Haystack causes a "list of nodes should not include schema" warning in elasticsearch

I'm working on a Django app. It has a settings.py that configures Haystack to use elasticsearch as per the example in http://django-haystack.readthedocs.org/en/latest/tutorial.html#elasticsearch:

HAYSTACK_CONNECTIONS = {
    'default': {
        'ENGINE': 'haystack.backends.elasticsearch_backend.ElasticsearchSearchEngine',  # noqa pylint: disable=line-too-long
        'URL': 'http://%s:%s/' % (
             # get port mappings from Docker
             os.environ['ELASTICSEARCH_PORT_9200_TCP_ADDR'],
             os.environ['ELASTICSEARCH_PORT_9200_TCP_PORT'],
        ),

This causes a warning to be emitted in elasticsearch.client._normalize_hosts:

WARNING elasticsearch 38 List of nodes should not include schema information (http://): u'http://0.0.0.0:49204 '. null

It seems that elasticsearch (I've got version 1.2.0 here) wants a simple hostname:port instead of a full URL.

I don't know if you want to fix this in haystack.backends.elasticsearch_backend or if you want to change the documentation. Actually, changing the documentation feels wrong: if the setting is named URL, it should be able to handle URLs without emitting warnings.

Start with haystack/backends/elasticsearch_backend.py and compare its URL handling with elasticsearch.client._normalize_hosts, using the configuration and warning shown in the issue. Check whether the documented URL setting or the backend integration is responsible, then verify that the warning no longer appears while the documented Elasticsearch connection still works.