DockerCLI/cli/command/image/build_session.go

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package image
import (
"bytes"
"crypto/rand"
"crypto/sha256"
"encoding/hex"
"fmt"
"io"
"io/ioutil"
"os"
"path/filepath"
"sync"
"time"
"github.com/docker/cli/cli/command"
"github.com/docker/cli/cli/command/image/build"
cliconfig "github.com/docker/cli/cli/config"
"github.com/docker/docker/api/types/versions"
"github.com/docker/docker/pkg/progress"
"github.com/moby/buildkit/session"
"github.com/moby/buildkit/session/filesync"
"github.com/pkg/errors"
"golang.org/x/time/rate"
)
const clientSessionRemote = "client-session"
func isSessionSupported(dockerCli command.Cli) bool {
return dockerCli.ServerInfo().HasExperimental && versions.GreaterThanOrEqualTo(dockerCli.Client().ClientVersion(), "1.31")
}
func trySession(dockerCli command.Cli, contextDir string) (*session.Session, error) {
var s *session.Session
if isSessionSupported(dockerCli) {
sharedKey, err := getBuildSharedKey(contextDir)
if err != nil {
return nil, errors.Wrap(err, "failed to get build shared key")
}
s, err = session.NewSession(filepath.Base(contextDir), sharedKey)
if err != nil {
return nil, errors.Wrap(err, "failed to create session")
}
}
return s, nil
}
func addDirToSession(session *session.Session, contextDir string, progressOutput progress.Output, done chan error) error {
excludes, err := build.ReadDockerignore(contextDir)
if err != nil {
return err
}
p := &sizeProgress{out: progressOutput, action: "Streaming build context to Docker daemon"}
workdirProvider := filesync.NewFSSyncProvider([]filesync.SyncedDir{
{Dir: contextDir, Excludes: excludes},
})
session.Allow(workdirProvider)
// this will be replaced on parallel build jobs. keep the current
// progressbar for now
if snpc, ok := workdirProvider.(interface {
SetNextProgressCallback(func(int, bool), chan error)
}); ok {
snpc.SetNextProgressCallback(p.update, done)
}
return nil
}
type sizeProgress struct {
out progress.Output
action string
limiter *rate.Limiter
}
func (sp *sizeProgress) update(size int, last bool) {
if sp.limiter == nil {
sp.limiter = rate.NewLimiter(rate.Every(100*time.Millisecond), 1)
}
if last || sp.limiter.Allow() {
sp.out.WriteProgress(progress.Progress{Action: sp.action, Current: int64(size), LastUpdate: last})
}
}
type bufferedWriter struct {
done chan error
io.Writer
buf *bytes.Buffer
flushed chan struct{}
mu sync.Mutex
}
func newBufferedWriter(done chan error, w io.Writer) *bufferedWriter {
bw := &bufferedWriter{done: done, Writer: w, buf: new(bytes.Buffer), flushed: make(chan struct{})}
go func() {
<-done
bw.flushBuffer()
}()
return bw
}
func (bw *bufferedWriter) Write(dt []byte) (int, error) {
select {
case <-bw.done:
bw.flushBuffer()
return bw.Writer.Write(dt)
default:
return bw.buf.Write(dt)
}
}
func (bw *bufferedWriter) flushBuffer() {
bw.mu.Lock()
select {
case <-bw.flushed:
default:
bw.Writer.Write(bw.buf.Bytes())
close(bw.flushed)
}
bw.mu.Unlock()
}
func getBuildSharedKey(dir string) (string, error) {
// build session is hash of build dir with node based randomness
s := sha256.Sum256([]byte(fmt.Sprintf("%s:%s", tryNodeIdentifier(), dir)))
return hex.EncodeToString(s[:]), nil
}
func tryNodeIdentifier() string {
out := cliconfig.Dir() // return config dir as default on permission error
if err := os.MkdirAll(cliconfig.Dir(), 0700); err == nil {
sessionFile := filepath.Join(cliconfig.Dir(), ".buildNodeID")
if _, err := os.Lstat(sessionFile); err != nil {
if os.IsNotExist(err) { // create a new file with stored randomness
b := make([]byte, 32)
if _, err := rand.Read(b); err != nil {
return out
}
if err := ioutil.WriteFile(sessionFile, []byte(hex.EncodeToString(b)), 0600); err != nil {
return out
}
}
}
dt, err := ioutil.ReadFile(sessionFile)
if err == nil {
return string(dt)
}
}
return out
}