Add event_deletion_enabled option to the config, useful for master-master/cluster setups

config.yml

@@ -30,6 +30,10 @@ event_database_location: data/registry_events.db
 # event_database_driver: mysql
 # event_database_location: user:password@tcp(localhost:3306)/docker_events
 
+# You can disable event deletion on some hosts when you are running docker-registry on master-master or
+# cluster setup to avoid deadlocks or replication break.
+event_deletion_enabled: True
+
 # Cache refresh interval in minutes.
 # How long to cache repository list and tag counts.
 cache_refresh_interval: 10

events/event_listener.go

@@ -10,6 +10,7 @@ import (
 
 	"github.com/hhkbp2/go-logging"
 	"github.com/quiq/docker-registry-ui/registry"
+
 	// 🐒 patching of "database/sql".
 	_ "github.com/go-sql-driver/mysql"
 	_ "github.com/mattn/go-sqlite3"
@@ -35,6 +36,7 @@ type EventListener struct {
 	databaseDriver   string
 	databaseLocation string
 	retention        int
+	eventDeletion    bool
 	logger           logging.Logger
 }
 
@@ -54,11 +56,12 @@ type EventRow struct {
 }
 
 // NewEventListener initialize EventListener.
-func NewEventListener(databaseDriver, databaseLocation string, retention int) *EventListener {
+func NewEventListener(databaseDriver, databaseLocation string, retention int, eventDeletion bool) *EventListener {
 	return &EventListener{
 		databaseDriver:   databaseDriver,
 		databaseLocation: databaseLocation,
 		retention:        retention,
+		eventDeletion:    eventDeletion,
 		logger:           registry.SetupLogging("events.event_listener"),
 	}
 }
@@ -112,6 +115,9 @@ func (e *EventListener) ProcessEvents(request *http.Request) {
 	}
 
 	// Purge old records.
+	if !e.eventDeletion {
+		return
+	}
 	var res sql.Result
 	if e.databaseDriver == "mysql" {
 		stmt, _ := db.Prepare("DELETE FROM events WHERE created < DATE_SUB(NOW(), INTERVAL ? DAY)")

main.go

@@ -31,6 +31,7 @@ type configData struct {
 	EventRetentionDays    int      `yaml:"event_retention_days"`
 	EventDatabaseDriver   string   `yaml:"event_database_driver"`
 	EventDatabaseLocation string   `yaml:"event_database_location"`
+	EventDeletionEnabled  bool     `yaml:"event_deletion_enabled"`
 	CacheRefreshInterval  uint8    `yaml:"cache_refresh_interval"`
 	AnyoneCanDelete       bool     `yaml:"anyone_can_delete"`
 	Admins                []string `yaml:"admins"`
@@ -128,7 +129,9 @@ func main() {
 	if a.config.EventDatabaseDriver != "sqlite3" && a.config.EventDatabaseDriver != "mysql" {
 		panic(fmt.Errorf("event_database_driver should be either sqlite3 or mysql"))
 	}
-	a.eventListener = events.NewEventListener(a.config.EventDatabaseDriver, a.config.EventDatabaseLocation, a.config.EventRetentionDays)
+	a.eventListener = events.NewEventListener(
+		a.config.EventDatabaseDriver, a.config.EventDatabaseLocation, a.config.EventRetentionDays, a.config.EventDeletionEnabled,
+	)
 
 	// Template engine init.
 	e := echo.New()