#4 Shorticles: AWS Glue’s integration with Apache Spark

When we start writing the program for glue first time, few lines which we first encountered are:

import sys
from awsglue.transforms import *
from awsglue.utils import getResolvedOptions
from pyspark.context import SparkContext
from awsglue.context import GlueContext
from awsglue.job import Job
glueContext = GlueContext(SparkContext.getOrCreate())

The above lines of code are used to set up the necessary dependencies and initialize the GlueContext object for AWS Glue ETL (Extract, Transform, Load) jobs using Apache Spark.

Let’s break down the code line by line and understand what exactly their meaning is:

import sys: This line imports the sys module, which provides access to system-specific parameters and functions.

from awsglue.transforms import *: This line imports all the classes and functions from the awsglue.transforms module. The awsglue.transforms module provides a set of transformation functions that can be used in AWS Glue ETL jobs.

from awsglue.utils import getResolvedOptions: This line imports the getResolvedOptions function from the awsglue.utils module. The getResolvedOptions function is used to retrieve the AWS Glue job arguments and their values.

from pyspark.context import SparkContext: This line imports the SparkContext class from the pyspark.context module. SparkContext is the entry point for creating a connection to Apache Spark.

from awsglue.context import GlueContext: This line imports the GlueContext class from the awsglue.context module. GlueContext is a high-level wrapper around Apache SparkContext that provides additional AWS Glue-specific functionality.

from awsglue.job import Job: This line imports the Job class from the awsglue.job module. The Job class represents an AWS Glue job and provides methods to configure and execute the job.

glueContext = GlueContext(SparkContext.getOrCreate()): This line creates an instance of GlueContext by passing the SparkContext.getOrCreate() method as an argument.

SparkContext.getOrCreate() returns an existing SparkContext instance or creates a new one if it doesn't exist. The glueContext object is then used to interact with the AWS Glue environment and perform ETL operations.

With these lines of code, you can leverage AWS Glue’s integration with Apache Spark to write and execute ETL scripts for data processing and transformation in the AWS Glue service.