Sparkler - Spark Crawler
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The document presents an overview of Sparkler, an open-source web crawler developed by the University of Southern California's Information Retrieval and Data Science Group, which is modeled after Apache Nutch but operates on Apache Spark. It addresses challenges faced in previous projects by offering real-time analytics, enhanced fault tolerance, and customizability, with features like JavaScript rendering and integration with Apache Kafka for output management. Looking ahead, the Sparkler team plans to improve user interfaces, add more plugins, and contribute to the Apache Incubator.
![SPARKLER #3: OSGI Plugins
Information Retrieval
and Data Science
● Plugins Interfaces are inspired by Nutch
● Plugins are developed as per Open Service Gateway
Interface (OSGI)
● We chose Apache Felix implementation of OSGI
● Migrated a plugin from Nutch
○ Regex URL Filter Plugin → The most used plugin in
Nutch
● Added JavaScript plugin (described in the next slide)
● //TODO: Migrate more plugins from Nutch
○ Mavenize nutch [NUTCH-2293]](https://image.slidesharecdn.com/sparkler-apacheconeu-161115154609/85/Sparkler-Spark-Crawler-19-320.jpg)
Sparkler - Spark Crawler
- 1. Nov 15th 2016 @ Apache Big Data EU 2016, Seville, Spain Thamme GowdaKaranjeet Singh SPARKLER Information Retrieval and Data Science Chris Mattmann
- 2. ABOUT: USC INFORMATION RETRIEVAL AND DATA SCIENCE GROUP ● Established in August 2012 at the University of Southern California (USC) ● Dr. Chris Mattmann, Director of IRDS and our Advisor ● Funding from NSF, DARPA, NASA, DHS, private industry and other agencies - in collaboration with NASA JPL ● 3 Postdocs, and 30+ Masters and PhD students, 20+ JPLers past 7 years ● Recent topical research in the DARPA XDATA/MEMEX program Information Retrieval and Data Science Email : irds-L@mymaillists.usc.edu Website : http://irds.usc.edu/ GitHub : https://github.com/USCDataScience/
- 3. ABOUT: US Karanjeet Singh Graduate Student at the University of Southern California, USA Research Interest: Information Retrieval & Natural Language Processing Research Affiliate at NASA Jet Propulsion Laboratory Committer and PMC member of Apache Nutch Information Retrieval and Data Science Thamme Gowda Graduate Student at the University of Southern California, USA Research Intern at NASA Jet Propulsion Laboratory, Co Founder at Datoin Research Interest: NLP, Machine Learning and Information Retrieval Committer and PMC member of Apache Nutch, Tika, and Joshua (Incubating) Dr. Chris Mattmann Director & Vice Chairman, Apache Software Foundation Research Interest: Data Science, Open Source, Information Retrieval & NLP Committer and PMC member of Apache Nutch, Tika, (former) Lucene, OODT, Incubator
- 4. OVERVIEW ● About Sparkler ● Motivations for building Sparkler ● Quick intro to Apache Spark ● Sparkler technology stack, internals ● Features of Sparkler ● Comparison with Nutch ● Going forward Information Retrieval and Data Science
- 5. ABOUT: SPARKLER ● New Open Source Web Crawler ○ A bot program that can fetch resources from the web ● Name: Spark Crawler ● Inspired by Apache Nutch ● Like Nutch: Distributed crawler that can scale horizontally ● Unlike Nutch: Runs on top of Apache Spark ● Easy to deploy and easy to use Information Retrieval and Data Science
- 6. Information Retrieval and Data Science MOTIVATION #1 ● Challenges in DARPA MEMEX ○ Intro: MEMEX System has crawlers to fetch deep and dark web data for assisting law keeping agencies ○ Crawls are kind of blackbox, we wanted real-time progress reports ● Dr. Chris Mattmann was considering an upgrade since 3 years ● Technology upgrade needed
- 7. Information Retrieval and Data Science https://twitter.com/cutting/status/796566255830503424 Modern Hadoop cluster has no Hadoop (Map-Reduce) left in it! WHY A NEW CRAWLER?
- 8. Information Retrieval and Data Science MOTIVATION #2 ● Challenges at DATOIN ○ Intro: Datoin is a distributed text analytics platform ○ Late 2014 - migrated the infrastructure from Hadoop Map Reduce to Apache Spark ○ But the crawler component (powered by Apache Nutch) was left behind ● Met Dr. Chris Mattmann at USC in Web Search Engines class ○ Enquired about his thoughts for running Nutch on Spark ○ Agreed to work on it.
- 9. ● High performance & Fault tolerance ● Real time crawl analysis ● Easy to customize Is the food ready? How is it going? I want less salt. Information Retrieval and Data Science KEY FEATURES
- 10. APACHE SPARK: OVERVIEW ● Introduction ● Resilient Distributed Dataset (RDD) ● Driver, Workers & Executors Information Retrieval and Data Science
- 11. APACHE SPARK: INTRODUCTION ● Fast and general engine for large scale data processing ● Started at UC Berkeley in 2009 ● The most popular distributed computing framework ● Provides high level APIs in Scala, Java, Python, R ● Integration with Hadoop and its ecosystem ● Open sourced in 2010 under Apache v2.0 license ● Mattmann helped to bring Spark to Apache under DARPA XDATA effort Information Retrieval and Data Science
- 12. Resilient Distributed Dataset (RDD) ● A basic abstraction in Spark ● Immutable, Partitioned collection of elements operated in parallel ● Data in persistent store (HDFS, Cassandra) or in cache (memory, disk) ● Partitions are recomputed on failure or cache eviction ● Two classes of operations ○ Transformations ○ Actions ● Custom RDDs can also be implemented - we have one! Information Retrieval and Data Science
- 13. Information Retrieval and Data Science Driver, Workers & Executors * Photo credit - spark.apache.org
- 14. SPARKLER: TECH STACK ● Batch crawling (similar to Apache Nutch) ● Apache Solr as crawl database ● Multi module Maven project with OSGi bundles ● Stream crawled content through Apache Kafka ● Parses everything using Apache Tika ● Crawl visualization - Banana Information Retrieval and Data Science
- 15. SPARKLER: INTERNALS & WORKFLOW Information Retrieval and Data Science
- 16. SPARKLER: FEATURES Information Retrieval and Data Science
- 17. ● Crawldb needed indexing ○ For real time analytics ○ For instant visualizations ● This is internal data structure of sparkler ○ Exposed over REST API ○ Used by Sparkler-ui, the web application ● We chose Apache Solr ● Standalone Solr Server or Solr Cloud? ● Glued the crawldb and spark using CrawldbRDD SPARKLER #1: Lucene/Solr powered Crawldb Information Retrieval and Data Science
- 18. SPARKLER #2: Partitioning by host Information Retrieval and Data Science ● Politeness * Doesn’t hit same server too many times in distributed mode ● First version ○ Group by: Host name ○ Sort by: depth, score ● Customization is easy ○ Write your own Solr query ○ Take advantage of boosting to alter the ranking ● Partitions the dataset based on the above criteria ● Lazy evaluations and delay between the requests ■ Performs parsing instead of waiting ■ Inserts delay only when it is necessary
- 19. SPARKLER #3: OSGI Plugins Information Retrieval and Data Science ● Plugins Interfaces are inspired by Nutch ● Plugins are developed as per Open Service Gateway Interface (OSGI) ● We chose Apache Felix implementation of OSGI ● Migrated a plugin from Nutch ○ Regex URL Filter Plugin → The most used plugin in Nutch ● Added JavaScript plugin (described in the next slide) ● //TODO: Migrate more plugins from Nutch ○ Mavenize nutch [NUTCH-2293]
- 20. SPARKLER #4: JavaScript Rendering Information Retrieval and Data Science ● Java Script Execution* has first class support ● Distributable on Spark Cluster without pain ○ Pure JVM based JavaScript engine ● This is an implementation of FetchFunction ● FetchFunction ○ Stream<URL> → Stream<Content> ○ Note: URLS are grouped by host ○ It preserves cookies and reuses sessions for each iteration Thanks to: Madhav Sharan Member of USC IRDS* JBrowserDriver by MachinePublishers
- 21. SPARKLER #5: Output in Kafka Streams Information Retrieval and Data Science ● Crawler is sometimes input for the applications that does deeper analysis ○ Can’t fit all those deeper analysis into crawler ● Integrating to such applications made easy via Queues ● We chose Apache Kafka ○ Suits our need ■ Distributable, Scalable, Fault Tolerant ● FIXME: Larger messages such as Videos ● This is optional, default output on Shared File System (such as HDFS), compatible with Nutch * Thanks to: Rahul Palamuttam MS CS @ Stanford University; Intern @ NASA JPL)
- 22. SPARKLER #6: Tika, the universal parser Information Retrieval and Data Science ● Apache Tika ○ Is a toolkit of parsers ○ Detects and extracts metadata, text, and URLS ○ Over a thousand different file types ● Main application is to discover outgoing links ● The default Implementation for our ParseFunction
- 23. SPARKLER #7: Visual Analytics Information Retrieval and Data Science ● Charts and Graphs provides nice summary of crawl job ● Real time analytics ● Example: ○ Distribution of URLS across hosts/domains ○ Temporal activities ○ Status reports ● Customizable in real time ● Using Banana Dashboard from Lucidworks ● Sparkler has a sub component named sparkler-ui * Thanks to : Manish Dwibedy MS CS University of Southern California
- 24. SPARKLER #Next: what’s coming? Information Retrieval and Data Science ● Interactive UI ● More plugins ● Scoring Crawled Pages ● Focussed Crawling ● Crawl Graph Analysis ● Domain Discovery (another research challenge) ● Other useful plugins from Nutch ● Detailed documentation and tutorials on wiki
- 25. Nutch Configuration Version : 1.12 topN : 50,000 Fetcher Thread : 1 Hadoop Configuration Version : 2.6.0-cdh5.8.2 Slaves : 2 Memory : 8G (Map), 16G (Reduce) 22 Mappers, 11 reducers HOW FAST IT RUNS - Comparison with Nutch Information Retrieval and Data Science Crawl Iterations : 5 Fetch Delay : 1 sec Sparkler Configuration Version : 0.1-SNAPSHOT topGroups : 252 topN : 1000 Spark Configuration Version : 1.6.1 with Scala v2.11 Slaves : 2 22 Worker Instances with 210G memory
- 26. Information Retrieval and Data Science DIVERSIFIED - Comparison with Nutch
- 27. Information Retrieval and Data Science Sparkler Dashboard
- 28. Information Retrieval and Data Science SPARKLER IS COMING TO APACHE proposal later this week! Look for
- 29. ● Get involved with our journey of Incubator ● Get started: Checkout README and wiki at https://github.com/USCDataScience/sparkler Information Retrieval and Data Science Questions? THANK YOU