jdiff not ble to catch reference key in dict of dicts

[lvrfrc87]

Environment

• Python version: 3.7
• jdiff version: 0.0.2

Expected Behavior

As it stands now, jdiff can catch a reference key only in a list of dictionary. There are case where NAPALM returns dict of dicts. In the example below, we want .local. and .local..0 to be the ref key of is_up

{
  ".local.": {
    "description": "",
    "is_enabled": true,
    "is_up": true,
    "last_flapped": -1,
    "mac_address": "Unspecified",
    "mtu": 0,
    "speed": -1
  },
  ".local..0": {
    "description": "",
    "is_enabled": true,
    "is_up": true,
    "last_flapped": -1,
    "mac_address": "Unspecified",
    "mtu": 0,
    "speed": -1
  },
}

@pszulczewski FYI

[lvrfrc87]

I believe this could be a limitation from JMSPATH. The most similar case I found is this one:https://jmespath.org/tutorial.html#object-projections

As we can see, the our hypothetical reference key is lost using *. I will drop a message on jmspath channel support but I feel that the user will have to do some post parsing using indexes

[lvrfrc87]

Looks like there is keys(@) which catches all dict keys. So in jdiff the path should be something like $keys(@)$.is_up and should work. @pszulczewski FYI

[pszulczewski]

keys(@) produce list of keys, similar to python dict.keys(), they don't have access to values.

Thus keys(@).is_up or $keys(@)$.is_up return None.

[lvrfrc87]

At this point we have 3 options:

• Let the user use index to create a mapping between key and value got from jdiff - this will not work out of the box with pre defined checks
• Make jdiff dynamically discovery the data type and act accordingly - for this case the expression would be something like $*$.is_up
• Create some sort of flag

[lvrfrc87]

As discussed with @pszulczewski we will support $*$.is_up and interpolate the list of keys with the list of values returned.