attract/attract_server/subversion.py

"""Subversion interface."""

from __future__ import absolute_import

import re

import attr
import blinker
import svn.remote

from . import attrs_extra

task_logged = blinker.NamedSignal('task_logged')
task_marker_re = re.compile(r'\[(?P<task_id>T\d+)\]')


def obtain(server_location):
    """Returns a Connection object for the given server location."""

    return svn.remote.RemoteClient(server_location)


@attr.s
class CommitLogObserver(object):
    svn_client = attr.ib(validator=attr.validators.instance_of(svn.remote.RemoteClient))
    last_seen_revision = attr.ib(default=0, validator=attr.validators.instance_of(int))
    _log = attrs_extra.log('%s.CommitLogObserver' % __name__)

    def fetch_and_observe(self):
        """Obtains task IDs from SVN logs."""

        self._log.debug('%s: fetch_and_observe()', self)

        svn_log = self.svn_client.log_default(
            revision_from=self.last_seen_revision + 1)

        for log_entry in svn_log:
            self._log.debug('- %r', log_entry)

            # assumption: revisions are always logged in strictly increasing order.
            self.last_seen_revision = log_entry.revision

            # Parse the commit log to see if there are any task markers.
            lines = log_entry.msg.split('\n', 1)
            first_line = lines[0]
            for match in task_marker_re.finditer(first_line):
                task_id = match.group('task_id')

                task_logged.send(self,
                                 task_id=task_id,
                                 log_entry=log_entry)