Spring Cloud Contract

You always need confidence when pushing new features into a new application or service in a distributed system. To that end, this project provides support for consumer-driven contracts and service schemas in Spring applications, covering a range of options for writing tests, publishing them as assets, and asserting that a contract is kept by producers and consumers — for both HTTP and message-based interactions.

Spring Cloud Contract workshops

If you prefer to learn about the project by doing some tutorials, you can check out the workshops under this link.

Project page

You can read more about Spring Cloud Contract by going to the project page

Contributing

Spring Cloud is released under the non-restrictive Apache 2.0 license, and follows a very standard Github development process, using Github tracker for issues and merging pull requests into master. If you want to contribute even something trivial please do not hesitate, but follow the guidelines below.

Sign the Contributor License Agreement

Before we accept a non-trivial patch or pull request we will need you to sign the Contributor License Agreement. Signing the contributor’s agreement does not grant anyone commit rights to the main repository, but it does mean that we can accept your contributions, and you will get an author credit if we do. Active contributors might be asked to join the core team, and given the ability to merge pull requests.

Code of Conduct

This project adheres to the Contributor Covenant code of conduct. By participating, you are expected to uphold this code. Please report unacceptable behavior to spring-code-of-conduct@pivotal.io.

Code Conventions and Housekeeping

None of these is essential for a pull request, but they will all help. They can also be added after the original pull request but before a merge.

  • Use the Spring Framework code format conventions. If you use Eclipse you can import formatter settings using the eclipse-code-formatter.xml file from the Spring Cloud Build project. If using IntelliJ, you can use the Eclipse Code Formatter Plugin to import the same file.

  • Make sure all new .java files to have a simple Javadoc class comment with at least an @author tag identifying you, and preferably at least a paragraph on what the class is for.

  • Add the ASF license header comment to all new .java files (copy from existing files in the project)

  • Add yourself as an @author to the .java files that you modify substantially (more than cosmetic changes).

  • Add some Javadocs and, if you change the namespace, some XSD doc elements.

  • A few unit tests would help a lot as well — someone has to do it.

  • If no-one else is using your branch, please rebase it against the current master (or other target branch in the main project).

  • When writing a commit message please follow these conventions, if you are fixing an existing issue please add Fixes gh-XXXX at the end of the commit message (where XXXX is the issue number).

Checkstyle

Spring Cloud Build comes with a set of checkstyle rules. You can find them in the spring-cloud-build-tools module. The most notable files under the module are:

spring-cloud-build-tools/
└── src
    ├── checkstyle
    │   └── checkstyle-suppressions.xml (3)
    └── main
        └── resources
            ├── checkstyle-header.txt (2)
            └── checkstyle.xml (1)
1 Default Checkstyle rules
2 File header setup
3 Default suppression rules

Checkstyle configuration

Checkstyle rules are disabled by default. To add checkstyle to your project just define the following properties and plugins.

pom.xml
<properties>
<maven-checkstyle-plugin.failsOnError>true</maven-checkstyle-plugin.failsOnError> (1)
        <maven-checkstyle-plugin.failsOnViolation>true
        </maven-checkstyle-plugin.failsOnViolation> (2)
        <maven-checkstyle-plugin.includeTestSourceDirectory>true
        </maven-checkstyle-plugin.includeTestSourceDirectory> (3)
</properties>

<build>
        <plugins>
            <plugin> (4)
                <groupId>io.spring.javaformat</groupId>
                <artifactId>spring-javaformat-maven-plugin</artifactId>
            </plugin>
            <plugin> (5)
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-checkstyle-plugin</artifactId>
            </plugin>
        </plugins>

    <reporting>
        <plugins>
            <plugin> (5)
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-checkstyle-plugin</artifactId>
            </plugin>
        </plugins>
    </reporting>
</build>
1 Fails the build upon Checkstyle errors
2 Fails the build upon Checkstyle violations
3 Checkstyle analyzes also the test sources
4 Add the Spring Java Format plugin that will reformat your code to pass most of the Checkstyle formatting rules
5 Add checkstyle plugin to your build and reporting phases

If you need to suppress some rules (e.g. line length needs to be longer), then it’s enough for you to define a file under ${project.root}/src/checkstyle/checkstyle-suppressions.xml with your suppressions. Example:

projectRoot/src/checkstyle/checkstyle-suppresions.xml
<?xml version="1.0"?>
<!DOCTYPE suppressions PUBLIC
		"-//Puppy Crawl//DTD Suppressions 1.1//EN"
		"https://www.puppycrawl.com/dtds/suppressions_1_1.dtd">
<suppressions>
	<suppress files=".*ConfigServerApplication\.java" checks="HideUtilityClassConstructor"/>
	<suppress files=".*ConfigClientWatch\.java" checks="LineLengthCheck"/>
</suppressions>

It’s advisable to copy the ${spring-cloud-build.rootFolder}/.editorconfig and ${spring-cloud-build.rootFolder}/.springformat to your project. That way, some default formatting rules will be applied. You can do so by running this script:

$ curl https://raw.githubusercontent.com/spring-cloud/spring-cloud-build/master/.editorconfig -o .editorconfig
$ touch .springformat

IDE setup

Intellij IDEA

In order to setup Intellij you should import our coding conventions, inspection profiles and set up the checkstyle plugin. The following files can be found in the Spring Cloud Build project.

spring-cloud-build-tools/
└── src
    ├── checkstyle
    │   └── checkstyle-suppressions.xml (3)
    └── main
        └── resources
            ├── checkstyle-header.txt (2)
            ├── checkstyle.xml (1)
            └── intellij
                ├── Intellij_Project_Defaults.xml (4)
                └── Intellij_Spring_Boot_Java_Conventions.xml (5)
1 Default Checkstyle rules
2 File header setup
3 Default suppression rules
4 Project defaults for Intellij that apply most of Checkstyle rules
5 Project style conventions for Intellij that apply most of Checkstyle rules
Code style
Figure 1. Code style

Go to File → Settings → Editor → Code style. There click on the icon next to the Scheme section. There, click on the Import Scheme value and pick the Intellij IDEA code style XML option. Import the spring-cloud-build-tools/src/main/resources/intellij/Intellij_Spring_Boot_Java_Conventions.xml file.

Code style
Figure 2. Inspection profiles

Go to File → Settings → Editor → Inspections. There click on the icon next to the Profile section. There, click on the Import Profile and import the spring-cloud-build-tools/src/main/resources/intellij/Intellij_Project_Defaults.xml file.

Checkstyle

To have Intellij work with Checkstyle, you have to install the Checkstyle plugin. It’s advisable to also install the Assertions2Assertj to automatically convert the JUnit assertions

Checkstyle

Go to File → Settings → Other settings → Checkstyle. There click on the + icon in the Configuration file section. There, you’ll have to define where the checkstyle rules should be picked from. In the image above, we’ve picked the rules from the cloned Spring Cloud Build repository. However, you can point to the Spring Cloud Build’s GitHub repository (e.g. for the checkstyle.xml : https://raw.githubusercontent.com/spring-cloud/spring-cloud-build/master/spring-cloud-build-tools/src/main/resources/checkstyle.xml). We need to provide the following variables:

Remember to set the Scan Scope to All sources since we apply checkstyle rules for production and test sources.

How to Build Spring Cloud Contract

You need to have all the necessary Groovy plugins installed for your IDE to properly resolve the sources. For example, in Intellij IDEA, having both the Eclipse Groovy Compiler Plugin and the GMavenPlus Intellij Plugin results in properly imported project.
Spring Cloud Contract builds Docker images. Remember to have Docker installed.
If you want to run the build in offline mode, you must have Maven 3.5.2+ installed.

Project structure

The following listing shows the Spring Cloud Contract folder structure:

├── config
├── docker
├── samples
├── scripts
├── specs
├── spring-cloud-contract-dependencies
├── spring-cloud-contract-shade
├── spring-cloud-contract-starters
├── spring-cloud-contract-stub-runner
├── spring-cloud-contract-stub-runner-boot
├── spring-cloud-contract-tools
├── spring-cloud-contract-verifier
├── spring-cloud-contract-wiremock
└── tests

The following list describes each of the top-level folders in the project structure:

  • config: Folder contains setup for Spring Cloud Release Tools automated release process

  • docker: Folder contains docker images

  • samples: Folder contains test samples together with standalone ones used also to build documentation

  • scripts: Contains scripts to build and test Spring Cloud Contract with Maven, Gradle and standalone projects

  • specs: Contains specifications for the Contract DSL.

  • spring-cloud-contract-dependencies: Contains Spring Cloud Contract BOM

  • spring-cloud-contract-shade: Shaded dependencies used by the plugins

  • spring-cloud-contract-starters: Contains Spring Cloud Contract Starters

  • spring-cloud-contract-spec: Contains specification modules (contains concept of a Contract)

  • spring-cloud-contract-stub-runner: Contains Stub Runner related modules

  • spring-cloud-contract-stub-runner-boot: Contains Stub Runner Boot app

  • spring-cloud-contract-tools: Gradle and Maven plugin for Spring Cloud Contract Verifier

  • spring-cloud-contract-verifier: Core of the Spring Cloud Contract Verifier functionality

  • spring-cloud-contract-wiremock: All WireMock related functionality

  • tests: Integration tests for different messaging technologies

Commands

To build the core functionality together with the Maven Plugin, you can run the following command:

./mvnw clean install -P integration

Calling that function builds the core, the Maven plugin, and the Gradle plugin and runs end-to_end tests on the standalone samples in the proper order (both for Maven and Gradle).

To build only the Gradle Plugin, you can run the following commands:

cd spring-cloud-contract-tools/spring-cloud-contract-gradle-plugin
./gradlew clean build

Helpful scripts

We provide a couple of helpful scripts to build the project.

To build the project in parallel (by default, it uses four cores, but you can change it), run the following command:

./scripts/parallelBuild.sh

To use eight 8 cores, run thke following command:

CORES=8 ./scripts/parallelBuild.sh

To build the project without any integration tests (by default, this uses one core), run the following command:

./scripts/noIntegration.sh

To use eight cores, run the following command:

CORES=8 ./scripts/noIntegration.sh

To generate the documentation (for both the root project and the maven plugin), run the following command:

./scripts/generateDocs.sh