package server import ( "context" "net" "net/http" "os" "os/signal" "strings" "syscall" "time" "github.com/containers/libpod/libpod" "github.com/containers/libpod/pkg/api/handlers" "github.com/coreos/go-systemd/v22/activation" "github.com/gorilla/mux" "github.com/gorilla/schema" "github.com/pkg/errors" "github.com/sirupsen/logrus" ) type APIServer struct { http.Server // The HTTP work happens here *schema.Decoder // Decoder for Query parameters to structs context.Context // Context to carry objects to handlers *libpod.Runtime // Where the real work happens net.Listener // mux for routing HTTP API calls to libpod routines context.CancelFunc // Stop APIServer *time.Timer // Hold timer for sliding window time.Duration // Duration of client access sliding window ActiveConnections uint64 // Number of handlers holding a connection TotalConnections uint64 // Number of connections handled ConnectionCh chan int // Channel for signalling handler enter/exit } // Number of seconds to wait for next request, if exceeded shutdown server const ( DefaultServiceDuration = 300 * time.Second UnlimitedServiceDuration = 0 * time.Second EnterHandler = 1 ExitHandler = -1 NOOPHandler = 0 ) // NewServer will create and configure a new API server with all defaults func NewServer(runtime *libpod.Runtime) (*APIServer, error) { return newServer(runtime, DefaultServiceDuration, nil) } // NewServerWithSettings will create and configure a new API server using provided settings func NewServerWithSettings(runtime *libpod.Runtime, duration time.Duration, listener *net.Listener) (*APIServer, error) { return newServer(runtime, duration, listener) } func newServer(runtime *libpod.Runtime, duration time.Duration, listener *net.Listener) (*APIServer, error) { // If listener not provided try socket activation protocol if listener == nil { if _, found := os.LookupEnv("LISTEN_FDS"); !found { return nil, errors.Errorf("Cannot create Server, no listener provided and socket activation protocol is not active.") } listeners, err := activation.Listeners() if err != nil { return nil, errors.Wrap(err, "Cannot retrieve file descriptors from systemd") } if len(listeners) != 1 { return nil, errors.Errorf("Wrong number of file descriptors for socket activation protocol (%d != 1)", len(listeners)) } listener = &listeners[0] } router := mux.NewRouter().UseEncodedPath() server := APIServer{ Server: http.Server{ Handler: router, ReadHeaderTimeout: 20 * time.Second, IdleTimeout: duration, }, Decoder: handlers.NewAPIDecoder(), Runtime: runtime, Listener: *listener, Duration: duration, ConnectionCh: make(chan int), } server.Timer = time.AfterFunc(server.Duration, func() { server.ConnectionCh <- NOOPHandler }) router.NotFoundHandler = http.HandlerFunc( func(w http.ResponseWriter, r *http.Request) { // We can track user errors... logrus.Infof("Failed Request: (%d:%s) for %s:'%s'", http.StatusNotFound, http.StatusText(http.StatusNotFound), r.Method, r.URL.String()) http.Error(w, http.StatusText(http.StatusNotFound), http.StatusNotFound) }, ) for _, fn := range []func(*mux.Router) error{ server.registerAuthHandlers, server.registerContainersHandlers, server.registerDistributionHandlers, server.registerEventsHandlers, server.registerExecHandlers, server.registerHealthCheckHandlers, server.registerImagesHandlers, server.registerInfoHandlers, server.registerManifestHandlers, server.registerMonitorHandlers, server.registerPingHandlers, server.registerPluginsHandlers, server.registerPodsHandlers, server.registerSwarmHandlers, server.registerSystemHandlers, server.registerVersionHandlers, server.registerVolumeHandlers, } { if err := fn(router); err != nil { return nil, err } } if logrus.IsLevelEnabled(logrus.DebugLevel) { router.Walk(func(route *mux.Route, r *mux.Router, ancestors []*mux.Route) error { // nolint path, err := route.GetPathTemplate() if err != nil { path = "" } methods, err := route.GetMethods() if err != nil { methods = []string{} } logrus.Debugf("Methods: %s Path: %s", strings.Join(methods, ", "), path) return nil }) } return &server, nil } // Serve starts responding to HTTP requests func (s *APIServer) Serve() error { // stalker to count the connections. Should the timer expire it will shutdown the service. go func() { for delta := range s.ConnectionCh { switch delta { case EnterHandler: s.Timer.Stop() s.ActiveConnections += 1 s.TotalConnections += 1 case ExitHandler: s.Timer.Stop() s.ActiveConnections -= 1 if s.ActiveConnections == 0 { // Server will be shutdown iff the timer expires before being reset or stopped s.Timer = time.AfterFunc(s.Duration, func() { if err := s.Shutdown(); err != nil { logrus.Errorf("Failed to shutdown APIServer: %v", err) os.Exit(1) } }) } else { s.Timer.Reset(s.Duration) } case NOOPHandler: // push the check out another duration... s.Timer.Reset(s.Duration) default: logrus.Errorf("ConnectionCh received unsupported input %d", delta) } } }() sigChan := make(chan os.Signal, 1) signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM) errChan := make(chan error, 1) go func() { err := s.Server.Serve(s.Listener) if err != nil && err != http.ErrServerClosed { errChan <- errors.Wrap(err, "Failed to start APIServer") return } errChan <- nil }() select { case err := <-errChan: return err case sig := <-sigChan: logrus.Infof("APIServer terminated by signal %v", sig) } return nil } // Shutdown is a clean shutdown waiting on existing clients func (s *APIServer) Shutdown() error { // Duration == 0 flags no auto-shutdown of the server if s.Duration == 0 { logrus.Debug("APIServer.Shutdown ignored as Duration == 0") return nil } logrus.Debugf("APIServer.Shutdown called %v, conn %d/%d", time.Now(), s.ActiveConnections, s.TotalConnections) // Gracefully shutdown server ctx, cancel := context.WithTimeout(context.Background(), s.Duration) defer cancel() go func() { err := s.Server.Shutdown(ctx) if err != nil && err != context.Canceled && err != http.ErrServerClosed { logrus.Errorf("Failed to cleanly shutdown APIServer: %s", err.Error()) } }() return nil } // Close immediately stops responding to clients and exits func (s *APIServer) Close() error { return s.Server.Close() }