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

[filter:turnstile]
paste.filter_factory = turnstile.middleware:turnstile_filter
turnstile = keystone_limits:KeystoneTurnstileMiddleware
preprocess = keystone_limits:keystone_preprocess
redis.host = <your Redis database host>

Then you must add the turnstile filter to your pipelines:

[pipeline:public_api]
pipeline = turnstile token_auth admin_token_auth xml_body json_body debug ec2_extension public_service

[pipeline:admin_api]
pipeline = turnstile token_auth admin_token_auth xml_body json_body debug ec2_extension crud_extension admin_service

In order to read and write limits, you need to use the turnstile setup_limits and load_limits commands. Sample configuration and limit files are provided in the etc/ directory:

setup_limits etc/keystone_limits.conf etc/default_limits.xml

dump_limits etc/keystone_limits.conf loaded_limits.xml

cat loaded_limits.xml

<?xml version='1.0' encoding='UTF-8'?>
<limits>
    <limit class="keystone_limits:KeystoneClassLimit">
        <attr name="rate_class">tokens</attr>
        <attr name="queries"/>
        <attr name="unit">minute</attr>
        <attr name="uri">/tokens</attr>
        <attr name="use"/>
        <attr name="uuid">d8b13e95-4a15-4816-aefd-cb5cef1e78da</attr>
        <attr name="value">2</attr>
        <attr name="verbs">
            <value>POST</value>
        </attr>
    </limit>
</limits>

These values are configurable in the XML. After you've changed them, they need to be reloaded into the redis database using the setup_limits command.

With the above configuration, the middleware will limit requests to the /tokens URL to 2 POSTs per minute.

You can set up additional rules using the Routes syntax.

For example, keeping the example above, in case you wanted to limit all the other requests using a different rule, you could add another limit to the configuration file (and then reload using setup_limits)

<?xml version='1.0' encoding='UTF-8'?>
<limits>
    <limit class="keystone_limits:KeystoneClassLimit">
        <attr name="rate_class">tokens</default>
        <attr name="unit">minute</attr>
        <attr name="uri">{everything:.*}</attr>
        <attr name="value">10</attr>
    </limit>
</limits>

Requests are limited based on incoming IP address.