added command filter for geofences

It's now possible to mask the fence notifications based on the
command. For example, if we only want "set" and "del" commands.

NEARBY fleet FENCE COMMANDS set,del POINT 33 -115 10000

Suggested by @amorskoy, closes #99

controller/fence.go

@@ -5,6 +5,7 @@ import (
 	"strconv"
 	"strings"
 
+	"github.com/tidwall/gjson"
 	"github.com/tidwall/tile38/controller/glob"
 	"github.com/tidwall/tile38/controller/server"
 	"github.com/tidwall/tile38/geojson"
@@ -14,11 +15,25 @@ var tmfmt = "2006-01-02T15:04:05.999999999Z07:00"
 
 // FenceMatch executes a fence match returns back json messages for fence detection.
 func FenceMatch(hookName string, sw *scanWriter, fence *liveFenceSwitches, details *commandDetailsT) []string {
+	msgs := fenceMatch(hookName, sw, fence, details)
+	if len(fence.accept) == 0 {
+		return msgs
+	}
+	nmsgs := make([]string, 0, len(msgs))
+	for _, msg := range msgs {
+		if fence.accept[gjson.Get(msg, "command").String()] {
+			nmsgs = append(nmsgs, msg)
+		}
+	}
+	return nmsgs
+}
+
+func fenceMatch(hookName string, sw *scanWriter, fence *liveFenceSwitches, details *commandDetailsT) []string {
 	jshookName := jsonString(hookName)
 	jstime := jsonString(details.timestamp.Format(tmfmt))
 	pattern := fence.glob
 	if details.command == "drop" {
-		return []string{`{"cmd":"drop","hook":` + jshookName + `,"time":` + jstime + `}`}
+		return []string{`{"command":"drop","hook":` + jshookName + `,"time":` + jstime + `}`}
 	}
 	match := true
 	if pattern != "" && pattern != "*" {
@@ -150,7 +165,7 @@ func FenceMatch(hookName string, sw *scanWriter, fence *liveFenceSwitches, detai
 	jskey := jsonString(details.key)
 
 	ores := res
-	msgs := make([]string, 0, 2)
+	msgs := make([]string, 0, 4)
 	if fence.detect == nil || fence.detect[detect] {
 		if strings.HasPrefix(ores, "{") {
 			res = `{"command":"` + details.command + `","group":"` + group + `","detect":"` + detect + `","hook":` + jshookName + `,"key":` + jskey + `,"time":` + jstime + `,` + ores[1:]

controller/token.go

@@ -164,6 +164,7 @@ type searchScanBaseTokens struct {
 	lineout   string
 	fence     bool
 	detect    map[string]bool
+	accept    map[string]bool
 	glob      string
 	wheres    []whereT
 	nofields  bool
@@ -279,6 +280,30 @@ func parseSearchScanBaseTokens(cmd string, vs []resp.Value) (vsout []resp.Value,
 				}
 				t.fence = true
 				continue
+			} else if (wtok[0] == 'C' || wtok[0] == 'c') && strings.ToLower(wtok) == "commands" {
+				vs = nvs
+				if t.accept != nil {
+					err = errDuplicateArgument(strings.ToUpper(wtok))
+					return
+				}
+				t.accept = make(map[string]bool)
+				var peek string
+				if vs, peek, ok = tokenval(vs); !ok || peek == "" {
+					err = errInvalidNumberOfArguments
+					return
+				}
+				for _, s := range strings.Split(peek, ",") {
+					part := strings.TrimSpace(strings.ToLower(s))
+					if t.accept[part] {
+						err = errDuplicateArgument(s)
+						return
+					}
+					t.accept[part] = true
+				}
+				if len(t.accept) == 0 {
+					t.accept = nil
+				}
+				continue
 			} else if (wtok[0] == 'D' || wtok[0] == 'd') && strings.ToLower(wtok) == "detect" {
 				vs = nvs
 				if t.detect != nil {