mysql

internal/db/db.go

@@ -7,10 +7,77 @@ import (
 	"fmt"
 	"sort"
 	"strings"
+	"time"
 
+	_ "github.com/go-sql-driver/mysql"
 	_ "modernc.org/sqlite"
 )
 
+// MySQLConfig targets a shared MySQL database for multi-operator logging
+// (multiple OpsLog instances on one logbook, à la Log4OM).
+type MySQLConfig struct {
+	Host     string
+	Port     int
+	User     string
+	Password string
+	Database string
+}
+
+func (c MySQLConfig) dsn() string {
+	port := c.Port
+	if port == 0 {
+		port = 3306
+	}
+	// parseTime + UTC so DATETIME columns scan into time.Time; utf8mb4 for full
+	// Unicode (names, comments…).
+	return fmt.Sprintf("%s:%s@tcp(%s:%d)/%s?parseTime=true&loc=UTC&charset=utf8mb4",
+		c.User, c.Password, c.Host, port, c.Database)
+}
+
+// validDBIdent guards a database name we splice into DDL (CREATE DATABASE can't
+// use a placeholder). Only plain identifiers allowed.
+func validDBIdent(s string) bool {
+	if s == "" {
+		return false
+	}
+	for _, r := range s {
+		if r != '_' && !(r >= 'a' && r <= 'z') && !(r >= 'A' && r <= 'Z') && !(r >= '0' && r <= '9') {
+			return false
+		}
+	}
+	return true
+}
+
+// PingMySQL verifies a shared-database connection and creates the logbook
+// database if it doesn't exist yet. It connects at server level first (no
+// database selected) so a not-yet-created DB isn't an error, then runs
+// CREATE DATABASE IF NOT EXISTS. Backs the settings "Test connection" button.
+func PingMySQL(c MySQLConfig) error {
+	if strings.TrimSpace(c.Host) == "" {
+		return fmt.Errorf("host is required")
+	}
+	server := c
+	server.Database = "" // connect to the server, not a specific DB
+	conn, err := sql.Open("mysql", server.dsn())
+	if err != nil {
+		return fmt.Errorf("open mysql: %w", err)
+	}
+	defer conn.Close()
+	conn.SetConnMaxLifetime(5 * time.Second)
+	if err := conn.Ping(); err != nil {
+		return fmt.Errorf("connect to %s:%d: %w", c.Host, c.Port, err)
+	}
+	if name := strings.TrimSpace(c.Database); name != "" {
+		if !validDBIdent(name) {
+			return fmt.Errorf("invalid database name %q (letters, digits, underscore only)", name)
+		}
+		if _, err := conn.Exec("CREATE DATABASE IF NOT EXISTS `" + name + "` CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci"); err != nil {
+			return fmt.Errorf("create database %q: %w", name, err)
+		}
+	}
+	return nil
+}
+
 //go:embed migrations/*.sql
 var migrationsFS embed.FS