зеркало из https://github.com/microsoft/docker.git
137 строки
3.4 KiB
Go
137 строки
3.4 KiB
Go
package future
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import (
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"bytes"
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"crypto/sha256"
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"errors"
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"fmt"
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"io"
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"math/rand"
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"net/http"
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"time"
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)
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func Seed() {
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rand.Seed(time.Now().UTC().UnixNano())
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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 HumanDuration(d time.Duration) string {
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if seconds := int(d.Seconds()); seconds < 1 {
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return "Less than a second"
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} else if seconds < 60 {
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return fmt.Sprintf("%d seconds", seconds)
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} else if minutes := int(d.Minutes()); minutes == 1 {
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return "About a minute"
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} else if minutes < 60 {
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return fmt.Sprintf("%d minutes", minutes)
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} else if hours := int(d.Hours()); hours == 1 {
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return "About an hour"
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} else if hours < 48 {
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return fmt.Sprintf("%d hours", hours)
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} else if hours < 24*7*2 {
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return fmt.Sprintf("%d days", hours/24)
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} else if hours < 24*30*3 {
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return fmt.Sprintf("%d weeks", hours/24/7)
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} else if hours < 24*365*2 {
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return fmt.Sprintf("%d months", hours/24/30)
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}
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return fmt.Sprintf("%d years", d.Hours()/24/365)
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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 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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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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// Pv wraps an io.Reader such that it is passed through unchanged,
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// but logs the number of bytes copied (comparable to the unix command pv)
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func Pv(src io.Reader, info io.Writer) io.Reader {
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var totalBytes int
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data := make([]byte, 2048)
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r, w := io.Pipe()
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go func() {
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for {
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if n, err := src.Read(data); err != nil {
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w.CloseWithError(err)
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return
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} else {
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totalBytes += n
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fmt.Fprintf(info, "--> %d bytes\n", totalBytes)
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if _, err = w.Write(data[:n]); err != nil {
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return
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}
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}
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}
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}()
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return r
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}
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// Request a given URL and return an io.Reader
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func Download(url string, stderr io.Writer) (*http.Response, error) {
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var resp *http.Response
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var err error = nil
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if resp, err = http.Get(url); err != nil {
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return nil, err
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}
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if resp.StatusCode >= 400 {
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return nil, errors.New("Got HTTP status code >= 400: " + resp.Status)
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}
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return resp, nil
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}
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// Reader with progress bar
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type progressReader struct {
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reader io.ReadCloser // Stream to read from
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output io.Writer // Where to send progress bar to
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read_total int // Expected stream length (bytes)
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read_progress int // How much has been read so far (bytes)
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last_update int // How many bytes read at least update
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}
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func (r *progressReader) Read(p []byte) (n int, err error) {
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read, err := io.ReadCloser(r.reader).Read(p)
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r.read_progress += read
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// Only update progress for every 1% read
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update_every := int(0.01 * float64(r.read_total))
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if r.read_progress-r.last_update > update_every || r.read_progress == r.read_total {
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fmt.Fprintf(r.output, "%d/%d (%.0f%%)\r",
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r.read_progress,
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r.read_total,
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float64(r.read_progress)/float64(r.read_total)*100)
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r.last_update = r.read_progress
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}
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// Send newline when complete
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if err == io.EOF {
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fmt.Fprintf(r.output, "\n")
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}
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return read, err
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}
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func (r *progressReader) Close() error {
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return io.ReadCloser(r.reader).Close()
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}
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func ProgressReader(r io.ReadCloser, size int, output io.Writer) *progressReader {
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return &progressReader{r, output, size, 0, 0}
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}
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