moby/builder/dispatchers.go

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package builder
// 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"
"path/filepath"
"regexp"
"sort"
"strings"
log "github.com/Sirupsen/logrus"
"github.com/docker/docker/nat"
flag "github.com/docker/docker/pkg/mflag"
"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 fmt.Errorf("ENV requires at least one argument")
}
if len(args)%2 != 0 {
// should never get here, but just in case
return fmt.Errorf("Bad input to ENV, too many args")
}
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.Config.Env {
envParts := strings.SplitN(envVar, "=", 2)
if envParts[0] == args[j] {
b.Config.Env[i] = newVar
gotOne = true
break
}
}
if !gotOne {
b.Config.Env = append(b.Config.Env, newVar)
}
j++
}
return b.commit("", b.Config.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 fmt.Errorf("MAINTAINER requires exactly one argument")
}
b.maintainer = args[0]
return b.commit("", b.Config.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 fmt.Errorf("LABEL is missing arguments")
}
if len(args)%2 != 0 {
// should never get here, but just in case
return fmt.Errorf("Bad input to LABEL, too many args")
}
commitStr := "LABEL"
if b.Config.Labels == nil {
b.Config.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.Config.Labels[args[j]] = args[j+1]
j++
}
return b.commit("", b.Config.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 fmt.Errorf("ADD requires at least two arguments")
}
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 fmt.Errorf("COPY requires at least two arguments")
}
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 fmt.Errorf("FROM requires one argument")
}
name := args[0]
if name == NoBaseImageSpecifier {
b.image = ""
b.noBaseImage = true
return nil
}
image, err := b.Daemon.Repositories().LookupImage(name)
if b.Pull {
image, err = b.pullImage(name)
if err != nil {
return err
}
}
if err != nil {
if b.Daemon.Graph().IsNotExist(err) {
image, err = b.pullImage(name)
}
// note that the top level err will still be !nil here if IsNotExist is
// not the error. This approach just simplifies hte logic a bit.
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 fmt.Errorf("ONBUILD requires at least one argument")
}
triggerInstruction := strings.ToUpper(strings.TrimSpace(args[0]))
switch triggerInstruction {
case "ONBUILD":
return fmt.Errorf("Chaining ONBUILD via `ONBUILD ONBUILD` isn't allowed")
case "MAINTAINER", "FROM":
return fmt.Errorf("%s isn't allowed as an ONBUILD trigger", triggerInstruction)
}
original = regexp.MustCompile(`(?i)^\s*ONBUILD\s*`).ReplaceAllString(original, "")
b.Config.OnBuild = append(b.Config.OnBuild, original)
return b.commit("", b.Config.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 fmt.Errorf("WORKDIR requires exactly one argument")
}
workdir := args[0]
if !filepath.IsAbs(workdir) {
workdir = filepath.Join("/", b.Config.WorkingDir, workdir)
}
b.Config.WorkingDir = workdir
return b.commit("", b.Config.Cmd, fmt.Sprintf("WORKDIR %v", workdir))
}
// RUN some command yo
//
// run a command and commit the image. Args are automatically prepended with
// 'sh -c' in the event there is only one argument. The difference in
// processing:
//
// RUN echo hi # sh -c echo hi
// RUN [ "echo", "hi" ] # echo hi
//
func run(b *Builder, args []string, attributes map[string]bool, original string) error {
if b.image == "" && !b.noBaseImage {
return fmt.Errorf("Please provide a source image with `from` prior to run")
}
args = handleJsonArgs(args, attributes)
if !attributes["json"] {
args = append([]string{"/bin/sh", "-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
}
cmd := b.Config.Cmd
// set Cmd manually, this is special case only for Dockerfiles
b.Config.Cmd = config.Cmd
runconfig.Merge(b.Config, config)
defer func(cmd []string) { b.Config.Cmd = cmd }(cmd)
log.Debugf("[BUILDER] Command to be executed: %v", b.Config.Cmd)
hit, err := b.probeCache()
if err != nil {
return err
}
if hit {
return nil
}
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
}
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 {
b.Config.Cmd = handleJsonArgs(args, attributes)
if !attributes["json"] {
b.Config.Cmd = append([]string{"/bin/sh", "-c"}, b.Config.Cmd...)
}
if err := b.commit("", b.Config.Cmd, fmt.Sprintf("CMD %q", b.Config.Cmd)); 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) 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.Config.Entrypoint
// is initialized at NewBuilder time instead of through argument parsing.
//
func entrypoint(b *Builder, args []string, attributes map[string]bool, original string) error {
parsed := handleJsonArgs(args, attributes)
switch {
case attributes["json"]:
// ENTRYPOINT ["echo", "hi"]
b.Config.Entrypoint = parsed
case len(parsed) == 0:
// ENTRYPOINT []
b.Config.Entrypoint = nil
default:
// ENTRYPOINT echo hi
b.Config.Entrypoint = []string{"/bin/sh", "-c", parsed[0]}
}
// when setting the entrypoint if a CMD was not explicitly set then
// set the command to nil
if !b.cmdSet {
b.Config.Cmd = nil
}
if err := b.commit("", b.Config.Cmd, fmt.Sprintf("ENTRYPOINT %q", b.Config.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.Config.ExposedPorts for runconfig.
//
func expose(b *Builder, args []string, attributes map[string]bool, original string) error {
portsTab := args
if len(args) == 0 {
return fmt.Errorf("EXPOSE requires at least one argument")
}
if b.Config.ExposedPorts == nil {
b.Config.ExposedPorts = make(nat.PortSet)
}
ports, bindingMap, err := nat.ParsePortSpecs(append(portsTab, b.Config.PortSpecs...))
if err != nil {
return err
}
for _, bindings := range bindingMap {
if bindings[0].HostIp != "" || bindings[0].HostPort != "" {
fmt.Fprintf(b.ErrStream, " ---> Using Dockerfile's EXPOSE instruction"+
" to map host ports to container ports (ip:hostPort:containerPort) is deprecated.\n"+
" Please use -p to publish the ports.\n")
}
}
// 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.Config.ExposedPorts[port]; !exists {
b.Config.ExposedPorts[port] = struct{}{}
}
portList[i] = string(port)
i++
}
sort.Strings(portList)
b.Config.PortSpecs = nil
return b.commit("", b.Config.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 fmt.Errorf("USER requires exactly one argument")
}
b.Config.User = args[0]
return b.commit("", b.Config.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 fmt.Errorf("VOLUME requires at least one argument")
}
if b.Config.Volumes == nil {
b.Config.Volumes = map[string]struct{}{}
}
for _, v := range args {
b.Config.Volumes[v] = struct{}{}
}
if err := b.commit("", b.Config.Cmd, fmt.Sprintf("VOLUME %v", args)); err != nil {
return err
}
return nil
}
// INSERT is no longer accepted, but we still parse it.
func insert(b *Builder, args []string, attributes map[string]bool, original string) error {
return fmt.Errorf("INSERT has been deprecated. Please use ADD instead")
}