Consumer Driven Contracts with Contracts in an External Repository

在此流程中，我们执行消费者驱动的契约测试。契约定义存储在一个单独的存储库中。

In this flow, we perform Consumer Driven Contract testing. The contract definitions are stored in a separate repository.

Prerequisites

若要对外部存储库中保留的契约使用消费者驱动的契约，你需要设置 Git 存储库，此存储库：

To use consumer-driven contracts with the contracts held in an external repository, you need to set up a git repository that:

Contains all the contract definitions for each producer.
Can package the contract definitions in a JAR.
For each contract producer, contains a way (for example, pom.xml) to install stubs locally through the Spring Cloud Contract Plugin (SCC Plugin).

更多信息，请参阅 How To section，我们描述了如何设置这样的存储库。对于此类项目的示例，请参阅 {samples_code}/beer_contracts[此示例]。

For more information, see the How To section, where we describe how to set up such a repository. For an example of such a project, see {samples_code}/beer_contracts[this sample].

您还需要具有已设置 Spring Cloud Contract Stub Runner 的使用者代码。对于此类项目的示例，请参阅 {samples_code}/consumer[此示例]。您还需要具有已设置 Spring Cloud Contract 的生产者代码，以及插件。对于此类项目的示例，请参阅 {samples_code}/producer_with_external_contracts[此示例]。存根存储是 Nexus 或 Artifactory。

You also need consumer code that has Spring Cloud Contract Stub Runner set up. For an example of such a project, see {samples_code}/consumer[this sample]. You also need producer code that has Spring Cloud Contract set up, together with a plugin. For an example of such a project, see {samples_code}/producer_with_external_contracts[this sample]. The stub storage is Nexus or Artifactory.

流程的高度概览如下：

At a high level, the flow is as follows:

The consumer works with the contract definitions from the separate repository.
Once the consumer’s work is done, a branch with working code is created on the consumer side, and a pull request is made to the separate repository that holds the contract definitions.
The producer takes over the pull request to the separate repository with contract definitions and installs the JAR with all contracts locally.
The producer generates tests from the locally stored JAR and writes the missing implementation to make the tests pass.
Once the producer’s work is done, the pull request to the repository that holds the contract definitions is merged.
After the CI tool builds the repository with the contract definitions and the JAR with contract definitions gets uploaded to Nexus or Artifactory, the producer can merge its branch.
Finally, the consumer can switch to working online to fetch stubs of the producer from a remote location, and the branch can be merged to master.

Consumer Flow

消费者：

The consumer:

Writes a test that would send a request to the producer.[.iokays-translated-d73cf48455a15e1af4877e31158a7fee] 由于不存在服务器，因此测试失败。

The test fails due to no server being present. . Clones the repository that holds the contract definitions. . Sets up the requirements as contracts under the folder, with the consumer name as a subfolder of the producer.[.iokays-translated-87b5ad595377bfffeedec62e245c8b8b] 例如，对于名为 producer 的生产者和名为 consumer 的消费者，契约存储在 src/main/resources/contracts/producer/consumer/) 下

For example, for a producer named producer and a consumer named consumer, the contracts would be stored under src/main/resources/contracts/producer/consumer/) . Once the contracts are defined, installs the producer stubs to local storage, as the following example shows:[source, bash]

$ cd src/main/resource/contracts/producer
$ ./mvnw clean install

Sets up Spring Cloud Contract (SCC) Stub Runner in the consumer tests, to:
- Fetch the producer stubs from local storage.
- Work in the stubs-per-consumer mode (this enables consumer driven contracts mode).[.iokays-translated-071d063289660d5f9cc5fc7d41d430fa] SCC Stub Runner：

The SCC Stub Runner: * Fetches the producer stubs. * Runs an in-memory HTTP server stub with the producer stubs. Now your test communicates with the HTTP server stub, and your tests pass. * Creates a pull request to the repository with contract definitions, with the new contracts for the producer. * Branches your consumer code, until the producer team has merged their code.

以下 UML 图显示了消费者流程：

The following UML diagram shows the consumer flow:

"Consumer"->"Repo\nwith\ncontracts": clone
"Repo\nwith\ncontracts"->"Repo\nwith\ncontracts\nclone": cloned
"Consumer"->"Repo\nwith\ncontracts\nclone": create contract\ndefinitions of\nthe [Producer]
"Repo\nwith\ncontracts\nclone"->"Local storage": install [Producer]\nstubs locally
"Consumer"->"Consumer\nBuild": run tests
"Consumer\nBuild"->"SCC\nStub Runner": Run [Producer] stubs
"SCC\nStub Runner"->"Local storage": fetch [Producer] stubs
"SCC\nStub Runner"->"Producer stub": stub is running
"Consumer\nBuild"->"Producer stub": send a request\nin the tests
"Producer stub"->"Consumer\nBuild": send a response
"Consumer\nBuild"->"Consumer": the tests are passing
"Consumer"->"Repo\nwith\ncontracts\nclone": send a pull request
"Repo\nwith\ncontracts\nclone"->"Repo\nwith\ncontracts": pull request sent
"Consumer"->"Consumer": branch the code

Producer Flow

生产者：

The producer:

Takes over the pull request to the repository with contract definitions. You can do it from the command line, as follows[source, bash]

$ git checkout -b the_branch_with_pull_request master
git pull https://github.com/user_id/project_name.git the_branch_with_pull_request

Installs the contract definitions, as follows[source, bash]

$ ./mvnw clean install

Sets up the plugin to fetch the contract definitions from a JAR instead of from src/test/resources/contracts, as follows:

===Maven

===

Maven

<plugin>
	<groupId>org.springframework.cloud</groupId>
	<artifactId>spring-cloud-contract-maven-plugin</artifactId>
	<version>${spring-cloud-contract.version}</version>
	<extensions>true</extensions>
	<configuration>
		<!-- We want to use the JAR with contracts with the following coordinates -->
		<contractDependency>
			<groupId>com.example</groupId>
			<artifactId>beer-contracts</artifactId>
		</contractDependency>
		<!-- The JAR with contracts should be taken from Maven local -->
		<contractsMode>LOCAL</contractsMode>
		<!-- ... additional configuration -->
	</configuration>
</plugin>

Gradle

contracts {
	// We want to use the JAR with contracts with the following coordinates
	// group id `com.example`, artifact id `beer-contracts`, LATEST version and NO classifier
	contractDependency {
		stringNotation = 'com.example:beer-contracts:+:'
	}
	// The JAR with contracts should be taken from Maven local
	contractsMode = "LOCAL"
	// Additional configuration
}

===

Runs the build to generate tests and stubs, as follows:

===Maven

===
Maven
./mvnw clean install
Gradle
./gradlew clean build
===
Writes the missing implementation, to make the tests pass.
Merges the pull request to the repository with contract definitions, as follows:[source, bash]

$ git commit -am "Finished the implementation to make the contract tests pass"
$ git checkout master
$ git merge --no-ff the_branch_with_pull_request
$ git push origin master

CI 系统使用契约定义构建项目，并将具有契约定义的 JAR 上传到 Nexus 或 Artifactory。

The CI system builds the project with the contract definitions and uploads the JAR with the contract definitions to Nexus or Artifactory. . Switches to working remotely. . Sets up the plugin so that the contract definitions are no longer taken from the local storage but from a remote location, as follows:

===Maven

=== Maven::

<plugin>
	<groupId>org.springframework.cloud</groupId>
	<artifactId>spring-cloud-contract-maven-plugin</artifactId>
	<version>${spring-cloud-contract.version}</version>
	<extensions>true</extensions>
	<configuration>
		<!-- We want to use the JAR with contracts with the following coordinates -->
		<contractDependency>
			<groupId>com.example</groupId>
			<artifactId>beer-contracts</artifactId>
		</contractDependency>
		<!-- The JAR with contracts should be taken from a remote location -->
		<contractsMode>REMOTE</contractsMode>
		<!-- ... additional configuration -->
	</configuration>
</plugin>

Gradle

contracts {
	// We want to use the JAR with contracts with the following coordinates
	// group id `com.example`, artifact id `beer-contracts`, LATEST version and NO classifier
	contractDependency {
		stringNotation = 'com.example:beer-contracts:+:'
	}
	// The JAR with contracts should be taken from a remote location
	contractsMode = "REMOTE"
	// Additional configuration
}

===

Merges the producer code with the new implementation.
The CI system:
- Builds the project.
- Generates tests, stubs, and the stub JAR.
- Uploads the artifact with the application and the stubs to Nexus or Artifactory.

以下 UML 图显示了生产者流程：

The following UML diagram shows the producer process:

"Producer"->"Repo\nwith\ncontracts": take over the pull request
"Producer"->"Repo\nwith\ncontracts": install the contract\ndefinitions JAR
"Repo\nwith\ncontracts"->"Local storage": install the\ncontract definitions\nJAR locally
"Local storage"->"Repo\nwith\ncontracts": contract definitions\nJAR installed
"Producer"->"Producer\nBuild": run build
"Producer\nBuild"->"SCC\nPlugin": generate tests,\nstubs\nand stub jar
"SCC\nPlugin"->"Local storage": fetch the contract definitions
"Local storage"->"SCC\nPlugin": contract definitions found
"SCC\nPlugin"->"SCC\nPlugin": generate tests
"Producer\nBuild"->"Producer\nBuild": run the\ngenerated tests
"Producer\nBuild"->"Producer": the tests failed to pass
"Producer"->"Producer": write the missing implementation
"Producer"->"Producer\nBuild": run the build again
"Producer\nBuild"->"Producer\nBuild": fetch the contract definitions\nrun the generated tests
"Producer\nBuild"->"Producer": the tests passed
"Producer"->"Repo\nwith\ncontracts": merge the pull request
"Repo\nwith\ncontracts"->"CI": build and upload the\ncontract definitions artifact
"CI"->"Stub Storage": upload the\ncontract definitions
"Producer"->"Producer": setup the SCC Plugin\nto work remotely
"Producer"->"Producer": merge the code\nwith the implementation
"Producer"->"CI": build and upload\nthe artifacts
"CI"->"Producer\nBuild\non CI": generate tests,\nstubs\nand stub jar
"Producer\nBuild\non CI"->"SCC\nPlugin": generate tests,\nstubs\nand stub jar
"SCC\nPlugin"->"Stub Storage": fetch the contract definitions
"Stub Storage"->"SCC\nPlugin": contract definitions found
"SCC\nPlugin"->"SCC\nPlugin": generate tests
"Producer\nBuild\non CI"->"CI": the build passed
"Producer\nBuild\non CI"->"Stub Storage": upload the application JAR\nand the stubs jar