inventory.py

import logging
import random

import jsonschema
import requests

logger = logging.getLogger(__name__)

# minimal inventory response schema for our purposes
INVENTORY_VERSION_SCHEMA = {
    '$schema': 'https://json-schema.org/draft/2020-12/schema',

    'definitions': {
        'latch': {
            'type': 'object',
            'properties': {
                'timestamp': {'type': 'number'}
            },
            'required': ['timestamp'],
            'additionalProperties': True
        }
    },

    'type': 'object',
    'properties': {
        'latch': {'$ref': '#/definitions/latch'}
    },
    'required': ['latch'],
    'additionalProperties': True
}

# minimal inventory response schema for our purposes
INVENTORY_INTERFACES_SCHEMA = {
    '$schema': 'https://json-schema.org/draft/2020-12/schema',

    'definitions': {
        'interface': {
            'type': 'object',
            'properties': {
                'router': {'type': 'string'},
                'name': {'type': 'string'},
            },
            'required': ['router', 'name'],
        }
    },

    'type': 'array',
    'items': {'$ref': '#/definitions/interface'}
}


# minimal inventory response schema for our purposes
GWS_DIRECT_SCHEMA = {
    '$schema': 'https://json-schema.org/draft/2020-12/schema',

    'definitions': {
        'interface-counters': {
            'type': 'object',
            'properties': {
                'nren': {'type': 'string'},
                'isp': {'type': 'string'},
                'hostname': {'type': 'string'},
                'tag': {'type': 'string'},
            },
            'required': ['nren', 'isp', 'hostname', 'tag']
        }
    },

    'type': 'array',
    'items': {'$ref': '#/definitions/interface-counters'}
}

GWS_INDIRECT_SCHEMA = {
    '$schema': 'https://json-schema.org/draft/2020-12/schema',

    'definitions': {
        'service': {
            'type': 'object',
            'properties': {
                # minimal validation for our purposes
                'name': {'type': 'string'},
                'hostname': {'type': 'string'}
            },
            'required': ['name', 'hostname']
        }
    },

    'type': 'array',
    'items': {'$ref': '#/definitions/service'}
}


# much less strict version of the actual schema
MULTICAST_SUBSCRIPTION_LIST_SCHEMA = {
    '$schema': 'https://json-schema.org/draft/2020-12/schema',

    'definitions': {
        'subscription': {
            'type': 'object',
            'properties': {
                # we really only use this field
                # don't depend strictly on unused data
                'router': {'type': 'string'}
            },
            'required': ['router']
        }
    },

    'type': 'array',
    'items': {'$ref': '#/definitions/subscription'}
}


def _pick_one(haystack):
    if not isinstance(haystack, (list, tuple, set)):
        haystack = [haystack]
    return random.choice(haystack)


def _load_inventory_json(api_route, base_urls, schema):
    """
    Load & decode the specified inventory api data

    :param api_route: the api-specific handler route
    :param base_urls: inventory provider base api url, or a list of them
    :param schema: jsonschema to validate the response against
    :return: the decoded json reponse
    """
    url = _pick_one(base_urls)
    logger.debug(f'using inventory base api url: {url}')

    rsp = requests.get(
        f'{url}/{api_route}',
        headers={'Accept': 'application/json'})
    rsp.raise_for_status()

    result = rsp.json()
    jsonschema.validate(result, schema)
    return result


def load_interfaces(base_urls):
    """
    Load /poller/interfaces from inventory provider
    and return a slightly reformatted dict.

    :param base_urls: inventory provider base api url, or a list of them
    :return: a list (INVENTORY_INTERFACES_SCHEMA)
    """
    return _load_inventory_json(
        'poller/interfaces', base_urls, INVENTORY_INTERFACES_SCHEMA)


def load_gws_direct_interfaces(base_urls):
    """
    Load /poller/gws/direct from inventory provider

    :param base_urls: inventory provider base api url, or a list of them
    :return: an interable of interface-specific check data
    """
    return _load_inventory_json(
        'poller/gws/direct', base_urls, GWS_DIRECT_SCHEMA)


def load_gws_indirect_services(base_urls):
    """
    Load /poller/gws/indirect from inventory provider

    :param base_urls: inventory provider base api url, or a list of them
    :return: an iterable of strings (service names)
    """
    return _load_inventory_json(
        'poller/gws/indirect', base_urls, GWS_INDIRECT_SCHEMA)


def load_eumetsat_multicast_subscriptions(base_urls):
    """
    Load /poller/eumetsat-multicast from inventory provider

    :param base_urls: inventory provider base api url, or a list of them
    :return: a list of dicts, each with a 'router' key
    """
    return _load_inventory_json(
        'poller/eumetsat-multicast',
        base_urls,
        MULTICAST_SUBSCRIPTION_LIST_SCHEMA)


def last_update_timestamp(base_urls) -> float:
    try:
        r = requests.get(
            f'{_pick_one(base_urls)}/version',
            headers={'Accept': 'application/json'})
        r.raise_for_status()

        result = r.json()
        jsonschema.validate(result, INVENTORY_VERSION_SCHEMA)
        return result['latch']['timestamp']
    except (IOError, jsonschema.ValidationError, ValueError):
        logger.exception('connection error')
        return None