Spring Cloud Contract customization

package com.example;

import java.util.regex.Pattern;

/**
 * If you want to use {@link Pattern} directly in your tests
 * then you can create a class resembling this one. It can
 * contain all the {@link Pattern} you want to use in the DSL.
 *
 * <pre>
 * {@code
 * request {
 *     body(
 *         [ age: $(c(PatternUtils.oldEnough()))]
 *     )
 * }
 * </pre>
 *
 * Notice that we're using both {@code $()} for dynamic values
 * and {@code c()} for the consumer side.
 *
 * @author Marcin Grzejszczak
 */
//tag::impl[]
public class PatternUtils {

    public static String tooYoung() {
        //remove::start[]
        return "[0-1][0-9]";
        //remove::end[return]
    }

    public static Pattern oldEnough() {
        //remove::start[]
        return Pattern.compile("[2-9][0-9]");
        //remove::end[return]
    }

    /**
     * Makes little sense but it's just an example ;)
     */
    public static Pattern ok() {
        //remove::start[]
        return Pattern.compile("OK");
        //remove::end[return]
    }
}
//end::impl[]

package com.example;

import org.springframework.cloud.contract.spec.internal.ClientDslProperty;

/**
 * DSL Properties passed to the DSL from the consumer's perspective.
 * That means that on the input side {@code Request} for HTTP
 * or {@code Input} for messaging you can have a regular expression.
 * On the {@code Response} for HTTP or {@code Output} for messaging
 * you have to have a concrete value.
 *
 * @author Marcin Grzejszczak
 */
//tag::impl[]
public class ConsumerUtils {
    /**
     * Consumer side property. By using the {@link ClientDslProperty}
     * you can omit most of boilerplate code from the perspective
     * of dynamic values. Example
     *
     * <pre>
     * {@code
     * request {
     *     body(
     *         [ age: $(ConsumerUtils.oldEnough())]
     *     )
     * }
     * </pre>
     *
     * That way it's in the implementation that we decide what value we will pass to the consumer
     * and which one to the producer.
     *
     * @author Marcin Grzejszczak
     */
    public static ClientDslProperty oldEnough() {
        //remove::start[]
        // this example is not the best one and
        // theoretically you could just pass the regex instead of `ServerDslProperty` but
        // it's just to show some new tricks :)
        return new ClientDslProperty(PatternUtils.oldEnough(), 40);
        //remove::end[return]
    }

}
//end::impl[]

package com.example;

import org.springframework.cloud.contract.spec.internal.ServerDslProperty;

/**
 * DSL Properties passed to the DSL from the producer's perspective.
 * That means that on the input side {@code Request} for HTTP
 * or {@code Input} for messaging you have to have a concrete value.
 * On the {@code Response} for HTTP or {@code Output} for messaging
 * you can have a regular expression.
 *
 * @author Marcin Grzejszczak
 */
//tag::impl[]
public class ProducerUtils {

    /**
     * Producer side property. By using the {@link ProducerUtils}
     * you can omit most of boilerplate code from the perspective
     * of dynamic values. Example
     *
     * <pre>
     * {@code
     * response {
     *     body(
     *         [ status: $(ProducerUtils.ok())]
     *     )
     * }
     * </pre>
     *
     * That way it's in the implementation that we decide what value we will pass to the consumer
     * and which one to the producer.
     */
    public static ServerDslProperty ok() {
        // this example is not the best one and
        // theoretically you could just pass the regex instead of `ServerDslProperty` but
        // it's just to show some new tricks :)
        return new ServerDslProperty( PatternUtils.ok(), "OK");
    }
}
//end::impl[]

package contracts.beer.rest

import com.example.ConsumerUtils
import com.example.ProducerUtils
import org.springframework.cloud.contract.spec.Contract

Contract.make {
    description("""
Represents a successful scenario of getting a beer

```
given:
    client is old enough
when:
    he applies for a beer
then:
    we'll grant him the beer
```

""")
    request {
        method 'POST'
        url '/check'
        body(
                age: $(ConsumerUtils.oldEnough())
        )
        headers {
            contentType(applicationJson())
        }
    }
    response {
        status 200
        body("""
            {
                "status": "${value(ProducerUtils.ok())}"
            }
            """)
        headers {
            contentType(applicationJson())
        }
    }
}

org.springframework.cloud.contract.verifier.dsl.wiremock.WireMockExtensions=\
org.springframework.cloud.contract.stubrunner.provider.wiremock.TestWireMockExtensions
org.springframework.cloud.contract.spec.ContractConverter=\
org.springframework.cloud.contract.stubrunner.TestCustomYamlContractConverter

/*
 * Copyright 2013-2020 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.cloud.contract.verifier.dsl.wiremock

import com.github.tomakehurst.wiremock.extension.Extension

/**
 * Extension that registers the default transformer and the custom one
 */
class TestWireMockExtensions implements WireMockExtensions {
    @Override
    List<Extension> extensions() {
        return [
                new DefaultResponseTransformer(),
                new CustomExtension()
        ]
    }
}

class CustomExtension implements Extension {

    @Override
    String getName() {
        return "foo-transformer"
    }
}

        @Bean
        WireMockConfigurationCustomizer optionsCustomizer() {
            return new WireMockConfigurationCustomizer() {
                @Override
                public void customize(WireMockConfiguration options) {
// perform your customization here
                }
            };
        }

package org.springframework.cloud.contract.spec;

import java.io.File;
import java.util.Collection;

/**
 * Converter to be used to convert FROM {@link File} TO {@link Contract} and from
 * {@link Contract} to {@code T}.
 *
 * @param <T> - type to which we want to convert the contract
 * @author Marcin Grzejszczak
 * @since 1.1.0
 */
public interface ContractConverter<T> extends ContractStorer<T>, ContractReader<T> {

    /**
     * Should this file be accepted by the converter. Can use the file extension to check
     * if the conversion is possible.
     * @param file - file to be considered for conversion
     * @return - {@code true} if the given implementation can convert the file
     */
    boolean isAccepted(File file);

    /**
     * Converts the given {@link File} to its {@link Contract} representation.
     * @param file - file to convert
     * @return - {@link Contract} representation of the file
     */
    Collection<Contract> convertFrom(File file);

    /**
     * Converts the given {@link Contract} to a {@link T} representation.
     * @param contract - the parsed contract
     * @return - {@link T} the type to which we do the conversion
     */
    T convertTo(Collection<Contract> contract);

}

org.springframework.cloud.contract.spec.ContractConverter=\
org.springframework.cloud.contract.verifier.converter.YamlContractConverter

package org.springframework.cloud.contract.verifier.builder;

import java.nio.file.Path;
import java.util.Collection;

import org.springframework.cloud.contract.verifier.config.ContractVerifierConfigProperties;
import org.springframework.cloud.contract.verifier.file.ContractMetadata;

/**
 * Builds a single test.
 *
 * @since 1.1.0
 */
public interface SingleTestGenerator {

    /**
     * Creates contents of a single test class in which all test scenarios from the
     * contract metadata should be placed.
     * @param properties - properties passed to the plugin
     * @param listOfFiles - list of parsed contracts with additional metadata
     * @param generatedClassData - information about the generated class
     * @param includedDirectoryRelativePath - relative path to the included directory
     * @return contents of a single test class
     */
    String buildClass(ContractVerifierConfigProperties properties, Collection<ContractMetadata> listOfFiles,
            String includedDirectoryRelativePath, GeneratedClassData generatedClassData);

    class GeneratedClassData {

        public final String className;

        public final String classPackage;

        public final Path testClassPath;

        public GeneratedClassData(String className, String classPackage, Path testClassPath) {
            this.className = className;
            this.classPackage = classPackage;
            this.testClassPath = testClassPath;
        }

    }

}

org.springframework.cloud.contract.verifier.builder.SingleTestGenerator=/
com.example.MyGenerator

package org.springframework.cloud.contract.verifier.converter;

import java.io.File;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

import org.springframework.cloud.contract.spec.Contract;
import org.springframework.cloud.contract.verifier.file.ContractMetadata;

/**
 * Converts contracts into their stub representation.
 *
 * @param <T> - type of stub mapping
 * @since 1.1.0
 */
public interface StubGenerator<T> {

    /**
     * @param mapping - potential stub mapping mapping
     * @return {@code true} if this converter could have generated this mapping stub.
     */
    default boolean canReadStubMapping(File mapping) {
        return mapping.getName().endsWith(fileExtension());
    }

    /**
     * @param rootName - root name of the contract
     * @param content - metadata of the contract
     * @return the collection of converted contracts into stubs. One contract can result
     * in multiple stubs.
     */
    Map<Contract, String> convertContents(String rootName, ContractMetadata content);

    /**
     * Post process a generated stub mapping.
     * @param stubMapping - mapping of a stub
     * @param contract - contract for which stub was generated
     * @return the converted stub mapping
     */
    default T postProcessStubMapping(T stubMapping, Contract contract) {
        List<StubPostProcessor> processors = StubPostProcessor.PROCESSORS.stream().filter(p -> p.isApplicable(contract))
                .collect(Collectors.toList());
        if (processors.isEmpty()) {
            return defaultStubMappingPostProcessing(stubMapping, contract);
        }
        T stub = stubMapping;
        for (StubPostProcessor processor : processors) {
            stub = (T) processor.postProcess(stub, contract);
        }
        return stub;
    }

    /**
     * Stub mapping to chose when no post processors where found on the classpath.
     * @param stubMapping - mapping of a stub
     * @param contract - contract for which stub was generated
     * @return the converted stub mapping
     */
    default T defaultStubMappingPostProcessing(T stubMapping, Contract contract) {
        return stubMapping;
    }

    /**
     * @param inputFileName - name of the input file
     * @return the name of the converted stub file. If you have multiple contracts in a
     * single file then a prefix will be added to the generated file. If you provide the
     * {@link Contract#getName} field then that field will override the generated file
     * name.
     *
     * Example: name of file with 2 contracts is {@code foo.groovy}, it will be converted
     * by the implementation to {@code foo.json}. The recursive file converter will create
     * two files {@code 0_foo.json} and {@code 1_foo.json}
     */
    String generateOutputFileNameForInput(String inputFileName);

    /**
     * Describes the file extension of the generated mapping that this stub generator can
     * handle.
     * @return string describing the file extension
     */
    default String fileExtension() {
        return ".json";
    }

}

# Stub converters
org.springframework.cloud.contract.verifier.converter.StubGenerator=\
org.springframework.cloud.contract.verifier.wiremock.DslToWireMockClientConverter

package org.springframework.cloud.contract.stubrunner.provider.moco

import com.github.dreamhead.moco.bootstrap.arg.HttpArgs
import com.github.dreamhead.moco.runner.JsonRunner
import com.github.dreamhead.moco.runner.RunnerSetting
import groovy.transform.CompileStatic
import groovy.util.logging.Commons

import org.springframework.cloud.contract.stubrunner.HttpServerStub
import org.springframework.cloud.contract.stubrunner.HttpServerStubConfiguration

@Commons
@CompileStatic
class MocoHttpServerStub implements HttpServerStub {

    private boolean started
    private JsonRunner runner
    private int port

    @Override
    int port() {
        if (!isRunning()) {
            return -1
        }
        return port
    }

    @Override
    boolean isRunning() {
        return started
    }

    @Override
    HttpServerStub start(HttpServerStubConfiguration configuration) {
        this.port = configuration.port
        return this
    }

    @Override
    HttpServerStub stop() {
        if (!isRunning()) {
            return this
        }
        this.runner.stop()
        return this
    }

    @Override
    HttpServerStub registerMappings(Collection<File> stubFiles) {
        List<RunnerSetting> settings = stubFiles.findAll { it.name.endsWith("json") }
            .collect {
            log.info("Trying to parse [${it.name}]")
            try {
                return RunnerSetting.aRunnerSetting().addStream(it.newInputStream()).
                    build()
            }
            catch (Exception e) {
                log.warn("Exception occurred while trying to parse file [${it.name}]", e)
                return null
            }
        }.findAll { it }
        this.runner = JsonRunner.newJsonRunnerWithSetting(settings,
            HttpArgs.httpArgs().withPort(this.port).build())
        this.runner.run()
        this.started = true
        return this
    }

    @Override
    String registeredMappings() {
        return ""
    }

    @Override
    boolean isAccepted(File file) {
        return file.name.endsWith(".json")
    }
}

org.springframework.cloud.contract.stubrunner.HttpServerStub=\
org.springframework.cloud.contract.stubrunner.provider.moco.MocoHttpServerStub

package com.example;

class CustomStubDownloaderBuilder implements StubDownloaderBuilder {

    @Override
    public StubDownloader build(final StubRunnerOptions stubRunnerOptions) {
        return new StubDownloader() {
            @Override
            public Map.Entry<StubConfiguration, File> downloadAndUnpackStubJar(
                    StubConfiguration config) {
                File unpackedStubs = retrieveStubs();
                return new AbstractMap.SimpleEntry<>(
                        new StubConfiguration(config.getGroupId(), config.getArtifactId(), version,
                                config.getClassifier()), unpackedStubs);
            }

            File retrieveStubs() {
                // here goes your custom logic to provide a folder where all the stubs reside
            }
        }
    }
}

# Example of a custom Stub Downloader Provider
org.springframework.cloud.contract.stubrunner.StubDownloaderBuilder=\
com.example.CustomStubDownloaderBuilder