Flask extension to send data to FnordMetric

flask_fnordmetric.py

# -*- coding: utf-8 -*-
"""
    flask_fnordmetric
    ~~~~~~~~~~~~~~~~~

    :copyright: (c) 2013 by Isman Firmansyah.
    :license: MIT, see LICENSE.txt for more details.
"""
import os
import json
import base64

from redis import from_url as redis_from_url


class FnordMetric(object):
    """A class that acts as data shipper to FnordMetric Classic.

    Typical usage:

    .. code-block:: python

        from flask import Flask
        from flask.ext.fnordmetric import FnordMetric

        FNORDMETRIC_REDIS_URL = 'redis://user:passwd@127.0.0.1:6379/0'
        FNORDMETRIC_REDIS_PREFIX = 'fnordmetric'

        app = Flask(__name__)
        app.config.from_object(__name__)

        fnord = FnordMetric(app)

        # If you're using application factory:
        # fnord = FnordMetric()
        # fnord.init_app(app)

        @app.route('/')
        def foobar():
            extras = {'value': 1, 'gauge': 'sales_per_minute'}
            fnord.push_event('_incr', extras=extras)
            return 'sales_per_minute gauge has been incremented'

        app.run(debug=True)

    """

    def __init__(self, app=None):
        self.redis = None
        self.prefix = None
        self.app = app

        if app is not None:
            self.init_app(app)

    def init_app(self, app):
        app.config.setdefault(
            'FNORDMETRIC_REDIS_URL', 'redis://127.0.0.1:6379/0')
        app.config.setdefault('FNORDMETRIC_REDIS_PREFIX', 'fnordmetric')

        self.prefix = app.config['FNORDMETRIC_REDIS_PREFIX']
        self.redis = redis_from_url(app.config['FNORDMETRIC_REDIS_URL'])

        if not hasattr(app, 'extensions'):
            app.extensions = {}

        app.extensions['fnordmetric'] = self

    def push_event(self, event_type, extras=None):
        assert self.app, \
               'FnordMetric extension is not initialized properly. ' \
               'Please make sure to call init_app() first.'

        data = {'_type': event_type}
        if isinstance(extras, dict):
            data.update(extras)

        event_id = base64.urlsafe_b64encode(os.urandom(33))
        self.redis.set(
            '{0}-event-{1}'.format(self.prefix, event_id), json.dumps(data))
        self.redis.expire(
            '{0}-event-{1}'.format(self.prefix, event_id), 60)
        self.redis.lpush('{0}-queue'.format(self.prefix), event_id)