Config: Refactor options and flags source files #2195

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

go.mod

@@ -55,7 +55,7 @@ require (
 	github.com/urfave/cli v1.22.5
 	go4.org v0.0.0-20201209231011-d4a079459e60 // indirect
 	golang.org/x/crypto v0.0.0-20220331220935-ae2d96664a29
-	golang.org/x/net v0.0.0-20220403103023-749bd193bc2b
+	golang.org/x/net v0.0.0-20220407224826-aac1ed45d8e3
 	golang.org/x/sys v0.0.0-20220330033206-e17cdc41300f // indirect
 	gonum.org/v1/gonum v0.11.0
 	google.golang.org/protobuf v1.28.0 // indirect

go.sum

@@ -398,8 +398,8 @@ golang.org/x/net v0.0.0-20200707034311-ab3426394381/go.mod h1:/O7V0waA8r7cgGh81R
 golang.org/x/net v0.0.0-20201021035429-f5854403a974/go.mod h1:sp8m0HH+o8qH0wwXwYZr8TS3Oi6o0r6Gce1SSxlDquU=
 golang.org/x/net v0.0.0-20211015210444-4f30a5c0130f/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
 golang.org/x/net v0.0.0-20211112202133-69e39bad7dc2/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
-golang.org/x/net v0.0.0-20220403103023-749bd193bc2b h1:vI32FkLJNAWtGD4BwkThwEy6XS7ZLLMHkSkYfF8M0W0=
-golang.org/x/net v0.0.0-20220403103023-749bd193bc2b/go.mod h1:CfG3xpIq0wQ8r1q4Su4UZFWDARRcnwPjda9FqA0JpMk=
+golang.org/x/net v0.0.0-20220407224826-aac1ed45d8e3 h1:EN5+DfgmRMvRUrMGERW2gQl3Vc+Z7ZMnI/xdEpPSf0c=
+golang.org/x/net v0.0.0-20220407224826-aac1ed45d8e3/go.mod h1:CfG3xpIq0wQ8r1q4Su4UZFWDARRcnwPjda9FqA0JpMk=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/oauth2 v0.0.0-20190226205417-e64efc72b421/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
 golang.org/x/oauth2 v0.0.0-20190604053449-0f29369cfe45/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=

internal/config/config_options.go

@@ -7,35 +7,16 @@ import (
 	"reflect"
 	"time"
 
-	"github.com/photoprism/photoprism/pkg/txt"
-
-	_ "github.com/jinzhu/gorm/dialects/mysql"
-	_ "github.com/jinzhu/gorm/dialects/sqlite"
-
 	"github.com/urfave/cli"
 	"gopkg.in/yaml.v2"
 
 	"github.com/photoprism/photoprism/pkg/fs"
+	"github.com/photoprism/photoprism/pkg/txt"
 )
 
-// SQL Databases.
-const (
-	MySQL           = "mysql"
-	MariaDB         = "mariadb"
-	Postgres        = "postgres" // TODO: Requires GORM 2.0 for generic column data types
-	SQLite3         = "sqlite3"
-	SQLiteTestDB    = ".test.db"
-	SQLiteMemoryDSN = ":memory:"
-)
-
-// Options provides a struct in which application configuration is stored.
-// Application code must use functions to get config options, for two reasons:
-//
-// 1. We do not want to leak implementation details so refactoring overhead is kept low
-// 2. Some config values are dynamically generated
-// 3. Paths may become dynamic too at a later time
-//
-// See https://github.com/photoprism/photoprism/issues/50#issuecomment-433856358
+// Options hold the global configuration values without further validation or processing.
+// Application code should retrieve option values via getter functions since they provide
+// validation and return defaults if a value is empty.
 type Options struct {
 	Name                  string        `json:"-"`
 	Version               string        `json:"-"`

internal/config/database.go

@@ -14,10 +14,27 @@ import (
 	"github.com/jinzhu/gorm"
 	_ "github.com/jinzhu/gorm/dialects/mysql"
 	_ "github.com/jinzhu/gorm/dialects/sqlite"
+
 	"github.com/photoprism/photoprism/internal/entity"
 	"github.com/photoprism/photoprism/internal/mutex"
 )
 
+// SQL Databases.
+// TODO: PostgresSQL support requires upgrading GORM, so generic column data types can be used.
+const (
+	MySQL    = "mysql"
+	MariaDB  = "mariadb"
+	Postgres = "postgres"
+	SQLite3  = "sqlite3"
+)
+
+// SQLite default DSNs.
+const (
+	SQLiteTestDB    = ".test.db"
+	SQLiteMemoryDSN = ":memory:"
+)
+
+// dsnPattern is a regular expression matching a database DSN string.
 var dsnPattern = regexp.MustCompile(
 	`^(?:(?P<user>.*?)(?::(?P<password>.*))?@)?` +
 		`(?:(?P<net>[^\(]*)(?:\((?P<server>[^\)]*)\))?)?` +