resilience4clj.rate-limiter — tessellator/resilience4clj-ratelimiter 0.4.0

Functions to create and execute rate limiters.

acquire-permission! clj

(acquire-permission! rate-limiter)

(acquire-permission! rate-limiter permits)

Attempts to acquire the specified number of permits from rate-limiter.

Blocks until all permits are received or the rate limiter timeout duration is exceeded. Returns a value indicating success.

The default permit value is 1.

add-configuration! clj

(add-configuration! name config)

(add-configuration! registry name config)

Adds config to the registry under the name.

Uses default-registry if registry is not provided.

all-rate-limiters clj

(all-rate-limiters)

(all-rate-limiters registry)

Gets all the rate limiters in registry.

Uses default-registry if registry is not provided.

change-limit-for-period! clj

(change-limit-for-period! rate-limiter limit-for-period)

Changes the number of allowable calls during a refresh period.

The new limit will take effect in the next refresh period. The current period is not affected.

change-timeout-duration! clj

(change-timeout-duration! rate-limiter timeout-duration)

Changes the timeout duration milliseconds for the rate limiter.

The new timeout duration will not affect calls currently waiting for permission to execute.

default-registry clj

The global ratelimiter and config registry.

drain-permissions! clj

(drain-permissions! rate-limiter)

Drains all the permits left in the current period.

emit-events! clj

(emit-events! rate-limiter out-chan & {:keys [only exclude] :or {exclude []}})

Offers events on rate-limiter to out-chan.

The event types are identified by event-types.

This function also accepts :only and :exclude keyword params that are sequences of the event types that should be included or excluded, respectively.

emit-registry-events! clj

(emit-registry-events! out-chan)

(emit-registry-events! registry
                       out-chan
                       &
                       {:keys [only exclude] :or {exclude []}})

Offers registry events to out-chan.

The event types are identified by registry-event-types.

This function also accepts :only and :exclude keyword params that are sequences of the event types that should be included or excluded, respectively.

Uses default-registry if registry is not provided.

event-types clj

execute clj

(execute rate-limiter f & args)

Apply args to f within a context protected by the rate limiter.

The function will wait up to the configured timeout duration if the rate limit has been exceeded. If the function is not allowed to execute before the timeout duration expires, this function will throw an exception.

find clj

(find name)

(find registry name)

Finds the rate limiter identified by name in registry.

Uses default-registry if registry is not provided.

name clj

(name rate-limiter)

Gets the name of the rate limiter.

rate-limiter clj

(rate-limiter name)

(rate-limiter name config)

Creates a rate limiter with the name and config.

rate-limiter! clj

(rate-limiter! name)

(rate-limiter! registry name)

(rate-limiter! registry name config)

Creates or fetches a rate limiter with the specified name and config and stores it in registry.

The config value can be either a config map or the name of a config map stored in the registry. If the rate limiter already exists in the registry, the config value is ignored.

Uses default-registry if registry is not provided.

registry clj

(registry)

(registry configs-map)

Creates a registry with default values or a map of name/config-map pairs.

registry-event-types clj

The event types that can be raised by a registry.

remove! clj

(remove! name)

(remove! registry name)

Removes the rate limiter identified by name from registry.

Uses default-registry if registry is not provided.

replace! clj

(replace! name rate-limiter)

(replace! registry name rate-limiter)

Replaces the rate limiter identified by name in registry with the specified rate-limiter.

Uses default-registry if registry is not provided.

reserve-permission! clj

(reserve-permission! rate-limiter)

(reserve-permission! rate-limiter permits)

Reserves the specified number of permits.

Returns the number of nanoseconds you must wait to use the permission. If the number is negative, the request to reserve permission failed. This failure mode may occur if the number of nanoseconds to wait exceeds the rate limiter timeout duration.

The default permit value is 1.

with-rate-limiter clj macro

(with-rate-limiter rate-limiter & body)

Executes body within a context protected by the rate limiter.

rate-limiter is either a rate limiter or the name of one in the global registry. If you provide a name and a rate limiter of that name does not already exist in the global registry, one will be created with the :default config.

The code in body will wait up to the configured timeout duration if the rate limit has been exceeded. If the function is not allowed to execute before the timeout duration expires, an exception will be thrown.