Logs: Allow restart of logging after database provider reset #47 #4831

Signed-off-by: Michael Mayer <michael@photoprism.app>

internal/config/config_db.go

@@ -324,6 +324,7 @@ func (c *Config) CloseDb() error {
 	if c.db != nil {
 		if err := c.db.Close(); err == nil {
 			c.db = nil
+			entity.SetDbProvider(nil)
 		} else {
 			return err
 		}

internal/entity/db.go

@@ -27,8 +27,3 @@ func Db() *gorm.DB {
 func UnscopedDb() *gorm.DB {
 	return Db().Unscoped()
 }
-
-// HasDb checks if a *gorm.DB connection exists.
-func HasDb() bool {
-	return dbConn != nil
-}

internal/entity/error.go

@@ -1,7 +1,7 @@
 package entity
 
 import (
-	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/sirupsen/logrus"
@@ -9,14 +9,18 @@ import (
 	"github.com/photoprism/photoprism/internal/event"
 )
 
-var logWarningsAndErrorsOnce sync.Once
+// logEvents is true when events are being recorded in the "errors" database table.
+var logEvents = atomic.Bool{}
 
-// LogWarningsAndErrors starts writing published error and warning events to the "errors" database table once.
+// LogWarningsAndErrors starts logging published error and warning
+// events to the errors database table if a database instance is set.
 func LogWarningsAndErrors() {
-	if HasDb() {
-		logWarningsAndErrorsOnce.Do(func() {
-			go Error{}.LogEvents(logrus.WarnLevel)
-		})
+	if !HasDbProvider() {
+		return
+	}
+
+	if logEvents.CompareAndSwap(false, true) {
+		go Error{}.LogEvents(logrus.WarnLevel)
 	}
 }
 
@@ -41,6 +45,7 @@ func (Error) LogEvents(minLevel logrus.Level) {
 	s := event.Subscribe("log.*")
 
 	defer func() {
+		logEvents.CompareAndSwap(true, false)
 		event.Unsubscribe(s)
 	}()
 
@@ -66,7 +71,7 @@ func (Error) LogEvents(minLevel logrus.Level) {
 			errLog.ErrorTime = val.(time.Time)
 		}
 
-		if HasDb() {
+		if HasDbProvider() {
 			Db().Create(&errLog)
 		} else {
 			break