restlosapi.py

#!/usr/bin/env python
# -*- coding: UTF-8 -*-

from flask import Flask, request, render_template, jsonify, abort
from flask import Request, Response
from flask.views import MethodView

from werkzeug.exceptions import HTTPException, InternalServerError
from werkzeug.exceptions import default_exceptions, BadRequest

from utils import Config
from utils.authentication import Authentify

from subprocess import check_output, CalledProcessError

from pynag import Model, Parsers
from json import dumps
from cgi import escape

import os
import logging
import logging.config

config = Config(os.path.join(os.path.dirname(__file__), 'config.json'))
VERSION="0.3"

class JSONHTTPException(HTTPException):
    """ JSONHTTPException: this exception provides a detailed error message
    if a json parsing error occures. More helpful that just the standard 400
    message which tells you that "something" is wrong
    """

    def get_body(self, environ):
        return dumps(dict(code=400, message=self.get_description(environ)))

    def get_headers(self, environ):
        return [('Content-Type', 'application/json')]


class JSONBadRequest(JSONHTTPException, BadRequest):
    description = ('The browser (or proxy) sent a request that this server could not understand.')


class CustomRequestClass(Request):
    def on_json_loading_failed(self, e):
        raise JSONBadRequest(str(e))


class ApiEndpoints(dict):
    """ ApiEndpoints: provides a dictionary for the available api endpoints.
    it also defines unique keys for the available nagios objects and some
    convenient functions for retrieving unique keys or validating object
    attributes.
    """

    main_cfg_values = {}

    def __init__(self):
        # create a map of valid endpoints/arguments
        for endpoint in Model.all_attributes.object_definitions.keys():
            self[endpoint] = Model.all_attributes.object_definitions[endpoint].keys()
            self[endpoint] += Model.all_attributes.object_definitions["any"]
        del self["any"]

        if not self.main_cfg_values:
            parser = Parsers.config(config['nagios_main_cfg'])
            parser.parse()
            self.main_cfg_values.update(dict(parser.maincfg_values))

        # set endpoint keys
        self.endpoint_keys = {
            'hostgroup':'hostgroup_name',
            'hostextinfo':'host_name',
            'host':'host_name',
            'service':'service_description',
            'servicegroup':'servicegroup_name',
            'contact':'contact_name',
            'contactgroup':'contactgroup_name',
            'timeperiod':'timeperiod_name',
            'command':'command_name',
        }

    def get_unique_key(self, endpoint):
        return self.endpoint_keys[endpoint]

    def validate(self, endpoint, data={}):
        for attr in data.keys():
            if not attr.startswith('_') and attr not in self[endpoint]:
                return {404: "unknown attribute: %s" % (attr, )}
            if attr == self.endpoint_keys[endpoint]:
                for illegal_char in self.main_cfg_values.get('illegal_object_name_chars', []):
                    if illegal_char in list(data[attr]):
                        if illegal_char == '*': continue # wildcards are allowed and will be stripped out
                        return {400: "illegal character (%s) found in attribute %s" % (illegal_char, attr)}
        return {200: "OK"}


class NagiosControlView(MethodView):
    """
    NagiosControlView: Provides a view function which is registered as an api
    endpoint as well. This '/control' endpoint provides convenient functions
    like reloading the core or verify the configuration
    """

    decorators = [Authentify(config['auth'])]

    def __init__(self, *args, **kwargs):
        MethodView.__init__(self, *args, **kwargs)

        try:
            self.command_file = Model.Control.Command.find_command_file(config['nagios_main_cfg'])
        except Exception, err:
            abort(500, 'unable to locate command file: %s' % (str(err), ))

        self.arguments = ['verify', 'restart']

    def _format(self, data):
        result = {'Error': [], 'Warning': [], 'Total Errors': [], 'Total Warnings': []}
        for line in data.split('\n'):
            for key in result.keys():
                if line.upper().startswith(key.upper()):
                    result[key].append(line[len(key)+1:].strip())

        for key in result.keys():
            if len(result[key]) == 1:
                result[key] = result[key][0]
            if not result[key]:
                del result[key]

        return result

    def _verify(self):
        try:
            if config['sudo']:
                output = check_output(['sudo', config['nagios_bin'], '-v', config['nagios_main_cfg']])
            else:
                print [config['nagios_bin'], '-v', config['nagios_main_cfg']]
                output = check_output([config['nagios_bin'], '-v', config['nagios_main_cfg']])
            returncode = 0
        except CalledProcessError, err:
            output = err.output
            returncode = err.returncode
        except Exception, err:
            output = str(err)
            returncode = 255

        result = self._format(output)

        return {'output': result if result else output, 'returncode': returncode}

    def _restart(self):
        logging.warn("[audit] [user: %s] triggered the restart command" % (request.authorization.username), )
        Model.Control.Command.restart_program(command_file=self.command_file)
        return { 'result': 'successfully sent command to command file' }

    def post(self):
        if len(request.args.keys()) != 1:
            abort(400, 'control endpoint accepts exactly ONE argument')

        action = request.args.keys()[0]

        if action not in self.arguments:
            abort(400, 'invalid argument: %s' % (escape(action), ))

        try:
            result = getattr(self,'_' + action)()
        except Exception, err:
            abort(500, 'unable to execute action %s: %s' % (action, str(err)))
        else:
            return jsonify(result)


class NagiosObjectView(MethodView):
    """
    NagiosObjectView: Wraps the flask MethodViews around the wonderful 
    pynag module providing a full featured RESTfull api for managing 
    Nagios/Icinga Configurations
    """

    decorators = [Authentify(config['auth'])]

    def __init__(self, *args, **kwargs):
        MethodView.__init__(self, *args, **kwargs)
        Model.cfg_file=config['nagios_main_cfg']
        Model.pynag_directory=config['output_dir']

        self.username = request.authorization.username
        self.endpoint = request.path.lstrip('/')
        self.endpoints = ApiEndpoints()

    def _summary(self, results):
        return {
            "succeeded": len([r for r in results if r.has_key(200) ]), 
            "failed": len([r for r in results if not r.has_key(200) ]), 
            "total": len(results)
        }

    def _build_query(self, arguments):
        """
        Build query for pynag. Currently supported:
        - key=*expr
        - key=expr*
        - key=*expr*
        - key=expr
        """
        query = {}
        for key, value in arguments.iteritems():
            if value.startswith('*') and value.endswith('*'):
                query_type = '__contains'
            elif value.startswith('*'):
                query_type='__endswith'
            elif value.endswith('*'):
                query_type='__startswith'
            else:
                query_type = ''

            query[key + query_type] = value.strip('*')

        return query

    def get(self):
        validate = self.endpoints.validate(self.endpoint, request.args)
        if not validate.has_key(200):
            abort(*validate.items()[0])
        endpoint_objects = getattr(Model, self.endpoint.capitalize()).objects

        query = self._build_query(request.args)

        try:
            result = [ obj['meta']['defined_attributes'] for obj in endpoint_objects.filter(**query)]
        except IOError, err:
            abort(500, "error opening config files: %s" % (str(err), ))
        except:
            abort(500)
        else:
            return Response(dumps(result, indent=None if request.is_xhr else 2), mimetype='application/json')

    def delete(self):
        validate = self.endpoints.validate(self.endpoint, request.args)
        if not validate.has_key(200):
            abort(*validate.items()[0])
        endpoint_objects = getattr(Model, self.endpoint.capitalize()).objects

        query = self._build_query(request.args)

        try:
            objects = endpoint_objects.filter(**query)
        except IOError, err:
            abort(500, "error opening config files: %s" % (str(err), ))
        except:
            abort(500)

        unique_key = self.endpoints.get_unique_key(self.endpoint)
        results = []
        for obj in objects:
            try:
                obj.delete()
            except Exception, err:
                results.append({ 500: "unable to delete %s object %s: %s" % (self.endpoint, obj[unique_key], str(err)) })
                logging.debug("[audit] [user: %s] failed to delete %s object %s: %s" % (self.username, self.endpoint, obj[unique_key], str(err)))
            else:
                results.append({ 200: "successfully deleted %s object: %s" % (self.endpoint, obj[unique_key]) })
                logging.info("[audit] [user: %s] deleted %s object: %s" % (self.username, self.endpoint, obj[unique_key]))

        summary = self._summary(results)
        logging.warn("[audit] [user: %s] deleted %d %s objects (out of %d requested)" % (
            self.username, summary['succeeded'], 
            self.endpoint, summary['total'])
        )
        return jsonify(results=results, summary=summary)

    def post(self):
        data = request.json

        if data is None:
            return jsonify(message='no json received. you need to set your content-type to application/json.')

        if type(data) == list:
            results = map(self._save_or_update, data)
        else:
            results = [self._save_or_update(data)]

        summary = self._summary(results)
        logging.warn("[audit] [user: %s] stored %d %s objects (out of %d requested)" % (
            self.username, 
            summary['succeeded'], 
            self.endpoint, 
            summary['total'])
        )
        return jsonify(results=results, summary=summary)

    def _save_or_update(self, item):
            # does this object already exist
            unique_key = self.endpoints.get_unique_key(self.endpoint)
            if unique_key in item.keys():
                query = { unique_key: item[unique_key] }
                try:
                    endpoint_object = getattr(Model, self.endpoint.capitalize()).objects.filter(**query)
                except IOError, err:
                    abort(500, "error opening config files: %s" % (str(err), ))
                except:
                    abort(500)

                if endpoint_object:
                    endpoint_object = endpoint_object[0]
                else:
                    endpoint_object = getattr(Model, self.endpoint.capitalize())()
            else:
                return { 500: 'required key for %s object not set: %s' % (self.endpoint, unique_key) }

            validate = self.endpoints.validate(self.endpoint, item)
            if not validate.has_key(200):
                return validate

            for key, value in item.iteritems():
                endpoint_object.set_attribute(key, value)

            try:
                endpoint_object.save()
            except Exception, err:
                logging.debug("[audit] [user: %s] failed to store %s object %s: %s" % (self.username, self.endpoint, item[unique_key], str(err)))
                return { 500: 'unable to save %s object %s: %s' % (self.endpoint, item[unique_key], str(err)) }

            logging.info("[audit] [user: %s] stored %s object %s" % (self.username, self.endpoint, item[unique_key]))
            return { 200: "successfully stored %s object: %s" % (self.endpoint, item[unique_key]) }

class NagiosAPI(Flask):
    """
    APIEndpoints: Handles the flask app, registers endpoints and wrapping 
    the run() function for development testing.

    @app: Flask app where the enpoints sould be registered at
    """

    def __init__(self, name):
        Flask.__init__(self, name)
        logging.config.dictConfig(config['logging'])

        self.request_class = CustomRequestClass
        self.endpoints = ApiEndpoints()

        self.__register_endpoints()
        self.__register_error_handler()
        self.__register_help_handler()

    def __error_handler(self, err):
        if not isinstance(err, HTTPException):
            err = InternalServerError(description="Something went wrong. RUN!")

        if request.content_type=='application/json':
            response = jsonify(code=err.code, message=str(err))
        else:
            response = Response(render_template('error.html', err=err))

        response.status_code = err.code

        if err.code == 401:
            response.headers['WWW-Authenticate'] = 'Basic realm="Login Required"'

        return response

    def __help(self):
        if request.content_type=='application/json':
            return jsonify(endpoints=self.endpoints)
        else:
            return render_template('help.html', endpoints=self.endpoints)

    def __register_help_handler(self):
        for endpoint, name in [('/', 'index'), ('/help', 'help')]:
            self.add_url_rule(endpoint, name, self.__help)

    def __register_error_handler(self):
        for code in default_exceptions.iterkeys():
            self.errorhandler(code)(self.__error_handler)

    def __register_endpoints(self):
        for endpoint in self.endpoints.keys():
            self.add_url_rule('/' + endpoint, view_func=NagiosObjectView.as_view(endpoint))
        self.add_url_rule('/control', view_func=NagiosControlView.as_view('control'))


if __name__ == '__main__':
    app = NagiosAPI(__name__)
    logging.info(" * starting restlos V%s" % (VERSION, ))
    app.run(host=config['host'], port=config['port'])