Apache Spark - A unified analytics engine for large-scale data processing
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Ilya Ganelin c5ed510135 [SPARK-6703][Core] Provide a way to discover existing SparkContext's
I've added a static getOrCreate method to the static SparkContext object that allows one to either retrieve a previously created SparkContext or to instantiate a new one with the provided config. The method accepts an optional SparkConf to make usage intuitive.

Still working on a test for this, basically want to create a new context from scratch, then ensure that subsequent calls don't overwrite that.

Author: Ilya Ganelin <ilya.ganelin@capitalone.com>

Closes #5501 from ilganeli/SPARK-6703 and squashes the following commits:

db9a963 [Ilya Ganelin] Closing second spark context
1dc0444 [Ilya Ganelin] Added ref equality check
8c884fa [Ilya Ganelin] Made getOrCreate synchronized
cb0c6b7 [Ilya Ganelin] Doc updates and code cleanup
270cfe3 [Ilya Ganelin] [SPARK-6703] Documentation fixes
15e8dea [Ilya Ganelin] Updated comments and added MiMa Exclude
0e1567c [Ilya Ganelin] Got rid of unecessary option for AtomicReference
dfec4da [Ilya Ganelin] Changed activeContext to AtomicReference
733ec9f [Ilya Ganelin] Fixed some bugs in test code
8be2f83 [Ilya Ganelin] Replaced match with if
e92caf7 [Ilya Ganelin] [SPARK-6703] Added test to ensure that getOrCreate both allows creation, retrieval, and a second context if desired
a99032f [Ilya Ganelin] Spacing fix
d7a06b8 [Ilya Ganelin] Updated SparkConf class to add getOrCreate method. Started test suite implementation
2015-04-17 18:28:42 -07:00
assembly [SPARK-6371] [build] Update version to 1.4.0-SNAPSHOT. 2015-03-20 18:43:57 +00:00
bagel [SPARK-6758]block the right jetty package in log 2015-04-09 17:44:08 -04:00
bin [SPARK-4897] [PySpark] Python 3 support 2015-04-16 16:20:57 -07:00
build SPARK-5856: In Maven build script, launch Zinc with more memory 2015-02-17 10:10:01 -08:00
conf [SPARK-6758]block the right jetty package in log 2015-04-09 17:44:08 -04:00
core [SPARK-6703][Core] Provide a way to discover existing SparkContext's 2015-04-17 18:28:42 -07:00
data/mllib [SPARK-5939][MLLib] make FPGrowth example app take parameters 2015-02-23 08:47:28 -08:00
dev [SPARK-4897] [PySpark] Python 3 support 2015-04-16 16:20:57 -07:00
docker [SPARK-1342] Scala 2.10.4 2014-04-01 18:35:50 -07:00
docs SPARK-6988 : Fix documentation regarding DataFrames using the Java API 2015-04-17 16:27:02 -05:00
ec2 [SPARK-4897] [PySpark] Python 3 support 2015-04-16 16:20:57 -07:00
examples [SPARK-6113] [ml] Stabilize DecisionTree API 2015-04-17 13:15:36 -07:00
external [Streaming][minor] Remove additional quote and unneeded imports 2015-04-16 10:39:02 +01:00
extras [SPARK-6440][CORE]Handle IPv6 addresses properly when constructing URI 2015-04-13 12:55:25 +01:00
graphx SPARK-6710 GraphX Fixed Wrong initial bias in GraphX SVDPlusPlus 2015-04-11 21:01:23 -07:00
launcher [SPARK-6890] [core] Fix launcher lib work with SPARK_PREPEND_CLASSES. 2015-04-14 18:51:39 -07:00
mllib [SPARK-6113] [ml] Stabilize DecisionTree API 2015-04-17 13:15:36 -07:00
network [SPARK-5931][CORE] Use consistent naming for time properties 2015-04-13 16:28:07 -07:00
project [SPARK-6703][Core] Provide a way to discover existing SparkContext's 2015-04-17 18:28:42 -07:00
python Minor fix to SPARK-6958: Improve Python docstring for DataFrame.sort. 2015-04-17 16:30:13 -05:00
R [SPARK-6807] [SparkR] Merge recent SparkR-pkg changes 2015-04-17 13:42:19 -07:00
repl [SPARK-6758]block the right jetty package in log 2015-04-09 17:44:08 -04:00
sbin [SPARK-6952] Handle long args when detecting PID reuse 2015-04-17 11:08:37 +01:00
sbt Adde LICENSE Header to build/mvn, build/sbt and sbt/sbt 2014-12-29 10:48:53 -08:00
sql [SPARK-6807] [SparkR] Merge recent SparkR-pkg changes 2015-04-17 13:42:19 -07:00
streaming [SPARK-6796][Streaming][WebUI] Add "Active Batches" and "Completed Batches" lists to StreamingPage 2015-04-14 16:51:36 -07:00
tools [SPARK-6428] Turn on explicit type checking for public methods. 2015-04-03 01:25:02 -07:00
yarn [SPARK-2669] [yarn] Distribute client configuration to AM. 2015-04-17 14:21:51 -05:00
.gitattributes [SPARK-3870] EOL character enforcement 2014-10-31 12:39:52 -07:00
.gitignore [SPARK-5654] Integrate SparkR 2015-04-08 22:45:40 -07:00
.rat-excludes [SPARK-5654] Integrate SparkR 2015-04-08 22:45:40 -07:00
CONTRIBUTING.md [Docs] minor grammar fix 2014-09-17 12:33:09 -07:00
LICENSE SPARK-5984: Fix TimSort bug causes ArrayOutOfBoundsException 2015-02-28 18:55:34 -08:00
make-distribution.sh [SPARK-6406] Launch Spark using assembly jar instead of a separate launcher jar 2015-03-29 12:40:37 +01:00
NOTICE SPARK-1827. LICENSE and NOTICE files need a refresh to contain transitive dependency info 2014-05-14 09:38:33 -07:00
pom.xml SPARK-6861 [BUILD] Scalastyle config prevents building Maven child modules alone 2015-04-15 15:17:58 +01:00
README.md [docs] [SPARK-6306] Readme points to dead link 2015-03-12 15:01:33 +00:00
scalastyle-config.xml [SPARK-6428] Turn on explicit type checking for public methods. 2015-04-03 01:25:02 -07:00
tox.ini [SPARK-3073] [PySpark] use external sort in sortBy() and sortByKey() 2014-08-26 16:57:40 -07:00

Apache Spark

Spark is a fast and general cluster computing system for Big Data. It provides high-level APIs in Scala, Java, and Python, and an optimized engine that supports general computation graphs for data analysis. It also supports a rich set of higher-level tools including Spark SQL for SQL and structured data processing, MLlib for machine learning, GraphX for graph processing, and Spark Streaming for stream processing.

http://spark.apache.org/

Online Documentation

You can find the latest Spark documentation, including a programming guide, on the project web page and project wiki. This README file only contains basic setup instructions.

Building Spark

Spark is built using Apache Maven. To build Spark and its example programs, run:

mvn -DskipTests clean package

(You do not need to do this if you downloaded a pre-built package.) More detailed documentation is available from the project site, at "Building Spark".

Interactive Scala Shell

The easiest way to start using Spark is through the Scala shell:

./bin/spark-shell

Try the following command, which should return 1000:

scala> sc.parallelize(1 to 1000).count()

Interactive Python Shell

Alternatively, if you prefer Python, you can use the Python shell:

./bin/pyspark

And run the following command, which should also return 1000:

>>> sc.parallelize(range(1000)).count()

Example Programs

Spark also comes with several sample programs in the examples directory. To run one of them, use ./bin/run-example <class> [params]. For example:

./bin/run-example SparkPi

will run the Pi example locally.

You can set the MASTER environment variable when running examples to submit examples to a cluster. This can be a mesos:// or spark:// URL, "yarn-cluster" or "yarn-client" to run on YARN, and "local" to run locally with one thread, or "local[N]" to run locally with N threads. You can also use an abbreviated class name if the class is in the examples package. For instance:

MASTER=spark://host:7077 ./bin/run-example SparkPi

Many of the example programs print usage help if no params are given.

Running Tests

Testing first requires building Spark. Once Spark is built, tests can be run using:

./dev/run-tests

Please see the guidance on how to run all automated tests.

A Note About Hadoop Versions

Spark uses the Hadoop core library to talk to HDFS and other Hadoop-supported storage systems. Because the protocols have changed in different versions of Hadoop, you must build Spark against the same version that your cluster runs.

Please refer to the build documentation at "Specifying the Hadoop Version" for detailed guidance on building for a particular distribution of Hadoop, including building for particular Hive and Hive Thriftserver distributions. See also "Third Party Hadoop Distributions" for guidance on building a Spark application that works with a particular distribution.

Configuration

Please refer to the Configuration guide in the online documentation for an overview on how to configure Spark.