Doesn't support IP address

[jfbette]

Hello,

I am experiencing the following problem when my hostname is an IP address :

ansible-inventory-grapher -i /etc/ansible/hosts 192.168.128.1 -d inventoryGraph --format "test-{hostname}.dot"
Traceback (most recent call last):
File "/bin/ansible-inventory-grapher", line 128, in
main()
File "/bin/ansible-inventory-grapher", line 124, in main
render_graph(arg, options)
File "/bin/ansible-inventory-grapher", line 106, in render_graph
filename = options.format.format(pattern)
KeyError: 'hostname'

whereas the a fdqn it doesn't repport the error.

Tanks

JF