WHOPPR: Refactoring with Spring Cloud Services

This is companion code to a medium article of the same name. The article is a step-by-step guide with each major step corresponding to a branch in this repo.

WHOPPR is a fictional pizza ordering sytem composed of various services all smushed up in one monolothical application. The following Spring Cloud services are then used to break it down into micro-services.

• Spring Cloud Netflix (Zuul and Eureka)
• Spring Cloud Feign
• Spring Cloud Contracts and
• Spring Cloud Security

Pre-requisites

• jdk 8
• gradle 6+
• Mongo DB community edition
• A good IDE
• After installing pre-requisites, do below to verify proper setup:

$ git clone https://github.com/mpdroid/whoppr.git

$ cd whoppr

$ ./gradlew clean build

Step 1 : Monolithic

• To view the application code in its monolithic state:

$ git checkout 1-strawman

• Verify with:

$ ./gradlew clean build

$ ./gradlew monolith:bootRun # In another terminal window

$ ./gradlew monolith:cucumber -PenableCucumber 

Step 2 : Foundations

• Create master build.gradle with common tasks and imports

• Move data model, configuration and exception classes to common library sub-project

• Move test helpers to test-utils library sub-project

• Move acceptance tests from monolith into acceptance sub-project

• To view the foundational elements added to the workspace before refactoring:

$ git checkout 2-foundations

• Verify with:

$ ./gradlew clean build

$ ./gradlew monolith:bootRun # In another terminal window

$ ./gradlew acceptance:cucumber -PenableCucumber 

Step 3 : Micro-services infrastructure

• Update master build.gradle with Spring Cloud imports.

• Enable Spring Cloud Contract in all sub-projects through master build.gradle.

• Add gateway capabilities to monolith with Netflix Zuul.

• Create service registry sub-project using Eureka Server.

• Add Eureka Client and OpenFeign to monolith and stir well.

• To view the infrastructure elements added to the workspace:

$ git checkout 3-eureka

• Verify with:

$ ./gradlew clean build

$ ./gradlew registry:bootRun # separate terminal

$ ./gradlew monolith:bootRun # separate terminal

$ ./gradlew acceptance:cucumber -PenableCucumber 

• Connect to http://localhost:8761 with configured credentials to verify that whoppr service (name of our monolith) is visible in the registry.

Step 4 : Start refactoring

• Move menu service out of monolith
• Write contract tests
• Publish contract stubs to local maven repo
• Create feign client in monolith
• Rewrite consumers to consume feign client
• Rewrite consumer integration tests to use contract stubs
• Update Zuul routes
• Verify with:

$ ./gradlew clean build

$ ./gradlew registry:bootRun # separate terminal

$ ./gradlew menu:bootRun # separate terminal

$ ./gradlew monolith:bootRun # separate terminal

$ ./gradlew acceptance:cucumber -PenableCucumber 

• Connect to http://localhost:8761 with configured credentials to verify that whoppr and menu services are visible in the registry.