How to use the ara.models.Host function in ara

def test_duplicate_host(self):
        host = m.Host(
            name='localhost',
            playbook=self.playbook,
        )
        m.db.session.add(host)

        with self.assertRaises(Exception):
            m.db.session.commit()

def get_or_create_host(self, hostname):
        try:
            host = (models.Host.query
                    .filter_by(name=hostname)
                    .filter_by(playbook_id=self.playbook.id)
                    .one())
        except models.NoResultFound:
            host = models.Host(name=hostname, playbook=self.playbook)
            db.session.add(host)
            db.session.commit()

        return host

def get_or_create_host(self, hostname):
        try:
            host = (models.Host.query
                    .filter_by(name=hostname)
                    .filter_by(playbook_id=self.playbook.id)
                    .one())
        except models.NoResultFound:
            host = models.Host(name=hostname, playbook=self.playbook)
            db.session.add(host)
            db.session.commit()

        return host

def index():
    """
    This is not served anywhere in the web application.
    It is used explicitly in the context of generating static files since
    flask-frozen requires url_for's to crawl content.
    url_for's are not used with host.show_host directly and are instead
    dynamically generated through javascript for performance purposes.
    """
    if current_app.config['ARA_PLAYBOOK_OVERRIDE'] is not None:
        override = current_app.config['ARA_PLAYBOOK_OVERRIDE']
        hosts = (models.Host.query
                 .filter(models.Host.playbook_id.in_(override)))
    else:
        hosts = models.Host.query.all()

    return render_template('host_index.html', hosts=hosts)

def take_action(self, args):
        results = (models.TaskResult.query
                   .join(models.Task)
                   .join(models.Host)
                   .filter(models.TaskResult.task_id == models.Task.id)
                   .filter(models.TaskResult.host_id == models.Host.id)
                   .order_by(models.Task.time_start, models.Task.sortkey))

        if args.playbook:
            results = results.filter(models.Task.playbook_id == args.playbook)
        elif args.play:
            results = results.filter(models.Task.play_id == args.play)
        elif args.task:
            results = results.filter(models.TaskResult.task_id == args.task)

        return [[field.name for field in LIST_FIELDS],
                [[field(result) for field in LIST_FIELDS]
                 for result in results]]

def take_action(self, args):
        try:
            if args.playbook:
                host = (models.Host.query
                        .filter_by(playbook_id=args.playbook)
                        .filter((models.Host.id == args.host) |
                                (models.Host.name == args.host)).one())
            else:
                host = models.Host.query.filter_by(id=args.host).one()
        except (models.NoResultFound, models.MultipleResultsFound):
            raise RuntimeError('Host %s could not be found' % args.host)

        if not host.facts:
            raise RuntimeError('No facts available for host %s' % args.host)

        facts = ((k, v) for k, v in
                 six.iteritems(jsonutils.loads(host.facts.values))
                 if not args.fact or k in args.fact
                 )
        return six.moves.zip(*sorted(facts))

def show_host(id):
    try:
        host = models.Host.query.get(id)
    except models.NoResultFound:
        abort(404)

    if host and host.facts:
        facts = sorted(six.iteritems(jsonutils.loads(host.facts.values)))
    else:
        abort(404)

    return render_template('host.html',
                           host=host,
                           facts=facts)

def main():
    """ Returns the about page """
    if current_app.config['ARA_PLAYBOOK_OVERRIDE'] is not None:
        override = current_app.config['ARA_PLAYBOOK_OVERRIDE']
        files = (models.File.query
                 .filter(models.File.playbook_id.in_(override)))
        host_facts = (models.HostFacts.query
                      .join(models.Host)
                      .filter(models.Host.playbook_id.in_(override)))
        hosts = (models.Host.query
                 .filter(models.Host.playbook_id.in_(override)))
        playbooks = (models.Playbook.query
                     .filter(models.Playbook.id.in_(override)))
        records = (models.Data.query
                   .filter(models.Data.playbook_id.in_(override)))
        tasks = (models.Task.query
                 .filter(models.Task.playbook_id.in_(override)))
        task_results = (models.TaskResult.query
                        .join(models.Task)
                        .filter(models.Task.playbook_id.in_(override)))
    else:
        files = models.File.query
        host_facts = models.HostFacts.query
        hosts = models.Host.query
        playbooks = models.Playbook.query

def take_action(self, parsed_args):
        stats = (models.Stats.query
                 .join(models.Playbook)
                 .join(models.Host)
                 .filter(models.Stats.playbook_id == models.Playbook.id)
                 .filter(models.Stats.host_id == models.Host.id)
                 .order_by(models.Playbook.time_start, models.Host.name))

        return [[field.name for field in LIST_FIELDS],
                [[field(stat) for field in LIST_FIELDS]
                 for stat in stats]]