Add flags to disable AOF or to use a custom path

New server flags:
  --appendonly     yes/no
  --appendfilename path

Please note that leaders that have disabled AOF cannot be followed.

cmd/tile38-server/main.go

@@ -53,6 +53,42 @@ func (s *hserver) Send(ctx context.Context, in *hservice.MessageRequest) (*hserv
 }
 
 func main() {
+	gitsha := " (" + core.GitSHA + ")"
+	if gitsha == " (0000000)" {
+		gitsha = ""
+	}
+	versionLine := `tile38-server version: ` + core.Version + gitsha
+
+	output := os.Stderr
+	flag.Usage = func() {
+		fmt.Fprintf(output,
+			versionLine+`
+
+Usage: tile38-server [-p port]
+
+Basic Options:
+  -h hostname : listening host
+  -p port     : listening port (default: 9851)
+  -d path     : data directory (default: data)
+  -q          : no logging. totally silent output
+  -v          : enable verbose logging
+  -vv         : enable very verbose logging
+
+Advanced Options: 
+  --pidfile path          : file that contains the pid
+  --appendonly yes/no     : AOF persistence (default: yes)
+  --appendonlyfile path   : AOF path (default: data/appendonly.aof)
+  --http-transport yes/no : HTTP transport (default: yes)
+  --protected-mode yes/no : protected mode (default: yes)
+
+Developer Options:
+  --dev                             : enable developer mode
+  --webhook-http-consumer-port port : Start a test HTTP webhook server
+  --webhook-grpc-consumer-port port : Start a test GRPC webhook server
+`,
+		)
+	}
+
 	if len(os.Args) == 3 && os.Args[1] == "--webhook-http-consumer-port" {
 		log.SetOutput(os.Stderr)
 		port, err := strconv.ParseUint(os.Args[2], 10, 16)
@@ -97,6 +133,13 @@ func main() {
 	nargs := []string{os.Args[0]}
 	for i := 1; i < len(os.Args); i++ {
 		switch os.Args[i] {
+		case "--help":
+			output = os.Stdout
+			flag.Usage()
+			return
+		case "--version":
+			fmt.Fprintf(os.Stdout, "%s\n", versionLine)
+			return
 		case "--protected-mode", "-protected-mode":
 			i++
 			if i < len(os.Args) {
@@ -113,6 +156,26 @@ func main() {
 		case "--dev", "-dev":
 			devMode = true
 			continue
+		case "--appendonly", "-appendonly":
+			i++
+			if i < len(os.Args) {
+				switch strings.ToLower(os.Args[i]) {
+				case "no":
+					core.AppendOnly = "no"
+				case "yes":
+					core.AppendOnly = "yes"
+				}
+				continue
+			}
+			fmt.Fprintf(os.Stderr, "appendonly must be 'yes' or 'no'\n")
+			os.Exit(1)
+		case "--appendfilename", "-appendfilename":
+			i++
+			if i == len(os.Args) || os.Args[i] == "" {
+				fmt.Fprintf(os.Stderr, "appendfilename must have a value\n")
+				os.Exit(1)
+			}
+			core.AppendFileName = os.Args[i]
 		case "--http-transport", "-http-transport":
 			i++
 			if i < len(os.Args) {
@@ -161,10 +224,6 @@ func main() {
 	if host != "" {
 		hostd = "Addr: " + host + ", "
 	}
-	gitsha := " (" + core.GitSHA + ")"
-	if gitsha == " (0000000)" {
-		gitsha = ""
-	}
 	var pidferr error
 
 	var cleanedup bool

controller/aof.go

@@ -165,11 +165,13 @@ func (c *Controller) writeAOF(value resp.Value, d *commandDetailsT) error {
 	if err != nil {
 		return err
 	}
-	n, err := c.aof.Write(data)
+	if c.aof != nil {
-	if err != nil {
+		n, err := c.aof.Write(data)
-		return err
+		if err != nil {
+			return err
+		}
+		c.aofsz += n
 	}
-	c.aofsz += n
 
 	// notify aof live connections that we have new data
 	c.fcond.L.Lock()
@@ -298,6 +300,9 @@ func (c *Controller) cmdAOFMD5(msg *server.Message) (res resp.Value, err error)
 }
 
 func (c *Controller) cmdAOF(msg *server.Message) (res resp.Value, err error) {
+	if c.aof == nil {
+		return server.NOMessage, errors.New("aof disabled")
+	}
 	vs := msg.Values[1:]
 
 	var ok bool

controller/aofshrink.go

@@ -3,7 +3,6 @@ package controller
 import (
 	"math"
 	"os"
-	"path"
 	"sort"
 	"strconv"
 	"strings"
@@ -11,6 +10,7 @@ import (
 
 	"github.com/tidwall/tile38/controller/collection"
 	"github.com/tidwall/tile38/controller/log"
+	"github.com/tidwall/tile38/core"
 	"github.com/tidwall/tile38/geojson"
 )
 
@@ -19,6 +19,9 @@ const maxids = 32
 const maxchunk = 4 * 1024 * 1024
 
 func (c *Controller) aofshrink() {
+	if c.aof == nil {
+		return
+	}
 	start := time.Now()
 	c.mu.Lock()
 	if c.shrinking {
@@ -39,7 +42,7 @@ func (c *Controller) aofshrink() {
 	}()
 
 	err := func() error {
-		f, err := os.Create(path.Join(c.dir, "shrink"))
+		f, err := os.Create(core.AppendFileName + "-shrink")
 		if err != nil {
 			return err
 		}
@@ -255,13 +258,13 @@ func (c *Controller) aofshrink() {
 			if err := c.aof.Close(); err != nil {
 				log.Fatalf("shrink live aof close fatal operation: %v", err)
 			}
-			if err := os.Rename(path.Join(c.dir, "appendonly.aof"), path.Join(c.dir, "appendonly.bak")); err != nil {
+			if err := os.Rename(core.AppendFileName, core.AppendFileName+"-bak"); err != nil {
 				log.Fatalf("shrink backup fatal operation: %v", err)
 			}
-			if err := os.Rename(path.Join(c.dir, "shrink"), path.Join(c.dir, "appendonly.aof")); err != nil {
+			if err := os.Rename(core.AppendFileName+"-shrink", core.AppendFileName); err != nil {
 				log.Fatalf("shrink rename fatal operation: %v", err)
 			}
-			c.aof, err = os.OpenFile(path.Join(c.dir, "appendonly.aof"), os.O_CREATE|os.O_RDWR, 0600)
+			c.aof, err = os.OpenFile(core.AppendFileName, os.O_CREATE|os.O_RDWR, 0600)
 			if err != nil {
 				log.Fatalf("shrink openfile fatal operation: %v", err)
 			}
@@ -272,7 +275,7 @@ func (c *Controller) aofshrink() {
 			}
 			c.aofsz = int(n)
 
-			os.Remove(path.Join(c.dir, "appendonly.bak")) // ignore error
+			os.Remove(core.AppendFileName + "-bak") // ignore error
 
 			// kill all followers connections
 			for conn := range c.aofconnM {

controller/controller.go

@@ -116,6 +116,10 @@ func ListenAndServe(host string, port int, dir string, http bool) error {
 	return ListenAndServeEx(host, port, dir, nil, http)
 }
 func ListenAndServeEx(host string, port int, dir string, ln *net.Listener, http bool) error {
+	if core.AppendFileName == "" {
+		core.AppendFileName = path.Join(dir, "appendonly.aof")
+	}
+
 	log.Infof("Server started, Tile38 version %s, git %s", core.Version, core.GitSHA)
 	c := &Controller{
 		host:     host,
@@ -177,13 +181,15 @@ func ListenAndServeEx(host string, port int, dir string, ln *net.Listener, http
 	if err := c.migrateAOF(); err != nil {
 		return err
 	}
-	f, err := os.OpenFile(path.Join(dir, "appendonly.aof"), os.O_CREATE|os.O_RDWR, 0600)
+	if core.AppendOnly == "yes" {
-	if err != nil {
+		f, err := os.OpenFile(core.AppendFileName, os.O_CREATE|os.O_RDWR, 0600)
-		return err
+		if err != nil {
-	}
+			return err
-	c.aof = f
+		}
-	if err := c.loadAOF(); err != nil {
+		c.aof = f
-		return err
+		if err := c.loadAOF(); err != nil {
+			return err
+		}
 	}
 	c.fillExpiresList()
 	if c.config.followHost() != "" {

core/options.go

@@ -8,3 +8,9 @@ var ShowDebugMessages = false
 
 // ProtectedMode forces Tile38 to default in protected mode.
 var ProtectedMode = "yes"
+
+// AppendOnly allows for disabling the appendonly file.
+var AppendOnly = "yes"
+
+// AppendFileName allows for custom appendonly file path
+var AppendFileName string