Delete old checkpoints

core/database.go

@@ -8,7 +8,6 @@ import (
 	"os"
 	"path"
 	"sort"
-	"strings"
 	"sync"
 	"time"
 
@@ -17,6 +16,8 @@ import (
 	. "git.exozy.me/exozyme/status/scanner"
 )
 
+const NumberOfCheckpointsToKeep = 3
+
 type Row struct {
 	time time.Time
 	kind EventType
@@ -123,9 +124,6 @@ func OpenDatabase(dir string) (Database, error) {
 	})
 	for _, file := range files {
 		filename := file.Name()
-		if strings.HasSuffix(filename, ".tmp") {
-			continue
-		}
 		_, err := ulid.Parse(filename)
 		if err != nil {
 			continue // because database files have ULID as names
@@ -165,10 +163,37 @@ func (db *dumbDatabase) Persist() error {
 	defer db.mutex.Unlock()
 
 	db.sortRows()
-	id := ulid.Make().String() // checkpoint filename is ULID
 
+	dir := db.rootDir
+	// [section] clean up old checkpoints
+	files, err := os.ReadDir(dir)
+	if err != nil {
+		return err
+	}
+	// sort the file name desc. Since the file names are ULID, newer files are sorted first
+	sort.Slice(files, func(i, j int) bool {
+		return files[i].Name() > files[j].Name()
+	})
+	// delete old files
+	if len(files) > NumberOfCheckpointsToKeep {
+		for _, file := range files[NumberOfCheckpointsToKeep:] {
+			filename := file.Name()
+			_, err := ulid.Parse(filename)
+			if err != nil {
+				continue // because database files have ULID as names
+			}
+			fullpath := path.Join(dir, filename)
+			err = os.Remove(fullpath)
+			if err != nil {
+				log.Printf("Error when os.Delete: %v", err)
+			}
+		}
+	}
+
+	id := ulid.Make().String() // checkpoint filename is ULID
 	filename_final := path.Join(db.rootDir, id)
 	filename_tmp := path.Join(db.rootDir, id+".tmp")
+
 	file, err := os.Create(filename_tmp)
 	if err != nil {
 		return err
@@ -187,6 +212,7 @@ func (db *dumbDatabase) Persist() error {
 		return err
 	}
 	log.Printf("Saved %d rows to: %v", len(db.rows), filename_final)
+
 	return nil
 }
 

readme.md

@@ -32,7 +32,7 @@ Services
 		- [x] self boot up/shutdown
 		- [x] check service status every 5 minutes since boot
 	- [x] persist data on disk
-	- [ ] clean up old checkpoints
+	- [x] clean up old checkpoints
 - [x] Matrix notification
 
 ## Environment Variables