[NOD-327] Add --migrate cli flag to API server (#407)

* [NOD-327] Add --migrate cli flag to API server

* [NOD-327] Change log messages

* [NOD-327] Remove `required` flag from API server RPC CLI arguments

* [NOD-327] Add database version in migrations logs

apiserver/config/config.go

@@ -23,9 +23,9 @@ var (
 // Config defines the configuration options for the API server.
 type Config struct {
 	LogDir      string `long:"logdir" description:"Directory to log output."`
-	RPCUser     string `short:"u" long:"rpcuser" description:"RPC username" required:"true"`
-	RPCPassword string `short:"P" long:"rpcpass" default-mask:"-" description:"RPC password" required:"true"`
-	RPCServer   string `short:"s" long:"rpcserver" description:"RPC server to connect to" required:"true"`
+	RPCUser     string `short:"u" long:"rpcuser" description:"RPC username"`
+	RPCPassword string `short:"P" long:"rpcpass" default-mask:"-" description:"RPC password"`
+	RPCServer   string `short:"s" long:"rpcserver" description:"RPC server to connect to"`
 	RPCCert     string `short:"c" long:"rpccert" description:"RPC server certificate chain for validation"`
 	DisableTLS  bool   `long:"notls" description:"Disable TLS"`
 	DBAddress   string `long:"dbaddress" description:"Database address"`
@@ -33,6 +33,7 @@ type Config struct {
 	DBPassword  string `long:"dbpass" description:"Database password" required:"true"`
 	DBName      string `long:"dbname" description:"Database name" required:"true"`
 	HTTPListen  string `long:"listen" description:"HTTP address to listen on (default: 0.0.0.0:8080)"`
+	Migrate     bool   `long:"migrate" description:"Migrate the database to the latest version. The server will not start when using this flag."`
 }
 
 // Parse parses the CLI arguments and returns a config struct.
@@ -49,6 +50,18 @@ func Parse() (*Config, error) {
 		return nil, err
 	}
 
+	if !cfg.Migrate {
+		if cfg.RPCUser == "" {
+			return nil, errors.New("--rpcuser is required if --migrate flag is not used")
+		}
+		if cfg.RPCPassword == "" {
+			return nil, errors.New("--rpcpass is required if --migrate flag is not used")
+		}
+		if cfg.RPCServer == "" {
+			return nil, errors.New("--rpcserver is required if --migrate flag is not used")
+		}
+	}
+
 	if cfg.RPCCert == "" && !cfg.DisableTLS {
 		return nil, errors.New("--notls has to be disabled if --cert is used")
 	}

apiserver/database/database.go

@@ -34,13 +34,17 @@ func (l gormLogger) Print(v ...interface{}) {
 // config variable.
 func Connect(cfg *config.Config) error {
 	connectionString := buildConnectionString(cfg)
-	isCurrent, err := isCurrent(connectionString)
+	migrator, driver, err := openMigrator(connectionString)
+	if err != nil {
+		return err
+	}
+	isCurrent, version, err := isCurrent(migrator, driver)
 	if err != nil {
 		return fmt.Errorf("Error checking whether the database is current: %s", err)
 	}
 	if !isCurrent {
-		return fmt.Errorf("Database is not current. Please migrate" +
-			" the database and start again.")
+		return fmt.Errorf("Database is not current (version %d). Please migrate"+
+			" the database by running the server with --migrate flag and then run it again.", version)
 	}
 
 	db, err = gorm.Open("mysql", connectionString)
@@ -68,35 +72,68 @@ func buildConnectionString(cfg *config.Config) string {
 
 // isCurrent resolves whether the database is on the latest
 // version of the schema.
-func isCurrent(connectionString string) (bool, error) {
-	driver, err := source.Open("file://migrations")
-	if err != nil {
-		return false, err
-	}
-	migrator, err := migrate.NewWithSourceInstance(
-		"migrations", driver, "mysql://"+connectionString)
-	if err != nil {
-		return false, err
-	}
-
+func isCurrent(migrator *migrate.Migrate, driver source.Driver) (bool, uint, error) {
 	// Get the current version
 	version, isDirty, err := migrator.Version()
 	if err == migrate.ErrNilVersion {
-		return false, nil
+		return false, 0, nil
 	}
 	if err != nil {
-		return false, err
+		return false, 0, err
 	}
 	if isDirty {
-		return false, fmt.Errorf("Database is dirty")
+		return false, 0, fmt.Errorf("Database is dirty")
 	}
 
 	// The database is current if Next returns ErrNotExist
 	_, err = driver.Next(version)
 	if pathErr, ok := err.(*os.PathError); ok {
 		if pathErr.Err == os.ErrNotExist {
-			return true, nil
+			return true, version, nil
 		}
 	}
-	return false, err
+	return false, version, err
+}
+
+func openMigrator(connectionString string) (*migrate.Migrate, source.Driver, error) {
+	driver, err := source.Open("file://migrations")
+	if err != nil {
+		return nil, nil, err
+	}
+	migrator, err := migrate.NewWithSourceInstance(
+		"migrations", driver, "mysql://"+connectionString)
+	if err != nil {
+		return nil, nil, err
+	}
+	return migrator, driver, nil
+}
+
+// Migrate database to the latest version.
+func Migrate(cfg *config.Config) error {
+	connectionString := buildConnectionString(cfg)
+	migrator, driver, err := openMigrator(connectionString)
+	if err != nil {
+		return err
+	}
+	isCurrent, version, err := isCurrent(migrator, driver)
+	if err != nil {
+		return fmt.Errorf("Error checking whether the database is current: %s", err)
+	}
+	if isCurrent {
+		log.Infof("Database is already up-to-date (version %d)", version)
+		return nil
+	}
+	err = migrator.Up()
+	if err != nil {
+		return err
+	}
+	version, isDirty, err := migrator.Version()
+	if err != nil {
+		return err
+	}
+	if isDirty {
+		return fmt.Errorf("error migrating database: database is dirty")
+	}
+	log.Infof("Migrated database to the latest version (version %d)", version)
+	return nil
 }

apiserver/main.go

@@ -23,6 +23,14 @@ func main() {
 		panic(fmt.Errorf("Error parsing command-line arguments: %s", err))
 	}
 
+	if cfg.Migrate {
+		err := database.Migrate(cfg)
+		if err != nil {
+			panic(fmt.Errorf("Error migrating database: %s", err))
+		}
+		return
+	}
+
 	err = database.Connect(cfg)
 	if err != nil {
 		panic(fmt.Errorf("Error connecting to database: %s", err))