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Absurdly Powerful & Scalable Rate Limiting

All Your Limits In One Place​

Use Prefab's UI to define your limits in one place. Prefab's Dynamic Configuration will push your limit definitions to all your servers instantly.

Use this for in-memory rate limits, rate limits backed by your Redis or rate limits in our cloud.

Respect Multiple Limits At Once​

Fast, efficient, bombproof and cost-effective rate limiting libraries that don't require any Redis/Memcached on your end.

# this will only fire if we are within our secondly,
# minutely and daily limits
if Prefab.pass("apis:facebook:get_user")
    Facebook.get_user(user_id)
end

Scales to Millions of Limits​

Paying your usage tracking service by the event? Do you really need to send an 50 event types for Bob every time he loads a page? How about only sending bob's unique events every 5 minutes? Done.

To do that, you need a limit per user per distinct event. If you have 100,000 users and 50 distinct events, that's 5 million limits. That's a lot, but that's no problem for Prefab.

if Prefab.pass?("events:pageviews:/pricing/:user12312")
    # this will fire 1 / hour / user
    TrackingService.trackPage(user12312, "/pricing/")
end

Prefab will efficiently keep track of the millions of individual token buckets needed to make this work.

Granular Overrides​

With clever limit key usage you can get a default limits for a key, and a more specific limit for a subkey.

if Prefab.pass?("events:pageviews:/pricing/:user12312")
    # this will fire 1 / hour / user
    TrackingService.trackPage(user12312, "/pricing/")
end
if Prefab.pass?("events:pageviews:/order_placed/:user12312")
    # this will fire 1 / sec / user
    TrackingService.trackPage(user12312, "/orded_placed/")
end

Deduplication​

Only want to send the 'Welcome Email' once per person, but have some nasty race conditions that could lead to doing it twice? Put an eternal semaphore for 'welcome-email:bob@example.com' and let us store that bit for you forever.

# this will only return true once per user forever
if Prefab.pass?("send_email:welcome_email:user12312")
    really_send_the_email()
end

Concurrency​

Want a reliable distributed semaphore that doesn't require setting up Zookeeper or Consul and won't make you worry about LRU expiry?

Prefab rate limits can be returnable. That means you can acquire a limit, do some work, and then return it.

And it doesn't need to be a single semaphore. That's the beauty of doing this as a limit. You can have a limit of 10 per forever then clients can pull a lease for an return when they're done. If they don't return it, use customizable expiry so it will still be available for someone else to use.

# attempt to acquire 10 tokens
# accept partial if we can't get them all
jobs_to_run = Prefab.acquire("jobs:email-processor",
                             desired: 10,
                             partial: true)

run_jobs(jobs_to_run.count)

# return the leases
jobs_to_run.return_all

Use From Everything From In Memory -> Distributed​

Each limit definition that you create can be created at any durability level.

L5_BOMBPROOF_DISTRIBUTED​

Prefab.cloud coordinated limits. All reads and writes hit the backing store which replicates data across three regions to provide fault tolerance in the event of a server failure or Availability Zone outage. 3 year Persistent

L4_BEST_EFFORT_DISTRIBUTED [Default]​

Prefab.cloud coordinated limits. Small likelihood of lost limit tracking in failure scenarios. Cheaper & faster than level-5.

L3_CUSTOMER_DISTRIBUTED​

Bring your own Redis instance and just use Prefab rate limit configuration so you can change the limits on the fly.

L2_IN_PROCESS​

In memory rate limiters, configurable on the fly with Prefab.

L1_IN_MEMORY​

Ultimate speed with no coordination between threads.