i read data from my config file like this:
ip_vlan1 = "10.10.($id+100).5"
ip_vlan2 = "10.11.($id*2+1).6"
v.v...
And for each vlan, I want calculate vlan address for it, based on ID and vlan-expression:
def calculate_vlan_id(id, vlan_exp):
...
return ip_addr # string
Example:
def(3, ip_vlan1) --> result: "10.10.103.5"
def(5, ip_vlan2) --> result: "10.11.11.6"
Do you have a solution for this?
Thanks in advance, folks!
You could use a text templating engine. (Which is safer than using eval based tricks).
Here's an example using genshi
from genshi.template import TextTemplate
ip_vlan1 = TextTemplate("10.10.${id+100}.5")
ip_vlan2 = TextTemplate("10.11.${2*id+1}.6")
print( ip_vlan1.generate(id=3) ) # prints 10.10.103.5
print( ip_vlan2.generate(id=5) ) # prints 10.11.11.6
If you really need the calculate_vlan_id function it would look something like this:
def calculate_vlan_id(id,ip_vlan):
return ip_vlan.generate(id=id)
Edit:
As requested here's an example using jinja2: This may not be the best way to do this, the jinja2 docs are large and confusing.
ip_vlan1 = jinja2.Template('10.10.{{id+100}}.5')
ip_vlan2 = jinja2.Template('10.11.{{2*id+1}}.6')
ip_vlan1.render(id=3)
ip_vlan2.render(id=5)
Both these methods are untested
def calculate_vlan_id(id, vlan_exp):
vlan_exp_list = vlan_exp.split(".")
vlan_exp_list[2].replace("$id", id);
vlan_exp_list[2] = eval(vlan_exp_list[2])
return '.'.join(vlan_exp_list) # string
IF you are sure that you have only only 'id', then you can do it like this.
def replace(id, vlan_exp):
vlan_exp = vlan_exp.replace('$id',str(id))
return ".".join(map(str,map(eval,vlan_exp.split('.'))))
But that uses eval and using eval can be harmful to your program.
