Due to a lack of resources, this project is unfortunately discontinued. If you require clustering functionality for your ruby consumers, please refer to: https://github.com/karafka/karafka
Poseidon Cluster is a cluster extension of the excellent Poseidon Ruby client for Kafka 0.8+. It implements the distribution concept of self-rebalancing Consumer Groups and supports the consumption of a single topic from multiple instances.
Consumer group instances share a common group name, and each message published to a topic is delivered to one instance within each subscribing consumer group. Consumer instances can be in separate processes or on separate machines.
Launch a consumer group:
require 'poseidon_cluster' consumer = Poseidon::ConsumerGroup.new( "my-group", # Group name ["kafka1.host:9092", "kafka2.host:9092"], # Kafka brokers ["kafka1.host:2181", "kafka2.host:2181"], # Zookeepers hosts "my-topic") # Topic name consumer.partitions # => [0, 1, 2, 3] - all partitions of 'my-topic' consumer.claimed # => [0, 1] - partitions this instance has claimed
Fetch a bulk of messages, auto-commit the offset:
consumer.fetch do |partition, bulk| bulk.each do |m| puts "Fetched '#{m.value}' at #{m.offset} from #{partition}" end end
Get the offset for a partition:
consumer.offset(0) # => 320 - current offset from partition 0
Fetch more messages, commit manually:
consumer.fetch commit: false do |partition, bulk| bulk.each do |m| puts "Fetched '#{m.value}' at #{m.offset} from #{partition}" end consumer.commit partition, bulk.last.offset+1 unless bulk.empty? end
Initiate a fetch-loop, consume indefinitely:
consumer.fetch_loop do |partition, bulk| bulk.each do |m| puts "Fetched '#{m.value}' at #{m.offset} from #{partition}" end end
For more details and information, please see the Poseidon::ConsumerGroup documentation and the Examples.
The test suite will automatically download, configure and run Kafka locally, you only need a JRE. Run the suite via:
bundle exec rake specCopyright (c) 2014 Black Square Media
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