Add cron tick of command queue

go.mod

@@ -5,5 +5,6 @@ go 1.14
 require (
 	github.com/google/uuid v1.1.1
 	github.com/gorilla/mux v1.7.4
+	github.com/robfig/cron v1.2.0
 	github.com/stretchr/testify v1.6.0
 )

go.sum

@@ -6,6 +6,8 @@ github.com/gorilla/mux v1.7.4 h1:VuZ8uybHlWmqV03+zRzdwKL4tUnIp1MAQtp1mIFE1bc=
 github.com/gorilla/mux v1.7.4/go.mod h1:DVbg23sWSpFRCP0SfiEN6jmj59UnW/n46BH5rLB71So=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/robfig/cron v1.2.0 h1:ZjScXvvxeQ63Dbyxy76Fj3AT3Ut0aKsyd2/tl3DTMuQ=
+github.com/robfig/cron v1.2.0/go.mod h1:JGuDeoQd7Z6yL4zQhZ3OPEVHB7fL6Ka6skscFHfmt2k=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.6.0 h1:jlIyCplCJFULU/01vCkhKuTyc3OorI3bJFuw6obfgho=
 github.com/stretchr/testify v1.6.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=

pkg/game/command_test.go

@@ -26,6 +26,9 @@ func TestCommand_Move(t *testing.T) {
 	moveCommand := Command{Command: CommandMove, Bearing: bearing.String(), Duration: duration}
 	assert.NoError(t, world.Enqueue(a, moveCommand), "Failed to execute move command")
 
+	// Tick the world
+	world.ExecuteCommandQueues()
+
 	newpos, err := world.RoverPosition(a)
 	assert.NoError(t, err, "Failed to set position for rover")
 	pos.Add(Vector{0.0, duration * attribs.Speed}) // We should have moved duration*speed north

pkg/game/world.go

@@ -204,7 +204,7 @@ func (w *World) Enqueue(rover uuid.UUID, commands ...Command) error {
 }
 
 // Execute will execute any commands in the current command queue
-func (w *World) Execute() error {
+func (w *World) ExecuteCommandQueues() {
 	w.cmdMutex.Lock()
 	defer w.cmdMutex.Unlock()
 
@@ -231,14 +231,10 @@ func (w *World) Execute() error {
 			delete(w.CommandQueue, rover)
 		}
 	}
-
-	return nil
 }
 
 // ExecuteCommand will execute a single command
 func (w *World) ExecuteCommand(c *Command, rover uuid.UUID) (finished bool, err error) {
-	w.worldMutex.Lock()
-	defer w.worldMutex.Unlock()
 
 	switch c.Command {
 	case "move":
@@ -263,3 +259,27 @@ func (w *World) ExecuteCommand(c *Command, rover uuid.UUID) (finished bool, err
 
 	return
 }
+
+// RLock read locks the world
+func (w *World) RLock() {
+	w.worldMutex.RLock()
+	w.cmdMutex.RLock()
+}
+
+// RUnlock read unlocks the world
+func (w *World) RUnlock() {
+	w.worldMutex.RUnlock()
+	w.cmdMutex.RUnlock()
+}
+
+// Lock locks the world
+func (w *World) Lock() {
+	w.worldMutex.Lock()
+	w.cmdMutex.Lock()
+}
+
+// Unlock unlocks the world
+func (w *World) Unlock() {
+	w.worldMutex.Unlock()
+	w.cmdMutex.Unlock()
+}

pkg/server/routes.go

@@ -84,7 +84,12 @@ func HandleRegister(s *Server, vars map[string]string, b io.ReadCloser, w io.Wri
 	} else if acc, err := s.accountant.RegisterAccount(data.Name); err != nil {
 		response.Error = err.Error()
 
+	} else if err := s.SaveAll(); err != nil {
+		response.Error = fmt.Sprintf("Internal server error when saving accounts: %s", err)
+
 	} else {
+		// Save out the new accounts
+
 		response.Id = acc.Id.String()
 		response.Success = true
 	}

pkg/server/routes_test.go

@@ -124,6 +124,9 @@ func TestHandleCommand(t *testing.T) {
 	attrib, err := s.world.RoverAttributes(inst)
 	assert.NoError(t, err, "Couldn't get rover attribs")
 
+	// Tick the command queues to progress the move command
+	s.world.ExecuteCommandQueues()
+
 	pos2, err := s.world.RoverPosition(inst)
 	assert.NoError(t, err, "Couldn't get rover position")
 	pos.Add(game.Vector{X: 0.0, Y: attrib.Speed * 1}) // Should have moved north by the speed and duration

pkg/server/server.go

@@ -15,6 +15,7 @@ import (
 	"github.com/mdiluz/rove/pkg/accounts"
 	"github.com/mdiluz/rove/pkg/game"
 	"github.com/mdiluz/rove/pkg/persistence"
+	"github.com/robfig/cron"
 )
 
 const (
@@ -27,19 +28,25 @@ const (
 
 // Server contains the relevant data to run a game server
 type Server struct {
-	address string
 
+	// Internal state
 	accountant *accounts.Accountant
 	world      *game.World
 
+	// HTTP server
 	listener net.Listener
 	server   *http.Server
+	router   *mux.Router
 
-	router *mux.Router
-
+	// Config settings
+	address     string
 	persistence int
 
+	// sync point for sub-threads
 	sync sync.WaitGroup
+
+	// cron schedule for world ticks
+	schedule *cron.Cron
 }
 
 // ServerOption defines a server creation option
@@ -69,6 +76,7 @@ func NewServer(opts ...ServerOption) *Server {
 		address:     "",
 		persistence: EphemeralData,
 		router:      router,
+		schedule:    cron.New(),
 	}
 
 	// Apply all options
@@ -93,10 +101,8 @@ func (s *Server) Initialise() (err error) {
 	s.sync.Add(1)
 
 	// Load the accounts if requested
-	if s.persistence == PersistentData {
-		if err := persistence.LoadAll("accounts", &s.accountant, "world", &s.world); err != nil {
-			return err
-		}
+	if err := s.LoadAll(); err != nil {
+		return err
 	}
 
 	// Set up the handlers
@@ -122,6 +128,20 @@ func (s *Server) Addr() string {
 func (s *Server) Run() {
 	defer s.sync.Done()
 
+	// Set up the schedule
+	s.schedule.AddFunc("0,30", func() {
+		// Ensure we don't quit during this function
+		s.sync.Add(1)
+		defer s.sync.Done()
+
+		// Run the command queues
+		s.world.ExecuteCommandQueues()
+
+		// Save out the new world state
+		s.SaveWorld()
+	})
+	s.schedule.Start()
+
 	// Serve the http requests
 	if err := s.server.Serve(s.listener); err != nil && err != http.ErrServerClosed {
 		log.Fatal(err)
@@ -130,6 +150,9 @@ func (s *Server) Run() {
 
 // Close closes up the server
 func (s *Server) Close() error {
+	// Stop the cron
+	s.schedule.Stop()
+
 	// Try and shut down the http server
 	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 	defer cancel()
@@ -137,11 +160,42 @@ func (s *Server) Close() error {
 		return err
 	}
 
-	// Wait until the server is shut down
+	// Wait until the server has shut down
 	s.sync.Wait()
 
+	// Save and return
+	return s.SaveAll()
+}
+
+// SaveWorld will save out the world file
+func (s *Server) SaveWorld() error {
+	if s.persistence == PersistentData {
+		s.world.RLock()
+		defer s.world.RUnlock()
+		if err := persistence.SaveAll("world", s.world); err != nil {
+			return fmt.Errorf("failed to save out persistent data: %s", err)
+		}
+	}
+	return nil
+}
+
+// SaveAccounts will save out the accounts file
+func (s *Server) SaveAccounts() error {
+	if s.persistence == PersistentData {
+		if err := persistence.SaveAll("accounts", s.accountant); err != nil {
+			return fmt.Errorf("failed to save out persistent data: %s", err)
+		}
+	}
+	return nil
+}
+
+// SaveAll will save out all server files
+func (s *Server) SaveAll() error {
 	// Save the accounts if requested
 	if s.persistence == PersistentData {
+		s.world.RLock()
+		defer s.world.RUnlock()
+
 		if err := persistence.SaveAll("accounts", s.accountant, "world", s.world); err != nil {
 			return err
 		}
@@ -149,6 +203,18 @@ func (s *Server) Close() error {
 	return nil
 }
 
+// LoadAll will load all persistent data
+func (s *Server) LoadAll() error {
+	if s.persistence == PersistentData {
+		s.world.Lock()
+		defer s.world.Unlock()
+		if err := persistence.LoadAll("accounts", &s.accountant, "world", &s.world); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 // wrapHandler wraps a request handler in http checks
 func (s *Server) wrapHandler(method string, handler Handler) func(w http.ResponseWriter, r *http.Request) {
 	return func(w http.ResponseWriter, r *http.Request) {