I have created a report to generate product labels. The report works fine if I access if via URL;

http://localhost:8069/report/pdf/my_labels.report_labels/24

However if I try to generate the report from a form (a wizard that allows me to specify language and currency), I'm getting a report with the correct data but with the barcode missing. The log shows multiple instances like the following;

GET /report/barcode/?type=Code128&value=5060487671297&width=600&height=100 HTTP/1.1" 302 -

followed by

GET /web/login?redirect=http%3A%2F%2Flocalhost%3A8069%2Freport%2Fbarcode%2F%3Ftype%3DCode128%26value%3D5060487670849%26width%3D600%26height%3D100 HTTP/1.1" 200 -

This is my code to call the report from my wizard class;

    @api.multi
    def print_request(self, context=None):

        #todo: use id from picking
        datas = {'ids': [24]} #self.picking_id.id}

        return {
            'type': 'ir.actions.report.xml',
            'report_name': 'my_labels.report_labels',
            'datas': datas,
            'context': context,
            'target': 'current',
        }