Allow configuration of tidy functions. Use a closure to decide what entries

to delete. The closure takes a *bolt.Bucket and returns an integer of the
number of entries deleted.

persist.go

@@ -40,23 +40,41 @@ type Config struct {
 	configured bool
 	MaxVars int
 	DBPath string
+	Tidy TidyConfig
 }
 
 func Init(x ...Config) {
 	mux.Lock()
-	c := Config{MaxVars: 64, DBPath: "db"} // default config
+	c := Config {
+		configured: true,
+		MaxVars: 64, // default config
+		DBPath: "db",
+	}
 	conf = c
 	if len(x) > 0 {
 		c = x[0]
 	}
 	if c.MaxVars != 0 {
 		conf.MaxVars = c.MaxVars
-		conf.configured = true
 	}
 	if c.DBPath != "" {
 		conf.DBPath = c.DBPath
-		conf.configured = true
 	}
+
+	if c.Tidy.Interval == 0 {
+		conf.Tidy.Interval = 10 * time.Second
+	} else {
+		fmt.Println("Setting conf.Tidy.Interval to",c.Tidy.Interval)
+		conf.Tidy.Interval = c.Tidy.Interval
+	}
+
+	if c.Tidy.Func == nil {
+		conf.Tidy.Func = ExpireAfter(24 * time.Hour)
+	} else {
+		fmt.Println("Setting conf.Tidy.Func")
+		conf.Tidy.Func = c.Tidy.Func
+	}
+
 	mux.Unlock()
 }
 
@@ -274,7 +292,9 @@ func start() {
 	launched = true
 
 	if conf.configured == false {
+		mux.Unlock()
 		Init()
+		mux.Lock()
 	}
 
 	var err error
@@ -423,6 +443,38 @@ func retrieve(name string, ts ...time.Time) ([]byte, time.Time, error) {
 	return ret, t, err
 }
 
+type TidyFunc func(*bolt.Bucket) int
+
+type TidyConfig struct {
+	Interval time.Duration
+	Func TidyFunc
+}
+
+func ExpireAfter(exp time.Duration) TidyFunc {
+	if exp > 0 {
+		exp = -1 * exp
+	}
+	fmt.Println("ExpireAfter(",exp,")")
+	return func(b *bolt.Bucket) int {
+		stime := time.Now()
+		etime := stime.Add(exp)
+		i := 0
+		c := b.Cursor()
+		end,_ := c.Last() // always keep the most recent on
+		for k,_ := c.First(); time.Since(stime) < 10 * time.Millisecond; k,_ = c.Next() {
+			if tdecode(k).After(etime) {
+				return i // entry not expired
+			}
+			if reflect.DeepEqual(k,end) {
+				return i // always keep the most recent entry
+			}
+			b.Delete(k)
+			i++
+		}
+		return i
+	}
+}
+
 func tidyThread() {
 	fmt.Println("tidyThread() starting")
 	lchan := make(chan string)
@@ -442,7 +494,7 @@ func tidyThread() {
 			close(lchan)
 		}
 	}()
-	tick := time.NewTicker(time.Second * 10)
+	tick := time.NewTicker(conf.Tidy.Interval)
 	for { select {
 	case <-tchan:
 		fmt.Println("closing loaded channel")
@@ -457,12 +509,9 @@ func tidyThread() {
 	} }
 }
 
-const expiration time.Duration = -24 * time.Hour
-
 // discard entries if they are too old.
 func Tidy(name string) {
 	stime := time.Now()
-	etime := stime.Add(expiration)
 	mux.Lock()
 	i := 0
 	db.Update(func(tx *bolt.Tx) error {
@@ -471,19 +520,7 @@ func Tidy(name string) {
 			fmt.Println("Can't open bucket for ",name)
 			return nil
 		}
-		c := b.Cursor()
+		i = conf.Tidy.Func(b)
-		end,_ := c.Last() // always keep the most recent on
-		for time.Since(stime) < 10 * time.Millisecond {
-			k,_ := c.First()
-			if tdecode(k).After(etime) {
-				return nil // entry not expired
-			}
-			if reflect.DeepEqual(k,end) {
-				return nil // always keep the most recent entry
-			}
-			b.Delete(k)
-			i++
-		}
 		return nil
 	})
 	mux.Unlock()

test/tidy/main.go

@@ -0,0 +1,27 @@
+package main
+
+import (
+	"fmt"
+	"time"
+	"gitlab.wow.st/gmp/persist"
+)
+
+func main() {
+	tc := persist.TidyConfig{
+		Interval: 2 * time.Second,
+		Func:persist.ExpireAfter(-5 * time.Second),
+	}
+	persist.Init(persist.Config{Tidy: tc})
+
+	x := persistInt("x",0)
+	persist.Commit()
+	x.Set(2)
+	persist.Commit()
+	x.Set(3)
+	persist.Commit()
+	fmt.Println(x.History())
+	time.Sleep(time.Second * 15)
+	fmt.Println(x.History())
+	persist.Shutdown()
+}
+