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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.RegisterSwaggerHandlers,
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()
}
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