class Druid::ZK
Public Class Methods
new(uri, opts = {})
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# File lib/druid/zk.rb, line 7 def initialize(uri, opts = {}) @zk = ::ZK.new(uri, chroot: :check) @registry = Hash.new { |hash, key| hash[key] = Array.new } @discovery_path = opts[:discovery_path] || '/discovery' @watched_services = Hash.new register end
Public Instance Methods
check_service(service)
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# File lib/druid/zk.rb, line 91 def check_service(service) return if @watched_services.include?(service) watch_service(service) known = @registry[service].map { |node| node[:name] } live = @zk.children(watch_path(service), watch: true) new_list = @registry[service].select { |node| live.include?(node[:name]) } $log.debug("druid.zk checking", service: service, known: known, live: live, new_list: new_list) if $log # verify the new entries to be living brokers (live - known).each do |name| uri, sources = verify_broker(service, name) new_list.push({ name: name, uri: uri, data_sources: sources }) if uri end if new_list.empty? # don't show services w/o active brokers unregister_service(service) else register_service(service, new_list) end end
check_services()
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# File lib/druid/zk.rb, line 59 def check_services $log.debug("druid.zk checking services") if $log zk_services = @zk.children(@discovery_path, watch: true) (services - zk_services).each do |service| unregister_service(service) end zk_services.each do |service| check_service(service) end end
close!()
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# File lib/druid/zk.rb, line 25 def close! $log.debug("druid.zk shutting down") if $log @zk.close! end
data_sources()
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# File lib/druid/zk.rb, line 119 def data_sources result = Hash.new { |hash, key| hash[key] = [] } @registry.each do |service, brokers| brokers.each do |broker| broker[:data_sources].each do |data_source| result["#{service}/#{data_source}"] << broker[:uri] end end end result.each do |source, uris| result[source] = uris.sample if uris.respond_to?(:sample) end result end
register()
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# File lib/druid/zk.rb, line 15 def register $log.debug("druid.zk register discovery path") if $log @zk.on_expired_session { register } @zk.register(@discovery_path, only: :child) do |event| $log.debug("druid.zk got event on discovery path") if $log check_services end check_services end
register_service(service, brokers)
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# File lib/druid/zk.rb, line 30 def register_service(service, brokers) $log.debug("druid.zk register", service: service, brokers: brokers) if $log # poor mans load balancing @registry[service] = brokers.shuffle end
services()
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# File lib/druid/zk.rb, line 115 def services @registry.keys end
to_s()
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# File lib/druid/zk.rb, line 137 def to_s @registry.to_s end
unregister_service(service)
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# File lib/druid/zk.rb, line 36 def unregister_service(service) $log.debug("druid.zk unregister", service: service) if $log @registry.delete(service) unwatch_service(service) end
unwatch_service(service)
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# File lib/druid/zk.rb, line 53 def unwatch_service(service) return unless @watched_services.include?(service) $log.debug("druid.zk unwatch", service: service) if $log @watched_services.delete(service).unregister end
verify_broker(service, name)
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# File lib/druid/zk.rb, line 72 def verify_broker(service, name) $log.debug("druid.zk verify", broker: name, service: service) if $log info = @zk.get("#{watch_path(service)}/#{name}") node = MultiJson.load(info[0]) uri = "http://#{node['address']}:#{node['port']}/druid/v2/" check = RestClient::Request.execute({ method: :get, url: "#{uri}datasources/", timeout: 5, open_timeout: 5 }) $log.debug("druid.zk verified", uri: uri, sources: check) if $log return [uri, MultiJson.load(check.to_str)] if check.code == 200 rescue return false end
watch_path(service)
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# File lib/druid/zk.rb, line 87 def watch_path(service) "#{@discovery_path}/#{service}" end
watch_service(service)
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# File lib/druid/zk.rb, line 42 def watch_service(service) return if @watched_services.include?(service) $log.debug("druid.zk watch", service: service) if $log watch = @zk.register(watch_path(service), only: :child) do |event| $log.debug("druid.zk got event on watch path for", service: service, event: event) if $log unwatch_service(service) check_service(service) end @watched_services[service] = watch end