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Contents
require 'delegate'
require 'set'
require 'wisper'
module Routemaster
module Dirty
# Collects information about entities whose state has changed and need to be
# refreshed.
# Typically +mark+ is called when notified state has changed (e.g. from the
# bus) and +sweep+ when one wants to know what has changed.
#
# Use case: when some entites are very volatile, the map will hold a "dirty"
# state for multiple updates until the client is ready to update.
#
class Map
include Wisper::Publisher
KEY = 'dirtymap:items'
def initialize(redis: nil)
@redis = redis || Config.drain_redis
end
# Marks an entity as dirty.
# Return true if newly marked, false if re-marking.
def mark(url)
@redis.sadd(KEY, url).tap do |marked|
publish(:dirty_entity, url) if marked
end
end
# Runs the block.
# The entity will only be marked as clean if the block returns truthy.
def sweep_one(url, &block)
return unless block.call(url)
@redis.srem(KEY, url)
end
def all
@redis.smembers(KEY)
end
# Yields URLs for dirty entitities.
# The entity will only be marked as clean if the block returns truthy.
# It is possible to call +next+ or +break+ from the block.
def sweep(limit = 0)
unswept = []
while (url = @redis.spop(KEY))
unswept.push url
is_swept = !! yield(url)
unswept.pop if is_swept
break if (limit -=1).zero?
end
ensure
@redis.sadd(KEY, unswept) if unswept.any?
end
# Number of currently dirty entities.
def count
@redis.scard(KEY)
end
end
end
end
Version data entries
31 entries across 31 versions & 1 rubygems