Module Expr Str ImportFrom alias ImportFrom alias ImportFrom alias ImportFrom alias
N/A N/A 
There are three filters included: AllHosts, InstanceType & JSON.

AllHosts just returns the full, unfiltered list of hosts.
InstanceType is a hard coded matching mechanism based on flavor criteria.
JSON is an ad-hoc filter grammar.

Why JSON? The requests for instances may come in through the
REST interface from a user or a parent Zone.
Currently InstanceTypes are used for specifing the type of instance desired.
Specific Nova users have noted a need for a more expressive way of specifying
instance requirements. Since we don't want to get into building full DSL,
this filter is a simple form as an example of how this could be done.
In reality, most consumers will use the more rigid filters such as the
InstanceType filter.
 abstract_filter AbstractHostFilter all_hosts_filter AllHostsFilter instance_type_filter InstanceTypeFilter json_filter JsonFilter