Taming and Testing the Cloud Environment for your Java apps with LocalStack & Testcontainers (Java Vienna 2024)

Presentation given at the Java Vienna meetup on the 8th of January 2024.
Resources used:
Main demo: https://github.com/localstack-samples/sample-shipment-list-demo-lambda-dynamodb-s3
Testcontainers demo using the Java AWS SDK for creating resources: https://github.com/tinyg210/testcontainers-shipment-list-demo
Testcontainers demo using Cloud Pods for pre-seeding the test environment: https://github.com/tinyg210/testcontainers-shipment-list-cloud-pods

Transcript

1. Taming and Testing the Cloud Environment for your Java apps with LocalStack & Testcontainers 08.01.2024 Vienna
2. Anca Ghenade - Developer Advocate - anca.ghenade@localstack.cloud @tinyg210
3. How does one go around developing applications using AWS services?
4. A Little Story About Cloud Development
5. 1. The Software Engineers are tasked with developing a new web application on AWS Cloud
6. 2. Developing on a local machine, they soon find out that there are lots of dependencies with resources in the cloud
7. 3. They realize that the dev & test loop is extremely slow and tedious. Every local change needs to be packaged and uploaded to the cloud for testing.
8. 4. Now someone has a red build on their feature branch, but can’t efficiently test and debug their code in the CI/CD pipeline.
9. 5. The whole team is using Git flow for development - one CI build per feature branch. There is an explosion of different environments required for development (branches x developers).
10. 6. The manager approaches the team and complains that AWS dev/test resources are not being cleaned up properly causing cost spikes.
11. So things are kind of… complicated. 󰤆
12. Additionally…
14. 5 minutes later…
15. What is LocalStack and how can it help you? A fully functional local cloud stack that was born out of these exact concerns.
16. • Enables a highly efficient dev & test loop for cloud apps • Ships as a Docker image, easy to install and start up • Support for 90 (-ish) services (and growing): ◦ compute (Lambda, ECS, EKS) ◦ various databases (DynamoDB, RDS) ◦ messaging (SQS, Kinesis, MSK) ◦ some sophisticated/exotic APIs (Athena, Glue) • CI integrations & advanced collaboration features • Branching out into other areas: Chaos Engineering, IAM Security Testing, Cloud Ephemeral Environments, 3rd Party Extensions, etc
18. https://github.com/localstack-samples/sample-shipment-list-demo-lambda-dynamodb-s3
20. Using Spring Profiles…
21. Scenario 1 (Production) Scenario 2 (Development)
22. Scenario 1 Scenario 2
23. “Your application won’t even know the difference”
24. What about integration tests?
27. Testing your application workflow
29. There are several ways to provision your infrastructure for testing.
30. 1. You do everything yourself. (https://github.com/tinyg210/testcontainers-shipment-list-demo)
31. 2. You use AWS CLI scripts via init hooks. (example: https://github.com/tinyg210/stack-bytes-apigw-lambda-s3)
34. 3. You get inventive and run Terraform configuration files from your Java tests.
35. But maybe don’t. 󰤆
36. 4. Use LocalStack Cloud Pods (https://github.com/tinyg210/testcontainers-shipment-list-cloud-pods)
39. 5. Use a mix of all of the above. - export only desired services with Cloud Pods - manage other resources via SDK clients
40. What about CI?
41. • Automated Testing • Continuous Deployment • Integration Testing • Code Quality Analysis • Infrastructure as Code (IaC) Validation • Containerization and Orchestration • Feature Branch Testing • Rollbacks and Blue/Green Deployments • Performance Testing and Scalability • Automated Documentation Generation
42. • Automated Testing • Continuous Deployment • Integration Testing • Code Quality Analysis • Infrastructure as Code (IaC) Validation • Containerization and Orchestration • Feature Branch Testing • Rollbacks and Blue/Green Deployments • Performance Testing and Scalability • Automated Documentation Generation
44. I’ll show you some stuff
45. Your local tests…
46. In CI…
47. Some Tips and Tricks
48. Use a waiter to make sure your Lambdas are in state ACTIVE and not just created.
49. Source: https://aws.amazon.com/blogs/compute/coming-soon-expansion-of-aws-lambda-states-to-all-functions/
51. Use this nifty configuration to scan the LocalStack logs and make sure your instance is in the right state before the tests are allowed to start:
53. Streaming container output to an SLF4J logger
55. We’re giving the OPS back to the DEVS.
56. Thank You