Introduction 

A plugin that can efficiently export data from Oracle to be used as a source in Hydrator.  Oracle includes command line tools to export data  that can be utilized to perform this task.  

User Stories

• As a Hydrator User I want to export data from Oracle to be used in my hydrator Pipeline.
• As a Hydrator User I want a Oracle Export plugin that exports data efficiently using existing existing Oracle tools. 
• As a Hydrator User I want the export data capability of the Oracle plugin to be based on a sql query that I issue.  
• User should be able to specify credentials.
• Passwords should not be viewable in plain text from inside pipeline viewer or hydrator studio.  
• User should be able to specify Oracle Instance
• User should be able to specify location of EXP Utility.   
• User should be able to specify type of output.
• User should be able to specify location of output files.  
• User should know of connectivity errors, or malformed queries/output identifier.   

Example

User wants to export the data from test table using filter on name='cask' i.e Select * from test where name='cask'

Plugin configurations:

"oracleServerHostname": "example.com",
"oracleServerPort": "22",
"serverUsername": "oracle",
"serverPassword": "oracle@123",
"dbUsername": "system",
"dbPassword": "cask",
"oracleHome": "/u01/app/oracle/product/11.2.0/xe",
"oracleSID": "cask",
"queryToExecute": "select * from test where name='cask'"
"columnSeparator" : ","
"outputFilename" : "results.csv"
"destinationDirectory" : "file:///home/cdap/export/"

Implementation Tips

Design 

Design:

{
    "name": "OracleExportAction",
      "plugin": {
        "name": "OracleExportAction",
        "type": "action",
        "label": "OracleExportAction",
        "artifact": {
          "name": "core-plugins",
          "version": "1.4.0-SNAPSHOT",
          "scope": "SYSTEM"
      },
      "properties": {
          "oracleServerHostname": "example.com",
          "oracleServerPort": "22",
          "serverUsername": "oracle",
          "serverPassword": "oracle@123",
          "dbUsername": "system",
          "dbPassword": "cask",
          "oracleHome": "/u01/app/oracle/product/11.2.0/xe",
          "oracleSID": "cask",
          "queryToExecute": "select * from test where name='cask'"
          "columnSeparator" : ","
          "outputFilename" : "results.csv"
          "destinationDirectory" : "file:///home/cdap/export/"
      }
}

oracleServerHostname:Host name of the remote DB machine where the data dump command is to be executed

oracleServerPort:Port of the remote DB machine to connect to.Defaults to 22

serverUsername:User name used to connect to remote DB host

serverPassword:Password used to connect to remote DB host

dbUsername:User name to connect to oracle DB

dbPassword:Password to connect to oracle DB

oracleHome:Path of the ORACLE_HOME

oracleSID:Oracle SID

queryToExecute: Query to be executed to export the data.

columnSeparator: Column separator to be used in the output file.

outputFilename: Output file name in which to export the data.

destinationDirectory: Absolute path of directory on the current machine where the file is to be copied. (Can be local or hdfs.)

Plugin would perform below steps:

1.SSH to the box using the provided $serverUsername and $userPassword.

2.Run below commands:

a.export ORACLE_HOME = $oracleHome;

b.export ORACLE_SID = $oracleSID

c. The plugin would internally create a temporary sql file(or else we can take sql script as an input from user to avoid temp file creation and deletion ) with the above contents and run the below command:

Eg - /u01/app/oracle/product/11.2.0/xe/bin/sqlplus -s system/cask@cask  @/tmp/test.sql

content of test.sql would be:

set colsep ","
set linesize 9999
set trimspool on
set heading off
set pagesize 0
set wrap off
set feedback off
spool /tmp/results.csv
select * from test where name='cask';
spool off

exit

NOTE : Cannot directly use spool in sqlplus prompt since it prints the query as well along with the data in the final output file.

d. Copy the exported file from the remote machine to the folder specified by the user on the current machine.

e. Remove temporary .sql and dump file.