braking things up into packages

internal/server/server.go

@@ -0,0 +1,112 @@
+package server
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"net"
+	"net/http"
+	"os"
+	"strconv"
+
+	"github.com/gorilla/websocket"
+	"github.com/jordanorelli/astro-domu/internal/errors"
+	"github.com/jordanorelli/astro-domu/internal/wire"
+	"github.com/jordanorelli/blammo"
+)
+
+type Server struct {
+	*blammo.Log
+	Host string
+	Port int
+
+	lastSessionID int
+}
+
+func (s *Server) Start() error {
+	if s.Host == "" {
+		s.Host = "127.0.0.1"
+	}
+	if s.Port == 0 {
+		s.Port = 12805
+	}
+	if s.Log == nil {
+		stdout := blammo.NewLineWriter(os.Stdout)
+		stderr := blammo.NewLineWriter(os.Stderr)
+
+		options := []blammo.Option{
+			blammo.DebugWriter(stdout),
+			blammo.InfoWriter(stdout),
+			blammo.ErrorWriter(stderr),
+		}
+
+		s.Log = blammo.NewLog("astro", options...).Child("server")
+	}
+
+	addr := fmt.Sprintf("%s:%d", s.Host, s.Port)
+	lis, err := net.Listen("tcp", addr)
+	if err != nil {
+		return fmt.Errorf("server failed to start a listener: %w", err)
+	}
+	s.Log.Info("listening for TCP traffic on %q", addr)
+	go s.runHTTPServer(lis)
+
+	return nil
+}
+
+func (s *Server) runHTTPServer(lis net.Listener) {
+	err := http.Serve(lis, s)
+	if err != nil && !errors.Is(err, http.ErrServerClosed) {
+		s.Error("error in http.Serve: %v", err)
+	}
+}
+
+func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	upgrader := websocket.Upgrader{}
+
+	conn, err := upgrader.Upgrade(w, r, nil)
+	if err != nil {
+		s.Error("upgrade error: %v", err)
+		return
+	}
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	s.lastSessionID++
+	sn := session{
+		Log:    s.Log.Child("sessions").Child(strconv.Itoa(s.lastSessionID)),
+		id:     s.lastSessionID,
+		conn:   conn,
+		outbox: make(chan wire.Response),
+	}
+	go sn.pump(ctx)
+
+	for {
+		t, r, err := conn.NextReader()
+		if err != nil {
+			s.Error("read error: %v", err)
+			return
+		}
+
+		switch t {
+		case websocket.TextMessage:
+			text, err := ioutil.ReadAll(r)
+			if err != nil {
+				s.Error("readall error: %v", err)
+				break
+			}
+			sn.Log.Child("received-frame").Info(string(text))
+			var req wire.Request
+			if err := json.Unmarshal(text, &req); err != nil {
+				s.Error("unable to parse request: %v", err)
+				sn.outbox <- wire.ErrorResponse(0, "unable to parse request: %v", err)
+				break
+			}
+			sn.outbox <- wire.NewResponse(req.Seq, wire.OK{})
+		case websocket.BinaryMessage:
+			sn.outbox <- wire.ErrorResponse(0, "unable to parse binary frames")
+		}
+	}
+}

internal/server/session.go

@@ -0,0 +1,59 @@
+package server
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"time"
+
+	"github.com/gorilla/websocket"
+	"github.com/jordanorelli/astro-domu/internal/wire"
+	"github.com/jordanorelli/blammo"
+)
+
+type session struct {
+	*blammo.Log
+	id     int
+	conn   *websocket.Conn
+	outbox chan wire.Response
+}
+
+// pump is the session send loop. Pump should pump the session's outbox
+// messages to the underlying connection until the context is closed.
+func (sn *session) pump(ctx context.Context) {
+	for {
+		select {
+		case res := <-sn.outbox:
+			if err := sn.sendResponse(res); err != nil {
+				sn.Error(err.Error())
+			}
+		case <-ctx.Done():
+			sn.Info("parent context done, shutting down write pump")
+			return
+		}
+	}
+}
+
+func (sn *session) sendResponse(res wire.Response) error {
+	payload, err := json.Marshal(res)
+	if err != nil {
+		return fmt.Errorf("failed to marshal outgoing response: %w", err)
+	}
+
+	if err := sn.conn.SetWriteDeadline(time.Now().Add(3 * time.Second)); err != nil {
+		return fmt.Errorf("failed to set write deadline: %w", err)
+	}
+
+	w, err := sn.conn.NextWriter(websocket.TextMessage)
+	if err != nil {
+		return fmt.Errorf("failed get a writer frame: %w", err)
+	}
+	if _, err := w.Write(payload); err != nil {
+		return fmt.Errorf("failed write payload: %w", err)
+	}
+	if err := w.Close(); err != nil {
+		return fmt.Errorf("failed to close write frame: %w", err)
+	}
+	sn.Child("sent-frame").Info(string(payload))
+	return nil
+}

internal/sim/entity.go

@@ -0,0 +1,7 @@
+package sim
+
+// entity is any entity that can be simulated.
+type entity interface {
+	// update is the standard tick function
+	update(time.Duration)
+}

internal/sim/room.go

@@ -0,0 +1,4 @@
+package sim
+
+type Room struct {
+}

internal/sim/world.go

@@ -0,0 +1,4 @@
+package sim
+
+type World struct {
+}

internal/wire/error.go

@@ -0,0 +1,17 @@
+package wire
+
+import (
+	"fmt"
+)
+
+type Error struct {
+	val error
+}
+
+func (e Error) Error() string { return e.val.Error() }
+func (e Error) NetTag() Tag   { return T_Error }
+func (e Error) Unwrap() error { return e.val }
+
+func Errorf(t string, args ...interface{}) Error {
+	return Error{val: fmt.Errorf(t, args...)}
+}

internal/wire/ok.go

@@ -0,0 +1,4 @@
+package wire
+
+type OK struct {}
+func (OK) NetTag() Tag { return T_OK }

internal/wire/request.go

@@ -0,0 +1,7 @@
+package wire
+
+type Request struct {
+	Seq  int         `json:"seq"`
+	Type string      `json:"type"`
+	Body interface{} `json:"body"`
+}

internal/wire/response.go

@@ -0,0 +1,19 @@
+package wire
+
+type Response struct {
+	Re   int         `json:"re,omitempty"`
+	Type Tag         `json:"type"`
+	Body interface{} `json:"body"`
+}
+
+func NewResponse(re int, v Value) Response {
+	return Response{
+		Re:   re,
+		Type: v.NetTag(),
+		Body: v,
+	}
+}
+
+func ErrorResponse(re int, t string, args ...interface{}) Response {
+	return NewResponse(re, Errorf(t, args...))
+}

internal/wire/tag.go

@@ -0,0 +1,45 @@
+package wire
+
+import (
+	"encoding/json"
+	"fmt"
+)
+
+type Tag uint
+
+const (
+	T_None Tag = iota
+	T_Error
+	T_OK
+)
+
+func (t Tag) String() string {
+	switch t {
+	case T_Error:
+		return "error"
+	case T_OK:
+		return "ok"
+	default:
+		panic("unknown type tag")
+	}
+}
+
+func (t *Tag) UnmarshalJSON(b []byte) error {
+	var name string
+	if err := json.Unmarshal(b, &name); err != nil {
+		return err
+	}
+
+	switch name {
+	case "error":
+		*t = T_Error
+		return nil
+	case "ok":
+		*t = T_OK
+		return nil
+	default:
+		return fmt.Errorf("unknown type tag: %q", name)
+	}
+}
+
+func (t Tag) MarshalJSON() ([]byte, error) { return json.Marshal(t.String()) }

internal/wire/value.go

@@ -0,0 +1,3 @@
+package wire
+
+type Value interface{ NetTag() Tag }

main.go

@@ -2,9 +2,11 @@ package main
 
 import (
 	"os"
+	"os/signal"
 	"time"
 
 	"github.com/jordanorelli/astro-domu/internal/exit"
+	"github.com/jordanorelli/astro-domu/internal/server"
 	"github.com/jordanorelli/blammo"
 )
 
@@ -34,23 +36,16 @@ func main() {
 	case "client":
 		runClient()
 	case "server":
-		stdout := blammo.NewLineWriter(os.Stdout)
-		stderr := blammo.NewLineWriter(os.Stderr)
-
-		options := []blammo.Option{
-			blammo.DebugWriter(stdout),
-			blammo.InfoWriter(stdout),
-			blammo.ErrorWriter(stderr),
+		s := server.Server{}
+		if err := s.Start(); err != nil {
+			exit.WithMessage(1, "unable to start server: %v", err)
 		}
-
-		log := blammo.NewLog("astro", options...).Child("server")
-		s := server{Log: log, host: "127.0.0.1", port: 12805}
-		err := s.listen()
-		log.Error("listen error: %v", err)
+		sig := make(chan os.Signal, 1)
+		signal.Notify(sig, os.Interrupt)
+		<-sig
 	default:
 		exit.WithMessage(1, "supported options are [client|server]")
 	}
-
 }
 
 func runClient() {

server.go

@@ -1,73 +0,0 @@
-package main
-
-import (
-	"context"
-	"encoding/json"
-	"fmt"
-	"io/ioutil"
-	"net/http"
-	"strconv"
-
-	"github.com/gorilla/websocket"
-	"github.com/jordanorelli/blammo"
-)
-
-type server struct {
-	*blammo.Log
-	host          string
-	port          int
-	lastSessionID int
-}
-
-func (s *server) listen() error {
-	return http.ListenAndServe(fmt.Sprintf("%s:%d", s.host, s.port), s)
-}
-
-func (s *server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
-	upgrader := websocket.Upgrader{}
-
-	conn, err := upgrader.Upgrade(w, r, nil)
-	if err != nil {
-		s.Error("upgrade error: %v", err)
-		return
-	}
-
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
-
-	s.lastSessionID++
-	sn := session{
-		Log:    s.Log.Child("sessions").Child(strconv.Itoa(s.lastSessionID)),
-		id:     s.lastSessionID,
-		conn:   conn,
-		outbox: make(chan response),
-	}
-	go sn.pump(ctx)
-
-	for {
-		t, r, err := conn.NextReader()
-		if err != nil {
-			s.Error("read error: %v", err)
-			return
-		}
-
-		switch t {
-		case websocket.TextMessage:
-			text, err := ioutil.ReadAll(r)
-			if err != nil {
-				s.Error("readall error: %v", err)
-				break
-			}
-			sn.Log.Child("received-frame").Info(string(text))
-			var body requestBody
-			if err := json.Unmarshal(text, &body); err != nil {
-				s.Error("unable to parse request: %v", err)
-				sn.outbox <- errorResponse(0, fmt.Errorf("unable to parse request: %v", err))
-				break
-			}
-			sn.outbox <- ok(body.Seq)
-		case websocket.BinaryMessage:
-			sn.outbox <- errorResponse(0, fmt.Errorf("unable to parse binary frames"))
-		}
-	}
-}