config.py

import json
import logging
import re

import jsonschema

CONFIG_SCHEMA = {
    "$schema": "http://json-schema.org/draft-07/schema#",
    "type": "object",
    "properties": {
        "alarms-db": {
            "type": "object",
            "properties": {
                "hostname": {"type": "string"},
                "dbname": {"type": "string"},
                "username": {"type": "string"},
                "password": {"type": "string"}
            },
            "required": ["hostname", "dbname", "username", "password"],
            "additionalProperties": False
        },
        "oid_list.conf": {"type": "string"},
        "routers_community.conf": {"type": "string"},
        "ssh": {
            "type": "object",
            "properties": {
                "private-key": {"type": "string"},
                "known-hosts": {"type": "string"}
            },
            "required": ["private-key", "known-hosts"],
            "additionalProperties": False
        }
    },
    "required": ["alarms-db", "oid_list.conf", "routers_community.conf"],
    "additionalProperties": False
}


def _load_oids(config_file):
    """
    :param config_file: file-like object
    :return:
    """
    result = {}
    for line in config_file:
        m = re.match(r'^([^=]+)=(.*)\s*$', line)
        if m:
            result[m.group(1)] = m.group(2)
    return result


def _load_routers(config_file):
    """
    :param config_file: file-like object
    :return:
    """
    for line in config_file:
        m = re.match(
            r'^([a-z\d]+\.[a-z\d]{3,4}\.[a-z\d]{2}'
            r'\.(geant|eumedconnect)\d*\.net)\s*=([^,]+)\s*,(.*)\s*$',
            line)
        if not m:
            logging.warning("malformed config file line: '%s'" % line.strip())
            continue
        yield {
            "hostname": m.group(1),
            "community": m.group(3),
            "address": m.group(4)
        }


def load(f):
    """
    loads, validates and returns configuration parameters

    :param f: file-like object that produces the config file
    :return:
    """
    config = json.loads(f.read())
    jsonschema.validate(config, CONFIG_SCHEMA)
    with open(config["oid_list.conf"]) as f:
        config["oids"] = _load_oids(f)
    with open(config["routers_community.conf"]) as f:
        config["routers"] = list(_load_routers(f))
    return config