Add data persistence

bootserver/bootoption/bootoption.go

@@ -4,14 +4,12 @@ import "github.com/google/uuid"
 
 type EFIApp struct {
 	Name string `json:"name"`
-	Description string `json:"description"`
 	Path string `json:"path"`
 }
 
 type Client struct {
 	ID             uuid.UUID
-	IP             string   `json:"ip"`
 	Name           string            `json:"name"`
-	Options        []EFIApp `json:"options"`
+	Options        map[string]EFIApp `json:"options"`
 	SelectedOption string            `json:"selected_option"`
 }

bootserver/config/config.go

@@ -42,6 +42,9 @@ type jsonConf struct {
 	Log struct {
 		Level string `json:"level"`
 	} `json:"log"`
+	Storage struct {
+		Path string `json:"path"`
+	} `json:"storage"`
 	Server struct {
 		Host     string `json:"host"`
 		Port     int    `json:"port"`
@@ -58,6 +61,7 @@ type jsonConf struct {
 type AppConfig struct {
 	LogLevel      logrus.Level
 	ServerMode    ListeningMode
+	DataFilepath  string
 	Host          string
 	Port          int
 	SockPath      string
@@ -93,12 +97,14 @@ func (ac *AppConfig) UnmarshalJSON(data []byte) error {
 	ac.UPDMcastGroup = jsonConf.BootProvider.McastGroup
 	ac.UDPIface = jsonConf.BootProvider.Iface
 	ac.UDPPort = jsonConf.BootProvider.Port
+	ac.DataFilepath = jsonConf.Storage.Path
 	return nil
 }
 
 var defaultConfig AppConfig = AppConfig{
 	LogLevel:      logrus.InfoLevel,
 	ServerMode:    ModeNet,
+	DataFilepath:  "boot_options.json",
 	Host:          "0.0.0.0",
 	Port:          5000,
 	UPDMcastGroup: "ff02::abcd:1234",

bootserver/controllers/client/enroll.go

@@ -4,7 +4,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"net"
 	"net/http"
 
 	"git.faercol.me/faercol/http-boot-server/bootserver/bootoption"
@@ -31,10 +30,6 @@ func (ec *EnrollController) enrollMachine(w http.ResponseWriter, r *http.Request
 	if r.Method != http.MethodPost {
 		return http.StatusMethodNotAllowed, nil
 	}
-	clientIP, _, err := net.SplitHostPort(r.RemoteAddr)
-	if err != nil {
-		return http.StatusInternalServerError, fmt.Errorf("failed to read remote IP: %w", err)
-	}
 
 	dat, err := io.ReadAll(r.Body)
 	if err != nil {
@@ -45,10 +40,9 @@ func (ec *EnrollController) enrollMachine(w http.ResponseWriter, r *http.Request
 	if err := json.Unmarshal(dat, &client); err != nil {
 		return http.StatusInternalServerError, fmt.Errorf("failed to parse body: %w", err)
 	}
-	client.IP = clientIP
 
 	ec.clientService.AddClient(&client)
-	ec.l.Infof("Added client %s", clientIP)
+	ec.l.Infof("Added client")
 	return http.StatusAccepted, nil
 }
 

bootserver/filelock/filelock.go

@@ -0,0 +1,54 @@
+package filelock
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"path"
+	"time"
+)
+
+var ErrLocked = errors.New("failed to get a lock in a timely manner")
+
+type FileLock struct {
+	lockPath string
+}
+
+func New(filepath string) *FileLock {
+	dir, filename := path.Split(filepath)
+	lockPath := path.Join(dir, fmt.Sprintf(".%s.lock", filename))
+	return &FileLock{
+		lockPath: lockPath,
+	}
+}
+
+func (fl *FileLock) lockFileExists() bool {
+	if _, err := os.Stat(fl.lockPath); errors.Is(err, os.ErrNotExist) {
+		return false
+	}
+	return true
+}
+
+func (fl *FileLock) Lock(timeout time.Duration) error {
+	start := time.Now().UTC()
+	end := start.Add(timeout)
+
+	for {
+		if !fl.lockFileExists() {
+			if _, err := os.Create(fl.lockPath); err != nil {
+				return fmt.Errorf("failed to create lock: %w", err)
+			}
+		}
+		if time.Now().After(end) {
+			return ErrLocked
+		}
+		time.Sleep(100 * time.Millisecond)
+	}
+}
+
+func (fl *FileLock) Unlock() error {
+	if err := os.Remove(fl.lockPath); err != nil {
+		return fmt.Errorf("failed to remove lock: %w", err)
+	}
+	return nil
+}

bootserver/server/server.go

@@ -64,9 +64,8 @@ func New(appConf *config.AppConfig, logger *logrus.Logger) (*Server, error) {
 	default:
 		panic(fmt.Errorf("unexpected listening mode %v", appConf.ServerMode))
 	}
-	service := services.NewClientHandlerService()
+	service := services.NewClientHandlerService(appConf.DataFilepath, logger)
 	controllers := map[string]http.Handler{
-		// client.BootRoute:   middlewares.WithLogger(client.NewBootController(logger, service), logger),
 		client.EnrollRoute: middlewares.WithLogger(client.NewEnrollController(logger, service), logger),
 	}
 

bootserver/services/services.go

@@ -1,32 +1,109 @@
 package services
 
 import (
+	"encoding/json"
 	"errors"
+	"fmt"
+	"os"
+	"time"
 
 	"git.faercol.me/faercol/http-boot-server/bootserver/bootoption"
+	"git.faercol.me/faercol/http-boot-server/bootserver/filelock"
 	"github.com/google/uuid"
+	"github.com/sirupsen/logrus"
 )
 
 var ErrUnknownClient = errors.New("unknown client")
 var ErrUnselectedBootOption = errors.New("unselected boot option")
 var ErrUnknownBootOption = errors.New("unknown boot option")
 
+const defaultLockTimeout = 1 * time.Second
+
 type ClientHandlerService struct {
-	clients map[uuid.UUID]*bootoption.Client
+	filepath    string
+	fileLock    *filelock.FileLock
+	lockTimeout time.Duration
+	logger      *logrus.Logger
 }
 
-func NewClientHandlerService() *ClientHandlerService {
+func NewClientHandlerService(filepath string, logger *logrus.Logger) *ClientHandlerService {
 	return &ClientHandlerService{
-		clients: make(map[uuid.UUID]*bootoption.Client),
+		filepath:    filepath,
+		fileLock:    filelock.New(filepath),
+		lockTimeout: defaultLockTimeout,
+		logger:      logger,
 	}
 }
 
-func (chs *ClientHandlerService) AddClient(client *bootoption.Client) {
-	chs.clients[client.ID] = client
+func (chs *ClientHandlerService) init() {
+	if _, err := os.Open(chs.filepath); errors.Is(err, os.ErrNotExist) {
+		if err := os.WriteFile(chs.filepath, nil, 0o644); err != nil {
+			panic(fmt.Errorf("failed to init data file: %w", err))
+		}
+	}
+}
+
+func (chs *ClientHandlerService) unload(conf map[uuid.UUID]*bootoption.Client) error {
+	dat, err := json.Marshal(conf)
+	if err != nil {
+		return fmt.Errorf("failed to marshal data to JSON: %w", err)
+	}
+
+	if err := os.WriteFile(chs.filepath, dat, 0o644); err != nil {
+		return fmt.Errorf("failed to commit to the data file: %w", err)
+	}
+	if err := chs.fileLock.Unlock(); err != nil {
+		return fmt.Errorf("failed to release the lock to data file: %w", err)
+	}
+	return nil
+}
+
+func (chs *ClientHandlerService) load() (map[uuid.UUID]*bootoption.Client, error) {
+	conf := make(map[uuid.UUID]*bootoption.Client)
+
+	if err := chs.fileLock.Lock(chs.lockTimeout); err != nil {
+		return nil, fmt.Errorf("failed to obtain a lock to the data file: %w", err)
+	}
+
+	dat, err := os.ReadFile(chs.filepath)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read data file: %w", err)
+	}
+	if err := json.Unmarshal(dat, &conf); err != nil {
+		return nil, fmt.Errorf("failed to parse data file: %w", err)
+	}
+	return conf, nil
+}
+
+func (chs *ClientHandlerService) unloadNoCommmit(conf map[uuid.UUID]*bootoption.Client) {
+	if err := chs.unload(conf); err != nil {
+		chs.logger.Errorf("Failed to unload config: %q", err.Error())
+	}
+}
+
+func (chs *ClientHandlerService) AddClient(client *bootoption.Client) (uuid.UUID, error) {
+	clients, err := chs.load()
+	if err != nil {
+		return uuid.Nil, fmt.Errorf("failed to load current config: %w", err)
+	}
+
+	client.ID = uuid.New()
+	clients[client.ID] = client
+
+	if err := chs.unload(clients); err != nil {
+		return uuid.Nil, fmt.Errorf("failed to save current config: %w", err)
+	}
+	return client.ID, nil
 }
 
 func (chs *ClientHandlerService) GetClientSelectedBootOption(client uuid.UUID) (*bootoption.EFIApp, error) {
-	clientDetails, ok := chs.clients[client]
+	clients, err := chs.load()
+	if err != nil {
+		return nil, fmt.Errorf("failed to load current config: %w", err)
+	}
+	defer chs.unloadNoCommmit(clients)
+
+	clientDetails, ok := clients[client]
 	if !ok {
 		return nil, ErrUnknownClient
 	}
@@ -35,25 +112,39 @@ func (chs *ClientHandlerService) GetClientSelectedBootOption(client uuid.UUID) (
 		return nil, ErrUnselectedBootOption
 	}
 
-	for _, o := range clientDetails.Options {
-		if o.Name == clientDetails.SelectedOption {
-			return &o, nil
-		}
-	}
+	if option, ok := clientDetails.Options[clientDetails.SelectedOption]; !ok {
 		return nil, ErrUnknownBootOption
+	} else {
+		return &option, nil
+	}
 }
 
 func (chs *ClientHandlerService) SetClientBootOption(client uuid.UUID, option string) error {
-	clientDetails, ok := chs.clients[client]
-	if !ok {
-		return ErrUnknownClient
+	var err error
+
+	clients, err := chs.load()
+	if err != nil {
+		return fmt.Errorf("failed to load current config: %w", err)
 	}
 
-	for _, o := range clientDetails.Options {
-		if o.Name == option {
+	clientDetails, ok := clients[client]
+	if !ok {
+		err = ErrUnknownClient
+	} else {
+		if _, ok := clientDetails.Options[option]; !ok {
+			err = ErrUnknownBootOption
+		} else {
 			clientDetails.SelectedOption = option
+		}
+	}
+
+	if err != nil {
+		defer chs.unloadNoCommmit(clients)
+		return err
+	}
+
+	if err := chs.unload(clients); err != nil {
+		return fmt.Errorf("failed to save current config: %w", err)
+	}
 	return nil
-		}
-	}
-	return ErrUnknownBootOption
 }