added migration script support

database/base.go

@@ -13,10 +13,13 @@ package database
 
 import (
 	"context"
-	_ "embed"
+	"embed"
 	"errors"
 	"fmt"
+	"io/fs"
+	"regexp"
 	"slices"
+	"strings"
 
 	"git.erbosoft.com/amy/amsterdam/config"
 	"github.com/go-sql-driver/mysql"
@@ -41,6 +44,9 @@ var installScriptMySQL string
 //go:embed mysql-convert.sql
 var convertScriptMySQL string
 
+//go:embed mysql-migrate/*
+var migrationsMySQL embed.FS
+
 // amdb is the reference to the Amsterdam database.
 var amdb *sqlx.DB
 
@@ -75,6 +81,12 @@ func databaseVersionNumber(db *sqlx.DB) (string, error) {
 	return ver, err
 }
 
+// setDatabaseVersionNumber resets the version number in the database.
+func setDatabaseVersionNumber(db *sqlx.DB, version string) error {
+	_, err := db.Exec("UPDATE globals SET version = ?", version)
+	return err
+}
+
 // databaseInstallScript returns the install script for the database.
 func databaseInstallScript() (string, error) {
 	switch config.GlobalComputedConfig.DatabaseDriver {
@@ -95,6 +107,41 @@ func databaseConvertScript() (string, error) {
 	}
 }
 
+// databaseMigrationScripts returns the migration scripts to apply to the database.
+func databaseMigrationScripts(version string) (fs.FS, []string, error) {
+	var myfs fs.FS
+	var err error
+	switch config.GlobalComputedConfig.DatabaseDriver {
+	case "mysql":
+		myfs, err = fs.Sub(migrationsMySQL, "mysql-migrate")
+	default:
+		err = fmt.Errorf("No migration scripts for database driver: %s", config.GlobalComputedConfig.DatabaseDriver)
+	}
+	if err != nil {
+		return nil, make([]string, 0), err
+	}
+	rdfs := myfs.(fs.ReadDirFS)
+	dents, err := rdfs.ReadDir("/")
+	if err != nil {
+		return nil, make([]string, 0), err
+	}
+	rc := make([]string, 0, len(dents))
+	for _, d := range dents {
+		s := strings.TrimSuffix(d.Name(), ".sql")
+		m, err := regexp.Match(`\d{10}`, []byte(s))
+		if err != nil {
+			return nil, make([]string, 0), err
+		}
+		if m && s > version {
+			rc = append(rc, d.Name())
+		}
+	}
+	if len(rc) > 1 {
+		slices.Sort(rc)
+	}
+	return myfs, rc, nil
+}
+
 // prepareDB prepares the database if it's not yet been loaded.
 func prepareDB() (string, error) {
 	dsn := buildMysqlDSN(true)
@@ -134,7 +181,27 @@ func prepareDB() (string, error) {
 			return "", err
 		}
 	}
-	// TODO: apply migration scripts
+	scriptfs, scripts, err := databaseMigrationScripts(version)
+	if err == nil {
+		log.Infof("%d migration script(s) to be applied", len(scripts))
+		rffs := scriptfs.(fs.ReadFileFS)
+		for _, script := range scripts {
+			log.Infof("applying migration script: %s", script)
+			var data []byte
+			data, err = rffs.ReadFile(script)
+			if err != nil {
+				return version, fmt.Errorf("Unable to read migration script %s: %w", script, err)
+			}
+			_, err = db.Exec(string(data))
+			if err != nil {
+				return version, fmt.Errorf("Unable to apply migration script %s: %w", script, err)
+			}
+			err = setDatabaseVersionNumber(db, strings.TrimSuffix(script, ".sql"))
+			if err != nil {
+				break
+			}
+		}
+	}
 	return version, err
 }
 

database/mysql-migrate/README.txt

@@ -0,0 +1,2 @@
+Migration scripts for MySQL go in this directory. Name them as YYYYMMDDNN.sql, where YYYYMMDD is the
+current date and NN is a two-digit sequence number beginning at 01.