144 lines
3.5 KiB
Go
144 lines
3.5 KiB
Go
package session
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import (
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"context"
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"net"
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"strings"
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"github.com/docker/docker/pkg/stringid"
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"github.com/grpc-ecosystem/grpc-opentracing/go/otgrpc"
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opentracing "github.com/opentracing/opentracing-go"
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"github.com/pkg/errors"
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"google.golang.org/grpc"
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"google.golang.org/grpc/health"
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"google.golang.org/grpc/health/grpc_health_v1"
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)
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const (
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headerSessionID = "X-Docker-Expose-Session-Uuid"
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headerSessionName = "X-Docker-Expose-Session-Name"
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headerSessionSharedKey = "X-Docker-Expose-Session-Sharedkey"
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headerSessionMethod = "X-Docker-Expose-Session-Grpc-Method"
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)
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// Dialer returns a connection that can be used by the session
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type Dialer func(ctx context.Context, proto string, meta map[string][]string) (net.Conn, error)
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// Attachable defines a feature that can be expsed on a session
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type Attachable interface {
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Register(*grpc.Server)
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}
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// Session is a long running connection between client and a daemon
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type Session struct {
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id string
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name string
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sharedKey string
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ctx context.Context
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cancelCtx func()
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done chan struct{}
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grpcServer *grpc.Server
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conn net.Conn
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}
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// NewSession returns a new long running session
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func NewSession(ctx context.Context, name, sharedKey string) (*Session, error) {
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id := stringid.GenerateRandomID()
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serverOpts := []grpc.ServerOption{}
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if span := opentracing.SpanFromContext(ctx); span != nil {
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tracer := span.Tracer()
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serverOpts = []grpc.ServerOption{
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grpc.StreamInterceptor(otgrpc.OpenTracingStreamServerInterceptor(span.Tracer(), traceFilter())),
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grpc.UnaryInterceptor(otgrpc.OpenTracingServerInterceptor(tracer, traceFilter())),
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}
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}
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s := &Session{
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id: id,
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name: name,
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sharedKey: sharedKey,
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grpcServer: grpc.NewServer(serverOpts...),
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}
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grpc_health_v1.RegisterHealthServer(s.grpcServer, health.NewServer())
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return s, nil
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}
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// Allow enable a given service to be reachable through the grpc session
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func (s *Session) Allow(a Attachable) {
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a.Register(s.grpcServer)
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}
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// ID returns unique identifier for the session
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func (s *Session) ID() string {
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return s.id
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}
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// Run activates the session
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func (s *Session) Run(ctx context.Context, dialer Dialer) error {
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ctx, cancel := context.WithCancel(ctx)
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s.cancelCtx = cancel
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s.done = make(chan struct{})
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defer cancel()
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defer close(s.done)
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meta := make(map[string][]string)
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meta[headerSessionID] = []string{s.id}
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meta[headerSessionName] = []string{s.name}
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meta[headerSessionSharedKey] = []string{s.sharedKey}
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for name, svc := range s.grpcServer.GetServiceInfo() {
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for _, method := range svc.Methods {
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meta[headerSessionMethod] = append(meta[headerSessionMethod], MethodURL(name, method.Name))
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}
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}
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conn, err := dialer(ctx, "h2c", meta)
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if err != nil {
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return errors.Wrap(err, "failed to dial gRPC")
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}
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s.conn = conn
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serve(ctx, s.grpcServer, conn)
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return nil
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}
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// Close closes the session
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func (s *Session) Close() error {
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if s.cancelCtx != nil && s.done != nil {
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if s.conn != nil {
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s.conn.Close()
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}
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s.grpcServer.Stop()
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<-s.done
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}
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return nil
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}
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func (s *Session) context() context.Context {
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return s.ctx
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}
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func (s *Session) closed() bool {
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select {
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case <-s.context().Done():
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return true
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default:
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return false
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}
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}
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// MethodURL returns a gRPC method URL for service and method name
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func MethodURL(s, m string) string {
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return "/" + s + "/" + m
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}
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func traceFilter() otgrpc.Option {
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return otgrpc.IncludingSpans(func(parentSpanCtx opentracing.SpanContext,
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method string,
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req, resp interface{}) bool {
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return !strings.HasSuffix(method, "Health/Check")
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})
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}
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