Storm and Cassandra
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The document discusses Apache Storm, a distributed event processor that enables reliable event handling through spouts, bolts, and tuples. It highlights the integration of Storm with Cassandra for web scraping applications, exemplified by the 'stormscraper' system, which structure allows efficient data processing and asynchronous updates. Key topology and data model concepts are presented, emphasizing the potential pitfalls in implementation.
Storm and Cassandra
- 1. Storm and Cassandra Cassandra NYC Meetup 11/5/2013 Jake Luciani (@tjake)
- 2. What is Storm? • Distributed event processor • Provides constructs to reliably process all events • Simple conceptual model • New to Apache Incubator: http://wiki.apache.org/incubator/StormProposal
- 3. Storm Concepts Spout - Collects work and submits it to be processed. Tracks success or failure of each tuple. … Tuple - A collection of data that is passed within storm. Bolt - Processes tuples and optionally emits more tuples. Stream - Identifies outputs from a Spout/Bolt. Forces tuples have some declared structure.
- 4. Storm Topologies A directed graph of spouts and bolts connected via streams A-F G-P Firehose Zookeeper Q-Z Host A Host B Host C Cassandra (optional)
- 5. Example Topologies • Track the top 10 most popular links being shared in the last N minutes.
- 6. Where does data end up? • Storm supports built in RPC so client requests can effectively become a spout. ! • Put the data into a database… • Why Cassandra though?
- 7. Why Cassandra? • Cassandra’s Data model allows incremental modifications to rows. • Different bolts can update different parts of a Cassandra row asynchronously.
- 8. Example
- 9. StormScraper! A web crawling system built on Storm + Cassandra ! http://github.com/tjake/stormscraper
- 10. StormScraper C* DataModel ! CREATE TABLE scrape_list ( url text PRIMARY KEY, last_update timestamp, depth int ); CREATE TABLE pages ( url text, scrape_date timestamp, title text, html text, text text, inbound_links set<text>, outbound_links set<text>, PRIMARY KEY (url, scrape_date) );
- 20. StormScraper Topology Html Writer Url Spout Scraper Bolt Link Writer Cassandra
- 21. StormScraper Topology Html Writer Url Spout Scraper Bolt Link Writer Text Extraction Bolt Cassandra
- 22. StormScraper Topology Html Writer Url Spout Scraper Bolt Link Writer Text Extraction Bolt Cassandra Text Writer
- 23. StormScraper Topology Html Writer Url Spout Scraper Bolt Link Writer Text Extraction Bolt Cassandra Text Writer
- 24. StormScraper Topology Html Writer Url Spout Scraper Bolt Link Writer Text Extraction Bolt Cassandra Text Writer
- 25. StormScraper Topology Html Writer Url Spout Scraper Bolt Link Writer Text Extraction Bolt Cassandra Text Writer
- 26. StormScraper Topology Html Writer Url Spout Scraper Bolt Link Writer Text Extraction Bolt Cassandra Text Writer
- 27. StormScraper Topology Html Writer Url Spout Scraper Bolt Link Writer Text Extraction Bolt Cassandra Text Writer
- 28. StormScraper Topology Fail Html Writer Url Spout Scraper Bolt Link Writer Text Extraction Bolt Cassandra Text Writer
- 29. StormScraper Topology Fail Html Writer Url Spout Scraper Bolt Link Writer Text Extraction Bolt Cassandra Text Writer
- 30. StormScraper Topology Fail Html Writer Url Spout Scraper Bolt Link Writer Text Extraction Bolt Cassandra Text Writer
- 32. Storm Summary • Powerful • But easy to make mistakes • Wrong tuple expectation, names, types • Bad topology wiring
- 33. Thank You! Q&A?