I got into a little discussion about jinja templates the other day and ended up putting together a little example that I thought might be of interest to others. Note that the approach demonstrated here is a little bit fragile, it depends on the way the NSO cli would interpret the template. But, as long as your template is in cisco ios format it should work fairly well.
Also, note that the xml templates are checked against the model at load time, and gives much more robustness than this approach. However especially for experiments in the development phase using templates looking more like dumps from the device can be attractive.
#!/usr/bin/env python
from jinja2 import Environment, FileSystemLoader
import ncs
import _ncs.maapi as maapi
import socket
# Make sure to set /ncs-config/cli/use-expose-ns-prefix to false in ncs.conf
def loadJinja(device, file, data,
sock=None, th=None, apply_trans=True):
# Load and apply jinja2 template
env = Environment(loader=FileSystemLoader('.'))
template = env.get_template(file)
t = template.render(data)
print t
# If no socket is given
if sock is None:
sock = socket.socket()
maapi.connect(sock, '127.0.0.1', ncs.NCS_PORT)
trans = None
# Setup a maapi transaction as admin
if th is None:
maapi.start_user_session(sock, 'admin', 'foo', [],'127.0.0.1',ncs.PROTO_TCP)
th = maapi.start_trans(sock, ncs.RUNNING, ncs.READ_WRITE)
# Load config
maapi.load_config_cmds(sock, th, maapi.CONFIG_MERGE | maapi.CONFIG_C_IOS, t, "/devices/device{%s}/config" % (device))
# Apply trans
if apply_trans:
maapi.apply_trans(sock, th, False)
# Example usage
fn = "ios.j2"
device = "ios0"
data = { "ip_addr" : "192.168.1.3", "ip_mask" : "255.255.255.0",
"routes" : [ { "network" : "0.0.0.0", "mask" : "0.0.0.0", "gw" : "192.168.1.254"}]}
loadJinja(device, fn, data)
ios.j2 is:
interface GigabitEthernet0/1
ip address {{ ip_addr }} {{ ip_mask }}
exit
{% for route in routes %}
ip route {{ route.network }} {{ route.mask }} {{ route.gw }}
{% endfor %}
Also, note that if use-expose-ns-prefix is true, or if there are conflicts between different namespaces you would have to type ios:interface and ios:ip.
