'Return a list of tags extracted from an event object'

def extract_event_tags(self, event):

    tags = []
    if ('reason' in event):
        tags.append(('reason:%s' % event.get('reason', '').lower()))
    if ('namespace' in event.get('metadata', {})):
        tags.append(('namespace:%s' % event['metadata']['namespace']))
    if ('host' in event.get('source', {})):
        tags.append(('node_name:%s' % event['source']['host']))
    if ('kind' in event.get('involvedObject', {})):
        tags.append(('object_type:%s' % event['involvedObject'].get('kind', '').lower()))
    return tags
