aboutsummaryrefslogtreecommitdiff
path: root/pkg/api/server/server.go
blob: a5922e5d73862a26bfe1c02351e800f7796371d4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
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/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.registerExecHandlers,
		server.registerEventsHandlers,
		server.registerHealthCheckHandlers,
		server.registerImagesHandlers,
		server.registerInfoHandlers,
		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()
}