One-stop guide: Kotlin + Spring Boot 2 + AWS S3 + Testcontainers

Read on Medium: One-stop guide: Kotlin + Spring Boot 2 + AWS S3 + Testcontainers

💡   Idea

Application implements the sample of CRUD REST API for AWS S3 (Simple Storage Service) to list, upload and download objects of buckets. Service covered by an integration test which starts AWS S3 mock inside Docker container using Localstack.

⚙️   Components

• Core:
  • Kotlin 1.4, JDK 11
  • Spring Boot 2.4
  • Gradle and OCI - Docker image assembling
  • AWS SDK for Java 2.0 with S3 integration test starter
• Testing:
  • JUnit 5
  • Testcontainers - library to use Docker in tests
  • Localstack - mocking framework to test AWS cloud services
• Utils:
  • Swagger 2
  • Spring Actuator

💼   Goal

Being accelerator for learning and diving into the best cutting edge tools listed above by demonstrating how they can work together.

Deployment

Environment variables

Variable	Description	Default value
AWS
AWS_REGION	Listening port of embedded Tomcat	us-east-1
AWS_ACCESS_KEY	Access key for an AWS IAM user
AWS_SECRET_KEY	Secret key for the Access Key
WEB-SERVER
SERVER_PORT	Listening port of embedded Tomcat	8080
MAX_FILE_SIZE	Maximum size of each uploading file of request	10MB
MAX_REQUEST_SIZE	Maximum size of request	10MB
DEBUG
SWAGGER_ENABLED	Switch on the JSON and GUI documentation for the REST API	false
LOG_FILE	Set the relative or absolute path to the log file	s3warehouse.log
ACTUATOR_LOG_FILE	Provides an access to log file through the /status/logfile	false

Main commands

Action	CLI command
Run app	./gradlew bootRun --args='--AWS_ACCESS_KEY=VALUE --AWS_SECRET_KEY=VALUE' *
Run tests	./gradlew test
Build Docker image	./gradlew bootBuildImage
Run container	docker run -dit -e AWS_ACCESS_KEY=VALUE -e AWS_SECRET_KEY=VALUE -p 8080:8080 antukhov/s3warehouse:0.1 *

[ * ] - don't forget to change values of environment variables

Quick start with the ready-to-use Docker

docker run -dit \
-e AWS_REGION=REGION_VALUE \
-e AWS_ACCESS_KEY=KEY_VALUE \
-e AWS_SECRET_KEY=SECRET_KEY \
-e SWAGGER_ENABLED=true \
-p 8085:8080 \
docker.pkg.github.com/antukhov/s3warehouse/s3warehouse:0.1

REST API documentation

Format	URL
HTML	http://localhost:8080/swagger-ui/index.html *
JSON	http://localhost:8080/v2/api-docs *

[ * ] - don't forget to change hostname and port if needed

Support

If you need any kind of support don't hesitate to let me know 😉

Created by Alex Antukhov