A QUICK INTRODUCTION TO THE CASCADING ECOSYSTEM

Chris K Wensel | Hadoop Summit EU 2014

• Lead developer of the Cascading open-source project

• Founder of Concurrent, Inc.

• Involved with Apache Hadoop since it was called Apache Nutch

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• Systems Architect, not a Data Scientist

WHO AM I?

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For creating data oriented applications, frameworks, and languages [on Apache Hadoop]

Originally designed to hide complexity of Hadoop and prevent thinking in MapReduce

cascading.org

• Started in 2007

• 2.0 released June 2012

• 2.5 out now

• 3.0 WIP (if you look for it)

• Apache 2.0 Licensed

• Supports all Hadoop distros

SOME STATS

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What’s it used for?

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• Cascading Java API

• Data normalization and cleansing of search and click-through

logs for use by analytics tools

• Easy to operationalize heavy lifting of data

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• Cascalog (Clojure)

• Weather pattern modeling to protect growers against loss

• ETL against 20+ datasets daily

• Machine learning to create models

• Purchased by Monsanto for $930M US

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• Scalding (Scala)

• Machine learning (linear algebra) to improve

• User experience

• Ad quality (matching users and ad effectiveness)

• All revenue applications are running on Cascading/Scalding

• IPO

TWITTER

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• Estimate suicide risk from what people write online

• Cascading + Cassandra

• You can do more than optimize add yields

• http://www.durkheimproject.org

KEY PROJECTS

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Lingual Pattern

Cascading

Apache Hadoop

Scalding Cascalog

• Java API (alternative to Hadoop MapReduce)

• Separates business logic from integration

• Testable at every lifecycle stage

• Works with any JVM language

• Many integration adapters

CASCADING

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Process Planner

Processing API Integration APIScheduler API

Scheduler

Apache Hadoop

Cascading

Data Stores

ScriptingScala, Clojure, JRuby, Jython, Groovy

Enterprise Java

• Functions • Filters • Joins ‣ Inner / Outer / Mixed ‣ Asymmetrical / Symmetrical

• Merge (Union) • Grouping ‣ Secondary Sorting ‣ Unique (Distinct)

• Aggregations ‣ Count, Average, etc ‣ Rolling windows

SOME COMMON PATTERNS

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filter

filter

function

functionfilterfunctiondata

PipelineSplit Join

Merge

data

Topology

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word count – Cascading Java API !String docPath = args[ 0 ];!String wcPath = args[ 1 ];!Properties properties = new Properties();!AppProps.setApplicationJarClass( properties, Main.class );!HadoopFlowConnector flowConnector = new HadoopFlowConnector( properties );!!// create source and sink taps!Tap docTap = new Hfs( new TextDelimited( true, "\t" ), docPath );!Tap wcTap = new Hfs( new TextDelimited( true, "\t" ), wcPath );!!// specify a regex to split "document" text lines into token stream!Fields token = new Fields( "token" );!Fields text = new Fields( "text" );!RegexSplitGenerator splitter = new RegexSplitGenerator( token, "[ \\[\\]\\(\\),.]" );!// only returns "token"!Pipe docPipe = new Each( "token", text, splitter, Fields.RESULTS );!// determine the word counts!Pipe wcPipe = new Pipe( "wc", docPipe );!wcPipe = new GroupBy( wcPipe, token );!wcPipe = new Every( wcPipe, Fields.ALL, new Count(), Fields.ALL );!!// connect the taps, pipes, etc., into a flow definition!FlowDef flowDef = FlowDef.flowDef().setName( "wc" )! .addSource( docPipe, docTap )! .addTailSink( wcPipe, wcTap );!// create the Flow!Flow wcFlow = flowConnector.connect( flowDef ); // <<-- Unit of Work!wcFlow.writeDOT( "wc.dot" ); // <<-- On Next Slide!wcFlow.complete(); // <<-- Runs jobs on Cluster

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scheduling

processing

integration

configuration

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map

reduceEvery('wc')[Count[decl:'count']]

Hfs['TextDelimited[[UNKNOWN]->['token', 'count']]']['output/wc']']

GroupBy('wc')[by:['token']]

Each('token')[RegexSplitGenerator[decl:'token'][args:1]]

Hfs['TextDelimited[['doc_id', 'text']->[ALL]]']['data/rain.txt']']

[head]

[tail]

[{2}:'token', 'count'][{1}:'token']

[{2}:'doc_id', 'text'][{2}:'doc_id', 'text']

wc[{1}:'token'][{1}:'token']

[{2}:'token', 'count'][{2}:'token', 'count']

[{1}:'token'][{1}:'token']

wc.dot

A REAL WORLD APP

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[1/75] map+reduce

[2/75] map+reduce [3/75] map+reduce [4/75] map+reduce[5/75] map+reduce [6/75] map+reduce[7/75] map+reduce [8/75] map+reduce [9/75] map+reduce[10/75] map+reduce [11/75] map+reduce [12/75] map+reduce[13/75] map+reduce [14/75] map+reduce [15/75] map+reduce[16/75] map+reduce [17/75] map+reduce [18/75] map+reduce

[19/75] map+reduce [20/75] map+reduce[21/75] map+reduce [22/75] map+reduce[23/75] map+reduce [24/75] map+reduce[25/75] map+reduce [26/75] map+reduce[27/75] map+reduce [28/75] map+reduce [29/75] map+reduce [30/75] map+reduce[31/75] map+reduce[32/75] map+reduce [33/75] map+reduce [34/75] map+reduce [35/75] map+reduce

[36/75] map+reduce

[37/75] map+reduce

[38/75] map+reduce[39/75] map+reduce [40/75] map+reduce[41/75] map+reduce [42/75] map+reduce[43/75] map+reduce [44/75] map+reduce[45/75] map+reduce [46/75] map+reduce [47/75] map+reduce [48/75] map+reduce[49/75] map+reduce[50/75] map+reduce [51/75] map+reduce [52/75] map+reduce [53/75] map+reduce

[54/75] map+reduce

[55/75] map [56/75] map+reduce [57/75] map[58/75] map[59/75] map

[60/75] map [61/75] map[62/75] map

[63/75] map+reduce[64/75] map+reduce [65/75] map+reduce [66/75] map+reduce[67/75] map+reduce[68/75] map+reduce [69/75] map+reduce[70/75] map+reduce

[71/75] map [72/75] map

[73/75] map+reduce [74/75] map+reduce

[75/75] map+reduce

1 App, 1 Flow, 75 Steps/MRJobs !green = map + reduce purple = map blue = join/merge orange = map split

A graph of jobs, not operations!

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It’s not just for Java

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word count – Scalding (Scala) // Sujit Pal!// sujitpal.blogspot.com/2012/08/scalding-for-impatient.html!!

package com.mycompany.impatient!!

import com.twitter.scalding._!!

class Part2(args : Args) extends Job(args) {!  val input = Tsv(args("input"), ('docId, 'text))!  val output = Tsv(args("output"))!  input.read.!    flatMap('text -> 'word) {! text : String => text.split("""\s+""")! }.!    groupBy('word) { group => group.size }.!    write(output)!}!

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word count – Cascalog (Clojure) ; Paul Lam!; github.com/Quantisan/Impatient!!(ns impatient.core!  (:use [cascalog.api]!        [cascalog.more-taps :only (hfs-delimited)])!  (:require [clojure.string :as s]!            [cascalog.ops :as c])!  (:gen-class))!!(defmapcatop split [line]!  "reads in a line of string and splits it by regex"!  (s/split line #"[\[\]\\\(\),.)\s]+"))!!(defn -main [in out & args]!  (?<- (hfs-delimited out)!       [?word ?count]!       ((hfs-delimited in :skip-header? true) _ ?line)!       (split ?line :> ?word)!       (c/count ?count)))!

• Step by step tutorials on Cascading on GitHub

• Community has ported them to Scalding and Cascalog

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• http://docs.cascading.org/impatient/

“FOR THE IMPATIENT” SERIES

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• Foundation of patterns and best practices for building

Languages, Frameworks, and Applications

• Designed to abstract Hadoop away from the business logic

• Other models than MapReduce on the way!

WHY CASCADING?

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• ANSI Compatible SQL

• JDBC Driver

• Cascading Java API

• SQL Command Shell

• Catalog Manager Tool

• Data Provider API

LINGUAL

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Query Planner

JDBC API Lingual APIProvider API

Cascading

Apache HadoopLingual

Data Stores

CLI / Shell Enterprise Java

Catalog

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Cascading API !

FlowDef flowDef = FlowDef.flowDef()! .setName( "sqlflow" )! .addSource( "example.employee", emplTap )! .addSource( "example.sales", salesTap )! .addSink( "results", resultsTap );! !SQLPlanner sqlPlanner = new SQLPlanner()! .setSql( sqlStatement );! !flowDef.addAssemblyPlanner( sqlPlanner );!

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JDBC driver public void run() throws ClassNotFoundException, SQLException {! Class.forName( "cascading.lingual.jdbc.Driver" );! Connection connection =! DriverManager.getConnection(! "jdbc:lingual:local;schemas=src/main/resources/data/example" );! Statement statement = connection.createStatement();! ! ResultSet resultSet = statement.executeQuery(! "select *\n"! + "from \"EXAMPLE\".\"SALES_FACT_1997\" as s\n"! + "join \"EXAMPLE\".\"EMPLOYEE\" as e\n"! + "on e.\"EMPID\" = s.\"CUST_ID\"" );! ! // do something!  ! resultSet.close();! statement.close();! connection.close();! }

SHELL - !TABLES

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# load the JDBC package!library(RJDBC)! !# set up the driver!drv <- JDBC("cascading.lingual.jdbc.Driver", ! "~/src/concur/lingual/lingual-local/build/libs/lingual-local-1.0.0-wip-dev-jdbc.jar")! !# set up a database connection to a local repository!connection <- dbConnect(drv, ! "jdbc:lingual:local;catalog=~/src/concur/lingual/lingual-examples/tables;schema=EMPLOYEES")! !# query the repository: in this case the MySQL sample database (CSV files)!df <- dbGetQuery(connection, ! "SELECT * FROM EMPLOYEES.EMPLOYEES WHERE FIRST_NAME = 'Gina'")!head(df)! !# use R functions to summarize and visualize part of the data!df$hire_age <- as.integer(as.Date(df$HIRE_DATE) - as.Date(df$BIRTH_DATE)) / 365.25!summary(df$hire_age)!!library(ggplot2)!m <- ggplot(df, aes(x=hire_age))!m <- m + ggtitle("Age at hire, people named Gina")!m + geom_histogram(binwidth=1, aes(y=..density.., fill=..count..)) + geom_density()

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> summary(df$hire_age) Min. 1st Qu. Median Mean 3rd Qu. Max. 20.86 27.89 31.70 31.61 35.01 43.92

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“But we use a custom data format”

• Any Cascading Tap and/or Scheme can be used from JDBC

• Use a “fat jar” on local disk or from a Maven repo

‣ cascading-jdbc:cascading-jdbc-oracle-provider:1.0

• The Jar is dynamically loaded into cluster

DATA PROVIDER API

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Amazon Elastic MapReduceJob Job Job Job

SELECT ... FROM file1 JOIN file2 ON file1.id = file2.id ...

Amazon S3

Amazon RedShift

file1 file2

results

• Quickly migrate existing work loads from RDBMS to Hadoop

• Quickly extract data from Hadoop into applications

WHY LINGUAL

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• Predictive model scoring • Java API and PMML parser • Supports: ‣ (General) Regression ‣ Clustering ‣ Decisions Trees ‣ Random Forest ‣ and ensembles of models

PATTERN

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PMML Parser Pattern API

Cascading

Apache Hadoop

Pattern

Data Stores

Enterprise Java

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FlowDef flowDef = FlowDef.flowDef()! .setName( "classifier" )! .addSource( "input", inputTap )! .addSink( "classify", classifyTap );! !PMMLPlanner pmmlPlanner = new PMMLPlanner()! .setPMMLInput( new File( pmmlModel ) )! .retainOnlyActiveIncomingFields();! !flowDef.addAssemblyPlanner( pmmlPlanner );!!

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• Standards compliance provides integration with many tools

• Models are independent of data and integration

• Only debugging Cascading, not an ensemble of applications

WHY PATTERN

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CLOSING THE LOOP

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Cluster

Pattern

Desktop

Job

PMMLFlow

JDBCFlowimport data

create models

export models

execute models

import resultsJDBC

Flow

PMML

DATA

DATA

test results

Job Job

• Understand how your application maps onto your cluster

• Identify bottlenecks (data, code, or the system)

• Jump to the line of code implicated on a failure

• Plugin available via Maven repo

• Beta UI hosted online

DRIVEN

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http://cascading.io/driven/

MANAGED WITH DRIVEN

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• New query planner ‣ User definable Assertion and Transformation rules

‣ Sub-Graph Isomorphism Pattern Matching

‣ Cordella, L. P., Foggia, P., Sansone, C., & VENTO, M. (2004). A (sub)graph isomorphism algorithm for matching large graphs. IEEE Transactions on Pattern Analysis and Machine Intelligence, 26(10), 1367–1372. doi:10.1109/TPAMI.2004.75

• Hadoop Tez support • And likely other platforms

CASCADING 3.0

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THERE’S A BOOK!

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Enterprise Data Workflows with Cascading

- Paco Nathan

O’Reilly, 2013 amazon.com/dp/1449358721

CONTACT

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@cwensel | @cascading

chris@wensel.net

www.cascading.org

www.concurrentinc.com