Class: RateLimiter::Bucket

Inherits:
Object
  • Object
show all
Defined in:
lib/fluent/plugin/rate_limiter.rb

Overview

Bucket class, contains the rate limiting logic for each group Attributes:

+group+: Group for which the bucket is created
+bucket_count+: Number of requests in the bucket
+bucket_count_total+: Number of requests in the bucket including the dropped requests
+bucket_last_reset+: Time when the bucket was last reset
+approx_rate_per_second+: Approximate rate of requests per second
+rate_last_reset+: Time when the rate was last reset
+curr_count+: Number of requests in the current second
+last_warning+: Time when the last warning was issued
+timeout_s+: Timeout for the bucket
+bucket_limit+: Maximum number of requests allowed in the bucket
+bucket_period+: Time period for the bucket
+rate_limit+: Maximum number of requests allowed per second

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(group, bucket_limit, bucket_period) ⇒ Bucket

Returns a new instance of Bucket.



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# File 'lib/fluent/plugin/rate_limiter.rb', line 23

def initialize( group, bucket_limit, bucket_period)
  now = Time.now
  @group = group
  @bucket_count = 0
  @bucket_count_total = 0
  @bucket_last_reset = now
  @approx_rate_per_second = 0
  @rate_last_reset = now
  @curr_count = 0
  @last_warning = nil
  @bucket_limit = bucket_limit
  @bucket_period = bucket_period
  @rate_limit = bucket_limit/bucket_period
  @timeout_s = 2*bucket_period
end

Instance Attribute Details

#approx_rate_per_second ⇒ Object

Returns the value of attribute approx_rate_per_second.



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# File 'lib/fluent/plugin/rate_limiter.rb', line 21

def approx_rate_per_second
  @approx_rate_per_second
end

#bucket_count ⇒ Object

Returns the value of attribute bucket_count.



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# File 'lib/fluent/plugin/rate_limiter.rb', line 21

def bucket_count
  @bucket_count
end

#bucket_count_total ⇒ Object

Returns the value of attribute bucket_count_total.



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# File 'lib/fluent/plugin/rate_limiter.rb', line 21

def bucket_count_total
  @bucket_count_total
end

#bucket_last_reset ⇒ Object

Returns the value of attribute bucket_last_reset.



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# File 'lib/fluent/plugin/rate_limiter.rb', line 21

def bucket_last_reset
  @bucket_last_reset
end

#bucket_limit ⇒ Object (readonly)

Returns the value of attribute bucket_limit.



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# File 'lib/fluent/plugin/rate_limiter.rb', line 22

def bucket_limit
  @bucket_limit
end

#bucket_period ⇒ Object (readonly)

Returns the value of attribute bucket_period.



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# File 'lib/fluent/plugin/rate_limiter.rb', line 22

def bucket_period
  @bucket_period
end

#curr_count ⇒ Object

Returns the value of attribute curr_count.



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# File 'lib/fluent/plugin/rate_limiter.rb', line 21

def curr_count
  @curr_count
end

#group ⇒ Object (readonly)

Returns the value of attribute group.



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# File 'lib/fluent/plugin/rate_limiter.rb', line 22

def group
  @group
end

#last_warning ⇒ Object

Returns the value of attribute last_warning.



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# File 'lib/fluent/plugin/rate_limiter.rb', line 21

def last_warning
  @last_warning
end

#rate_last_reset ⇒ Object

Returns the value of attribute rate_last_reset.



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# File 'lib/fluent/plugin/rate_limiter.rb', line 21

def rate_last_reset
  @rate_last_reset
end

#rate_limit ⇒ Object (readonly)

Returns the value of attribute rate_limit.



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# File 'lib/fluent/plugin/rate_limiter.rb', line 22

def rate_limit
  @rate_limit
end

#timeout_s ⇒ Object (readonly)

Returns the value of attribute timeout_s.



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# File 'lib/fluent/plugin/rate_limiter.rb', line 22

def timeout_s
  @timeout_s
end

Instance Method Details

#allow ⇒ Object

Checks if the bucket is free or full Returns:

+true+ if the bucket is free
+false+ if the bucket is full



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# File 'lib/fluent/plugin/rate_limiter.rb', line 43

def allow
  if @bucket_limit == -1
    return true
  end
  now = Time.now
  @curr_count += 1
  @bucket_count_total += 1
  time_lapsed = now - @rate_last_reset

  if time_lapsed.to_i >= 1
    @approx_rate_per_second = @curr_count / time_lapsed
    @rate_last_reset = now
    @curr_count = 0
  end

  if now.to_i / @bucket_period > @bucket_last_reset.to_i / @bucket_period
    reset_bucket
  end

  if @bucket_count == -1 or @bucket_count > @bucket_limit
    @bucket_count = -1
    return false
  else
    @bucket_count += 1
    true
  end
end

#expired ⇒ Object

Checks if bucket is expired Returns:

+true+ if the bucket is expired
+false+ if the bucket is not expired



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# File 'lib/fluent/plugin/rate_limiter.rb', line 75

def expired
  now = Time.now
  now.to_i - @rate_last_reset.to_i > @timeout_s
end