初版功能完成

internal/database/settings.go

@@ -0,0 +1,34 @@
+package database
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"fmt"
+	"time"
+)
+
+// GetSetting returns a setting and whether it exists.
+func GetSetting(ctx context.Context, db *sql.DB, key string) (string, bool, error) {
+	var value string
+	err := db.QueryRowContext(ctx, `SELECT value FROM settings WHERE key = ?`, key).Scan(&value)
+	if errors.Is(err, sql.ErrNoRows) {
+		return "", false, nil
+	}
+	if err != nil {
+		return "", false, fmt.Errorf("get setting %q: %w", key, err)
+	}
+	return value, true, nil
+}
+
+// SetSetting upserts a setting with an RFC3339 UTC timestamp.
+func SetSetting(ctx context.Context, db *sql.DB, key, value string) error {
+	_, err := db.ExecContext(ctx, `
+        INSERT INTO settings(key, value, updated_at) VALUES(?, ?, ?)
+        ON CONFLICT(key) DO UPDATE SET value = excluded.value, updated_at = excluded.updated_at
+    `, key, value, time.Now().UTC().Format(time.RFC3339Nano))
+	if err != nil {
+		return fmt.Errorf("set setting %q: %w", key, err)
+	}
+	return nil
+}