helpers.py 文件源码

def get_data(self):
        """
        Retrieve the relation data for each unit involved in a relation and,
        if complete, store it in a list under `self[self.name]`.  This
        is automatically called when the RelationContext is instantiated.

        The units are sorted lexographically first by the service ID, then by
        the unit ID.  Thus, if an interface has two other services, 'db:1'
        and 'db:2', with 'db:1' having two units, 'wordpress/0' and 'wordpress/1',
        and 'db:2' having one unit, 'mediawiki/0', all of which have a complete
        set of data, the relation data for the units will be stored in the
        order: 'wordpress/0', 'wordpress/1', 'mediawiki/0'.

        If you only care about a single unit on the relation, you can just
        access it as `{{ interface[0]['key'] }}`.  However, if you can at all
        support multiple units on a relation, you should iterate over the list,
        like::

            {% for unit in interface -%}
                {{ unit['key'] }}{% if not loop.last %},{% endif %}
            {%- endfor %}

        Note that since all sets of relation data from all related services and
        units are in a single list, if you need to know which service or unit a
        set of data came from, you'll need to extend this class to preserve
        that information.
        """
        if not hookenv.relation_ids(self.name):
            return

        ns = self.setdefault(self.name, [])
        for rid in sorted(hookenv.relation_ids(self.name)):
            for unit in sorted(hookenv.related_units(rid)):
                reldata = hookenv.relation_get(rid=rid, unit=unit)
                if self._is_ready(reldata):
                    ns.append(reldata)