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# Copyright 2016 Canonical Ltd. This software is licensed under the
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# GNU Affero General Public License version 3 (see the file LICENSE).
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"""The Discovery handler for the WebSocket connection."""
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from maasserver.websockets import dehydrate_datetime
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from maasserver.websockets.handlers.viewmodel import ViewModelHandler
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from maasserver.models import Discovery
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from provisioningserver.logger import get_maas_logger
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maaslog = get_maas_logger("websockets.discovery")
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class DiscoveryHandler(ViewModelHandler):
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Discovery.objects.by_unknown_ip_and_mac()
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.order_by("-last_seen")
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# Need an incrementing row number to use for a batch key.
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# The extra select needs to specify the ordering with which
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# to apply the row_number(); it must match Django's
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# order_by() in order to be consistent.
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'ROW_NUMBER() OVER (ORDER BY last_seen DESC)'
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# This batch key isn't guaranteed to be stable, since newly-discovered
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# items can come in as the new first-items in the query. But that's why
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# we're also going to poll. But using row_number() seems to be a good
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batch_key = '_row_number'
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def dehydrate_last_seen(self, datetime):
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return dehydrate_datetime(datetime)
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src/maasserver/websockets/handlers/discovery.py
