nova_limits 0.2

Nova-specific rate-limit class for turnstile

This package provides the nova_limits Python module, which contains the nova_preprocess() preprocessor, the NovaClassLimit limit class, and the NovaTurnstileMiddleware replacement middleware class, all for use with Turnstile. These pieces work together to provide class-based rate limiting integration with nova. To use, you must configure the Turnstile middleware with the following configuration:

[filter:turnstile]
paste.filter_factory = turnstile.middleware:turnstile_filter
turnstile = nova_limits:NovaTurnstileMiddleware
preprocess = nova_limits:nova_preprocess
redis.host = <your Redis database host>

Then, simply use the nova_limits:NovaClassLimit rate limit class in your configuration.

Using NovaClassLimit

In addition to the other attributes provided by turnstile.limits:Limit, the NovaClassLimit limit class provides one additional required argument: the rate_class. Each tenant is associated with a given rate-limit class through the Redis database. (If no such association is present, the rate-limit class for a tenant is default.) Setting rate_class on NovaClassLimit restricts the limiting action to only those tenants in the given rate-limit class.

Also note that, for nova, the URIs used in configuring rate limiting must include the version identifier, i.e., “/v2/{tenant}/servers/detail”.