| commit | 498063c11b21a72ba42ab5de40bdf8d83e7161ee | [log] [tgz] |
|---|---|---|
| author | xiliu <xiliu@xiliu-ld1.linkedin.biz> | Tue Oct 24 15:50:47 2017 -0700 |
| committer | xiliu <xiliu@xiliu-ld1.linkedin.biz> | Tue Oct 24 15:50:47 2017 -0700 |
| tree | c12747a689d390e1d467a86b488a3dca1d7b8000 | |
| parent | 1a34a83d132ffe0e6a4a08d3fc3646cd14d4e0ad [diff] |
Add instructions to README.md
Hello Samza is a starter project for Apache Samza jobs.
Please see Hello Samza and Hello Samza High Level API to get started.
Hello Samza is developed as part of the Apache Samza project. Please direct questions, improvements and bug fixes there. Questions about Hello Samza are welcome on the dev list and the Samza JIRA has a hello-samza component for filing tickets.
To start contributing on Hello Samza first read Rules and Contributor Corner. Notice that Hello Samza git repository does not support git pull request.
The Hello Samza project contains example Samza applications of high-level API as well as low-level API. The following are the instructions to install the binaries and run the applications in a local Yarn cluster.
Check out the hello-samza project:
{% highlight bash %} git clone https://git.apache.org/samza-hello-samza.git hello-samza cd hello-samza git checkout latest {% endhighlight %}
This project contains everything you'll need to run your first Samza application.
A Samza grid usually comprises three different systems: YARN, Kafka, and ZooKeeper. The hello-samza project comes with a script called “grid” to help you setup these systems. Start by running:
{% highlight bash %} ./bin/grid bootstrap {% endhighlight %}
This command will download, install, and start ZooKeeper, Kafka, and YARN. It will also check out the latest version of Samza and build it. All package files will be put in a sub-directory called “deploy” inside hello-samza's root folder.
If you get a complaint that JAVA_HOME is not set, then you'll need to set it to the path where Java is installed on your system.
Once the grid command completes, you can verify that YARN is up and running by going to http://localhost:8088. This is the YARN UI.
Before you can run a Samza application, you need to build a package for it. This package is what YARN uses to deploy your apps on the grid.
NOTE: if you are building from the latest branch of hello-samza project, make sure that you run the following step from your local Samza project first:
{% highlight bash %} git clone https://github.com/apache/samza.git cd samza ./gradlew publishToMavenLocal {% endhighlight %}
Then, you can continue w/ the following command in hello-samza project:
{% highlight bash %} mvn clean package mkdir -p deploy/samza tar -xvf ./target/hello-samza-0.14.0-SNAPSHOT-dist.tar.gz -C deploy/samza {% endhighlight %}
After you've built your Samza package, you can start the example applications on the grid.
Package samza.examples.cookbook contains various examples of high-level API operator usage, such as map, partitionBy, window and join. Each example is a runnable Samza application, and the steps to run is in the class javadocs, e.g PageViewAdClickJoiner.
Package samza.examples.wikipedia.application contains a small Samza application which consumes the real-time feeds from Wikipedia, extracts the metadata of the events, and calculates statistics of all edits in a 10-second window. You can start the app on the grid using the run-app.sh script:
{% highlight bash %} ./deploy/samza/bin/run-app.sh --config-factory=org.apache.samza.config.factories.PropertiesConfigFactory --config-path=file://$PWD/deploy/samza/config/wikipedia-application.properties {% endhighlight %}
Once the job is started, we can tail the kafka topic by:
{% highlight bash %} ./deploy/kafka/bin/kafka-console-consumer.sh --zookeeper localhost:2181 --topic wikipedia-stats {% endhighlight %}
A code walkthrough of this application can be found here.
Package samza.examples.wikipedia.task contains the low-level API Samza code for the Wikipedia example. To run it, use the following scripts:
{% highlight bash %} deploy/samza/bin/run-app.sh --config-factory=org.apache.samza.config.factories.PropertiesConfigFactory --config-path=file://$PWD/deploy/samza/config/wikipedia-feed.properties deploy/samza/bin/run-app.sh --config-factory=org.apache.samza.config.factories.PropertiesConfigFactory --config-path=file://$PWD/deploy/samza/config/wikipedia-parser.properties deploy/samza/bin/run-app.sh --config-factory=org.apache.samza.config.factories.PropertiesConfigFactory --config-path=file://$PWD/deploy/samza/config/wikipedia-stats.properties {% endhighlight %}
Once the jobs are started, you can use the same kafka-console-consumer.sh command as in High-level API Wikipedia example to check out the output of the statistics.