Class: RedisTokenBucket::Limiter

Inherits:
Object
  • Object
show all
Defined in:
lib/redis_token_bucket/limiter.rb

Instance Method Summary collapse

Constructor Details

#initialize(redis, clock = nil) ⇒ Limiter

Returns a new instance of Limiter.



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# File 'lib/redis_token_bucket/limiter.rb', line 3

def initialize(redis, clock = nil)
  @redis = redis
  @clock = clock
end

Instance Method Details

#batch_charge(*charges) ⇒ Object

performs several bucket charge operations in batch.

each operation is passed in as an Array, containing the parameters for ‘batch`.

charging only happens if all buckets have sufficient tokens. the charges are done transactionally, so either all buckets are charged or none.

returns a tuple (= Array with two elements) containing ‘success:boolean` and `levels:Hash<String, Numeric>` where `levels` is a hash from bucket keys to bucket levels.



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# File 'lib/redis_token_bucket/limiter.rb', line 32

def batch_charge(*charges)
  charges.each do |(bucket, amount, options)|
    unless amount > 0
      message = "tried to charge #{amount}, needs to be Numeric and > 0"
      raise ArgumentError, message
    end
  end

  run_script(charges)
end

#charge(bucket, amount, options = nil) ⇒ Object

charges ‘amount` tokens to the specified `bucket`.

charging only happens if the bucket has sufficient tokens. the level of “sufficient tokens” can be adjusted by passing in option

returns a tuple (= Array with two elements) containing ‘success:boolean` and `level:Numeric`



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# File 'lib/redis_token_bucket/limiter.rb', line 15

def charge(bucket, amount, options = nil)
  success, levels = batch_charge([bucket, amount, options])

  return success, levels[bucket[:key]]
end

#read_level(bucket) ⇒ Object

returns the current level of tokens in the specified ‘bucket`.



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# File 'lib/redis_token_bucket/limiter.rb', line 44

def read_level(bucket)
  read_levels(bucket)[bucket[:key]]
end

#read_levels(*buckets) ⇒ Object

reports the current level of tokens for each of the specified ‘buckets`. returns the levels as a Hash from bucket keys to bucket levels.



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# File 'lib/redis_token_bucket/limiter.rb', line 50

def read_levels(*buckets)
  _, levels = run_script(buckets.map { |bucket| [bucket, 0] })

  levels
end