Add PHOTOPRISM_DATABASE_CONNS config parameter

Signed-off-by: Michael Mayer <michael@liquidbytes.net>

internal/commands/config.go

@@ -86,6 +86,7 @@ func configAction(ctx *cli.Context) error {
 	// Database config
 	fmt.Printf("%-25s %s\n", "database-driver", conf.DatabaseDriver())
 	fmt.Printf("%-25s %s\n", "database-dsn", conf.DatabaseDsn())
+	fmt.Printf("%-25s %d\n", "database-conns", conf.DatabaseConns())
 
 	// External binaries
 	fmt.Printf("%-25s %s\n", "sips-bin", conf.SipsBin())

internal/config/db.go

@@ -33,6 +33,15 @@ func (c *Config) DatabaseDsn() string {
 	return c.params.DatabaseDsn
 }
 
+// DatabaseConns sets the maximum number of open connections to the database.
+func (c *Config) DatabaseConns() int {
+	if c.params.DatabaseConns > 1024 || c.params.DatabaseConns < 0 {
+		return 0
+	}
+
+	return c.params.DatabaseConns
+}
+
 // Db returns the db connection.
 func (c *Config) Db() *gorm.DB {
 	if c.db == nil {
@@ -133,7 +142,7 @@ func (c *Config) connectToDatabase(ctx context.Context) error {
 	db.LogMode(false)
 	db.SetLogger(log)
 	db.DB().SetMaxIdleConns(0)
-	db.DB().SetMaxOpenConns(256)
+	db.DB().SetMaxOpenConns(c.DatabaseConns())
 
 	c.db = db
 	return err

internal/config/flags.go

@@ -243,6 +243,12 @@ var GlobalFlags = []cli.Flag{
 		Value:  "root:@tcp(localhost:2343)/photoprism?parseTime=true",
 		EnvVar: "PHOTOPRISM_DATABASE_DSN",
 	},
+	cli.IntFlag{
+		Name:   "database-conns",
+		Usage:  "maximum `NUMBER` of open connections to the database",
+		Value:  256,
+		EnvVar: "PHOTOPRISM_DATABASE_CONNS",
+	},
 	cli.BoolFlag{
 		Name:   "detect-nsfw",
 		Usage:  "flag photos as private that may be offensive",

internal/config/params.go

@@ -56,6 +56,7 @@ type Params struct {
 	ResourcesPath      string `yaml:"resources-path" flag:"resources-path"`
 	DatabaseDriver     string `yaml:"database-driver" flag:"database-driver"`
 	DatabaseDsn        string `yaml:"database-dsn" flag:"database-dsn"`
+	DatabaseConns      int    `yaml:"database-conns" flag:"database-conns"`
 	TidbServerHost     string `yaml:"tidb-host" flag:"tidb-host"`
 	TidbServerPort     uint   `yaml:"tidb-port" flag:"tidb-port"`
 	TidbServerPassword string `yaml:"tidb-password" flag:"tidb-password"`