Prototyping with a mock CLI and daemon
This commit is contained in:
Solomon Hykes
parent
a27b4b8cb8
commit
e5323e7c9a
2 changed files with 274 additions and 0 deletions
39
docker/docker.go
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39
docker/docker.go
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package main
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import (
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"io"
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"log"
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"os"
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"flag"
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"net/http"
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"net/url"
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)
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// Use this key to encode an RPC call into an URL,
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// eg. domain.tld/path/to/method?q=get_user&q=gordon
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const ARG_URL_KEY = "q"
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func CallToURL(host string, cmd string, args []string) *url.URL {
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qValues := make(url.Values)
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for _, v := range args {
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qValues.Add(ARG_URL_KEY, v)
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}
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return &url.URL{
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Scheme: "http",
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Host: host,
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Path: "/" + cmd,
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RawQuery: qValues.Encode(),
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}
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}
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func main() {
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flag.Parse()
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u := CallToURL(os.Getenv("DOCKER"), flag.Args()[0], flag.Args()[1:])
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resp, err := http.Get(u.String())
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if err != nil {
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log.Fatal(err)
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}
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io.Copy(os.Stdout, resp.Body)
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}
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235
dockerd/dockerd.go
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235
dockerd/dockerd.go
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package main
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import (
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"errors"
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"log"
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"io"
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// "io/ioutil"
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"net/http"
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"net/url"
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"os/exec"
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"flag"
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"reflect"
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"fmt"
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"github.com/kr/pty"
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"path"
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"strings"
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"time"
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"math/rand"
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"crypto/sha256"
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"bytes"
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"text/tabwriter"
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)
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func (docker *Docker) CmdUsage(stdin io.ReadCloser, stdout io.Writer, args ...string) error {
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fmt.Fprintf(stdout, "Usage: docker COMMAND [arg...]\n\nCommands:\n")
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for _, cmd := range [][]interface{}{
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{"run", "Run a command in a container"},
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{"list", "Display a list of containers"},
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{"layers", "Display a list of layers"},
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{"download", "Download a layer from a remote location"},
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{"upload", "Upload a layer"},
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{"wait", "Wait for the state of a container to change"},
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{"stop", "Stop a running container"},
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{"logs", "Fetch the logs of a container"},
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{"export", "Extract changes to a container's filesystem into a new layer"},
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{"attach", "Attach to the standard inputs and outputs of a running container"},
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{"info", "Display system-wide information"},
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} {
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fmt.Fprintf(stdout, " %-10.10s%s\n", cmd...)
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}
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return nil
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}
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func (docker *Docker) CmdLayers(stdin io.ReadCloser, stdout io.Writer, args ...string) error {
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w := tabwriter.NewWriter(stdout, 20, 1, 3, ' ', 0)
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fmt.Fprintf(w, "ID\tSOURCE\tADDED\n")
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for _, layer := range docker.layers {
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fmt.Fprintf(w, "%s\t%s\t%s ago\n", layer.Id, layer.Name, time.Now().Sub(layer.Added))
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}
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w.Flush()
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return nil
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}
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func (docker *Docker) CmdUpload(stdin io.ReadCloser, stdout io.Writer, args ...string) error {
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layer := Layer{Id: randomId(), Name: args[0], Added: time.Now()}
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docker.layers = append(docker.layers, layer)
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fmt.Fprintf(stdout, "New layer: %s (%s)\n", layer.Id, layer.Name)
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return nil
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}
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func (docker *Docker) CmdRun(stdin io.ReadCloser, stdout io.Writer, args ...string) error {
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if len(docker.layers) == 0 {
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return errors.New("No layers")
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}
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container := Container{
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Id: randomId(),
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Cmd: args[0],
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Args: args[1:],
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Layers: docker.layers[:1],
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}
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docker.containers = append(docker.containers, container)
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cmd := exec.Command(args[0], args[1:]...)
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cmd_stdin, cmd_stdout, err := startCommand(cmd, false)
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if err != nil {
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return err
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}
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copy_out := Go(func() error {
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_, err := io.Copy(stdout, cmd_stdout)
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return err
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})
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copy_in := Go(func() error {
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//_, err := io.Copy(cmd_stdin, stdin)
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cmd_stdin.Close()
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stdin.Close()
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//return err
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return nil
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})
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if err := cmd.Wait(); err != nil {
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return err
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}
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if err := <-copy_in; err != nil {
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return err
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}
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if err := <-copy_out; err != nil {
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return err
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}
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return nil
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}
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func startCommand(cmd *exec.Cmd, interactive bool) (io.WriteCloser, io.ReadCloser, error) {
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if interactive {
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term, err := pty.Start(cmd)
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if err != nil {
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return nil, nil, err
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}
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return term, term, nil
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}
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stdin, err := cmd.StdinPipe()
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if err != nil {
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return nil, nil, err
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}
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stdout, err := cmd.StdoutPipe()
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if err != nil {
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return nil, nil, err
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}
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if err := cmd.Start(); err != nil {
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return nil, nil, err
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}
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return stdin, stdout, nil
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}
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func (docker *Docker) CmdList(stdin io.ReadCloser, stdout io.Writer, args ...string) error {
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w := tabwriter.NewWriter(stdout, 20, 1, 3, ' ', 0)
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fmt.Fprintf(w, "ID\tCMD\tSTATUS\tLAYERS\n")
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for _, container := range docker.containers {
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var layers []string
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for _, layer := range container.Layers {
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layers = append(layers, layer.Name)
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}
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fmt.Fprintf(w, "%s\t%s %s\t?\t%s\n",
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container.Id,
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container.Cmd,
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strings.Join(container.Args, " "),
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strings.Join(layers, ", "))
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}
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w.Flush()
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return nil
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}
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func main() {
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rand.Seed(time.Now().UTC().UnixNano())
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flag.Parse()
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if err := http.ListenAndServe(":4242", new(Docker)); err != nil {
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log.Fatal(err)
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}
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}
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func (docker *Docker) ServeHTTP(w http.ResponseWriter, r *http.Request) {
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cmd, args := URLToCall(r.URL)
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method := docker.getMethod(cmd)
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if method == nil {
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docker.CmdUsage(r.Body, w, cmd)
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} else {
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err := method(r.Body, w, args...)
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if err != nil {
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fmt.Fprintf(w, "Error: %s\n", err)
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}
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}
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}
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func (docker *Docker) getMethod(name string) Cmd {
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methodName := "Cmd"+strings.ToUpper(name[:1])+strings.ToLower(name[1:])
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method, exists := reflect.TypeOf(docker).MethodByName(methodName)
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if !exists {
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return nil
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}
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return func(stdin io.ReadCloser, stdout io.Writer, args ...string) error {
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ret := method.Func.CallSlice([]reflect.Value{
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reflect.ValueOf(docker),
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reflect.ValueOf(stdin),
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reflect.ValueOf(stdout),
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reflect.ValueOf(args),
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})[0].Interface()
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if ret == nil {
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return nil
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}
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return ret.(error)
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}
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}
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func Go(f func() error) chan error {
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ch := make(chan error)
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go func() {
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ch <- f()
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}()
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return ch
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}
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type Docker struct {
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layers []Layer
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containers []Container
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}
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type Layer struct {
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Id string
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Name string
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Added time.Time
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}
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type Container struct {
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Id string
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Cmd string
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Args []string
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Layers []Layer
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}
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type Cmd func(io.ReadCloser, io.Writer, ...string) error
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type CmdMethod func(*Docker, io.ReadCloser, io.Writer, ...string) error
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// Use this key to encode an RPC call into an URL,
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// eg. domain.tld/path/to/method?q=get_user&q=gordon
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const ARG_URL_KEY = "q"
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func URLToCall(u *url.URL) (method string, args []string) {
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return path.Base(u.Path), u.Query()[ARG_URL_KEY]
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}
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func randomBytes() io.Reader {
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return bytes.NewBuffer([]byte(fmt.Sprintf("%x", rand.Int())))
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}
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func ComputeId(content io.Reader) (string, error) {
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h := sha256.New()
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if _, err := io.Copy(h, content); err != nil {
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return "", err
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}
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return fmt.Sprintf("%x", h.Sum(nil)[:8]), nil
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}
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func randomId() string {
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id, _ := ComputeId(randomBytes()) // can't fail
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return id
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}
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