baseplate.lib.ratelimit

Configuring a rate limiter for your request context requires a context factory for the backend and a factory for the rate limiter itself:

redis_pool = pool_from_config(app_config)
backend_factory = RedisRateLimitBackendContextFactory(redis_pool)
ratelimiter_factory = RateLimiterContextFactory(backend_factory, allowance, interval)
baseplate.add_to_context('ratelimiter', ratelimiter_factory)

The rate limiter can then be used during a request with:

try:
    context.ratelimiter.consume(context.request_context.user.id)
    print('Ratelimit passed')
except RateLimitExceededException:
    print('Too many requests')

Classes

class baseplate.lib.ratelimit.RateLimiter(backend, allowance, interval)

A class for rate limiting actions.

Parameters:

• backend (RateLimitBackend) – The backend to use for storing rate limit counters.

• allowance (int) – The maximum allowance allowed per key.

• interval (int) – The interval (in seconds) to reset allowances.

consume(key, amount=1)

Consume the given amount from the allowance for the given key.

This will raise baseplate.lib.ratelimit.RateLimitExceededException if the allowance for key is exhausted.

Parameters:

• key (str) – The name of the rate limit bucket to consume from.

• amount (int) – The amount to consume from the rate limit bucket.

Return type:

None

class baseplate.lib.ratelimit.RateLimiterContextFactory(backend_factory, allowance, interval)

RateLimiter context factory.

Parameters:

• backend_factory (ContextFactory) – An instance of baseplate.clients.ContextFactory. The context factory must return an instance of baseplate.lib.ratelimit.backends.RateLimitBackend

• allowance (int) – The maximum allowance allowed per key.

• interval (int) – The interval (in seconds) to reset allowances.

make_object_for_context(name, span)

Return an object that can be added to the context object.

Parameters:

• name (str) – The name assigned to this object on the context.

• span (Span) – The current span this object is being made for.

Return type:

RateLimiter

class baseplate.lib.ratelimit.RateLimitExceededException

This exception gets raised whenever a rate limit is exceeded.

Backends

class baseplate.lib.ratelimit.backends.RateLimitBackend

An interface for rate limit backends to implement.

consume(key, amount, allowance, interval)

Consume the given amount from the allowance for the given key.

This will return true if the key remains below the allowance after consuming the given amount.

Parameters:

• key (str) – The name of the rate limit bucket to consume from.

• amount (int) – The amount to consume from the rate limit bucket.

• allowance (int) – The maximum allowance for the rate limit bucket.

• interval (int) – The interval to reset the allowance.

Return type:

bool

Memcache

class baseplate.lib.ratelimit.backends.memcache.MemcacheRateLimitBackendContextFactory(memcache_pool, prefix='rl:')

MemcacheRateLimitBackend context factory.

Parameters:

• memcache_pool (PooledClient) – The memcache pool to back this ratelimit.

• prefix (str) – A prefix to add to keys during rate limiting. This is useful if you will have two different rate limiters that will receive the same keys.

make_object_for_context(name, span)

Return an object that can be added to the context object.

Parameters:

• name (str) – The name assigned to this object on the context.

• span (Span) – The current span this object is being made for.

Return type:

MemcacheRateLimitBackend

class baseplate.lib.ratelimit.backends.memcache.MemcacheRateLimitBackend(memcache, prefix='rl:')

A Memcache backend for rate limiting.

Parameters:

• memcache (MonitoredMemcacheConnection) – A memcached connection.

• prefix (str) – A prefix to add to keys during rate limiting. This is useful if you will have two different rate limiters that will receive the same keys.

consume(key, amount, allowance, interval)

Consume the given amount from the allowance for the given key.

This will return true if the key remains below the allowance after consuming the given amount.

Parameters:

• key (str) – The name of the rate limit bucket to consume from.

• amount (int) – The amount to consume from the rate limit bucket.

• allowance (int) – The maximum allowance for the rate limit bucket.

• interval (int) – The interval to reset the allowance.

Return type:

bool

Redis

class baseplate.lib.ratelimit.backends.redis.RedisRateLimitBackendContextFactory(redis_pool, prefix='rl:')

RedisRateLimitBackend context factory.

Parameters:

• redis_pool (ConnectionPool) – The redis pool to back this ratelimit.

• prefix (str) – A prefix to add to keys during rate limiting. This is useful if you will have two different rate limiters that will receive the same keys.

make_object_for_context(name, span)

Return an object that can be added to the context object.

Parameters:

• name (str) – The name assigned to this object on the context.

• span (Span) – The current span this object is being made for.

Return type:

RedisRateLimitBackend

class baseplate.lib.ratelimit.backends.redis.RedisRateLimitBackend(redis, prefix='rl:')

A Redis backend for rate limiting.

Parameters:

• redis (MonitoredRedisConnection) – An instance of baseplate.clients.redis.MonitoredRedisConnection.

• prefix (str) – A prefix to add to keys during rate limiting. This is useful if you will have two different rate limiters that will receive the same keys.

consume(key, amount, allowance, interval)

Consume the given amount from the allowance for the given key.

This will return true if the key remains below the allowance after consuming the given amount.

Parameters:

• key (str) – The name of the rate limit bucket to consume from.

• amount (int) – The amount to consume from the rate limit bucket.

• allowance (int) – The maximum allowance for the rate limit bucket.

• interval (int) – The interval to reset the allowance.

Return type:

bool