEnv := []string{}
configEnv := runconfig.ConvertKVStringsToMap(b.runConfig.Env)
for key, val := range b.BuildArgs {
if !b.isBuildArgAllowed(key) {
// skip build-args that are not in allowed list, meaning they have
// not been defined by an "ARG" Dockerfile command yet.
// This is an error condition but only if there is no "ARG" in the entire
// Dockerfile, so we'll generate any necessary errors after we parsed
// the entire file (see 'leftoverArgs' processing in evaluator.go )
continue
}
if _, ok := configEnv[key]; !ok {
cmdBuildEnv = append(cmdBuildEnv, fmt.Sprintf("%s=%s", key, val))
}
}
// derive the command to use for probeCache() and to commit in this container.
// Note that we only do this if there are any build-time env vars. Also, we
// use the special argument "|#" at the start of the args array. This will
// avoid conflicts with any RUN command since commands can not
// start with | (vertical bar). The "#" (number of build envs) is there to
// help ensure proper cache matches. We don't want a RUN command
// that starts with "foo=abc" to be considered part of a build-time env var.
saveCmd := config.Cmd
if len(cmdBuildEnv) > 0 {
sort.Strings(cmdBuildEnv)
tmpEnv := append([]string{fmt.Sprintf("|%d", len(cmdBuildEnv))}, cmdBuildEnv...)
saveCmd = stringutils.NewStrSlice(append(tmpEnv, saveCmd.Slice()...)...)
}
b.runConfig.Cmd = saveCmd
hit, err := b.probeCache()
if err != nil {
return err
}
if hit {
return nil
}
// set Cmd manually, this is special case only for Dockerfiles
b.runConfig.Cmd = config.Cmd
// set build-time environment for 'run'.
b.runConfig.Env = append(b.runConfig.Env, cmdBuildEnv...)
logrus.Debugf("[BUILDER] Command to be executed: %v", b.runConfig.Cmd)
c, err := b.create()
if err != nil {
return err
}
// Ensure that we keep the container mounted until the commit
// to avoid unmounting and then mounting directly again
c.Mount()
defer c.Unmount()
err = b.run(c)
if err != nil {
return err
}
// revert to original config environment and set the command string to
// have the build-time env vars in it (if any) so that future cache look-ups
// properly match it.
b.runConfig.Env = env
b.runConfig.Cmd = saveCmd
if err := b.commit(c.ID, cmd, "run"); err != nil {
return err
}
return nil
}
// CMD foo
//
// Set the default command to run in the container (which may be empty).
// Argument handling is the same as RUN.
//
func cmd(b *Builder, args []string, attributes map[string]bool, original string) error {
if err := b.flags.Parse(); err != nil {
return err
}
cmdSlice := handleJSONArgs(args, attributes)
if !attributes["json"] {
if runtime.GOOS != "windows" {
cmdSlice = append([]string{"/bin/sh", "-c"}, cmdSlice...)
} else {
cmdSlice = append([]string{"cmd", "/S", "/C"}, cmdSlice...)
}
}
b.runConfig.Cmd = stringutils.NewStrSlice(cmdSlice...)
if err := b.commit("", b.runConfig.Cmd, fmt.Sprintf("CMD %q", cmdSlice)); err != nil {
return err
}
if len(args) != 0 {
b.cmdSet = true
}
return nil
}
// ENTRYPOINT /usr/sbin/nginx
//
// Set the entrypoint (which defaults to sh -c on linux, or cmd /S /C on Windows) to
// /usr/sbin/nginx. Will accept the CMD as the arguments to /usr/sbin/nginx.
//
// Handles command processing similar to CMD and RUN, only b.runConfig.Entrypoint
// is initialized at NewBuilder time instead of through argument parsing.
//
func entrypoint(b *Builder, args []string, attributes map[string]bool, original string) error {
if err := b.flags.Parse(); err != nil {
return err
}
parsed := handleJSONArgs(args, attributes)
switch {
case attributes["json"]:
// ENTRYPOINT ["echo", "hi"]
b.runConfig.Entrypoint = stringutils.NewStrSlice(parsed...)
case len(parsed) == 0:
// ENTRYPOINT []
b.runConfig.Entrypoint = nil
default:
// ENTRYPOINT echo hi
if runtime.GOOS != "windows" {
b.runConfig.Entrypoint = stringutils.NewStrSlice("/bin/sh", "-c", parsed[0])
} else {
b.runConfig.Entrypoint = stringutils.NewStrSlice("cmd", "/S /C", parsed[0])
}
}
// when setting the entrypoint if a CMD was not explicitly set then
// set the command to nil
if !b.cmdSet {
b.runConfig.Cmd = nil
}
if err := b.commit("", b.runConfig.Cmd, fmt.Sprintf("ENTRYPOINT %q", b.runConfig.Entrypoint)); err != nil {
return err
}
return nil
}
// EXPOSE 6667/tcp 7000/tcp
//
// Expose ports for links and port mappings. This all ends up in
// b.runConfig.ExposedPorts for runconfig.
//
func expose(b *Builder, args []string, attributes map[string]bool, original string) error {
portsTab := args
if len(args) == 0 {
return derr.ErrorCodeAtLeastOneArg.WithArgs("EXPOSE")
}
if err := b.flags.Parse(); err != nil {
return err
}
if b.runConfig.ExposedPorts == nil {
b.runConfig.ExposedPorts = make(nat.PortSet)
}
ports, _, err := nat.ParsePortSpecs(portsTab)
if err != nil {
return err
}
// instead of using ports directly, we build a list of ports and sort it so
// the order is consistent. This prevents cache burst where map ordering
// changes between builds
portList := make([]string, len(ports))
var i int
for port := range ports {
if _, exists := b.runConfig.ExposedPorts[port]; !exists {
b.runConfig.ExposedPorts[port] = struct{}{}
}
portList[i] = string(port)
i++
}
sort.Strings(portList)
return b.commit("", b.runConfig.Cmd, fmt.Sprintf("EXPOSE %s", strings.Join(portList, " ")))
}
// USER foo
//
// Set the user to 'foo' for future commands and when running the
// ENTRYPOINT/CMD at container run time.
//
func user(b *Builder, args []string, attributes map[string]bool, original string) error {
if len(args) != 1 {
return derr.ErrorCodeExactlyOneArg.WithArgs("USER")
}
if err := b.flags.Parse(); err != nil {
return err
}
b.runConfig.User = args[0]
return b.commit("", b.runConfig.Cmd, fmt.Sprintf("USER %v", args))
}
// VOLUME /foo
//
// Expose the volume /foo for use. Will also accept the JSON array form.
//
func volume(b *Builder, args []string, attributes map[string]bool, original string) error {
if len(args) == 0 {
return derr.ErrorCodeAtLeastOneArg.WithArgs("VOLUME")
}
if err := b.flags.Parse(); err != nil {
return err
}
if b.runConfig.Volumes == nil {
b.runConfig.Volumes = map[string]struct{}{}
}
for _, v := range args {
v = strings.TrimSpace(v)
if v == "" {
return derr.ErrorCodeVolumeEmpty
}
b.runConfig.Volumes[v] = struct{}{}
}
if err := b.commit("", b.runConfig.Cmd, fmt.Sprintf("VOLUME %v", args)); err != nil {
return err
}
return nil
}
// STOPSIGNAL signal
//
// Set the signal that will be used to kill the container.
func stopSignal(b *Builder, args []string, attributes map[string]bool, original string) error {
if len(args) != 1 {
return fmt.Errorf("STOPSIGNAL requires exactly one argument")
}
sig := args[0]
_, err := signal.ParseSignal(sig)
if err != nil {
return err
}
b.runConfig.StopSignal = sig
return b.commit("", b.runConfig.Cmd, fmt.Sprintf("STOPSIGNAL %v", args))
}
// ARG name[=value]
//
// Adds the variable foo to the trusted list of variables that can be passed
// to builder using the --build-arg flag for expansion/subsitution or passing to 'run'.
// Dockerfile author may optionally set a default value of this variable.
func arg(b *Builder, args []string, attributes map[string]bool, original string) error {
if len(args) != 1 {
return fmt.Errorf("ARG requires exactly one argument definition")
}
var (
name string
value string
hasDefault bool
)
arg := args[0]
// 'arg' can just be a name or name-value pair. Note that this is different
// from 'env' that handles the split of name and value at the parser level.
// The reason for doing it differently for 'arg' is that we support just
// defining an arg and not assign it a value (while 'env' always expects a
// name-value pair). If possible, it will be good to harmonize the two.
if strings.Contains(arg, "=") {
parts := strings.SplitN(arg, "=", 2)
name = parts[0]
value = parts[1]
hasDefault = true
} else {
name = arg
hasDefault = false
}
// add the arg to allowed list of build-time args from this step on.
b.allowedBuildArgs[name] = true
// If there is a default value associated with this arg then add it to the
// b.buildArgs if one is not already passed to the builder. The args passed
// to builder override the defaut value of 'arg'.
if _, ok := b.BuildArgs[name]; !ok && hasDefault {
b.BuildArgs[name] = value
}
return b.commit("", b.runConfig.Cmd, fmt.Sprintf("ARG %s", arg))
}