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 is missing arguments") } 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 // // 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 only one argument") } b.maintainer = args[0] return b.commit("", b.Config.Cmd, fmt.Sprintf("MAINTAINER %s", b.maintainer)) } // 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 { 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 len(args) == 1 { args = append([]string{"/bin/sh", "-c"}, args[0]) } 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 %v", 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 %v", 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 b.Config.ExposedPorts == nil { b.Config.ExposedPorts = make(nat.PortSet) } ports, _, err := nat.ParsePortSpecs(append(portsTab, b.Config.PortSpecs...)) 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.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 cannot be empty") } 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") }