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Lab 09 - Exploring Nested Objects

The goal of this lab is to explore complex data structures which are encountered very often when working within the realm of automation - structured data comes from APIs, can be saved to disk, or specify configuration, and can even be the output of CLI commands.

Task 1 - Nested Dictionary Objects

Step 1-1

Create a variable called facts_list that has the following value:

>>> facts_list = [{'customer': 'acme', 'vendor': 'arista', 'hostname': 'APAC1', 'location': 'Sydney', 'device_type': 'switch', 'model': '7050', 'os': 'eos'}, {'customer': 'acme', 'vendor': 'juniper', 'hostname': 'EMEA1', 'location': 'London', 'device_type': 'switch', 'model': 'mx', 'os': 'junos'}, {'customer': 'acme', 'vendor': 'cisco', 'hostname': 'nycr01', 'location': 'new_york', 'device_type': 'switch', 'model': 'catalyst', 'os': 'ios'}]

Step 1-2

Pretty print facts_list by using json.dumps:

>>> import json
>>>
>>> print(json.dumps(facts_list, indent=4))
[
    {
        "customer": "acme",
        "vendor": "arista",
        "hostname": "APAC1",
        "location": "Sydney",
        "device_type": "switch",
        "model": "7050",
        "os": "eos"
    },
    {
        "customer": "acme",
        "vendor": "juniper",
        "hostname": "EMEA1",
        "location": "London",
        "device_type": "switch",
        "model": "mx",
        "os": "junos"
    },
    {
        "customer": "acme",
        "vendor": "cisco",
        "hostname": "nycr01",
        "location": "new_york",
        "device_type": "switch",
        "model": "catalyst",
        "os": "ios"
    }
]
>>>

Step 1-3

Can you tell this is a list of dictionaries?

  • You can tell this visually by seeing the object start with square brackets.
  • You can also do a type check!

Step 1-4

Do a type check on facts_list:

>>> type(facts_list)
<class 'list'>
>>>

We now know it's a list, but what is it a list of? Generally speaking, you wouldn't have a list of different data types. We'll make the assumption every element is of the same data type for now.

Step 1-5

First, do a length check of facts_list:

>>> len(facts_list)
3
>>>

You know there are 3 elements now. Let's check the first one.

Step 1-6

Check the data type of the first element in the list.

>>> type(facts_list[0])
<class 'dict'>
>>>

OR

>>> first = facts_list[0]
>>>
>>> type(first)
<class 'dict'>
>>>

We can tell now that this object is a list of dictionaries.

Step 1-7

Our goal is to print out the "location" of the "APAC1" device.

To do this, you will need to reference the visual print out and see that it's the first element or the element that has an index value of zero.

First, print out the whole first element:

>>> print(facts_list[0])
{'customer': 'acme', 'vendor': 'arista', 'hostname': 'APAC1', 'location': 'Sydney', 'device_type': 'switch', 'model': '7050', 'os': 'eos'}
>>>

Step 1-8

You can see that a dictionary is returned since the element begins with curly brackets. Let's print out the location.

>>> print(facts_list[0]['location'])
Sydney
>>>

Notice how we have [0] and ['location'] in the same print statement. You need to be very careful and understand the data type for each element inside a nested object.

Let's continue to build onto this.

Step 1-9

Create two new dictionary objects that depict the attributes of neighbor devices and then print them out.

>>> neighbor1 = {'neighbor_interface': 'Eth1/2', 'local_interface': 'Eth1/1', 'neighbor': 'R1'}
>>>
>>> neighbor2 = {'neighbor_interface': 'Eth1/4', 'local_interface': 'Eth1/2', 'neighbor': 'R2'}
>>>

Step 1-10

Create a list that is comprised of these neighbors.

>>> neighbors = [neighbor1, neighbor2]
>>>

Step 1-11

Print neighbors to see the newly formed list:

>>> print(neighbors)
[{'neighbor_interface': 'Eth1/2', 'local_interface': 'Eth1/1', 'neighbor': 'R1'}, {'neighbor_interface': 'Eth1/4', 'local_interface': 'Eth1/2', 'neighbor': 'R2'}]
>>>

Now pretty print them:

>>> print(json.dumps(neighbors, indent=4))
[
    {
        "neighbor_interface": "Eth1/2",
        "local_interface": "Eth1/1",
        "neighbor": "R1"
    },
    {
        "neighbor_interface": "Eth1/4",
        "local_interface": "Eth1/2",
        "neighbor": "R2"
    }
]
>>>

Remember to always pretty print complex objects as it makes them much easier to read.

Nothing new yet - you just created an isolated list of two dictionaries that represent neighbors of a given device.

Step 1-12

These neighbors created are the simulated neighbors of "APAC1" which is the device in facts_list[0], i.e. the first element of facts_list.

Now add the neighbors list as a key/value pair in the dictionary that APAC1 is currently part of. Use the neighbors key.

>>> facts_list[0]['neighbors'] = neighbors
>>>

Think about this:

  • facts_list is a list of dictionaries.
  • facts_list[0] is a dictionary.
  • We know to add key-value pairs to a dictionary, we use:
    • dict["key"] = "value"

Knowing the above, we can add the new key called neighbors and assign it the value of the variable that just happens to also be called neighbors.

Step 1-13

Pretty print the facts_list to see the newly updated dictionary.

>>> print(json.dumps(facts_list, indent=4))
[
    {
        "customer": "acme",
        "vendor": "arista",
        "hostname": "APAC1",
        "location": "Sydney",
        "device_type": "switch",
        "model": "7050",
        "os": "eos",
        "neighbors": [
            {
                "neighbor_interface": "Eth1/2",
                "local_interface": "Eth1/1",
                "neighbor": "R1"
            },
            {
                "neighbor_interface": "Eth1/4",
                "local_interface": "Eth1/2",
                "neighbor": "R2"
            }
        ]
    },
    {
        "customer": "acme",
        "vendor": "juniper",
        "hostname": "EMEA1",
        "location": "London",
        "device_type": "switch",
        "model": "mx",
        "os": "junos"
    },
    {
        "customer": "acme",
        "vendor": "cisco",
        "hostname": "nycr01",
        "location": "new_york",
        "device_type": "switch",
        "model": "catalyst",
        "os": "ios"
    }
]
>>>

This gives you a better look at the complete object. Notice how nested this object became now?

Step 1-14

Now print just the hostname of the second neighbor of "APAC1".

>>> print(facts_list[0]['neighbors'][1]['neighbor'])
R2
>>>

Take your time to ensure you understand how we are accessing "R2".

Task 2 - Work with a Nested Facts Dictionary Object

Understanding nested lists and dictionary objects are very important to use network APIs as you'll often get back a list of dictionaries for interfaces and neighbors, as an example.

In this task, we'll walk through a more gradual process helpful with parsing complex nested objects.

Step 2-1

Start a new Python shell and import the json module.

ntc@ntc-training:~$ python
Python 3.8.12 (default, Oct 13 2021, 09:22:51)
[GCC 8.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import json
>>>

Step 2-2

Create a new variable called content and assign the following object like so:

>>> content = {'output': {'ansible_facts': {'fan_info': [{'status': 'Ok', 'model': None, 'hw_ver': '0.0', 'name': 'ChassisFan1'}, {'status': 'None', 'model': None, 'hw_ver': '0.0', 'name': 'ChassisFan2'}, {'status': 'Ok', 'model': '--', 'hw_ver': '--', 'name': 'Fan_in_PS1'}, {'status': 'Failure', 'model': '--', 'hw_ver': '--', 'name': 'Fan_in_PS2'}], 'ansible_net_model': 'NX-OSv Chassis', 'ansible_net_interfaces': {'Ethernet2/13': {'macaddress': '2cc2.604f.feb2', 'state': 'down', 'mode': 'routed', 'duplex': 'auto', 'speed': 'auto-speed', 'type': 'Ethernet', 'bandwidth': 1000000, 'mtu': '1500'}, 'Ethernet2/12': {'macaddress': '2cc2.604f.feb2', 'state': 'down', 'mode': 'routed', 'duplex': 'auto', 'speed': 'auto-speed', 'type': 'Ethernet', 'bandwidth': 1000000, 'mtu': '1500'}, 'Ethernet2/11': {'macaddress': '2cc2.604f.feb2', 'state': 'down', 'mode': 'routed', 'duplex': 'auto', 'speed': 'auto-speed', 'type': 'Ethernet', 'bandwidth': 1000000, 'mtu': '1500'}, 'Ethernet2/10': {'macaddress': '2cc2.604f.feb2', 'state': 'down', 'mode': 'routed', 'duplex': 'auto', 'speed': 'auto-speed', 'type': 'Ethernet', 'bandwidth': 1000000, 'mtu': '1500'}, 'Ethernet2/15': {'macaddress': '2cc2.604f.feb2', 'state': 'down', 'mode': 'routed', 'duplex': 'auto', 'speed': 'auto-speed', 'type': 'Ethernet', 'bandwidth': 1000000, 'mtu': '1500'}, 'Ethernet2/14': {'macaddress': '2cc2.604f.feb2', 'state': 'down', 'mode': 'routed', 'duplex': 'auto', 'speed': 'auto-speed', 'type': 'Ethernet', 'bandwidth': 1000000, 'mtu': '1500'}, 'Ethernet2/1': {'macaddress': '2cc2.604f.feb2', 'state': 'up', 'mode': 'routed', 'duplex': 'full', 'speed': '1000 Mb/s', 'type': 'Ethernet', 'bandwidth': 1000000, 'mtu': '1500'}}, 'ansible_net_all_ipv4_addresses': ['10.0.0.71'], 'ansible_net_hostname': 'nxos-spine1', 'hostname': 'nxos-spine1', 'ansible_net_serialnum': 'TM6017D760B', 'interfaces_list': ['mgmt0', 'Ethernet2/1', 'Ethernet2/2', 'Ethernet2/3', 'Ethernet2/4', 'Ethernet2/5', 'Ethernet2/6', 'Ethernet2/7', 'Ethernet2/8', 'Ethernet2/9', 'Ethernet2/10', 'Ethernet2/11', 'Ethernet2/12', 'Ethernet2/13', 'Ethernet2/14', 'Ethernet2/15'], 'ansible_net_gather_subset': ['hardware', 'default', 'interfaces', 'legacy'], 'power_supply_info': [{'status': 'Ok', 'model': 'DS-CAC-845W', 'number': 1}, {'status': 'Absent', 'model': '------------', 'number': 2}], 'platform': 'NX-OSv Chassis', 'ansible_net_version': '7.3(1)D1(1) [build 7.3(1)D1(0.10)]', 'module': [{'status': 'active *', 'model': 'N7K-SUP1', 'type': 'NX-OSv Supervisor Module', 'ports': 0}, {'status': 'ok', 'model': 'N7K-F248XP-25', 'type': 'NX-OSv Ethernet Module', 'ports': 48}, {'status': 'ok', 'model': 'N7K-F248XP-25', 'type': 'NX-OSv Ethernet Module', 'ports': 48}, {'status': 'ok', 'model': 'N7K-F248XP-25', 'type': 'NX-OSv Ethernet Module', 'ports': 48}], 'ansible_net_all_ipv6_addresses': [], 'ansible_net_memtotal_mb': 3908, 'ansible_net_filesystems': ['bootflash:'], 'ansible_net_image': 'bootflash:///titanium-d1.7.3.1.D1.0.10.bin', 'os': '7.3(1)D1(1) [build 7.3(1)D1(0.10)]', 'vlan_list': [1]}}}
>>>

Step 2-3

As you can see it's a very long and complex object. Let's simplify it and pretty print it.

>>> print(json.dumps(content, indent=4))
{
    "output": {
        "ansible_facts": {
            "fan_info": [
                {
                    "status": "Ok",
                    "model": null,
                    "hw_ver": "0.0",
                    "name": "ChassisFan1"
                },
                {
                    "status": "None",
                    "model": null,
                    "hw_ver": "0.0",
                    "name": "ChassisFan2"
                },
                {
                    "status": "Ok",
                    "model": "--",
                    "hw_ver": "--",
                    "name": "Fan_in_PS1"
                },
                {
                    "status": "Failure",
                    "model": "--",
                    "hw_ver": "--",
                    "name": "Fan_in_PS2"
                }
            ],
            "ansible_net_model": "NX-OSv Chassis",
            "ansible_net_interfaces": {
                "Ethernet2/13": {
                    "macaddress": "2cc2.604f.feb2",
                    "state": "down",
                    "mode": "routed",
                    "duplex": "auto",
                    "speed": "auto-speed",
                    "type": "Ethernet",
                    "bandwidth": 1000000,
                    "mtu": "1500"
                },
                "Ethernet2/12": {
                    "macaddress": "2cc2.604f.feb2",
                    "state": "down",
                    "mode": "routed",
                    "duplex": "auto",
                    "speed": "auto-speed",
                    "type": "Ethernet",
                    "bandwidth": 1000000,
                    "mtu": "1500"
                },
                "Ethernet2/11": {
                    "macaddress": "2cc2.604f.feb2",
                    "state": "down",
                    "mode": "routed",
                    "duplex": "auto",
                    "speed": "auto-speed",
                    "type": "Ethernet",
                    "bandwidth": 1000000,
                    "mtu": "1500"
                },
                "Ethernet2/10": {
                    "macaddress": "2cc2.604f.feb2",
                    "state": "down",
                    "mode": "routed",
                    "duplex": "auto",
                    "speed": "auto-speed",
                    "type": "Ethernet",
                    "bandwidth": 1000000,
                    "mtu": "1500"
                },
                "Ethernet2/15": {
                    "macaddress": "2cc2.604f.feb2",
                    "state": "down",
                    "mode": "routed",
                    "duplex": "auto",
                    "speed": "auto-speed",
                    "type": "Ethernet",
                    "bandwidth": 1000000,
                    "mtu": "1500"
                },
                "Ethernet2/14": {
                    "macaddress": "2cc2.604f.feb2",
                    "state": "down",
                    "mode": "routed",
                    "duplex": "auto",
                    "speed": "auto-speed",
                    "type": "Ethernet",
                    "bandwidth": 1000000,
                    "mtu": "1500"
                },
                "Ethernet2/1": {
                    "macaddress": "2cc2.604f.feb2",
                    "state": "up",
                    "mode": "routed",
                    "duplex": "full",
                    "speed": "1000 Mb/s",
                    "type": "Ethernet",
                    "bandwidth": 1000000,
                    "mtu": "1500"
                }
            },
            "ansible_net_all_ipv4_addresses": [
                "10.0.0.71"
            ],
            "ansible_net_hostname": "nxos-spine1",
            "hostname": "nxos-spine1",
            "ansible_net_serialnum": "TM6017D760B",
            "interfaces_list": [
                "mgmt0",
                "Ethernet2/1",
                "Ethernet2/2",
                "Ethernet2/3",
                "Ethernet2/4",
                "Ethernet2/5",
                "Ethernet2/6",
                "Ethernet2/7",
                "Ethernet2/8",
                "Ethernet2/9",
                "Ethernet2/10",
                "Ethernet2/11",
                "Ethernet2/12",
                "Ethernet2/13",
                "Ethernet2/14",
                "Ethernet2/15"
            ],
            "ansible_net_gather_subset": [
                "hardware",
                "default",
                "interfaces",
                "legacy"
            ],
            "power_supply_info": [
                {
                    "status": "Ok",
                    "model": "DS-CAC-845W",
                    "number": 1
                },
                {
                    "status": "Absent",
                    "model": "------------",
                    "number": 2
                }
            ],
            "platform": "NX-OSv Chassis",
            "ansible_net_version": "7.3(1)D1(1) [build 7.3(1)D1(0.10)]",
            "module": [
                {
                    "status": "active *",
                    "model": "N7K-SUP1",
                    "type": "NX-OSv Supervisor Module",
                    "ports": 0
                },
                {
                    "status": "ok",
                    "model": "N7K-F248XP-25",
                    "type": "NX-OSv Ethernet Module",
                    "ports": 48
                },
                {
                    "status": "ok",
                    "model": "N7K-F248XP-25",
                    "type": "NX-OSv Ethernet Module",
                    "ports": 48
                },
                {
                    "status": "ok",
                    "model": "N7K-F248XP-25",
                    "type": "NX-OSv Ethernet Module",
                    "ports": 48
                }
            ],
            "ansible_net_all_ipv6_addresses": [],
            "ansible_net_memtotal_mb": 3908,
            "ansible_net_filesystems": [
                "bootflash:"
            ],
            "ansible_net_image": "bootflash:///titanium-d1.7.3.1.D1.0.10.bin",
            "os": "7.3(1)D1(1) [build 7.3(1)D1(0.10)]",
            "vlan_list": [
                1
            ]
        }
    }
}
>>>

Step 2-4

You can see that content is a dictionary with a single key called output, and multiple levels of nested objects. Take some time to read through the structured data.

Step 2-5

After visually seeing it, we'll prove it.

Print its length using the len() function.

>>> len(content)
1
>>>

This confirms that the outer dictionary is composed of only one "root" key. In other words, there is only ONE item - one item means, one key and one value. The value just happens to be a very nested object.

Step 2-6

Verify the single key of the dictionary by using the keys method.

>>> print(content.keys())
dict_keys(['output'])
>>>

This is exactly what we said in Step 4.

Step 2-7

Let's extract the value of the output key by now saving it into a new variable called output.

>>> output = content['output']
>>>

You can repeat the steps 5 - 7 for every element in this object.

Check the data type and check the length. If it's a list, you'll need to extract the value using an index (integer) value. If it's a dictionary, you'll need to supply a key to extract the value, and remember, you can see all available keys by using the keys() method.

This workflow can be repeated until you get to the data you're looking for.

Let's try it.

>>> type(output)
<class 'dict'>
>>>

Now that you know it's a dictionary, print the keys.s

>>> print(output.keys())
dict_keys(['ansible_facts'])
>>>

Let's continue and print output.

Step 2-8

Pretty print the new variable called output.

>>> print(json.dumps(output, indent=4))
{
    "ansible_facts": {
        "fan_info": [
            {
                "status": "Ok",
                "model": null,
                "hw_ver": "0.0",
                "name": "ChassisFan1"
            },
            {
                "status": "None",
                "model": null,
                "hw_ver": "0.0",
                "name": "ChassisFan2"
            },
            {
                "status": "Ok",
                "model": "--",
                "hw_ver": "--",
                "name": "Fan_in_PS1"
            },
            {
                "status": "Failure",
                "model": "--",
                "hw_ver": "--",
                "name": "Fan_in_PS2"
            }
        ],
        "ansible_net_model": "NX-OSv Chassis",
        "ansible_net_interfaces": {
            "Ethernet2/13": {
                "macaddress": "2cc2.604f.feb2",
                "state": "down",
                "mode": "routed",
                "duplex": "auto",
                "speed": "auto-speed",
                "type": "Ethernet",
                "bandwidth": 1000000,
                "mtu": "1500"
            },
            "Ethernet2/12": {
                "macaddress": "2cc2.604f.feb2",
                "state": "down",
                "mode": "routed",
                "duplex": "auto",
                "speed": "auto-speed",
                "type": "Ethernet",
                "bandwidth": 1000000,
                "mtu": "1500"
            },
            "Ethernet2/11": {
                "macaddress": "2cc2.604f.feb2",
                "state": "down",
                "mode": "routed",
                "duplex": "auto",
                "speed": "auto-speed",
                "type": "Ethernet",
                "bandwidth": 1000000,
                "mtu": "1500"
            },
            "Ethernet2/10": {
                "macaddress": "2cc2.604f.feb2",
                "state": "down",
                "mode": "routed",
                "duplex": "auto",
                "speed": "auto-speed",
                "type": "Ethernet",
                "bandwidth": 1000000,
                "mtu": "1500"
            },
            "Ethernet2/15": {
                "macaddress": "2cc2.604f.feb2",
                "state": "down",
                "mode": "routed",
                "duplex": "auto",
                "speed": "auto-speed",
                "type": "Ethernet",
                "bandwidth": 1000000,
                "mtu": "1500"
            },
            "Ethernet2/14": {
                "macaddress": "2cc2.604f.feb2",
                "state": "down",
                "mode": "routed",
                "duplex": "auto",
                "speed": "auto-speed",
                "type": "Ethernet",
                "bandwidth": 1000000,
                "mtu": "1500"
            },
            "Ethernet2/1": {
                "macaddress": "2cc2.604f.feb2",
                "state": "up",
                "mode": "routed",
                "duplex": "full",
                "speed": "1000 Mb/s",
                "type": "Ethernet",
                "bandwidth": 1000000,
                "mtu": "1500"
            }
        },
        "ansible_net_all_ipv4_addresses": [
            "10.0.0.71"
        ],
        "ansible_net_hostname": "nxos-spine1",
        "hostname": "nxos-spine1",
        "ansible_net_serialnum": "TM6017D760B",
        "interfaces_list": [
            "mgmt0",
            "Ethernet2/1",
            "Ethernet2/2",
            "Ethernet2/3",
            "Ethernet2/4",
            "Ethernet2/5",
            "Ethernet2/6",
            "Ethernet2/7",
            "Ethernet2/8",
            "Ethernet2/9",
            "Ethernet2/10",
            "Ethernet2/11",
            "Ethernet2/12",
            "Ethernet2/13",
            "Ethernet2/14",
            "Ethernet2/15"
        ],
        "ansible_net_gather_subset": [
            "hardware",
            "default",
            "interfaces",
            "legacy"
        ],
        "power_supply_info": [
            {
                "status": "Ok",
                "model": "DS-CAC-845W",
                "number": 1
            },
            {
                "status": "Absent",
                "model": "------------",
                "number": 2
            }
        ],
        "platform": "NX-OSv Chassis",
        "ansible_net_version": "7.3(1)D1(1) [build 7.3(1)D1(0.10)]",
        "module": [
            {
                "status": "active *",
                "model": "N7K-SUP1",
                "type": "NX-OSv Supervisor Module",
                "ports": 0
            },
            {
                "status": "ok",
                "model": "N7K-F248XP-25",
                "type": "NX-OSv Ethernet Module",
                "ports": 48
            },
            {
                "status": "ok",
                "model": "N7K-F248XP-25",
                "type": "NX-OSv Ethernet Module",
                "ports": 48
            },
            {
                "status": "ok",
                "model": "N7K-F248XP-25",
                "type": "NX-OSv Ethernet Module",
                "ports": 48
            }
        ],
        "ansible_net_all_ipv6_addresses": [],
        "ansible_net_memtotal_mb": 3908,
        "ansible_net_filesystems": [
            "bootflash:"
        ],
        "ansible_net_image": "bootflash:///titanium-d1.7.3.1.D1.0.10.bin",
        "os": "7.3(1)D1(1) [build 7.3(1)D1(0.10)]",
        "vlan_list": [
            1
        ]
    }
}

Step 2-9

This is again a dictionary of one root key, ansible_facts, whose value is still a dictionary, which you saw in Step 8 by printing all keys of output. You could verify it with len() too.

Repeat the step by step process as necessary in order to print just the value of the fan_info key.

>>> print(json.dumps(output['ansible_facts']['fan_info'], indent=4))
[
    {
        "status": "Ok",
        "model": null,
        "hw_ver": "0.0",
        "name": "ChassisFan1"
    },
    {
        "status": "None",
        "model": null,
        "hw_ver": "0.0",
        "name": "ChassisFan2"
    },
    {
        "status": "Ok",
        "model": "--",
        "hw_ver": "--",
        "name": "Fan_in_PS1"
    },
    {
        "status": "Failure",
        "model": "--",
        "hw_ver": "--",
        "name": "Fan_in_PS2"
    }
]
>>>

Step 2-10

This time the value is not a dictionary but a list of four dictionaries. You can see that it's a list visually because the value starts with a [ and ends with a ].

But you can also verify using the following type function statement.

>>> print(type(output['ansible_facts']['fan_info']))
<class 'list'>
>>>

Since it's a list, we need to supply an index value.

Step 2-11

Print the second dictionary in this list.

>>> print(json.dumps(output['ansible_facts']['fan_info'][1], indent=4))
{
    "status": "None",
    "model": null,
    "hw_ver": "0.0",
    "name": "ChassisFan2"
}
>>>

Step 2-12

Store the value of the name key ("ChassisFan2") into a new variable called fan_name.

Finally, print the variable called fan_name.

>>> fan_name = output['ansible_facts']['fan_info'][1]['name']
>>>
>>> print(fan_name)
ChassisFan2
>>>

Step 2-13 - Challenge!

Now print the list of all interfaces found under the ansible_net_interfaces key. Only print the interface names - do not print their values.

Use a dictionary built-in method to accomplish this.

Continue scrolling for the solution

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>>> interfaces = output['ansible_facts']['ansible_net_interfaces']
>>> print(interfaces.keys())
dict_keys(['Ethernet2/13', 'Ethernet2/12', 'Ethernet2/11', 'Ethernet2/10', 'Ethernet2/15', 'Ethernet2/14', 'Ethernet2/1'])

Step 2-14 - Challenge!

Print output again.

Take a deeper look at its format and focus on the ansible_net_interfaces key. This is another nested dictionary.

Store the "Ethernet2/11" MAC address value in a variable called mac and print it.

Continue scrolling for the solution

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>>> mac = output['ansible_facts']['ansible_net_interfaces']['Ethernet2/11']['macaddress']
>>> print(mac)
2cc2.604f.feb2
>>>

Task 3 - Handle VLAN Objects

Step 3-1

Create a new variable called vlans that contains the following object:

vlans = {
    "output": {
        "proposed": {
            "name": "NTC"
        },
        "existing_vlans_list": [
            "1"
        ],
        "end_state_vlans_list": [
            "1",
            "100"
        ],
        "existing": {},
        "updates": [
            "vlan 100",
            "name NTC",
            "exit"
        ],
        "end_state": {
            "vlan_state": "active",
            "mapped_vni": "",
            "admin_state": "up",
            "name": "NTC",
            "vlan_id": "100"
        },
        "proposed_vlans_list": [
            "100"
        ]
    }
}

This is a nested dictionary with just one outer key, output.

Step 3-2

Search for existing_vlans_list and proposed_vlans_list keys and store their values into existing_vlans and proposed_vlans.

>>> existing_vlans = vlans['output']['existing_vlans_list']
>>> proposed_vlans = vlans['output']['proposed_vlans_list']
>>>

Step 3-3

Print both existing_vlans and proposed_vlans.

>>> print(existing_vlans)
['1']
>>> print(proposed_vlans)
['100']
>>>

These are two lists of one element each.

Step 3-4

Create a new variable called end_state_vlans and assign it the sum of existing_vlans and proposed_vlans and print the result.

>>> end_state_vlans = existing_vlans + proposed_vlans
>>>
>>> print(end_state_vlans)
['1', '100']
>>>

Step 3-5

Verify that end_state_vlans is equal to the end_state_vlans_list inner key from vlans dictionary.

>>> end_state_vlans == vlans['output']['end_state_vlans_list']
True
>>>

Step 3-6

You'll also find a key called updates in this VLAN object.

Print exactly and only the last command found in the updates list.

>>> print(vlans['output']['updates'][2])
exit
>>>

You could have also done this without knowing how many items are in the list:

>>> print(vlans['output']['updates'][-1])
exit
>>>

Python supports negative indexing and -1 is always the last element in the list. -2 is the second to last, and so on.

Conclusion

As you finish this lab, please take your time to go back and review it because understanding how to parse nested objects is critical to working with network APIs, Python, and also even in Ansible. If something doesn't make sense, please don't hesitate to ask.