# copyright 2014 LOGILAB S.A. (Paris, FRANCE), all rights reserved.

# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr

#

# This file is part of CubicWeb.

#

# CubicWeb is free software: you can redistribute it and/or modify it under the

# terms of the GNU Lesser General Public License as published by the Free

# Software Foundation, either version 2.1 of the License, or (at your option)

# any later version.

#

# CubicWeb is distributed in the hope that it will be useful, but WITHOUT

# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS

# FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more

# details.

#

# You should have received a copy of the GNU Lesser General Public License along

# with CubicWeb.  If not, see <http://www.gnu.org/licenses/>.

"""looping task for dumping instance's stats in a file

"""

from datetime import datetime

import json

from cubicweb.server import hook

class LogStatsStartHook(hook.Hook):

    """register task to regularly dump instance's stats in a file

    data are stored as one json entry per row

    """

    __regid__ = 'cubicweb.hook.logstats.start'

    events = ('server_startup',)

    def __call__(self):

        interval = self.repo.config.get('logstat-interval', 0)

        if interval <= 0:

            return            

        def dump_stats(repo):

            statsfile = repo.config.get('logstat-file')

            with repo.internal_cnx() as cnx:

                stats = cnx.call_service('repo_stats')

                gcstats = cnx.call_service('repo_gc_stats', nmax=5)

            allstats = {'resources': stats,

                        'memory': gcstats,

                        'timestamp': datetime.utcnow().isoformat(),

                       }

            try:

                with open(statsfile, 'ab') as ofile:

                    json.dump(allstats, ofile)

                    ofile.write('\n')

            except IOError:

                repo.warning('Cannot open stats file for writing: %s', statsfile)

        self.repo.looping_task(interval, dump_stats, self.repo)