pkg/jsonmessage/jsonmessage.go
package jsonmessage // import "github.com/docker/docker/pkg/jsonmessage"
import (
"encoding/json"
"fmt"
"io"
"strings"
"time"
units "github.com/docker/go-units"
"github.com/moby/term"
"github.com/morikuni/aec"
)
// RFC3339NanoFixed is time.RFC3339Nano with nanoseconds padded using zeros to
// ensure the formatted time isalways the same number of characters.
const RFC3339NanoFixed = "2006-01-02T15:04:05.000000000Z07:00"
// JSONError wraps a concrete Code and Message, Code is
// an integer error code, Message is the error message.
type JSONError struct {
Code int `json:"code,omitempty"`
Message string `json:"message,omitempty"`
}
func (e *JSONError) Error() string {
return e.Message
}
// JSONProgress describes a progress message in a JSON stream.
type JSONProgress struct {
// Current is the current status and value of the progress made towards Total.
Current int64 `json:"current,omitempty"`
// Total is the end value describing when we made 100% progress for an operation.
Total int64 `json:"total,omitempty"`
// Start is the initial value for the operation.
Start int64 `json:"start,omitempty"`
// HideCounts. if true, hides the progress count indicator (xB/yB).
HideCounts bool `json:"hidecounts,omitempty"`
// Units is the unit to print for progress. It defaults to "bytes" if empty.
Units string `json:"units,omitempty"`
// terminalFd is the fd of the current terminal, if any. It is used
// to get the terminal width.
terminalFd uintptr
// nowFunc is used to override the current time in tests.
nowFunc func() time.Time
// winSize is used to override the terminal width in tests.
winSize int
}
func (p *JSONProgress) String() string {
var (
width = p.width()
pbBox string
numbersBox string
timeLeftBox string
)
if p.Current <= 0 && p.Total <= 0 {
return ""
}
if p.Total <= 0 {
switch p.Units {
case "":
return fmt.Sprintf("%8v", units.HumanSize(float64(p.Current)))
default:
return fmt.Sprintf("%d %s", p.Current, p.Units)
}
}
percentage := int(float64(p.Current)/float64(p.Total)*100) / 2
if percentage > 50 {
percentage = 50
}
if width > 110 {
// this number can't be negative gh#7136
numSpaces := 0
if 50-percentage > 0 {
numSpaces = 50 - percentage
}
pbBox = fmt.Sprintf("[%s>%s] ", strings.Repeat("=", percentage), strings.Repeat(" ", numSpaces))
}
switch {
case p.HideCounts:
case p.Units == "": // no units, use bytes
current := units.HumanSize(float64(p.Current))
total := units.HumanSize(float64(p.Total))
numbersBox = fmt.Sprintf("%8v/%v", current, total)
if p.Current > p.Total {
// remove total display if the reported current is wonky.
numbersBox = fmt.Sprintf("%8v", current)
}
default:
numbersBox = fmt.Sprintf("%d/%d %s", p.Current, p.Total, p.Units)
if p.Current > p.Total {
// remove total display if the reported current is wonky.
numbersBox = fmt.Sprintf("%d %s", p.Current, p.Units)
}
}
if p.Current > 0 && p.Start > 0 && percentage < 50 {
fromStart := p.now().Sub(time.Unix(p.Start, 0))
perEntry := fromStart / time.Duration(p.Current)
left := time.Duration(p.Total-p.Current) * perEntry
left = (left / time.Second) * time.Second
if width > 50 {
timeLeftBox = " " + left.String()
}
}
return pbBox + numbersBox + timeLeftBox
}
// now returns the current time in UTC, but can be overridden in tests
// by setting JSONProgress.nowFunc to a custom function.
func (p *JSONProgress) now() time.Time {
if p.nowFunc != nil {
return p.nowFunc()
}
return time.Now().UTC()
}
// width returns the current terminal's width, but can be overridden
// in tests by setting JSONProgress.winSize to a non-zero value.
func (p *JSONProgress) width() int {
if p.winSize != 0 {
return p.winSize
}
ws, err := term.GetWinsize(p.terminalFd)
if err == nil {
return int(ws.Width)
}
return 200
}
// JSONMessage defines a message struct. It describes
// the created time, where it from, status, ID of the
// message. It's used for docker events.
type JSONMessage struct {
Stream string `json:"stream,omitempty"`
Status string `json:"status,omitempty"`
Progress *JSONProgress `json:"progressDetail,omitempty"`
ProgressMessage string `json:"progress,omitempty"` // deprecated
ID string `json:"id,omitempty"`
From string `json:"from,omitempty"`
Time int64 `json:"time,omitempty"`
TimeNano int64 `json:"timeNano,omitempty"`
Error *JSONError `json:"errorDetail,omitempty"`
ErrorMessage string `json:"error,omitempty"` // deprecated
// Aux contains out-of-band data, such as digests for push signing and image id after building.
Aux *json.RawMessage `json:"aux,omitempty"`
}
func clearLine(out io.Writer) {
eraseMode := aec.EraseModes.All
cl := aec.EraseLine(eraseMode)
fmt.Fprint(out, cl)
}
func cursorUp(out io.Writer, l uint) {
fmt.Fprint(out, aec.Up(l))
}
func cursorDown(out io.Writer, l uint) {
fmt.Fprint(out, aec.Down(l))
}
// Display prints the JSONMessage to out. If isTerminal is true, it erases
// the entire current line when displaying the progressbar. It returns an
// error if the [JSONMessage.Error] field is non-nil.
func (jm *JSONMessage) Display(out io.Writer, isTerminal bool) error {
if jm.Error != nil {
return jm.Error
}
var endl string
if isTerminal && jm.Stream == "" && jm.Progress != nil {
clearLine(out)
endl = "\r"
fmt.Fprint(out, endl)
} else if jm.Progress != nil && jm.Progress.String() != "" { // disable progressbar in non-terminal
return nil
}
if jm.TimeNano != 0 {
fmt.Fprintf(out, "%s ", time.Unix(0, jm.TimeNano).Format(RFC3339NanoFixed))
} else if jm.Time != 0 {
fmt.Fprintf(out, "%s ", time.Unix(jm.Time, 0).Format(RFC3339NanoFixed))
}
if jm.ID != "" {
fmt.Fprintf(out, "%s: ", jm.ID)
}
if jm.From != "" {
fmt.Fprintf(out, "(from %s) ", jm.From)
}
if jm.Progress != nil && isTerminal {
fmt.Fprintf(out, "%s %s%s", jm.Status, jm.Progress.String(), endl)
} else if jm.ProgressMessage != "" { // deprecated
fmt.Fprintf(out, "%s %s%s", jm.Status, jm.ProgressMessage, endl)
} else if jm.Stream != "" {
fmt.Fprintf(out, "%s%s", jm.Stream, endl)
} else {
fmt.Fprintf(out, "%s%s\n", jm.Status, endl)
}
return nil
}
// DisplayJSONMessagesStream reads a JSON message stream from in, and writes
// each [JSONMessage] to out. It returns an error if an invalid JSONMessage
// is received, or if a JSONMessage containers a non-zero [JSONMessage.Error].
//
// Presentation of the JSONMessage depends on whether a terminal is attached,
// and on the terminal width. Progress bars ([JSONProgress]) are suppressed
// on narrower terminals (< 110 characters).
//
// - isTerminal describes if out is a terminal, in which case it prints
// a newline ("\n") at the end of each line and moves the cursor while
// displaying.
// - terminalFd is the fd of the current terminal (if any), and used
// to get the terminal width.
// - auxCallback allows handling the [JSONMessage.Aux] field. It is
// called if a JSONMessage contains an Aux field, in which case
// DisplayJSONMessagesStream does not present the JSONMessage.
func DisplayJSONMessagesStream(in io.Reader, out io.Writer, terminalFd uintptr, isTerminal bool, auxCallback func(JSONMessage)) error {
var (
dec = json.NewDecoder(in)
ids = make(map[string]uint)
)
for {
var diff uint
var jm JSONMessage
if err := dec.Decode(&jm); err != nil {
if err == io.EOF {
break
}
return err
}
if jm.Aux != nil {
if auxCallback != nil {
auxCallback(jm)
}
continue
}
if jm.Progress != nil {
jm.Progress.terminalFd = terminalFd
}
if jm.ID != "" && (jm.Progress != nil || jm.ProgressMessage != "") {
line, ok := ids[jm.ID]
if !ok {
// NOTE: This approach of using len(id) to
// figure out the number of lines of history
// only works as long as we clear the history
// when we output something that's not
// accounted for in the map, such as a line
// with no ID.
line = uint(len(ids))
ids[jm.ID] = line
if isTerminal {
fmt.Fprintf(out, "\n")
}
}
diff = uint(len(ids)) - line
if isTerminal {
cursorUp(out, diff)
}
} else {
// When outputting something that isn't progress
// output, clear the history of previous lines. We
// don't want progress entries from some previous
// operation to be updated (for example, pull -a
// with multiple tags).
ids = make(map[string]uint)
}
err := jm.Display(out, isTerminal)
if jm.ID != "" && isTerminal {
cursorDown(out, diff)
}
if err != nil {
return err
}
}
return nil
}
// Stream is an io.Writer for output with utilities to get the output's file
// descriptor and to detect wether it's a terminal.
//
// it is subset of the streams.Out type in
// https://pkg.go.dev/github.com/docker/cli@v20.10.17+incompatible/cli/streams#Out
type Stream interface {
io.Writer
FD() uintptr
IsTerminal() bool
}
// DisplayJSONMessagesToStream prints json messages to the output Stream. It is
// used by the Docker CLI to print JSONMessage streams.
func DisplayJSONMessagesToStream(in io.Reader, stream Stream, auxCallback func(JSONMessage)) error {
return DisplayJSONMessagesStream(in, stream, stream.FD(), stream.IsTerminal(), auxCallback)
}