package imagebuilder import ( "bytes" "fmt" "io/ioutil" "log" "os" "path/filepath" "runtime" "strconv" "strings" docker "github.com/fsouza/go-dockerclient" "github.com/docker/docker/builder/dockerfile/command" "github.com/docker/docker/builder/dockerfile/parser" ) // Copy defines a copy operation required on the container. type Copy struct { // If true, this is a copy from the file system to the container. If false, // the copy is from the context. FromFS bool // If set, this is a copy from the named stage or image to the container. From string Src []string Dest string Download bool // If set, the owner:group for the destination. This value is passed // to the executor for handling. Chown string } // Run defines a run operation required in the container. type Run struct { Shell bool Args []string } type Executor interface { Preserve(path string) error Copy(excludes []string, copies ...Copy) error Run(run Run, config docker.Config) error UnrecognizedInstruction(step *Step) error } type logExecutor struct{} func (logExecutor) Preserve(path string) error { log.Printf("PRESERVE %s", path) return nil } func (logExecutor) Copy(excludes []string, copies ...Copy) error { for _, c := range copies { log.Printf("COPY %v -> %s (from:%s download:%t), chown: %s", c.Src, c.Dest, c.From, c.Download, c.Chown) } return nil } func (logExecutor) Run(run Run, config docker.Config) error { log.Printf("RUN %v %t (%v)", run.Args, run.Shell, config.Env) return nil } func (logExecutor) UnrecognizedInstruction(step *Step) error { log.Printf("Unknown instruction: %s", strings.ToUpper(step.Command)) return nil } type noopExecutor struct{} func (noopExecutor) Preserve(path string) error { return nil } func (noopExecutor) Copy(excludes []string, copies ...Copy) error { return nil } func (noopExecutor) Run(run Run, config docker.Config) error { return nil } func (noopExecutor) UnrecognizedInstruction(step *Step) error { return nil } type VolumeSet []string func (s *VolumeSet) Add(path string) bool { if path == "/" { set := len(*s) != 1 || (*s)[0] != "" *s = []string{""} return set } path = strings.TrimSuffix(path, "/") var adjusted []string for _, p := range *s { if p == path || strings.HasPrefix(path, p+"/") { return false } if strings.HasPrefix(p, path+"/") { continue } adjusted = append(adjusted, p) } adjusted = append(adjusted, path) *s = adjusted return true } func (s VolumeSet) Has(path string) bool { if path == "/" { return len(s) == 1 && s[0] == "" } path = strings.TrimSuffix(path, "/") for _, p := range s { if p == path { return true } } return false } func (s VolumeSet) Covers(path string) bool { if path == "/" { return len(s) == 1 && s[0] == "" } path = strings.TrimSuffix(path, "/") for _, p := range s { if p == path || strings.HasPrefix(path, p+"/") { return true } } return false } var ( LogExecutor = logExecutor{} NoopExecutor = noopExecutor{} ) type Stages []Stage func (stages Stages) ByName(name string) (Stage, bool) { for _, stage := range stages { if stage.Name == name { return stage, true } } return Stage{}, false } func (stages Stages) ByTarget(target string) (Stages, bool) { if len(target) == 0 { return stages, true } for i, stage := range stages { if stage.Name == target { return stages[i : i+1], true } } return nil, false } type Stage struct { Position int Name string Builder *Builder Node *parser.Node } func NewStages(node *parser.Node, b *Builder) (Stages, error) { var stages Stages if err := b.extractHeadingArgsFromNode(node); err != nil { return stages, err } for i, root := range SplitBy(node, command.From) { name, _ := extractNameFromNode(root.Children[0]) if len(name) == 0 { name = strconv.Itoa(i) } stages = append(stages, Stage{ Position: i, Name: name, Builder: &Builder{ Args: b.Args, AllowedArgs: b.AllowedArgs, }, Node: root, }) } return stages, nil } func (b *Builder) extractHeadingArgsFromNode(node *parser.Node) error { var args []*parser.Node var children []*parser.Node extract := true for _, child := range node.Children { if extract && child.Value == command.Arg { args = append(args, child) } else { if child.Value == command.From { extract = false } children = append(children, child) } } for _, c := range args { step := b.Step() if err := step.Resolve(c); err != nil { return err } if err := b.Run(step, NoopExecutor, false); err != nil { return err } } node.Children = children return nil } func extractNameFromNode(node *parser.Node) (string, bool) { if node.Value != command.From { return "", false } n := node.Next if n == nil || n.Next == nil { return "", false } n = n.Next if !strings.EqualFold(n.Value, "as") || n.Next == nil || len(n.Next.Value) == 0 { return "", false } return n.Next.Value, true } type Builder struct { RunConfig docker.Config Env []string Args map[string]string CmdSet bool Author string AllowedArgs map[string]bool Volumes VolumeSet Excludes []string PendingVolumes VolumeSet PendingRuns []Run PendingCopies []Copy Warnings []string } func NewBuilder(args map[string]string) *Builder { allowed := make(map[string]bool) for k, v := range builtinAllowedBuildArgs { allowed[k] = v } return &Builder{ Args: args, AllowedArgs: allowed, } } func ParseFile(path string) (*parser.Node, error) { f, err := os.Open(path) if err != nil { return nil, err } defer f.Close() return ParseDockerfile(f) } // Step creates a new step from the current state. func (b *Builder) Step() *Step { dst := make([]string, len(b.Env)+len(b.RunConfig.Env)) copy(dst, b.Env) dst = append(dst, b.RunConfig.Env...) dst = append(dst, b.Arguments()...) return &Step{Env: dst} } // Run executes a step, transforming the current builder and // invoking any Copy or Run operations. noRunsRemaining is an // optimization hint that allows the builder to avoid performing // unnecessary work. func (b *Builder) Run(step *Step, exec Executor, noRunsRemaining bool) error { fn, ok := evaluateTable[step.Command] if !ok { return exec.UnrecognizedInstruction(step) } if err := fn(b, step.Args, step.Attrs, step.Flags, step.Original); err != nil { return err } copies := b.PendingCopies b.PendingCopies = nil runs := b.PendingRuns b.PendingRuns = nil // Once a VOLUME is defined, future ADD/COPY instructions are // all that may mutate that path. Instruct the executor to preserve // the path. The executor must handle invalidating preserved info. for _, path := range b.PendingVolumes { if b.Volumes.Add(path) && !noRunsRemaining { if err := exec.Preserve(path); err != nil { return err } } } if err := exec.Copy(b.Excludes, copies...); err != nil { return err } for _, run := range runs { config := b.Config() config.Env = step.Env if err := exec.Run(run, *config); err != nil { return err } } return nil } // RequiresStart returns true if a running container environment is necessary // to invoke the provided commands func (b *Builder) RequiresStart(node *parser.Node) bool { for _, child := range node.Children { if child.Value == command.Run { return true } } return false } // Config returns a snapshot of the current RunConfig intended for // use with a container commit. func (b *Builder) Config() *docker.Config { config := b.RunConfig if config.OnBuild == nil { config.OnBuild = []string{} } if config.Entrypoint == nil { config.Entrypoint = []string{} } config.Image = "" return &config } // Arguments returns the currently active arguments. func (b *Builder) Arguments() []string { var envs []string for key, val := range b.Args { if _, ok := b.AllowedArgs[key]; ok { envs = append(envs, fmt.Sprintf("%s=%s", key, val)) } } return envs } // ErrNoFROM is returned if the Dockerfile did not contain a FROM // statement. var ErrNoFROM = fmt.Errorf("no FROM statement found") // From returns the image this dockerfile depends on, or an error // if no FROM is found or if multiple FROM are specified. If a // single from is found the passed node is updated with only // the remaining statements. The builder's RunConfig.Image field // is set to the first From found, or left unchanged if already // set. func (b *Builder) From(node *parser.Node) (string, error) { if err := b.extractHeadingArgsFromNode(node); err != nil { return "", err } children := SplitChildren(node, command.From) switch { case len(children) == 0: return "", ErrNoFROM case len(children) > 1: return "", fmt.Errorf("multiple FROM statements are not supported") default: step := b.Step() if err := step.Resolve(children[0]); err != nil { return "", err } if err := b.Run(step, NoopExecutor, false); err != nil { return "", err } return b.RunConfig.Image, nil } } // FromImage updates the builder to use the provided image (resetting RunConfig // and recording the image environment), and updates the node with any ONBUILD // statements extracted from the parent image. func (b *Builder) FromImage(image *docker.Image, node *parser.Node) error { SplitChildren(node, command.From) b.RunConfig = *image.Config b.Env = b.RunConfig.Env b.RunConfig.Env = nil // Check to see if we have a default PATH, note that windows won't // have one as its set by HCS if runtime.GOOS != "windows" && !hasEnvName(b.Env, "PATH") { b.RunConfig.Env = append(b.RunConfig.Env, "PATH="+defaultPathEnv) } // Join the image onbuild statements into node if image.Config == nil || len(image.Config.OnBuild) == 0 { return nil } extra, err := ParseDockerfile(bytes.NewBufferString(strings.Join(image.Config.OnBuild, "\n"))) if err != nil { return err } for _, child := range extra.Children { switch strings.ToUpper(child.Value) { 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", child.Value) } } node.Children = append(extra.Children, node.Children...) // Since we've processed the OnBuild statements, clear them from the runconfig state. b.RunConfig.OnBuild = nil return nil } // SplitChildren removes any children with the provided value from node // and returns them as an array. node.Children is updated. func SplitChildren(node *parser.Node, value string) []*parser.Node { var split []*parser.Node var children []*parser.Node for _, child := range node.Children { if child.Value == value { split = append(split, child) } else { children = append(children, child) } } node.Children = children return split } func SplitBy(node *parser.Node, value string) []*parser.Node { var split []*parser.Node var current *parser.Node for _, child := range node.Children { if current == nil || child.Value == value { copied := *node current = &copied current.Children = nil current.Next = nil split = append(split, current) } current.Children = append(current.Children, child) } return split } // StepFunc is invoked with the result of a resolved step. type StepFunc func(*Builder, []string, map[string]bool, []string, string) error var evaluateTable = map[string]StepFunc{ command.Env: env, command.Label: label, command.Maintainer: maintainer, command.Add: add, command.Copy: dispatchCopy, // copy() is a go builtin command.From: from, command.Onbuild: onbuild, command.Workdir: workdir, command.Run: run, command.Cmd: cmd, command.Entrypoint: entrypoint, command.Expose: expose, command.Volume: volume, command.User: user, command.StopSignal: stopSignal, command.Arg: arg, command.Healthcheck: healthcheck, command.Shell: shell, } // builtinAllowedBuildArgs is list of built-in allowed build args var builtinAllowedBuildArgs = map[string]bool{ "HTTP_PROXY": true, "http_proxy": true, "HTTPS_PROXY": true, "https_proxy": true, "FTP_PROXY": true, "ftp_proxy": true, "NO_PROXY": true, "no_proxy": true, } // ParseDockerIgnore returns a list of the excludes in the .dockerignore file. // extracted from fsouza/go-dockerclient. func ParseDockerignore(root string) ([]string, error) { var excludes []string ignore, err := ioutil.ReadFile(filepath.Join(root, ".dockerignore")) if err != nil && !os.IsNotExist(err) { return excludes, fmt.Errorf("error reading .dockerignore: '%s'", err) } return strings.Split(string(ignore), "\n"), nil } // ExportEnv creates an export statement for a shell that contains all of the // provided environment. func ExportEnv(env []string) string { if len(env) == 0 { return "" } out := "export" for _, e := range env { if len(e) == 0 { continue } out += " " + BashQuote(e) } return out + "; " } // BashQuote escapes the provided string and surrounds it with double quotes. // TODO: verify that these are all we have to escape. func BashQuote(env string) string { out := []rune{'"'} for _, r := range env { switch r { case '$', '\\', '"': out = append(out, '\\', r) default: out = append(out, r) } } out = append(out, '"') return string(out) }