node (2)

There are several use cases where data extracted from live data streams such as Twitter may need to be persisted into external databases. In this example, you will learn how to filter incoming live Twitter data and write relevant subsets of Twitter data into IBM database DB2. Sample program will work against all flavors of IBM databases i.e. DB2 for z/OS, DB2 distributed, dashDB and SQLDB.

We will use Spark Streaming to receive live data streams from Twitter and filter the tweets by a keyword . We will then extract the twitter user names associated with the matching tweets and insert them into DB2. These user names extracted from Twitter can have many applications – such as a more comprehensive analysis on whether these Twitter users are account holders of the bank by performing joins with other tables such as customer table.

1) For a background on Spark Streaming, refer to http://spark.apache.org/docs/latest/streaming-programming-guide.html.

2) We will use TwitterUtils class provided by Spark Streaming. TwitterUtils uses Twitte4J under the covers, which is a Java library for Twitter API.

3) Create a table in DB2 called TWITTERUSERS using -

CREATE TABLE TWITTERUSERS (NAME VARCHAR(255))

4) Create a new Scala class in Eclipse with contents available at this link. Change database and Twitter credentials to yours (as shown in Step 7).

5) Make sure the Project Build Path contains the jars db2jcc.jar (DB2 JDBC driver), spark-assembly-1.3.1_IBM_1-hadoop2.6.0.jar and spark-examples-1.3.1_IBM_1-hadoop2.6.0.jar, as shown below -

9524598097?profile=original

6)Lines 12 to 15 loads the DB2 driver class, establishes a connection to the database and prepares an INSERT statement that is used to insert Twitter user names into DB2.

7) Lines 17 to 24 sets the system properties for consumerKey, consumerSecret, accessToken and accessTokenSecret that will be used by Twitter4j library to generate Oauth credentials. You do this by configuring consumer key/secret pair and access token/secret pair in your account at this link – https://dev.twitter.com/apps. Detailed instructions on how to generate the two pairs are contained at http://ampcamp.berkeley.edu/big-data-mini-course/realtime-processing-with-spark-streaming.html.

8) Lines 26 and 27 create a local StreamingContext with 16 threads and batch interval of 2 seconds. StreamingContext is the entry point for all streaming functionality.

9) Using the StreamingContext created above, Line 30 creates an object DStream called stream. DStream is the basic abstraction in Spark Streaming and is a continuous stream of RDDs containing object of Type twitter4j.Status (http://twitter4j.org/javadoc/twitter4j/Status.html). A filter is also specified (“Paris”) which will select only those tweets that have keyword “Paris” in them.

10) In Line 31, map operation on stream maps each status object to its user name to create a new DStream called users.

11) Line 32 returns a new DStream called recentUsers where user names are aggregated over 60 seconds.

12) Lines 34 to 41 iterate over each RDD in the DStream recentUsers to return number of users every 60 seconds, and inserting those users into the database table TWITTERUSERS through JDBC.

13) Lines 44 starts real processing and awaits termination.

14) Following screenshot shows a snippet of console output when the program is run. Of course, you can change the filter to any keyword in line 29.

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15) You can also run SELECT * from TWITTERUSERS on your database to confirm that the Twitter users get inserted.

Above simple Twitter program can be extended to more complicated use cases using Spark Streaming to do analysis of social media data more effectively, persist subset of social media data into databases and join social media data with relational data to derive additional business insights.

You can reach us for questions (Pallavi pallavipr@in.ibm.com or Param param.bng@in.ibm.com).

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We are seeing a trend of DB2 data being accessed by modern distributed applications written in new APIs and frameworks. JavaScript has become extremely popular for Web application development. JavaScript adoption was revolutionized by Node.js which makes it possible to run JavaScript on the server-side. There is an increasing interest amongst developers to write analytics applications in Node.js that need to access DB2 data (both z/OS and distributed). Modern DB2 provides a Node.js driver that makes Node.js connectivity straight forward. Below are step-by-step instructions for a basic end-to-end Node.js application on Windows for accessing data from DB2 for z/OS and DB2 distributed -

1) Install Node and its companion NPM. NPM is a tool to manage Node modules. Download the installer from https://nodejs.org/dist/v0.12.7/x64/node-v0.12.7-x64.msi.

2) Note that DB2 Node.js driver does not support Node 4 on Windows yet. Node 4 support is already available for Mac and Linux. We will have Node 4 support for Windows out very soon.

3) Install a 64-bit version of Node since DB2 Node.js driver does not support 32-bit.

4) Run the installer (in my case node-v0.12.7-x64.msi). You should see a screen like Screenshot 1.

9524595887?profile=originalScreenshot 1

5) Follow the instructions on license and folder choice until you reach the screen for the features you want installed. Default selection is recommended and click Next to start intsall (Screenshot 2).

9524596664?profile=originalScreenshot 2

6) Verify that the installation is complete by opening the command prompt and executing node -v and npm -v as shown in Screenshot 3.

9524596487?profile=originalScreenshot 3

7) You can write a simple JavaScript program to test the installation. Create a file called Confirmation.js with contents console.log('You have successfully installed Node and NPM.');

8) Navigate to the folder you have created the file n and run the application using command

node Confirmation.js. Output looks like Screenshot 4.

9524597055?profile=originalScreenshot 4

9) Now install the DB2 Node.js driver using the following command from Windows command line: npm install ibm_db (For NodeJS 4+, installation command would be different as follows

npm install git+https://git@github.com/ibmdb/node-ibm_db.git#v4_support).

10) Under the covers, the npm command downloads node-ibm_db package from github and includes the DB2 ODBC CLI driver to provide connectivity to the DB2 backend. You should see following output (Screenshot 5).

9524596886?profile=originalScreenshot 5

11) Copy the following simple DB2 access program in a file called DB2Test.js and change the database credentials to yours -

var ibmdb = require('ibm_db');

ibmdb.open("DRIVER={DB2};DATABASE=<dbname>;HOSTNAME=<myhost>;UID=db2user;PWD=password;PORT=<dbport>;PROTOCOL=TCPIP", function (err,conn) {

if (err) return console.log(err);

conn.query('select 1 from sysibm.sysdummy1', function (err, data) {

if (err) console.log(err);

else console.log(data);

conn.close(function () {

console.log('done');

});

});

});

12) Run the following command from Windows command line to execute the program: node DB2Test.js. You should see Screenshot 6, containing the output of SQL SELECT 1 from SYSIBM.SYSDUMMY1. Your simple Node application can now access DB2.

9524597068?profile=originalScreenshot 6

13) For connecting to DB2 for z/OS, modify the Connection URL, DB name, port, user name and password to DB2 for z/OS credentials.

14) DB2 for z/OS access needs DB2 Connect license entitlement. In most production DB2 for z/OS systems with DB2 Connect Unlimited Edition licensing, server side license activation would have already been done, in which case you don't need to do anything about licensing. If you get any license error on executing the program, server side activation may not have been done. In that case, copy the DB2 Connect ODBC client side license file into ibm_db/installer/clidriver/license folder.

15) Also make sure that the DB2 for z/OS server you are testing against has CLI packages already bound (this would have been already done as part of DB2 Connect setup on the DB2 z/OS server).

16) Run the program with DB2 for z/OS credentials and you will observe similar output as Step 12.

17) Attached is a Node.js program (NodeDb2zosSelect.js) that fetches rows from DB2 for z/OS Employee table in the sample database (DSN8A10.EMP). For running the same program with DB2 distributed, make sure to not only change the database credentials, but also change the table name in the SELECT SQL to EMPLOYEE. In both DB2 for z/OS and DB2 distributed, you should see an output as shown in Screenshot 7.

9524597490?profile=originalScreenshot 7

Continue enjoying your Node.js test drive with DB2!

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