Prod-Like Integration Testing for Distributed Containerized Applications
1 like316 views
This document discusses the challenges and solutions for performing production-like integration testing for distributed containerized applications, emphasizing the limitations of in-memory testing solutions. It introduces Testcontainers, a Java library that allows developers to create disposable Docker containers for testing, enhancing integration testing fidelity. The talk also highlights the use of Toxiproxy for simulating network conditions and Cloud Native Buildpacks for ensuring consistent build and run environments.
Prod-Like Integration Testing for Distributed Containerized Applications
- 1. Prod-Like Integration Testing for Distributed Containerized Applications Maria Gabriella Brodi ⸱ @BrodiMg Staff Solutions Engineer, VMware ⸺ Cora Iberkleid ⸱ @ciberkleid Developer Advocate, VMware
- 2. Abstract Integration testing for distributed containerized applications poses new challenges in terms of practices, tools, and environments for developers who want to carry out more prod-like integration testing earlier in the development lifecycle. In-memory databases are useful but cannot provide the level of assurance needed as you test against a real database. This option is also limited to data services, but not all services provide an in-memory alternative. Testcontainers is a framework for instantiating standalone containers for any number of services to test against. The framework offers some out-of-the-box options, but you can also provide your own image, and even your own Dockerfile to instantiate the service of your choice. In this talk, we'll explore testcontainers and push the boundaries in order to explore how they may be used in conjunction with Cloud Native Buildpacks. This approach has the added benefit of ensuring that all testing is carried out on the same container stack.
- 3. Agenda - Intro - Testcontainers 101 - DB integration testing - Network affinity testing - Environment parity - Takeaways
- 4. INTRO
- 5. What do we mean by “prod-like” integration testing? ● Integration vs Unit tests ● Greater fidelity to run-time conditions ● Type of system ● Network reliability ● OS environment ● Shifted left ● Local developer machine ● Iterate locally
- 6. Common Approaches to Integration Test In Integration tests we are interested in verifying the behavior and interactions of multiple modules. For this purpose we can use: - Shared instances - Local installation - In memory solutions
- 7. In-memory testing App Mock server or in-memory service Options: ● Mock server (Wiremock, Loki…) ● In-memory service (h2, hsql...)
- 8. Limitations of in-memory testing App Mock server or in-memory service Limitations: ● Requires framework support ● Behavior differences to real system ● Latency/bandwidth testing can be challenging ● Not every service has an in-memory option ● Differences in security configuration
- 9. New challenges with in-memory testing App Challenge exacerbated with explosion in microservices and variety of service options over the last 10 years. Mock server or in-memory service Limitations: ● Requires framework support ● Behavior differences to real system ● Latency/bandwidth testing can be challenging ● Not every service has an in-memory option ● Differences in security configuration
- 10. New challenges with in-memory testing App Challenge exacerbated with explosion in microservices and variety of service options over the last 10 years. Mock server or in-memory service Limitations: ● Requires framework support ● Behavior differences to real system ● Latency/bandwidth testing can be challenging ● Not every service has an in-memory option ● Differences in security configuration
- 11. Containerization Helps! ● Containerization per se is a big part of the solution ● Docker Compose - works for any framework However… ● Cumbersome lifecycle management ● Additional skill set for developers to learn However! ● There is an easier solution :)
- 12. Testcontainers: easy testing with external services Service on Docker App Testcontainers dependency
- 14. Testcontainers intro/overview ● Java library that creates instances of Docker containers for testing ● Supports JUnit4, JUnit5, and Spock
- 15. Support for other languages (check GitHub for more complete information)
- 16. Available Modules ● Provides lightweight, throwaway instances of common databases, Selenium web browsers, and more ● Can start anything else that can run in a Docker container
- 17. Why Testcontainers? Where to use them? ● Prod-like systems: ● Easier instantiation of disposable services that lack an in-memory option ● Test against any application that can run as a container ● Integration testing: ● Data access layer integration ● Application integration ● Browser-based acceptance
- 18. inspiration...
- 19. package org.testcontainers.junit.jupiter; import ... class TestcontainersExtension implements BeforeEachCallback, BeforeAllCallback, AfterEachCallback, AfterAllCallback, ExecutionCondition, TestInstancePostProcessor { @Testcontainers (JUnit 5) JUnit5 Extension - intercepts JUnit lifecycle events and manages container lifecycles @Testcontainers public class MyIntegrationTests { @Container // In JUnit 4, use @Rule/@ClassRule static PostgreSQLContainer<?> db = new PostgreSQLContainer<>("postgres"); ... @ExtendWith({TestcontainersExtension.class})
- 20. @Container (JUnit 5) / @Rule (JUnit 4) @Testcontainers public class MyIntegrationTests { @Container // In JUnit 4, use @Rule/@ClassRule PostgreSQLContainer<?> db = new PostgreSQLContainer<>("postgres"); ... Flags TestcontainersExtension about a container to manage ● New container is started/stopped for every test ● Declare as static to re-use the same container
- 23. Close...but different! ...ish Elephant by Anton from the Noun Project
- 24. DEMO TIME DB INTEGRATION TESTING
- 26. Which Challenges in a Real Environment? Network can misbehave: - Increase Latency - Decrease Bandwidth - Unexpected Closed Connections - Changes in Packet Size And Everything goes … BANANAS
- 27. Toxiproxy A framework for simulating network conditions. It's made specifically to work in testing, CI and development environments. https://github.com/Shopify/toxiproxy
- 28. Toxiproxy & Testcontainers Toxiproxy available as a Testcontainers Module Started as separate container on the Docker daemon The toxiproxy container proxies all the traffics to the service container Requires toxiproxy and service containers to be on the same network
- 29. Network Definition Service on Docker (e.g. postgres) Toxiproxy Network We can facilitate connections between containers without exposing ports on the hosts by using a Network object App testcontainers
- 30. Network Definition Service on Docker (e.g. postgres) Toxiproxy Network App testcontainers A maximum of one network can be shared between containers. Service on Docker (e.g. redis)
- 33. OS Base Layer Path to Production - Environment Parity CI Test Job CI Build Job Build Layer 1 Build Layer N OS = ? Runtime= ? OS = ? Runtime= ? OS = ? Runtime= ?
- 34. Common Approaches ● Test and Build and Run environments often configured separately ○ Test job environment in CI toolchain ○ Build job environment in CI toolchain (separately, sometimes) ○ Run environment often configure in Dockerfile (‘FROM’ base image) ○ Very hard to keep synchronized ● Two-stage Dockerfiles help with specifying same build and run base images ○ Two ‘FROM’ statements in the same Dockerfile ○ Stil, hard to manage across applications at scale
- 35. A Better Way: Cloud Native Buildpacks ● Buildpacks provide a consistent way to build images at scale ● Build and run stacks guaranteed to be the same ● Distributed as a standalone “builder” image - easily shared across an organization ● Polyglot ● Choice in user experience ○ CLI, Maven/Gradle plugin, Kubernetes operator, and more…
- 36. ● Default configuration of Maven Buildpack: BP_MAVEN_BUILD_ARGUMENTS='-Dmaven.test.skip=true package' Cloud Native Buildpacks (CNB) CNB Run Image CI Test Job CNB Builder CNB BP Layer(s) CNB App Layer(s) OS = ✅ Runtime= ✅ OS = ? Runtime= ? OS = ✅ Runtime= ✅
- 37. ● Custom configuration: BP_MAVEN_BUILD_ARGUMENTS='-Dmaven.test.skip=false package' Cloud Native Buildpacks (CNB) CNB Run Image Test & Build! CNB Builder CNB BP Layer(s) CNB App Layer(s) OS = ✅ Runtime= ✅ OS = ✅ Runtime= ✅
- 38. Test & Build! CNB Builder pack build my-springone-app --builder paketobuildpacks/builder:base --env BP_MAVEN_BUILD_ARGUMENTS='Dtest=Demo2_Toxiproxy_Tst test package'
- 39. Test & Build! CNB Builder
- 41. testcontainers-java CNB Builder Hold your horses… buildpacks can’t start containers on Docker Postgres DOCKER_HOST = unix:///var/run/docker.sock
- 42. testcontainers-java CNB Builder Postgres TCP DOCKER_HOST = unix:///var/run/docker.sock
- 43. testcontainers-java CNB Builder Postgres TCP DOCKER_HOST = unix:///var/run/docker.sock DOCKER_HOST = tcp://${DOCKER_HOST_IP}:${DOCKER_PORT} Still respects security guardrails of CNB ✅
- 44. Pack + Testcontainers Docker Host Detection ● We use a common utility (socat) to map the TCP port to the Unix socket socat TCP-LISTEN:2375,reuseaddr,fork UNIX-CONNECT:/var/run/docker.sock & pack build my-springone-app --builder paketobuildpacks/builder:base --env BP_MAVEN_BUILD_ARGUMENTS='Dtest=Demo2_Toxiproxy_Tst test package' --env DOCKER_HOST=tcp://${DOCKER_HOST_IP}:2375 pkill socat
- 46. TAKEAWAYS
- 47. Get more “prod-like” integration testing using... ★ Testcontainers for improved system affinity ★ Toxiproxy for network resiliency testing ★ CNB with pack CLI and Paketo Buildpacks
- 48. Get more “prod-like” integration testing using... ★ Testcontainers for improved system affinity ★ Toxiproxy for network resiliency testing ★ CNB with pack CLI and Paketo Buildpacks ★ And… all from the comfort of your local machine!
- 50. Thank you! Please join us on Slack for 15 min of Q&A