seisokeii/nornir_jinja2

Jinja2 plugins for nornir with formatting feature

nornir_jinja2

Collection of simple plugins for nornir

Installation

pip install nornir-jinja2

Plugins

Tasks

• template_file - Render a jinja2 template from a file
• template_string Render a jinja2 template from a string

Usage

Arguments:

• template (str): The filename of the Jinja2 template.
• path (str): The path to the directory where Jinja2 template is located.
• jinja_filters (dict, optional): A dictionary of custom Jinja2 filters for data manipulation within the template.
• jinja_env (jinja2.Environment, optional): A custom Jinja2 environment object for more fine-grained template control.
• formatFunc (callable, optional): A formatting function to post-process the rendered results.

Detailed Parameter Explanations

template (str)

• Purpose: Specifies the Jinja2 template file that defines the structure and content of the rendered result.

path (str)

• Purpose: Specifies the directory where the Jinja2 template file is located.

jinja_filters (dict, optional)

• Purpose: Provides custom Jinja2 filters for transforming or formatting data within the template.

jinja_env (jinja2.Environment, optional)

• Purpose: Provides a custom Jinja2 environment for configuring template loaders, syntax options, etc.

formatFunc (callable, optional)

• Purpose: Post-processes the rendered results, e.g., formatting them as XML, JSON, or other formats to make develop easier.

Example

In Nornir main script, use below code for example:

result = task.run(
    task="NXOS VLAN",
    template="vlan.j2",
    path="./templates/NXOS/features",
    jinja_filters={"rep": jinja_replacement},
    formatFunc=format_xml
)

In the Jinja2 template, you can use the filter as below:

{% set vlan = host.facts.VLAN %}
{% for key, value in vlan.items() %}
    {% if key == "vlan_id" %}
        <{{ key | rep }}>vlan-{{ value }}</{{ key | rep }}>
    {% else %}
        <{{ key | rep }}>{{ value }}</{{ key | rep }}>
    {% endif %}
{% endfor %}

To use replacement filter, you can define a function as below in the Nornir main script or somewhere else:

def jinja_replacement(s):
   f = open("./script/NXOS/replacement.json")
   rep = json.load(f)
   f.close()

   for key, value in rep.items():
       s = s.replace(key, value)
   return s

In replacement.json file, you can define the key value pairs as below:

{
    "description": "descr",
    "vlan_id": "fabEncap",
    "interface-vlan": "ifvlan"
}

To use format function, you can define a function as below in the Nornir main script:

def format_json(text: str) -> str:
    try:
        json.loads(text)
    except ValueError as e:
        return text

    reform = json.dumps(json.loads(text), indent=4)

    return reform


def format_xml(text: str) -> str:
    try:
        elementTree.fromstring(text)
    except elementTree.ParseError as e:
        return text

    reform = minidom.parseString(text).toprettyxml(indent="      ")
    reform = re.sub(r'^<\?xml.*?\?>', '', reform).strip()
    reform = re.sub(r'\n\s*\n', '\n', reform)
    reform = re.sub(r'&quot;', '"', reform)

    return reform