Refactor the bitcaskd (redis compatible server) sample to improve code quality (#88)

cmd/bitcaskd/main.go

@@ -3,26 +3,22 @@ package main
 import (
 	"fmt"
 	"os"
-	"strings"
 
 	log "github.com/sirupsen/logrus"
 	flag "github.com/spf13/pflag"
-	"github.com/tidwall/redcon"
 
-	"github.com/prologic/bitcask"
 	"github.com/prologic/bitcask/internal"
 )
 
 var (
-	bind            string
+	bind    string
-	debug           bool
+	debug   bool
-	version         bool
+	version bool
-	maxDatafileSize int
 )
 
 func init() {
 	flag.Usage = func() {
-		fmt.Fprintf(os.Stderr, "Usage: %s [options] <path>\n", os.Args[0])
+		fmt.Fprintf(os.Stderr, "Usage: %s [options] <dbpath>\n", os.Args[0])
 		flag.PrintDefaults()
 	}
 
@@ -30,8 +26,6 @@ func init() {
 	flag.BoolVarP(&debug, "debug", "d", false, "enable debug logging")
 
 	flag.StringVarP(&bind, "bind", "b", ":6379", "interface and port to bind to")
-
-	flag.IntVar(&maxDatafileSize, "max-datafile-size", 1<<20, "maximum datafile size in bytes")
 }
 
 func main() {
@@ -55,86 +49,11 @@ func main() {
 
 	path := flag.Arg(0)
 
-	db, err := bitcask.Open(path, bitcask.WithMaxDatafileSize(maxDatafileSize))
+	server, err := newServer(bind, path)
 	if err != nil {
-		log.WithError(err).WithField("path", path).Error("error opening database")
+		log.WithError(err).Error("error creating server")
-		os.Exit(1)
+		os.Exit(2)
 	}
 
-	log.WithField("bind", bind).WithField("path", path).Infof("starting bitcaskd v%s", internal.FullVersion())
+	log.Fatal(server.Run())
-
-	err = redcon.ListenAndServe(bind,
-		func(conn redcon.Conn, cmd redcon.Command) {
-			switch strings.ToLower(string(cmd.Args[0])) {
-			case "ping":
-				conn.WriteString("PONG")
-			case "quit":
-				conn.WriteString("OK")
-				conn.Close()
-			case "set":
-				if len(cmd.Args) != 3 {
-					conn.WriteError("ERR wrong number of arguments for '" + string(cmd.Args[0]) + "' command")
-					return
-				}
-				key := cmd.Args[1]
-				value := cmd.Args[2]
-				err = db.Put(key, value)
-				if err != nil {
-					conn.WriteString(fmt.Sprintf("ERR: %s", err))
-				} else {
-					conn.WriteString("OK")
-				}
-			case "get":
-				if len(cmd.Args) != 2 {
-					conn.WriteError("ERR wrong number of arguments for '" + string(cmd.Args[0]) + "' command")
-					return
-				}
-				key := cmd.Args[1]
-				value, err := db.Get(key)
-				if err != nil {
-					conn.WriteNull()
-				} else {
-					conn.WriteBulk(value)
-				}
-			case "keys":
-				conn.WriteArray(db.Len())
-				for key := range db.Keys() {
-					conn.WriteBulk([]byte(key))
-				}
-			case "exists":
-				if len(cmd.Args) != 2 {
-					conn.WriteError("ERR wrong number of arguments for '" + string(cmd.Args[0]) + "' command")
-					return
-				}
-				key := cmd.Args[1]
-				if db.Has(key) {
-					conn.WriteInt(1)
-				} else {
-					conn.WriteInt(0)
-				}
-			case "del":
-				if len(cmd.Args) != 2 {
-					conn.WriteError("ERR wrong number of arguments for '" + string(cmd.Args[0]) + "' command")
-					return
-				}
-				key := cmd.Args[1]
-				err := db.Delete(key)
-				if err != nil {
-					conn.WriteInt(0)
-				} else {
-					conn.WriteInt(1)
-				}
-			default:
-				conn.WriteError("ERR unknown command '" + string(cmd.Args[0]) + "'")
-			}
-		},
-		func(conn redcon.Conn) bool {
-			return true
-		},
-		func(conn redcon.Conn, err error) {
-		},
-	)
-	if err != nil {
-		log.WithError(err).Fatal("oops")
-	}
 }

cmd/bitcaskd/server.go

@@ -0,0 +1,122 @@
+package main
+
+import (
+	"fmt"
+	"strings"
+
+	log "github.com/sirupsen/logrus"
+	"github.com/tidwall/redcon"
+
+	"github.com/prologic/bitcask"
+)
+
+type server struct {
+	bind string
+	db   *bitcask.Bitcask
+}
+
+func newServer(bind, dbpath string) (*server, error) {
+	db, err := bitcask.Open(dbpath)
+	if err != nil {
+		log.WithError(err).WithField("dbpath", dbpath).Error("error opening database")
+		return nil, err
+	}
+
+	return &server{
+		bind: bind,
+		db:   db,
+	}, nil
+}
+
+func (s *server) handleSet(cmd redcon.Command, conn redcon.Conn) {
+	if len(cmd.Args) != 3 {
+		conn.WriteError("ERR wrong number of arguments for '" + string(cmd.Args[0]) + "' command")
+		return
+	}
+	key := cmd.Args[1]
+	value := cmd.Args[2]
+	if err := s.db.Put(key, value); err != nil {
+		conn.WriteString(fmt.Sprintf("ERR: %s", err))
+	} else {
+		conn.WriteString("OK")
+	}
+}
+
+func (s *server) handleGet(cmd redcon.Command, conn redcon.Conn) {
+	if len(cmd.Args) != 2 {
+		conn.WriteError("ERR wrong number of arguments for '" + string(cmd.Args[0]) + "' command")
+		return
+	}
+	key := cmd.Args[1]
+	value, err := s.db.Get(key)
+	if err != nil {
+		conn.WriteNull()
+	} else {
+		conn.WriteBulk(value)
+	}
+}
+
+func (s *server) handleKeys(cmd redcon.Command, conn redcon.Conn) {
+	conn.WriteArray(s.db.Len())
+	for key := range s.db.Keys() {
+		conn.WriteBulk([]byte(key))
+	}
+}
+
+func (s *server) handleExists(cmd redcon.Command, conn redcon.Conn) {
+	if len(cmd.Args) != 2 {
+		conn.WriteError("ERR wrong number of arguments for '" + string(cmd.Args[0]) + "' command")
+		return
+	}
+	key := cmd.Args[1]
+	if s.db.Has(key) {
+		conn.WriteInt(1)
+	} else {
+		conn.WriteInt(0)
+	}
+}
+
+func (s *server) handleDel(cmd redcon.Command, conn redcon.Conn) {
+	if len(cmd.Args) != 2 {
+		conn.WriteError("ERR wrong number of arguments for '" + string(cmd.Args[0]) + "' command")
+		return
+	}
+	key := cmd.Args[1]
+	if err := s.db.Delete(key); err != nil {
+		conn.WriteInt(0)
+	} else {
+		conn.WriteInt(1)
+	}
+}
+
+func (s *server) Run() (err error) {
+	err = redcon.ListenAndServe(s.bind,
+		func(conn redcon.Conn, cmd redcon.Command) {
+			switch strings.ToLower(string(cmd.Args[0])) {
+			case "ping":
+				conn.WriteString("PONG")
+			case "quit":
+				conn.WriteString("OK")
+				conn.Close()
+			case "set":
+				s.handleSet(cmd, conn)
+			case "get":
+				s.handleGet(cmd, conn)
+			case "keys":
+				s.handleKeys(cmd, conn)
+			case "exists":
+				s.handleExists(cmd, conn)
+			case "del":
+				s.handleDel(cmd, conn)
+			default:
+				conn.WriteError("ERR unknown command '" + string(cmd.Args[0]) + "'")
+			}
+		},
+		func(conn redcon.Conn) bool {
+			return true
+		},
+		func(conn redcon.Conn, err error) {
+		},
+	)
+	return
+}