use in-memory lock for database access

server/main/src/database/db.go

@@ -19,7 +19,6 @@ import (
 	"github.com/schollz/find3/server/main/src/models"
 	"github.com/schollz/sqlite3dump"
 	"github.com/schollz/stringsizer"
-	flock "github.com/theckman/go-flock"
 )
 
 // MakeTables creates two tables, a `keystore` table:
@@ -196,22 +195,22 @@ func (d *Database) AddPrediction(timestamp int64, aidata []models.LocationPredic
 	}
 	tx, err := d.db.Begin()
 	if err != nil {
-		return errors.Wrap(err, "AddPrediction")
+		return errors.Wrap(err, "begin AddPrediction")
 	}
 	stmt, err := tx.Prepare("insert or replace into location_predictions (timestamp,prediction) values (?, ?)")
 	if err != nil {
-		return errors.Wrap(err, "AddPrediction")
+		return errors.Wrap(err, "stmt AddPrediction")
 	}
 	defer stmt.Close()
 
 	_, err = stmt.Exec(timestamp, string(b))
 	if err != nil {
-		return errors.Wrap(err, "AddPrediction")
+		return errors.Wrap(err, "exec AddPrediction")
 	}
 
 	err = tx.Commit()
 	if err != nil {
-		return errors.Wrap(err, "AddPrediction")
+		return errors.Wrap(err, "commit AddPrediction")
 	}
 	return
 }
@@ -832,14 +831,19 @@ func Open(family string, readOnly ...bool) (d *Database, err error) {
 
 	// obtain a lock on the database
 	// logger.Log.Debugf("getting filelock on %s", d.name+".lock")
-	d.fileLock = flock.NewFlock(d.name + ".lock")
 	for {
-		locked, err := d.fileLock.TryLock()
-		if err == nil && locked {
+		var ok bool
+		databaseLock.Lock()
+		if _, ok = databaseLock.Locked[d.name]; !ok {
+			databaseLock.Locked[d.name] = true
+		}
+		databaseLock.Unlock()
+		if !ok {
 			break
 		}
 		time.Sleep(10 * time.Millisecond)
 	}
+	// logger.Log.Debugf("got filelock")
 
 	// check if it is a new database
 	newDatabase := false
@@ -887,12 +891,10 @@ func (d *Database) Close() (err error) {
 	}
 
 	// close filelock
-	err = d.fileLock.Unlock()
-	if err != nil {
-		logger.Log.Error(err)
-	} else {
-		os.Remove(d.name + ".lock")
-	}
+	// logger.Log.Debug("closing lock")
+	databaseLock.Lock()
+	delete(databaseLock.Locked, d.name)
+	databaseLock.Unlock()
 	d.isClosed = true
 	return
 }

server/main/src/database/models.go

@@ -2,10 +2,10 @@ package database
 
 import (
 	"database/sql"
+	"sync"
 
 	_ "github.com/mattn/go-sqlite3"
 	"github.com/schollz/find3/server/main/src/logging"
-	flock "github.com/theckman/go-flock"
 )
 
 // DataFolder is set to where you want each Sqlite3 database to be stored
@@ -17,7 +17,20 @@ type Database struct {
 	name     string
 	family   string
 	db       *sql.DB
-	fileLock *flock.Flock
 	logger   *logging.SeelogWrapper
 	isClosed bool
 }
+
+type DatabaseLock struct {
+	Locked map[string]bool
+	sync.RWMutex
+}
+
+var databaseLock *DatabaseLock
+
+func init() {
+	databaseLock = new(DatabaseLock)
+	databaseLock.Lock()
+	defer databaseLock.Unlock()
+	databaseLock.Locked = make(map[string]bool)
+}

server/main/src/learning/nb2/nb2.go

@@ -57,8 +57,8 @@ func (a *Algorithm) Fit(datas []models.SensorData) (err error) {
 	if err != nil {
 		return
 	}
-	defer db.Close()
 	err = db.Set("NB2", a.Data)
+	db.Close()
 	return
 }