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package server // import "github.com/docker/docker/api/server"
import (
"context"
"crypto/tls"
"net"
"net/http"
"strings"
"time"
"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
// Hosts is a list of addresses for the API to listen on.
Hosts []string
}
// 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,
ReadHeaderTimeout: 5 * time.Minute, // "G112: Potential Slowloris Attack (gosec)"; not a real concern for our use, so setting a long timeout.
},
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
}
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