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Helping Travellers Make Better Hotel Choices 50...

Helping Travellers Make Better Hotel Choices 500 Million Times a Month

Presentation give at the Meetup Big Data Colombia (now Colombia IA) based on my PyCONDE 2016

Miguel Cabrera

March 15, 2017
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  1. Helping Travellers Make Better Hotel Choices 500 Million Times a

    Month Miguel Cabrera @mfcabrera https://www.flickr.com/photos/18694857@N00/5614701858/
  2. •  Neuberliner •  Ing. Sistemas e Inf. Universidad Nacional -

    Med •  M.Sc. In Informatics TUM, Hons. Technology Management. •  Work for TrustYou as Data (Scientist|Engineer| Juggler)™ •  Founder and former organizer of Munich DataGeeks ABOUT ME
  3. •  What we do •  Architecture •  Technology •  Crawling

    •  Textual Processing •  Workflow Management and Scale •  Sample Application AGENDA
  4. •  Crawling •  Natural Language Processing / Semantic Analysis • 

    Record Linkage / Deduplication •  Ranking •  Recommendation •  Classification •  Clustering Tasks
  5. Data Flow Crawling   Seman-c   Analysis    Database  

    API   Clients • Google • Kayak+ • TY Analytics
  6. Batch Layer • Hadoop • Python • Pig* • Java* Service Layer • PostgreSQL • MongoDB

    • Redis • Cassandra DATA DATA Hadoop Cluster Application Machines Stack
  7. •  Build your own web crawlers •  Extract data via

    CSS selectors, XPath, regexes, etc. •  Handles queuing, request parallelism, cookies, throttling … •  Comprehensive and well-designed •  Commercial support by http://scrapinghub.com/
  8. •  2 - 3 million new reviews/week •  Customers want

    alerts 8 - 24h after review publication! •  Smart crawl frequency & depth, but still high overhead •  Pools of constantly refreshed EC2 proxy IPs •  Direct API connections with many sites Crawling at TrustYou
  9. •  Custom framework very similar to scrapy •  Runs on

    Hadoop cluster (100 nodes) •  Not 100% suitable for MapReduce •  Nodes mostly waiting •  Coordination/messaging between nodes required: –  Distributed queue –  Rate Limiting Crawling at TrustYou
  10. Text Processing Raw  text   Setence   spli:ng   Tokenizing

      Stopwords   Stemming Topic Models Word Vectors Classification
  11. •  “great rooms” •  “great hotel” •  “rooms are terrible”

    •  “hotel is terrible” Text Processing JJ NN JJ NN NN VB JJ NN VB JJ >> nltk.pos_tag(nltk.word_tokenize("hotel is terrible")) [('hotel', 'NN'), ('is', 'VBZ'), ('terrible', 'JJ')]
  12. •  25+ languages •  Linguistic system (morphology, taggers, grammars, parsers

    …) •  Hadoop: Scale out CPU •  ~1B opinions in the database •  Python for ML & NLP libraries Semantic Analysis
  13. Luigi •  Build complex pipelines of batch jobs •  Dependency

    resolution •  Parallelism •  Resume failed jobs •  Some support for Hadoop
  14. Luigi •  Dependency definition •  Hadoop / HDFS Integration • 

    Object oriented abstraction •  Parallelism •  Resume failed jobs •  Visualization of pipelines •  Command line integration
  15. Minimal Bolerplate Code class WordCount(luigi.Task): date = luigi.DateParameter() def requires(self):

    return InputText(date) def output(self): return luigi.LocalTarget(’/tmp/%s' % self.date_interval) def run(self): count = {} for f in self.input(): for line in f.open('r'): for word in line.strip().split(): count[word] = count.get(word, 0) + 1 f = self.output().open('w') for word, count in six.iteritems(count): f.write("%s\t%d\n" % (word, count)) f.close()
  16. class WordCount(luigi.Task): date = luigi.DateParameter() def requires(self): return InputText(date) def

    output(self): return luigi.LocalTarget(’/tmp/%s' % self.date_interval) def run(self): count = {} for f in self.input(): for line in f.open('r'): for word in line.strip().split(): count[word] = count.get(word, 0) + 1 f = self.output().open('w') for word, count in six.iteritems(count): f.write("%s\t%d\n" % (word, count)) f.close() Task Parameters
  17. class WordCount(luigi.Task): date = luigi.DateParameter() def requires(self): return InputText(date) def

    output(self): return luigi.LocalTarget(’/tmp/%s' % self.date_interval) def run(self): count = {} for f in self.input(): for line in f.open('r'): for word in line.strip().split(): count[word] = count.get(word, 0) + 1 f = self.output().open('w') for word, count in six.iteritems(count): f.write("%s\t%d\n" % (word, count)) f.close() Programmatically Defined Dependencies
  18. class WordCount(luigi.Task): date = luigi.DateParameter() def requires(self): return InputText(date) def

    output(self): return luigi.LocalTarget(’/tmp/%s' % self.date_interval) def run(self): count = {} for f in self.input(): for line in f.open('r'): for word in line.strip().split(): count[word] = count.get(word, 0) + 1 f = self.output().open('w') for word, count in six.iteritems(count): f.write("%s\t%d\n" % (word, count)) f.close() Each Task produces an ouput
  19. class WordCount(luigi.Task): date = luigi.DateParameter() def requires(self): return InputText(date) def

    output(self): return luigi.LocalTarget(’/tmp/%s' % self.date_interval) def run(self): count = {} for f in self.input(): for line in f.open('r'): for word in line.strip().split(): count[word] = count.get(word, 0) + 1 f = self.output().open('w') for word, count in six.iteritems(count): f.write("%s\t%d\n" % (word, count)) f.close() Write Logic in Python
  20. Hadoop Streaming hadoop jar contrib/streaming/hadoop-*streaming*.jar \ -file /home/hduser/mapper.py -mapper /home/hduser/mapper.py

    \ -file /home/hduser/reducer.py -reducer /home/hduser/reducer.py \ -input /user/hduser/text.txt -output /user/hduser/gutenberg-output
  21. class WordCount(luigi.hadoop.JobTask): date = luigi.DateParameter() def requires(self): return InputText(date) def

    output(self): return luigi.hdfs.HdfsTarget(’%s' % self.date_interval) def mapper(self, line): for word in line.strip().split(): yield word, 1 def reducer(self, key, values): yield key, sum(values) Luigi + Hadoop/HDFS
  22. Before •  Bash scripts + Cron •  Manual cleanup • 

    Manual failure recovery •  Hard(er) to debug
  23. We use it for… •  Standalone executables •  Dump data

    from databases •  General Hadoop Streaming •  Bash Scripts / MRJob •  Pig* Scripts
  24. Snippets from Reviews “Hips don’t lie” “Maid was banging” “Beautiful

    bowl flowers” “Irish dance, I love that” “No ghost sighting” “One ghost touching” “Too much cardio, not enough squats in the gym” “it is like hugging a bony super model”
  25. from gensim.models.doc2vec import Doc2Vec class LearnModelTask(luigi.Task): # Parameters.... blah blah

    blah def output(self): return luigi.LocalTarget(os.path.join(self.output_directory, self.model_out)) def requires(self): return LearnBigramsTask() def run(self): sentences = LabeledClusterIDSentence(self.input().path) model = Doc2Vec(sentences=sentences, size=int(self.size), dm=int(self.distmem), negative=int(self.negative), workers=int(self.workers), window=int(self.window), min_count=int(self.min_count), train_words=True) model.save(self.output().path)
  26. Takeaways •  It is possible to use Python as the

    primary language for doing large data processing on Hadoop. •  It is not a perfect setup but works well most of the time. •  Keep your ecosystem open to other technologies.