package server // import "github.com/docker/docker/api/server" import ( "context" "crypto/tls" "net" "net/http" "strings" "github.com/docker/docker/api/server/httpstatus" "github.com/docker/docker/api/server/httputils" "github.com/docker/docker/api/server/middleware" "github.com/docker/docker/api/server/router" "github.com/docker/docker/api/server/router/debug" "github.com/docker/docker/dockerversion" "github.com/gorilla/mux" "github.com/sirupsen/logrus" ) // versionMatcher defines a variable matcher to be parsed by the router // when a request is about to be served. const versionMatcher = "/v{version:[0-9.]+}" // Config provides the configuration for the API server type Config struct { CorsHeaders string Version string SocketGroup string TLSConfig *tls.Config } // Server contains instance details for the server type Server struct { cfg *Config servers []*HTTPServer routers []router.Router middlewares []middleware.Middleware } // New returns a new instance of the server based on the specified configuration. // It allocates resources which will be needed for ServeAPI(ports, unix-sockets). func New(cfg *Config) *Server { return &Server{ cfg: cfg, } } // UseMiddleware appends a new middleware to the request chain. // This needs to be called before the API routes are configured. func (s *Server) UseMiddleware(m middleware.Middleware) { s.middlewares = append(s.middlewares, m) } // Accept sets a listener the server accepts connections into. func (s *Server) Accept(addr string, listeners ...net.Listener) { for _, listener := range listeners { httpServer := &HTTPServer{ srv: &http.Server{ Addr: addr, }, l: listener, } s.servers = append(s.servers, httpServer) } } // Close closes servers and thus stop receiving requests func (s *Server) Close() { for _, srv := range s.servers { if err := srv.Close(); err != nil { logrus.Error(err) } } } // serveAPI loops through all initialized servers and spawns goroutine // with Serve method for each. It sets createMux() as Handler also. func (s *Server) serveAPI() error { var chErrors = make(chan error, len(s.servers)) for _, srv := range s.servers { srv.srv.Handler = s.createMux() go func(srv *HTTPServer) { var err error logrus.Infof("API listen on %s", srv.l.Addr()) if err = srv.Serve(); err != nil && strings.Contains(err.Error(), "use of closed network connection") { err = nil } chErrors <- err }(srv) } for range s.servers { err := <-chErrors if err != nil { return err } } return nil } // HTTPServer contains an instance of http server and the listener. // srv *http.Server, contains configuration to create an http server and a mux router with all api end points. // l net.Listener, is a TCP or Socket listener that dispatches incoming request to the router. type HTTPServer struct { srv *http.Server l net.Listener } // Serve starts listening for inbound requests. func (s *HTTPServer) Serve() error { return s.srv.Serve(s.l) } // Close closes the HTTPServer from listening for the inbound requests. func (s *HTTPServer) Close() error { return s.l.Close() } func (s *Server) makeHTTPHandler(handler httputils.APIFunc) http.HandlerFunc { return func(w http.ResponseWriter, r *http.Request) { // Define the context that we'll pass around to share info // like the docker-request-id. // // The 'context' will be used for global data that should // apply to all requests. Data that is specific to the // immediate function being called should still be passed // as 'args' on the function call. // use intermediate variable to prevent "should not use basic type // string as key in context.WithValue" golint errors ctx := context.WithValue(r.Context(), dockerversion.UAStringKey{}, r.Header.Get("User-Agent")) r = r.WithContext(ctx) handlerFunc := s.handlerWithGlobalMiddlewares(handler) vars := mux.Vars(r) if vars == nil { vars = make(map[string]string) } if err := handlerFunc(ctx, w, r, vars); err != nil { statusCode := httpstatus.FromError(err) if statusCode >= 500 { logrus.Errorf("Handler for %s %s returned error: %v", r.Method, r.URL.Path, err) } makeErrorHandler(err)(w, r) } } } // InitRouter initializes the list of routers for the server. // This method also enables the Go profiler. func (s *Server) InitRouter(routers ...router.Router) { s.routers = append(s.routers, routers...) } type pageNotFoundError struct{} func (pageNotFoundError) Error() string { return "page not found" } func (pageNotFoundError) NotFound() {} // createMux initializes the main router the server uses. func (s *Server) createMux() *mux.Router { m := mux.NewRouter() logrus.Debug("Registering routers") for _, apiRouter := range s.routers { for _, r := range apiRouter.Routes() { f := s.makeHTTPHandler(r.Handler()) logrus.Debugf("Registering %s, %s", r.Method(), r.Path()) m.Path(versionMatcher + r.Path()).Methods(r.Method()).Handler(f) m.Path(r.Path()).Methods(r.Method()).Handler(f) } } debugRouter := debug.NewRouter() s.routers = append(s.routers, debugRouter) for _, r := range debugRouter.Routes() { f := s.makeHTTPHandler(r.Handler()) m.Path("/debug" + r.Path()).Handler(f) } notFoundHandler := makeErrorHandler(pageNotFoundError{}) m.HandleFunc(versionMatcher+"/{path:.*}", notFoundHandler) m.NotFoundHandler = notFoundHandler m.MethodNotAllowedHandler = notFoundHandler return m } // Wait blocks the server goroutine until it exits. // It sends an error message if there is any error during // the API execution. func (s *Server) Wait(waitChan chan error) { if err := s.serveAPI(); err != nil { logrus.Errorf("ServeAPI error: %v", err) waitChan <- err return } waitChan <- nil }