79 lines
1.6 KiB
Ruby
79 lines
1.6 KiB
Ruby
# frozen_string_literal: true
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module Strategy
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class RoundRobin
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CacheError = Class.new(StandardError)
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COUNTER_EXPIRE_TIME = 86400 # one day
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def initialize(key, variants)
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@key = key
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@variants = variants
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end
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def execute
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increment_counter
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resolve_variant_name
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end
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# When the counter would expire
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#
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# @api private Used internally by SRE and debugging purpose
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# @return [Integer] Number in seconds until expiration or false if never
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def counter_expires_in
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Gitlab::Redis::SharedState.with do |redis|
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redis.ttl(key)
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end
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end
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# Return the actual counter value
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#
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# @return [Integer] value
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def counter_value
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Gitlab::Redis::SharedState.with do |redis|
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(redis.get(key) || 0).to_i
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end
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end
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# Reset the counter
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#
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# @private Used internally by SRE and debugging purpose
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# @return [Boolean] whether reset was a success
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def reset!
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redis_cmd do |redis|
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redis.del(key)
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end
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end
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private
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attr_reader :key, :variants
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# Increase the counter
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#
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# @return [Boolean] whether operation was a success
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def increment_counter
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redis_cmd do |redis|
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redis.incr(key)
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redis.expire(key, COUNTER_EXPIRE_TIME)
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end
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end
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def resolve_variant_name
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remainder = counter_value % variants.size
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variants[remainder]
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end
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def redis_cmd
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Gitlab::Redis::SharedState.with { |redis| yield(redis) }
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true
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rescue CacheError => e
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Gitlab::AppLogger.warn("GitLab: An unexpected error occurred in writing to Redis: #{e}")
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false
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end
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end
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end
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