DockerCLI/vendor/github.com/moby/buildkit/session/manager.go

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package session
import (
"net"
"net/http"
"strings"
"sync"
"github.com/pkg/errors"
"golang.org/x/net/context"
"google.golang.org/grpc"
)
// Caller can invoke requests on the session
type Caller interface {
Context() context.Context
Supports(method string) bool
Conn() *grpc.ClientConn
Name() string
SharedKey() string
}
type client struct {
Session
cc *grpc.ClientConn
supported map[string]struct{}
}
// Manager is a controller for accessing currently active sessions
type Manager struct {
sessions map[string]*client
mu sync.Mutex
updateCondition *sync.Cond
}
// NewManager returns a new Manager
func NewManager() (*Manager, error) {
sm := &Manager{
sessions: make(map[string]*client),
}
sm.updateCondition = sync.NewCond(&sm.mu)
return sm, nil
}
// HandleHTTPRequest handles an incoming HTTP request
func (sm *Manager) HandleHTTPRequest(ctx context.Context, w http.ResponseWriter, r *http.Request) error {
hijacker, ok := w.(http.Hijacker)
if !ok {
return errors.New("handler does not support hijack")
}
id := r.Header.Get(headerSessionID)
proto := r.Header.Get("Upgrade")
sm.mu.Lock()
if _, ok := sm.sessions[id]; ok {
sm.mu.Unlock()
return errors.Errorf("session %s already exists", id)
}
if proto == "" {
sm.mu.Unlock()
return errors.New("no upgrade proto in request")
}
if proto != "h2c" {
sm.mu.Unlock()
return errors.Errorf("protocol %s not supported", proto)
}
conn, _, err := hijacker.Hijack()
if err != nil {
sm.mu.Unlock()
return errors.Wrap(err, "failed to hijack connection")
}
resp := &http.Response{
StatusCode: http.StatusSwitchingProtocols,
ProtoMajor: 1,
ProtoMinor: 1,
Header: http.Header{},
}
resp.Header.Set("Connection", "Upgrade")
resp.Header.Set("Upgrade", proto)
// set raw mode
conn.Write([]byte{})
resp.Write(conn)
return sm.handleConn(ctx, conn, r.Header)
}
// HandleConn handles an incoming raw connection
func (sm *Manager) HandleConn(ctx context.Context, conn net.Conn, opts map[string][]string) error {
sm.mu.Lock()
return sm.handleConn(ctx, conn, opts)
}
// caller needs to take lock, this function will release it
func (sm *Manager) handleConn(ctx context.Context, conn net.Conn, opts map[string][]string) error {
ctx, cancel := context.WithCancel(ctx)
defer cancel()
opts = canonicalHeaders(opts)
h := http.Header(opts)
id := h.Get(headerSessionID)
name := h.Get(headerSessionName)
sharedKey := h.Get(headerSessionSharedKey)
ctx, cc, err := grpcClientConn(ctx, conn)
if err != nil {
sm.mu.Unlock()
return err
}
c := &client{
Session: Session{
id: id,
name: name,
sharedKey: sharedKey,
ctx: ctx,
cancelCtx: cancel,
done: make(chan struct{}),
},
cc: cc,
supported: make(map[string]struct{}),
}
for _, m := range opts[headerSessionMethod] {
c.supported[strings.ToLower(m)] = struct{}{}
}
sm.sessions[id] = c
sm.updateCondition.Broadcast()
sm.mu.Unlock()
defer func() {
sm.mu.Lock()
delete(sm.sessions, id)
sm.mu.Unlock()
}()
<-c.ctx.Done()
conn.Close()
close(c.done)
return nil
}
// Get returns a session by ID
func (sm *Manager) Get(ctx context.Context, id string) (Caller, error) {
ctx, cancel := context.WithCancel(ctx)
defer cancel()
go func() {
select {
case <-ctx.Done():
sm.updateCondition.Broadcast()
}
}()
var c *client
sm.mu.Lock()
for {
select {
case <-ctx.Done():
sm.mu.Unlock()
return nil, errors.Wrapf(ctx.Err(), "no active session for %s", id)
default:
}
var ok bool
c, ok = sm.sessions[id]
if !ok || c.closed() {
sm.updateCondition.Wait()
continue
}
sm.mu.Unlock()
break
}
return c, nil
}
func (c *client) Context() context.Context {
return c.context()
}
func (c *client) Name() string {
return c.name
}
func (c *client) SharedKey() string {
return c.sharedKey
}
func (c *client) Supports(url string) bool {
_, ok := c.supported[strings.ToLower(url)]
return ok
}
func (c *client) Conn() *grpc.ClientConn {
return c.cc
}
func canonicalHeaders(in map[string][]string) map[string][]string {
out := map[string][]string{}
for k := range in {
out[http.CanonicalHeaderKey(k)] = in[k]
}
return out
}