Add support for modifying daemon configuration on-the-fly

config/config.go

@@ -17,6 +17,12 @@ import (
 )
 
 type Configuration struct {
+	sync.RWMutex `json:"-" yaml:"-"`
+
+	// Locker specific to writing the configuration to the disk, this happens
+	// in areas that might already be locked so we don't want to crash the process.
+	writeLock sync.Mutex
+
 	// Determines if wings should be running in debug mode. This value is ignored
 	// if the debug flag is passed through the command line arguments.
 	Debug bool
@@ -207,7 +213,7 @@ func ReadConfiguration(path string) (*Configuration, error) {
 
 	c := new(Configuration)
 	// Configures the default values for many of the configuration options present
-	// in the structs. Valkues set in the configuration file take priority over the
+	// in the structs. Values set in the configuration file take priority over the
 	// default values.
 	if err := defaults.Set(c); err != nil {
 		return nil, err
@@ -224,20 +230,29 @@ func ReadConfiguration(path string) (*Configuration, error) {
 	return c, nil
 }
 
+var Mutex sync.RWMutex
 var _config *Configuration
 var _debugViaFlag bool
 
-// Set the global configuration instance.
+// Set the global configuration instance. This is a blocking operation such that
+// anything trying to set a different configuration value, or read the configuration
+// will be paused until it is complete.
 func Set(c *Configuration) {
+	Mutex.Lock()
 	_config = c
+	Mutex.Unlock()
 }
 
 func SetDebugViaFlag(d bool) {
 	_debugViaFlag = d
 }
 
-// Get the global configuration instance.
+// Get the global configuration instance. This is a read-safe operation that will block
+// if the configuration is presently being modified.
 func Get() *Configuration {
+	Mutex.RLock()
+	defer Mutex.RUnlock()
+
 	return _config
 }
 
@@ -294,6 +309,9 @@ func (c *Configuration) setSystemUser(u *user.User) error {
 	uid, _ := strconv.Atoi(u.Uid)
 	gid, _ := strconv.Atoi(u.Gid)
 
+	c.Lock()
+	defer c.Unlock()
+
 	c.System.Username = u.Username
 	c.System.User.Uid = uid
 	c.System.User.Gid = gid
@@ -369,6 +387,10 @@ func (c *Configuration) WriteToDisk() error {
 		return err
 	}
 
+	// Obtain an exclusive write against the configuration file.
+	c.writeLock.Lock()
+	defer c.writeLock.Unlock()
+
 	if err := ioutil.WriteFile("config.yml", b, 0644); err != nil {
 		return err
 	}

router/router.go

@@ -30,6 +30,7 @@ func Configure() *gin.Engine {
 	// All of the routes beyond this mount will use an authorization middleware
 	// and will not be accessible without the correct Authorization header provided.
 	protected := router.Use(AuthorizationMiddleware)
+	protected.POST("/api/update", postUpdateConfiguration)
 	protected.GET("/api/system", getSystemInformation)
 	protected.GET("/api/servers", getAllServers)
 	protected.POST("/api/servers", postCreateServer)

router/router_system.go

@@ -3,6 +3,7 @@ package router
 import (
 	"bytes"
 	"github.com/gin-gonic/gin"
+	"github.com/pterodactyl/wings/config"
 	"github.com/pterodactyl/wings/installer"
 	"github.com/pterodactyl/wings/server"
 	"github.com/pterodactyl/wings/system"
@@ -63,3 +64,25 @@ func postCreateServer(c *gin.Context) {
 
 	c.Status(http.StatusAccepted)
 }
+
+// Updates the running configuration for this daemon instance.
+func postUpdateConfiguration(c *gin.Context) {
+	// A backup of the configuration for error purposes.
+	ccopy := *config.Get()
+	// A copy of the configuration we're using to bind the data recevied into.
+	cfg := *config.Get()
+
+	c.BindJSON(&cfg)
+
+	config.Set(&cfg)
+	if err := config.Get().WriteToDisk(); err != nil {
+		// If there was an error writing to the disk, revert back to the configuration we had
+		// before this code was run.
+		config.Set(&ccopy)
+
+		TrackedError(err).AbortWithServerError(c)
+		return
+	}
+
+	c.Status(http.StatusNoContent)
+}

server/collection.go

@@ -16,6 +16,9 @@ func NewCollection(servers []*Server) *Collection {
 
 // Return all of the items in the collection.
 func (c *Collection) All() []*Server {
+	c.RLock()
+	defer c.RUnlock()
+
 	return c.items
 }
 

server/update.go

@@ -69,10 +69,6 @@ func (s *Server) UpdateDataStructure(data []byte, background bool) error {
 		s.Allocations.Mappings = src.Allocations.Mappings
 	}
 
-	/*if _, err := s.WriteConfigurationToDisk(); err != nil {
-		return errors.WithStack(err)
-	}*/
-
 	if background {
 		s.runBackgroundActions()
 	}
@@ -105,14 +101,6 @@ func (s *Server) runBackgroundActions() {
 		if server.Suspended && server.GetState() != ProcessOfflineState {
 			zap.S().Infow("server suspended with running process state, terminating now", zap.String("server", server.Uuid))
 
-			/*if err := server.Environment.Terminate(os.Kill); err != nil {
-				zap.S().Warnw(
-					"failed to terminate server environment after seeing suspension",
-					zap.String("server", server.Uuid),
-					zap.Error(err),
-				)
-			}*/
-
 			if err := server.Environment.WaitForStop(10, true); err != nil {
 				zap.S().Warnw(
 					"failed to stop server environment after seeing suspension",