feat: collect and display usage stats

.gitignore

@@ -9,3 +9,4 @@
 tools/
 /CHANGELOG.md
 /.chglog
+/stats.json

.goreleaser.yaml

@@ -9,7 +9,7 @@ builds:
     ldflags:
       - -s
       - -w
-      - -X 'main.Version=${MKT_PROJECT_VERSION}'
+      - -X "main.Version={{ .Env.GORELEASER_CURRENT_TAG }}"
     gcflags:
       - -trimpath="${PWD}"
     asmflags:

cmd/server/main.go

@@ -11,6 +11,8 @@ import (
 	"github.com/pkg/errors"
 )
 
+var Version string = "unknown"
+
 func main() {
 	opts := rebound.DefaultOptions()
 
@@ -18,8 +20,12 @@ func main() {
 		log.Fatalf("[ERROR] %+v", errors.WithStack(err))
 	}
 
+	opts.HTTP.TemplateData.Version = Version
+
 	server := rebound.NewServer(
 		rebound.WithAddress(opts.Address),
+		rebound.WithStatsFile(opts.StatsFile),
+		rebound.WithStatsFileSaveInterval(opts.StatsFileSaveInterval),
 		rebound.WithSSHOption(
 			ssh.WithSockDir(opts.SSH.SockDir),
 			ssh.WithPublicHost(opts.SSH.PublicHost),

http/options.go

@@ -2,16 +2,20 @@ package http
 
 import (
 	"log"
+
+	"forge.cadoles.com/wpetit/rebound/stat"
 )
 
 type Options struct {
 	Logger       func(message string, args ...any)
 	CustomDir    string        `env:"CUSTOM_DIR"`
 	TemplateData *TemplateData `envPrefix:"TEMPLATE_DATA_"`
+	Stats        *stat.Store
 }
 
 type TemplateData struct {
 	Title         string `env:"TITLE"`
+	Version       string
 	SSHPublicHost string `env:"SSH_PUBLIC_HOST"`
 	SSHPublicPort int    `env:"SSH_PUBLIC_PORT"`
 }
@@ -27,6 +31,7 @@ func DefaultOptions() *Options {
 			SSHPublicHost: "127.0.0.1",
 			SSHPublicPort: 2222,
 		},
+		Stats: stat.NewStore(),
 	}
 }
 
@@ -47,3 +52,9 @@ func WithTemplateData(templateData *TemplateData) func(*Options) {
 		opts.TemplateData = templateData
 	}
 }
+
+func WithStats(stats *stat.Store) func(*Options) {
+	return func(opts *Options) {
+		opts.Stats = stats
+	}
+}

http/server.go

@@ -3,9 +3,11 @@ package http
 import (
 	"bytes"
 	"embed"
+	"fmt"
 	"html/template"
 	"io"
 	"io/fs"
+	"log/slog"
 	"net"
 	"net/http"
 	"os"
@@ -29,8 +31,45 @@ type Server struct {
 	templates template.Template
 }
 
+var templateFuncs = template.FuncMap{
+	"humanSize": func(b float64) string {
+		const unit = 1000
+		if b < unit {
+			return fmt.Sprintf("%d B", int64(b))
+		}
+
+		div, exp := int64(unit), 0
+
+		for n := b / unit; n >= unit; n /= unit {
+			div *= unit
+			exp++
+		}
+
+		return fmt.Sprintf("%.1f %cB",
+			float64(b)/float64(div), "kMGTPE"[exp])
+	},
+}
+
 func (s *Server) serveHomepage(w http.ResponseWriter, r *http.Request) {
-	s.renderTemplate(w, "index", s.opts.TemplateData)
+	stats, err := s.opts.Stats.Snapshot()
+	if err != nil {
+		slog.Error("could not make stats snapshot", slog.Any("error", errors.WithStack(err)))
+		http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
+
+		return
+	}
+
+	data := struct {
+		TemplateData
+		Stats map[string]float64
+	}{
+		TemplateData: *s.opts.TemplateData,
+		Stats:        stats,
+	}
+
+	s.opts.Stats.Add(StatTotalPageView, 1, 0)
+
+	s.renderTemplate(w, "index", data)
 }
 
 func (s *Server) Serve(l net.Listener) error {
@@ -67,7 +106,7 @@ func (s *Server) Serve(l net.Listener) error {
 }
 
 func (s *Server) parseTemplates(fs fs.FS) error {
-	templates, err := template.ParseFS(fs, "templates/*.html")
+	templates, err := template.New("").Funcs(templateFuncs).ParseFS(fs, "templates/*.html")
 	if err != nil {
 		return errors.WithStack(err)
 	}

http/stats.go

@@ -0,0 +1,5 @@
+package http
+
+const (
+	StatTotalPageView = "total_page_view"
+)

http/templates/footer.html

@@ -2,7 +2,7 @@
 <footer class="footer">
     <div class="container">
         <div class="content has-text-centered">
-            Ce service est propulsé par <a href="https://forge.cadoles.com/wpetit/rebound" title="Rebound repository">Rebound</a>, un logiciel libre diffusé sous licence <a href="https://www.gnu.org/licenses/agpl-3.0.en.html#license-text">AGPL-3.0</a>.
+            Ce service est propulsé par <a href="https://forge.cadoles.com/wpetit/rebound" title="Rebound repository">rebound@{{ .Version }}</a>, un logiciel libre diffusé sous licence <a href="https://www.gnu.org/licenses/agpl-3.0.en.html#license-text">AGPL-3.0</a>.
         </div>
     </div>
 </footer>

http/templates/index.html

@@ -13,14 +13,46 @@
             <p class="subtitle is-size-3">
                 Bienvenue sur <strong>Rebound</strong>!
             </p>
-            <div class="content">
-                <p>Rebound est un serveur SSH permettant de créer des tunnels TCP/IP éphémères et privés entre 2 machines positionnées
-                    derrière un <abbr title="Network Address Traversal">NAT</abbr>.</p>
-                <p>Pour l'utiliser <strong>un simple client SSH suffit !</strong></p>
-                <pre class="has-background-dark	has-text-white-ter is-family-monospace">ssh -R 0:127.0.0.1:<span class="has-text-info">&lt;port&gt;</span> rebound@{{ .SSHPublicHost }} -p {{ .SSHPublicPort }}</pre>
-                <p class="is-italic">Où <span class="has-text-info">&lt;port&gt;</span> est à remplacer par le port du service
-                    s'exécutant sur votre machine en local.</span>
-                <p>Une fois connecté, suivez les instructions. 😉</p>
+            <div class="block">
+                <div class="content">
+                    <p>Rebound est un serveur SSH permettant de créer des tunnels TCP/IP éphémères et privés entre 2 machines positionnées
+                        derrière un <abbr title="Network Address Traversal">NAT</abbr>.</p>
+                    <p>Pour l'utiliser <strong>un simple client SSH suffit !</strong></p>
+                    <pre class="has-background-dark	has-text-white-ter is-family-monospace">ssh -R 0:127.0.0.1:<span class="has-text-info">&lt;port&gt;</span> rebound@{{ .SSHPublicHost }} -p {{ .SSHPublicPort }}</pre>
+                    <p class="is-italic">Où <span class="has-text-info">&lt;port&gt;</span> est à remplacer par le port du service
+                        s'exécutant sur votre machine en local.</span>
+                    <p>Une fois connecté, suivez les instructions. 😉</p>
+                </div>
+            </div>
+            <hr />
+            <div class="block">
+                <div class="columns">
+                    <div class="column is-4">
+                        <h3 class="title is-size-4">En savoir plus</h3>
+                        <div class="content">
+                            À venir...
+                        </div>
+                    </div>
+                    <div class="column is-4">
+                        <h3 class="title is-size-4">Statistiques</h3>
+                        <table class="table is-bordered is-striped is-fullwidth">
+                            <tbody>
+                                <tr>
+                                    <td><strong>Total tunnels ouverts</strong></td>
+                                    <td>{{ index .Stats "total_opened_tunnels" }}</td>
+                                </tr>
+                                <tr>
+                                    <td><strong>Total données entrantes</strong></td>
+                                    <td>{{ humanSize ( index .Stats "total_rx_bytes" ) }}</td>
+                                </tr>
+                                <tr>
+                                    <td><strong>Total données sortantes</strong></td>
+                                    <td>{{ humanSize ( index .Stats "total_tx_bytes" ) }}</td>
+                                </tr>
+                            </tbody>
+                        </table>
+                    </div>
+                </div>
             </div>
         </div>
     </section>

misc/packaging/openrc/rebound.conf

@@ -4,6 +4,7 @@ export REBOUND_SSH_PUBLIC_HOST=rebound
 export REBOUND_SSH_PUBLIC_PORT=2222
 export REBOUND_SSH_SOCK_DIR=/var/lib/rebound/socks
 export REBOUND_SSH_HOST_KEY=/etc/rebound/host.key
+export REBOUND_STATS_FILE=/var/lib/rebound/stats.json
 export REBOUND_HTTP_TEMPLATE_DATA_TITLE=Rebound
 export REBOUND_HTTP_TEMPLATE_DATA_SSH_PUBLIC_HOST=127.0.0.1
 export REBOUND_HTTP_TEMPLATE_DATA_SSH_PUBLIC_PORT=8080

misc/packaging/systemd/rebound.env

@@ -4,6 +4,7 @@ REBOUND_SSH_PUBLIC_HOST=rebound
 REBOUND_SSH_PUBLIC_PORT=8080
 REBOUND_SSH_SOCK_DIR=/var/lib/rebound/socks
 REBOUND_SSH_HOST_KEY=/var/lib/rebound/host.key
+REBOUND_STATS_FILE=/var/lib/rebound/stats.json
 REBOUND_HTTP_TEMPLATE_DATA_TITLE=Rebound
 REBOUND_HTTP_TEMPLATE_DATA_SSH_PUBLIC_HOST=127.0.0.1
 REBOUND_HTTP_TEMPLATE_DATA_SSH_PUBLIC_PORT=8080

options.go

@@ -2,6 +2,7 @@ package rebound
 
 import (
 	"log"
+	"time"
 
 	"forge.cadoles.com/wpetit/rebound/http"
 	"forge.cadoles.com/wpetit/rebound/ssh"
@@ -10,10 +11,12 @@ import (
 )
 
 type Options struct {
-	Address string `env:"REBOUND_ADDRESS"`
-	Logger  func(message string, args ...any)
-	SSH     *ssh.Options  `envPrefix:"REBOUND_SSH_"`
-	HTTP    *http.Options `envPrefix:"REBOUND_HTTP_"`
+	Address               string        `env:"REBOUND_ADDRESS"`
+	StatsFile             string        `env:"REBOUND_STATS_FILE"`
+	StatsFileSaveInterval time.Duration `env:"REBOUND_STATS_FILE_SAVE_INTERVAL"`
+	Logger                func(message string, args ...any)
+	SSH                   *ssh.Options  `envPrefix:"REBOUND_SSH_"`
+	HTTP                  *http.Options `envPrefix:"REBOUND_HTTP_"`
 }
 
 func (o *Options) ParseEnv() error {
@@ -28,10 +31,12 @@ type OptionFunc func(*Options)
 
 func DefaultOptions() *Options {
 	return &Options{
-		Address: "127.0.0.1:2222",
-		Logger:  log.Printf,
-		SSH:     ssh.DefaultOptions(),
-		HTTP:    http.DefaultOptions(),
+		Address:               "127.0.0.1:2222",
+		StatsFile:             "stats.json",
+		StatsFileSaveInterval: 30 * time.Second,
+		Logger:                log.Printf,
+		SSH:                   ssh.DefaultOptions(),
+		HTTP:                  http.DefaultOptions(),
 	}
 }
 
@@ -49,6 +54,18 @@ func WithLogger(logger func(message string, args ...any)) func(*Options) {
 	}
 }
 
+func WithStatsFile(path string) func(*Options) {
+	return func(o *Options) {
+		o.StatsFile = path
+	}
+}
+
+func WithStatsFileSaveInterval(interval time.Duration) func(*Options) {
+	return func(o *Options) {
+		o.StatsFileSaveInterval = interval
+	}
+}
+
 func WithSSHOption(funcs ...ssh.OptionFunc) func(*Options) {
 	return func(o *Options) {
 		for _, fn := range funcs {

server.go

@@ -1,21 +1,34 @@
 package rebound
 
 import (
+	"log/slog"
 	"net"
+	"os"
+	"time"
 
 	"forge.cadoles.com/wpetit/rebound/http"
 	"forge.cadoles.com/wpetit/rebound/ssh"
+	"forge.cadoles.com/wpetit/rebound/stat"
 	"github.com/pkg/errors"
 )
 
 type Server struct {
 	listener net.Listener
 	opts     *Options
+	stats    *stat.Store
 }
 
 func (s *Server) Start() error {
 	s.log("[INFO] listening on %s", s.opts.Address)
 
+	if err := s.stats.Load(s.opts.StatsFile); err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			s.log("[INFO] stats file does not exist. ignoring.")
+		} else {
+			return errors.WithStack(err)
+		}
+	}
+
 	listener, err := net.Listen("tcp", s.opts.Address)
 	if err != nil {
 		return errors.WithStack(err)
@@ -34,6 +47,7 @@ func (s *Server) Start() error {
 			ssh.WithPublicPort(s.opts.SSH.PublicPort),
 			ssh.WithSockDir(s.opts.SSH.SockDir),
 			ssh.WithLogger(s.opts.SSH.Logger),
+			ssh.WithStats(s.stats),
 		)
 
 		if err := server.Serve(sshListener); err != nil {
@@ -49,6 +63,7 @@ func (s *Server) Start() error {
 			http.WithCustomDir(s.opts.HTTP.CustomDir),
 			http.WithTemplateData(s.opts.HTTP.TemplateData),
 			http.WithLogger(s.opts.HTTP.Logger),
+			http.WithStats(s.stats),
 		)
 
 		if err := server.Serve(httpListener); err != nil {
@@ -57,6 +72,23 @@ func (s *Server) Start() error {
 		}
 	}()
 
+	go func() {
+		defer listener.Close()
+
+		ticker := time.NewTicker(s.opts.StatsFileSaveInterval)
+
+		for {
+			<-ticker.C
+
+			slog.Info("saving stats", slog.String("file", s.opts.StatsFile), slog.Duration("interval", s.opts.StatsFileSaveInterval))
+			if err := s.stats.Save(s.opts.StatsFile); err != nil {
+				slog.Error("could not save stat file", slog.Any("error", errors.WithStack(err)))
+
+				return
+			}
+		}
+	}()
+
 	return nil
 }
 
@@ -85,6 +117,7 @@ func NewServer(funcs ...OptionFunc) *Server {
 	}
 
 	return &Server{
-		opts: opts,
+		opts:  opts,
+		stats: stat.NewStore(),
 	}
 }

ssh/direct_tcp_handler.go

@@ -77,7 +77,13 @@ func (s *Server) handleDirectTCP(srv *ssh.Server, conn *gossh.ServerConn, newCha
 		defer dconn.Close()
 		defer ch.Close()
 
-		if _, err := io.Copy(ch, dconn); err != nil {
+		reader := &instrumentedReader{
+			internal: dconn,
+			stats:    s.opts.Stats,
+			name:     StatTotalRxBytes,
+		}
+
+		if _, err := io.Copy(ch, reader); err != nil {
 			if errors.Is(err, net.ErrClosed) {
 				return
 			}
@@ -90,7 +96,13 @@ func (s *Server) handleDirectTCP(srv *ssh.Server, conn *gossh.ServerConn, newCha
 		defer dconn.Close()
 		defer ch.Close()
 
-		if _, err := io.Copy(dconn, ch); err != nil {
+		writer := &instrumentedWriter{
+			internal: dconn,
+			stats:    s.opts.Stats,
+			name:     StatTotalTxBytes,
+		}
+
+		if _, err := io.Copy(writer, ch); err != nil {
 			s.log("[ERROR] %+v", errors.WithStack(err))
 		}
 	}()

ssh/options.go

@@ -1,6 +1,10 @@
 package ssh
 
-import "log"
+import (
+	"log"
+
+	"forge.cadoles.com/wpetit/rebound/stat"
+)
 
 type Options struct {
 	Logger     func(message string, args ...any)
@@ -8,6 +12,7 @@ type Options struct {
 	PublicPort uint   `env:"PUBLIC_PORT"`
 	PublicHost string `env:"PUBLIC_HOST"`
 	HostKey    string `env:"HOST_KEY"`
+	Stats      *stat.Store
 }
 
 type OptionFunc func(*Options)
@@ -19,6 +24,7 @@ func DefaultOptions() *Options {
 		PublicPort: 2222,
 		PublicHost: "127.0.0.1",
 		HostKey:    "./host.key",
+		Stats:      stat.NewStore(),
 	}
 }
 
@@ -51,3 +57,9 @@ func WithLogger(logger func(message string, args ...any)) func(*Options) {
 		opts.Logger = logger
 	}
 }
+
+func WithStats(stats *stat.Store) func(*Options) {
+	return func(opts *Options) {
+		opts.Stats = stats
+	}
+}

ssh/request_handler.go

@@ -91,6 +91,8 @@ func (s *Server) handleRequest(ctx ssh.Context, srv *ssh.Server, req *gossh.Requ
 			return false, []byte{}
 		}
 
+		s.opts.Stats.Add(StatTotalOpenedTunnels, 1, 0)
+
 		destPort := 1
 
 		s.requestHandlerLock.Lock()

ssh/stats.go

@@ -0,0 +1,43 @@
+package ssh
+
+import (
+	"io"
+
+	"forge.cadoles.com/wpetit/rebound/stat"
+)
+
+const (
+	StatTotalOpenedTunnels = "total_opened_tunnels"
+	StatTotalTxBytes       = "total_tx_bytes"
+	StatTotalRxBytes       = "total_rx_bytes"
+)
+
+type instrumentedWriter struct {
+	name     string
+	stats    *stat.Store
+	internal io.Writer
+}
+
+// Write implements io.Writer.
+func (w *instrumentedWriter) Write(p []byte) (n int, err error) {
+	n, err = w.internal.Write(p)
+	w.stats.Add(w.name, float64(n), 0)
+	return n, err
+}
+
+var _ io.Writer = &instrumentedWriter{}
+
+type instrumentedReader struct {
+	name     string
+	stats    *stat.Store
+	internal io.Reader
+}
+
+// Read implements io.Reader.
+func (w *instrumentedReader) Read(p []byte) (n int, err error) {
+	n, err = w.internal.Read(p)
+	w.stats.Add(w.name, float64(n), 0)
+	return n, err
+}
+
+var _ io.Reader = &instrumentedReader{}

stat/store.go

@@ -0,0 +1,154 @@
+package stat
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"sync"
+
+	"log/slog"
+
+	"github.com/pkg/errors"
+)
+
+type Store struct {
+	data         sync.Map
+	loadSaveLock sync.Mutex
+}
+
+func (s *Store) Load(path string) error {
+	s.loadSaveLock.Lock()
+	defer s.loadSaveLock.Unlock()
+
+	file, err := os.OpenFile(path, os.O_RDONLY, os.ModePerm)
+	if err != nil {
+		return errors.WithStack(err)
+	}
+
+	decoder := json.NewDecoder(file)
+	data := map[string]any{}
+
+	if err := decoder.Decode(&data); err != nil {
+		return errors.WithStack(err)
+	}
+
+	s.data.Range(func(key, value any) bool {
+		s.data.Delete(key)
+		return true
+	})
+
+	for k, v := range data {
+		s.data.Store(k, v)
+	}
+
+	return nil
+}
+
+func (s *Store) Save(path string) error {
+	s.loadSaveLock.Lock()
+	defer s.loadSaveLock.Unlock()
+
+	data, err := s.Snapshot()
+	if err != nil {
+		return errors.WithStack(err)
+	}
+
+	dir := filepath.Dir(path)
+	filename := filepath.Base(path)
+
+	temp, err := os.CreateTemp(dir, filename+".new*")
+	if err != nil {
+		return errors.WithStack(err)
+	}
+
+	defer func() {
+		if err := os.Remove(temp.Name()); err != nil && !errors.Is(err, os.ErrNotExist) {
+			slog.Error("could not remove temporary file",
+				slog.String("file", temp.Name()),
+				slog.Any("error", errors.WithStack(err)),
+			)
+		}
+	}()
+
+	encoder := json.NewEncoder(temp)
+	if err := encoder.Encode(data); err != nil {
+		return errors.WithStack(err)
+	}
+
+	if err := os.Rename(temp.Name(), path); err != nil {
+		return errors.WithStack(err)
+	}
+
+	return nil
+}
+
+func (s *Store) Snapshot() (map[string]float64, error) {
+	data := map[string]float64{}
+
+	var err error
+	s.data.Range(func(rawKey, rawValue any) bool {
+		key, ok := rawKey.(string)
+		if !ok {
+			err = errors.Errorf("unexpected stat key of '%v'", rawKey)
+
+			return false
+		}
+
+		value, ok := rawValue.(float64)
+		if !ok {
+			err = errors.Errorf("unexpected stat value of '%v'", rawValue)
+
+			return false
+		}
+
+		data[key] = value
+
+		return true
+	})
+	if err != nil {
+		return nil, errors.WithStack(err)
+	}
+
+	return data, nil
+}
+
+func (s *Store) Add(name string, added float64, defaultValue float64) float64 {
+	for {
+		value := s.Get(name, defaultValue)
+		if value == defaultValue {
+			s.data.Store(name, defaultValue)
+		}
+
+		sum := value + added
+		if s.data.CompareAndSwap(name, value, value+added) {
+			return sum
+		}
+	}
+}
+
+func (s *Store) Set(name string, value float64) float64 {
+	s.data.Store(name, value)
+
+	return value
+}
+
+func (s *Store) Get(name string, defaultValue float64) float64 {
+	rawValue, ok := s.data.Load(name)
+	if !ok {
+		return defaultValue
+	}
+
+	value, ok := rawValue.(float64)
+	if !ok {
+		return defaultValue
+	}
+
+	return value
+}
+
+func NewStore() *Store {
+	return &Store{
+		data:         sync.Map{},
+		loadSaveLock: sync.Mutex{},
+	}
+}