AWS Glue Tutorial

Amazon has provided a broad-gauged, compendious platform named AWS (Amazon Web Services), which is a fusion of various offerings such as platform as a service (PaaS), infrastructure as a service (IaaS), and packaged software as a service (SaaS). AWS services offer many organizational tools: content delivery, computing power, and database storage. These tools are used in the data centers of around 190 different countries.

Nonprofit private organizations, educational institutions, and government agencies are some organizations that use AWS services.AWS Glue is a managed service by AWS, and it does not require any infrastructure to be set up or managed. AWS Glue can work with structured or even semi-structured data, and its console can be used in querying, transforming, and discovering data. The console can edit and modify the ETL scripts generated and executed.

AWS Glue Tutorial - Table of Content

• What is AWS Glue?
• What is the use of AWS Glue?
• AWS Glue vs Lambda?
• Components of AWS Glue
• Key Features
• AWS Glue Terminology
• How does AWS Glue work?

What is AWS Glue?

AWS Glue is a perfectly and skillfully addressed ETL (extract, transform and load) service to automate the process of data analysis. It has dramatically reduced the time taken for preparing the data for analysis. It automatically discovers and lists the data using AWS Glue Data Catalog, suggests, selects, and generates the Python or Scala code for data transmission from the source, loads and transforms the Job based on the timed events, providing flexible schedules and developing Apache Spark environment that is scalable for a targeted data loading.

Alteration, balancing and security, and monitoring of Complex data streams are provided by AWS Glue service. AWS Glue offers a serverless solution by making the complex operations involved in application development elementary. AWS Glue also provides quick integration procedures for merging various valid data and breakdown and authorizing the data in no time.

AWS Glue is a contended, cost-effective  ETL (extract, transform, and load) service used to clean, enhance, categorize, and move the data securely among the data streams and stores. AWS Glue acts as a center of metadata repository called AWS Glue Data Catalog, a flexible scheduler to handle dependency resolution, data retrieval, and job monitoring, and an ETL engine to automatically generate Python or Scala code. As the AWS Glue is serverless, there is no need to set up or manage infrastructure.

What is the use of AWS Glue?

AWS Glue is applicable in all the stages of Data Warehousing, i.e., from the extraction of data to visualization. The Glue in AWS authorizes other tools like Athena, Amazon Redshift, and S3 Data Lake. It helps in highlighting the delivery issues and tracks and creates the ETL pipelines by using monitors and alarms. By integrating data from all the sources, AWS Glue optimizes the data visualization process.

There are various tools and widgets to track the progress, and any issues that may come up in the future are alerted through email and slack notifications. Data is constructed for analytics through AWS Glue with customized cleaning, maintaining, and categorizing data. The significant uses of AWS Glue are

• Cost-Effective
• Less Hassle
• Proper scheduling of Job
• Serverless
• Raised visibility of data
• Pay-as-per-usage
• More Power
• Automatic ETL functioning

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AWS Glue vs Lambda?

• Lambda runs faster for smaller loads, whereas Glue runs faster for larger workloads.
• Various languages, such as Go, Java, Node.js, Python, etc., are used by Lambda to execute jobs, whereas AWS Glue can only use Python or Scala code.
• The run time of Lambda is very low for smaller tasks, and the initialization of Glue jobs requires more extended time for its distributed processing.
• Triggers execute code in Lambda from other services like DynamoDB, CloudWatch, SQS, Kafka, etc., whereas Glue code is executed and triggered by lambda events, manually or through scheduling the events.
• Lambda needs complex coding to integrate data sources such as DBs running on ECS instances, DynamoDB, S3, Redshift, etc. Glue can easily be combined with any of the sources.
• Glue has additional components such as a scheduler to handle the job execution time, and Data Catalog, which acts as a store, unlike Lambda.

[Related Article: AWS Tutorial]

Components of AWS Glue

The essential components of AWS Glue are

AWS Glue Data Catalog

The data catalog acts as a central metadata storehouse by creating tables to store the metadata information. Every table in this AWS Glue Data Catalog points to a single data store. Precisely, it acts as an index to the schema storing runtime metrics and location, which are very helpful in identifying the sources and targets of the ETL jobs.

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Job Scheduling System

This system automates and binds the ETL pipelines. The AWS Glue Job Scheduling System plays a crucial role as it maintains the timing in the system. The scheduler is flexible and can set up triggers based on the events and job execution.

ETL Engine

The component of AWS Glue that addresses the code generation is the ETL engine. The code is automatically presented in Python or Scala, and it is open code allowing the users to customize the code.

Key Features

This approach collected the whole data from various parts of the business and stored it centrally in a data warehouse by storing the business information in a single place. The following are the essential features of AWS Glue.

• The resources are automated to scale the current needs of the situation.
• Schedules, specific events, or triggers decide the execution of ETL jobs.
• The changes made to the database schema and services are easily recognized for quick response.
• Metrics, Logs of ETL procedures, and KPIs (Key Performance Indicators) are reported and monitored by AWS Glue.
• Metadata and the data sources are securely archived in AWS Glue Data Catalog.
• AWS Glue handles the errors with the error handling mechanism and resolves a pile-up of issues.
• ETL scripts are generated for a rich experience when data is transferred from source to target.

[Related Article: ETL Tutorial]

AWS Glue Terminology

The terms used in Amazon Web Services Glue are briefly explained below:

Classifier

The classifier provides information on the schema, i.e., a description of the data. File types such as CSV, XML, JSON, etc., have different classifiers provided by AWS Glue.

AWS Glue Data Catalog

The data catalog is a storehouse of metadata. The reference sources and the targets used in the ETL jobs are stored in the AWS Glue Data Catalog tables. It categorizes the data and saves it in a Data Warehouse or Data Lake. The index to location and schema of the data present in the storehouse is contained by the data catalog and written in the container of tables. 

Connection

When there is a need to connect the data catalog to a particular table, the "connection" property is required. When the data source and the target are the same, there is no need to establish any connection.

Database

The database collects data in tables from various sources, and the tables are arranged in separate categories.

Crawler

The AWS Glue Data Catalog is filled in with metadata using a crawler. The filling is done by pointing the crawler at a data store in the data catalog. Crawlers can turn the semi-structured data into a relational schema.

Data Target, Data Source, and Data Store

Data Store is storing the data in a repository. Though Data Store and Data Source are similar, Data Source is used as input data for transformations. This transformed data is written to a Data Target, a Data Store.

Dynamic Frame

The limitations of Frames in Apache Spark are subdued by the Dynamic Frames used in AWS Glue. Each record describes itself and undergoes advanced transformation operations for ETL and data cleaning. Dynamic Frame can also be converted to Data Frame and reversed.

Script

The data is extracted, worked upon, inserted into the data target, and stored from various data sources using the scripts like Python and Scala.

Job

ETL (Extract, Transform, Load) scripts create a job. Time intervals can be scheduled to run the assignments, and also sometimes, the jobs are run on demand.

Table

Tables contain the definition of the data and can be in any form, i.e., a file like S3 files or a service like an amazon RD service.

Preparing for AWS Glue Interview? Here Are the Top AWS Glue Interview Questions and Answers

How does AWS Glue work?

AWS Glue uses AWS services to successfully carry out the ETL (extract, transform, and load) jobs by building data warehouses and data lakes and obtaining the desired output streams. AWS Glue also uses API operations to change, create, and store the data from different sources and set the jobs' alerts.

The services are connected using an application by the AWS Glue console for monitoring the ETL work, which solely carries out all the operations. AWS Glue also creates an infrastructure for the ETL tool to run the workload. In Data Catalog, jobs are created using table definitions. The jobs created contain the scripts used for data transformation, i.e., initiating a job or scheduling an event.

Conclusion

Being a cost-effective and serverless service provider makes AWS Glue, a gem among the providers. AWS Glue gives easy tools to use and can help categorize, sort, validate, enhance, and move data stored in warehouses and data lakes. Semi-structured or clustered data can be worked upon using AWS Glue. This service is amicable in running other Amazon services and offers centralized storage by combining data from various sources and getting ready for different phases like reporting and data analysis. The AWS Glue service cinches high efficiency and performance with its seamless integration with other platforms for easy and speedy data analysis at a low cost.