jinja2 keep indentaion when render multi line string

I'm using jinja2 with python to config network device automatically.Now I'm in trouble with line indentaion. Here is my demo: reading config info from csv file and render into config string.

.j2 file

interface {{ interface }}
    description {{ ip }}-{{ server }}-{{ contact }}
    port link-type {{ port_type }}
    {% if port_type == "access" -%}
    port default vlan {{ vlan }}
    {% endif %}

.py

def generate_config():
    """
    Parameter:None
    Return:device config string
    """
        
    template_fd = open(template_file,'r')
    server_info_fd = open(server_info_file,'r')
    
    jinja_template = Template(template_fd.read(),keep_trailing_newline=True)
    server_info = csv.DictReader(server_info_fd)
    
  开发者_如何学编程  config_set=''
    for info in server_info:
        interface_config = jinja_template.render(
            interface=info['Interface'],
            ip=info['Ip'],
            server=info['Server'],
            contact=info['Contact'],
            vlan=info['Vlan'],
            port_type=info['Port-type']
        )
        config_set += interface_config
        
    template_fd.close()
    server_info_fd.close()
    return config_set

What I got is:

interface GigabitEthernet0/0/17
    description x.x.x.x-test-101
    port link-type access
    port default vlan 2101
    interface GigabitEthernet0/0/18
    description x.x.x.x-test-102
    port link-type access
    port default vlan 2101

The second interface 0/0/18 still keeps indentation which I don't want. Thx for you great help