XMLParser

This extractor will read an XML an extract data from it.

To illustrate the examples below we will use the following configuration:

<configuration>
    <interfaces>
        <interface>
            <name>ge-0/0/0</name>
            <description>adasdasd</description>
        </interface>
        <interface>
            <name>lo0</name>
            <disable/>
        </interface>
    </interfaces>
</configuration>

List - xpath

Advances in the XML document up to the point where the relevant list of elements is found.

Arguments:

  • xpath (mandatory): elements to traverse
  • key (mandatory): which element is the key of the list

Example:

Starting from the root, the following action will move us to interface so we can parse each interface individually:

interface:
    _process:
        mode: xpath
        xpath: "interfaces/interface"
        key: name
        from: "{{ bookmarks.interfaces }}"

This means after this action we will have a list of interface blocks like this:

- <interface>
    <name>ge-0/0/0</name>
    <description>adasdasd</description>
  </interface>
- <interface>
    <name>lo0</name>
    <disable/>
  </interface>

And we will be able to keep processing them individually.

Leaf - xpath

Extracts a value from an element.

Arguments:

  • xpath (mandatory): element to extract
  • regexp (optional): Apply regexp to the value of the element. Must capture value group. See “leaf - map” example for more details.
  • default (optional): Set this value if no element is found.
  • attribute (optional): Instead of the text of the element extracted, extract this attribute of the element.

Example:

For each interface, read the element description and map it into the object:

description:
    _process:
        mode: xpath
        xpath: description
        from: "{{ bookmarks['parent'] }}"

Leaf - value

Apply a user-defined value to the object.

Arguments:

  • value (mandatory): What value to apply

Example:

In the following example we can assign a value we already have to the interface.name attribute:

name:
    _process:
        mode: value
        value: "{{ interface_key }}"

Leaf - map

Extract value and do a lookup to choose value.

Arguments:

  • xpath (mandatory): Same as xpath action.
  • regexp (optional): Same as xpath action.
  • map (mandatory): Dictionary where we will do the lookup action.

Example:

We can read an element, extract some information and then apply the lookup function, for example, we can read the interface name, extract some of the first few characters and figure out the type of interface like this:

type:
    _process:
        mode: map
        xpath: name
        regexp: "(?P<value>[a-z]+).*"
        from: "{{ bookmarks['parent'] }}"
        map:
            ge: ethernetCsmacd
            lo: softwareLoopback
            ae: ieee8023adLag

The regular expression will give ge and lo which we can map into ethernetCsmacd and ieee8023adLag respectively.

Leaf - is_absent

Works exactly like xpath but if the evaluation is None, it will return True.

Example:

We could check if an interface is enabled with this:

enabled:
    _process:
        mode: is_absent
        xpath: "disable"
        from: "{{ bookmarks['parent'] }}"

As disable is missing in the interface ge-0/0/0 we know it’s enabled while lo0 will be not as it was present.

Leaf - is_present

Works exactly like xpath but if the evaluation is None, it will return False.