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package session
import (
"context"
"net"
"sync"
"github.com/moby/buildkit/identity"
"github.com/moby/buildkit/util/grpcerrors"
"github.com/moby/buildkit/util/tracing"
"github.com/pkg/errors"
"go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc"
"go.opentelemetry.io/otel/propagation"
"go.opentelemetry.io/otel/trace"
"google.golang.org/grpc"
"google.golang.org/grpc/health"
"google.golang.org/grpc/health/grpc_health_v1"
)
const (
headerSessionID = "X-Docker-Expose-Session-Uuid"
headerSessionName = "X-Docker-Expose-Session-Name"
headerSessionSharedKey = "X-Docker-Expose-Session-Sharedkey"
headerSessionMethod = "X-Docker-Expose-Session-Grpc-Method"
)
var propagators = propagation.NewCompositeTextMapPropagator(propagation.TraceContext{}, propagation.Baggage{})
// Dialer returns a connection that can be used by the session
type Dialer func(ctx context.Context, proto string, meta map[string][]string) (net.Conn, error)
// Attachable defines a feature that can be exposed on a session
type Attachable interface {
Register(*grpc.Server)
}
// Session is a long running connection between client and a daemon
type Session struct {
mu sync.Mutex // synchronizes conn run and close
id string
name string
sharedKey string
ctx context.Context
cancelCtx func(error)
done chan struct{}
grpcServer *grpc.Server
conn net.Conn
closeCalled bool
}
// NewSession returns a new long running session
func NewSession(ctx context.Context, name, sharedKey string) (*Session, error) {
id := identity.NewID()
serverOpts := []grpc.ServerOption{
grpc.UnaryInterceptor(grpcerrors.UnaryServerInterceptor),
grpc.StreamInterceptor(grpcerrors.StreamServerInterceptor),
}
if span := trace.SpanFromContext(ctx); span.SpanContext().IsValid() {
statsHandler := tracing.ServerStatsHandler(
otelgrpc.WithTracerProvider(span.TracerProvider()),
otelgrpc.WithPropagators(propagators),
)
serverOpts = append(serverOpts, grpc.StatsHandler(statsHandler))
}
s := &Session{
id: id,
name: name,
sharedKey: sharedKey,
grpcServer: grpc.NewServer(serverOpts...),
}
grpc_health_v1.RegisterHealthServer(s.grpcServer, health.NewServer())
return s, nil
}
// Allow enables a given service to be reachable through the grpc session
func (s *Session) Allow(a Attachable) {
a.Register(s.grpcServer)
}
// ID returns unique identifier for the session
func (s *Session) ID() string {
return s.id
}
// Run activates the session
func (s *Session) Run(ctx context.Context, dialer Dialer) error {
s.mu.Lock()
if s.closeCalled {
s.mu.Unlock()
return nil
}
ctx, cancel := context.WithCancelCause(ctx)
s.cancelCtx = cancel
s.done = make(chan struct{})
defer cancel(errors.WithStack(context.Canceled))
defer close(s.done)
meta := make(map[string][]string)
meta[headerSessionID] = []string{s.id}
meta[headerSessionName] = []string{s.name}
meta[headerSessionSharedKey] = []string{s.sharedKey}
for name, svc := range s.grpcServer.GetServiceInfo() {
for _, method := range svc.Methods {
meta[headerSessionMethod] = append(meta[headerSessionMethod], MethodURL(name, method.Name))
}
}
conn, err := dialer(ctx, "h2c", meta)
if err != nil {
s.mu.Unlock()
return errors.Wrap(err, "failed to dial gRPC")
}
s.conn = conn
s.mu.Unlock()
serve(ctx, s.grpcServer, conn)
return nil
}
// Close closes the session
func (s *Session) Close() error {
s.mu.Lock()
if s.cancelCtx != nil && s.done != nil {
if s.conn != nil {
s.conn.Close()
}
s.grpcServer.Stop()
<-s.done
}
s.closeCalled = true
s.mu.Unlock()
return nil
}
func (s *Session) context() context.Context {
return s.ctx
}
func (s *Session) closed() bool {
select {
case <-s.context().Done():
return true
default:
return false
}
}
// MethodURL returns a gRPC method URL for service and method name
func MethodURL(s, m string) string {
return "/" + s + "/" + m
}
|
