Setup and migration UI refactor (#1190)

* Make config instance-based
* Remove config dependency in paths
* Refactor config init
* Allow startup without database
* Get system status at UI initialise
* Add setup wizard
* Cache and Metadata optional. Database mandatory
* Handle metadata not set during full import/export
* Add links
* Remove config check middleware
* Stash not mandatory
* Panic on missing mandatory config fields
* Redirect setup to main page if setup not required
* Add migration UI
* Remove unused stuff
* Move UI initialisation into App
* Don't create metadata paths on RefreshConfig
* Add folder selector for generated in setup
* Env variable to set and create config file.
Make docker images use a fixed config file.
* Set config file during setup

pkg/manager/config/init.go

@@ -0,0 +1,104 @@
+package config
+
+import (
+	"net"
+	"os"
+	"sync"
+
+	"github.com/spf13/pflag"
+	"github.com/spf13/viper"
+
+	"github.com/stashapp/stash/pkg/logger"
+	"github.com/stashapp/stash/pkg/utils"
+)
+
+var once sync.Once
+
+type flagStruct struct {
+	configFilePath string
+}
+
+func Initialize() (*Instance, error) {
+	var err error
+	once.Do(func() {
+		instance = &Instance{}
+
+		flags := initFlags()
+		err = initConfig(flags)
+		initEnvs()
+	})
+	return instance, err
+}
+
+func initConfig(flags flagStruct) error {
+	// The config file is called config.  Leave off the file extension.
+	viper.SetConfigName("config")
+
+	if flagConfigFileExists, _ := utils.FileExists(flags.configFilePath); flagConfigFileExists {
+		viper.SetConfigFile(flags.configFilePath)
+	}
+	viper.AddConfigPath(".")            // Look for config in the working directory
+	viper.AddConfigPath("$HOME/.stash") // Look for the config in the home directory
+
+	// for Docker compatibility, if STASH_CONFIG_FILE is set, then touch the
+	// given filename
+	envConfigFile := os.Getenv("STASH_CONFIG_FILE")
+	if envConfigFile != "" {
+		utils.Touch(envConfigFile)
+		viper.SetConfigFile(envConfigFile)
+	}
+
+	err := viper.ReadInConfig() // Find and read the config file
+	// continue, but set an error to be handled by caller
+
+	postInitConfig()
+	instance.SetInitialConfig()
+
+	return err
+}
+
+func postInitConfig() {
+	c := instance
+	if c.GetConfigFile() != "" {
+		viper.SetDefault(Database, c.GetDefaultDatabaseFilePath())
+	}
+
+	// Set generated to the metadata path for backwards compat
+	viper.SetDefault(Generated, viper.GetString(Metadata))
+
+	// Set default scrapers and plugins paths
+	viper.SetDefault(ScrapersPath, c.GetDefaultScrapersPath())
+	viper.SetDefault(PluginsPath, c.GetDefaultPluginsPath())
+
+	viper.WriteConfig()
+}
+
+func initFlags() flagStruct {
+	flags := flagStruct{}
+
+	pflag.IP("host", net.IPv4(0, 0, 0, 0), "ip address for the host")
+	pflag.Int("port", 9999, "port to serve from")
+	pflag.StringVarP(&flags.configFilePath, "config", "c", "", "config file to use")
+
+	pflag.Parse()
+	if err := viper.BindPFlags(pflag.CommandLine); err != nil {
+		logger.Infof("failed to bind flags: %s", err.Error())
+	}
+
+	return flags
+}
+
+func initEnvs() {
+	viper.SetEnvPrefix("stash")    // will be uppercased automatically
+	viper.BindEnv("host")          // STASH_HOST
+	viper.BindEnv("port")          // STASH_PORT
+	viper.BindEnv("external_host") // STASH_EXTERNAL_HOST
+	viper.BindEnv("generated")     // STASH_GENERATED
+	viper.BindEnv("metadata")      // STASH_METADATA
+	viper.BindEnv("cache")         // STASH_CACHE
+
+	// only set stash config flag if not already set
+	if instance.GetStashPaths() == nil {
+		viper.BindEnv("stash") // STASH_STASH
+	}
+}