Jinja2 is a full-featured template engine for Python. The first time I used it with Flask, it comes packaged with the powerful Jinja templating language. But it also could be used for rendering configuration. Jinja templates use: {{ … }} – for variable {% … %} – for expressions or logic (like for loops) Jinja2 also allows for conditional statements: Jinja2...
Iterator An iterator is an object that contains a countable number of values and consists of the methods __iter__ and __next__. __iter__: This method is called when an iterator is required for a container. Must always return an iterator __next__: Return the next item from the container. Generator Generator functions allow you to declare a function that behaves like an iterator...
Magic methods __new__: Called to create a new instance of class cls. What is happening at the moment of class creation (like checking if there should be only one instance of such class) __init__: Called after the instance has been created (by __new__())__del__: better not to change:)__str__: Called by str(object) and the built-in functions format() and print() to compute the “informal”...
Files Opening files using the with statement is recommended because it ensures that the file is automatically closed at the ends of the with the statement. Exceptions Standard exceptions and users exceptions It’s better to catch and work with the specific exception try/except could include: else, that will be executed if no exception occurred finally, will be executed no matter what...
Inheritance A Derived class inherits from a Base class and is a specialized version of Base. It allows defining a class that inherits all the methods and properties of another class. The syntax for a subclass definition looks like this: Super() function will make the child class inherit all the methods and properties from its parent: Example: Pet is a Base...
My previous post “Python and ISE Monitor Mode” was about how to collect access-session information from the switch and use it for endpoint verification. Specifically for MAB-only devices – add in the proper Endpoint Group in the Cisco ISE. The result of the script was the file with “failed” devices: With this info, we had to log in to the ISE...
There are several ways to run ISE (wired) in monitor mode and AuthZ results: dACL, another VLAN, etc. It is always a good idea 🙂 to run ISE in monitor mode first to verify everything is working and then pull the trigger and change it to the production and actually enforce the policy. What We Need and What We Want Cisco...
Everything is a object in Python. the simplest class in Python: Class and Instance Attributes Class attributes are attributes that are owned by the class itself. Instance attributes are owned by the specific instances of a class Dynamically created attributes for existing instances of a class – not the way to properly create instance attributes, but an option. Python checks first,...
Dictionaries Dictionary – a collection of keys and values, unordered, changeable and indexed. Dictionary comprehensions Creating a dictionary from the list of keys with default value: Dictionary from list of keys and list of values: get(<key>,<value if does not exist>) If we try to get value from the non-existing key, KeyError Exception will be raise. To avoid the crush because of...
It is not about range feature:) After my post about how to get into the switch with “not sure” credentials, let’s assume you fixed access and configured devices with TACACS and SSH. It’s time to drop the interface-level config for ISE NAC (as an example) to all user ports, servers/wireless/trunk must be excluded. With proper segmentation using VLANs, we should have...
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