Connect to Cloudant Data in AWS Glue Jobs Using JDBC

AWS Glue is an ETL service from Amazon that allows you to easily prepare and load your data for storage and analytics. Using the PySpark module along with AWS Glue, you can create jobs that work with data over JDBC connectivity, loading the data directly into AWS data stores. In this article, we walk through uploading the CData JDBC Driver for Cloudant into an Amazon S3 bucket and creating and running an AWS Glue job to extract Cloudant data and store it in S3 as a CSV file.

Upload the CData JDBC Driver for Cloudant to an Amazon S3 Bucket

In order to work with the CData JDBC Driver for Cloudant in AWS Glue, you will need to store it (and any relevant license files) in a bucket in Amazon S3.

1. Open the Amazon S3 Console.
2. Select an existing bucket (or create a new one).
3. Click Upload
4. Select the JAR file (cdata.jdbc.cloudant.jar) found in the lib directory in the installation location for the driver.

Configure the Amazon Glue Job

1. Navigate to ETL -> Jobs from the AWS Glue Console.
2. Click Add Job to create a new Glue job.
3. Fill in the Job properties:
   • Name: Fill in a name for the job, for example, CloudantGlueJob.
   • IAM Role: Select (or create) an IAM role that has the AWSGlueServiceRole and AmazonS3FullAccess (because the JDBC Driver and destination are in an Amazon S3 bucket) permissions policies.
   • This job runs: Select "A new script to be authored by you."
     Populate the script properties:
   • Script file name: A name for the script file, for example, GlueCloudantJDBC
   • S3 path where the script is stored: Fill in or browse to an S3 bucket.
   • Temporary directory: Fill in or browse to an S3 bucket.
   • Expand Script Libraries and job parameters (optional). For Dependent jars path, fill in or browse to the S3 bucket where you loaded the JAR file.
4. Click Next. Here you will have the option to add a connection to other AWS endpoints, so if your Destination is Redshift, MySQL, etc, you can create and use connections to those data sources.
5. Click Next to review your job configuration.
6. Clicking Finish will create the job.
7. In the editor that opens, write a Python script for the job. You can use the sample script (see below) as an example.

Sample Glue Script

To connect to Cloudant using the CData JDBC driver, you will need to create a JDBC URL, populating the necessary connection properties. Additionally (unless you are using a Beta driver), you will need to set the RTK property in the JDBC URL. You can view the licensing file included in the installation for information on how to set this property.

Set the following connection properties to connect to Cloudant:

• User: Set this to your username.
• Password: Set this to your password.

Below is a sample script that uses the CData JDBC driver with the PySpark and AWSGlue modules to extract Cloudant data and write it to an S3 bucket in CSV format. Make any changes to the script you need to suit your needs and save the job.

import sys
from awsglue.transforms import *
from awsglue.utils import getResolvedOptions
from pyspark.context import SparkContext
from awsglue.context import GlueContext
from awsglue.dynamicframe import DynamicFrame
from awsglue.job import Job

args = getResolvedOptions(sys.argv, ['JOB_NAME'])

sparkContext = SparkContext()
glueContext = GlueContext(sparkContext)
sparkSession = glueContext.spark_session

##Use the CData JDBC driver to read Cloudant data from the Movies table into a DataFrame
##Note the populated JDBC URL and driver class name
source_df = sparkSession.read.format("jdbc").option("url","jdbc:cloudant:RTK=5246...;User=abc123; Password=abcdef;").option("dbtable","Movies").option("driver","cdata.jdbc.cloudant.CloudantDriver").load()

glueJob = Job(glueContext)
glueJob.init(args['JOB_NAME'], args)

##Convert DataFrames to AWS Glue's DynamicFrames Object
dynamic_dframe = DynamicFrame.fromDF(source_df, glueContext, "dynamic_df")

##Write the DynamicFrame as a file in CSV format to a folder in an S3 bucket.
##It is possible to write to any Amazon data store (SQL Server, Redshift, etc) by using any previously defined connections.
retDatasink4 = glueContext.write_dynamic_frame.from_options(frame = dynamic_dframe, connection_type = "s3", connection_options = {"path": "s3://mybucket/outfiles"}, format = "csv", transformation_ctx = "datasink4")

glueJob.commit()

Run the Glue Job

With the script written, we are ready to run the Glue job. Click Run Job and wait for the extract/load to complete. You can view the status of the job from the Jobs page in the AWS Glue Console. Once the Job has succeeded, you will have a CSV file in your S3 bucket with data from the Cloudant Movies table.

Using the CData JDBC Driver for Cloudant in AWS Glue, you can easily create ETL jobs for Cloudant data, writing the data to an S3 bucket, or loading it into any other AWS data store.