Generate stubs at runtime (#1152)

* Generate stubs at runtime

without this change the producer side must publish the stubs for the consumer side to use them
with this change the consumer can toggle a switch so that the stubs get generated at runtime. This might of course lead to false positivies but we assume that the users know what they're doing

fixes gh-881

docs/src/main/asciidoc/verifier_contract.adoc

@@ -1820,7 +1820,7 @@ own implementation of the `StubGenerator` interface. The following code listing
 
 [source,groovy]
 ----
-include::{converters_path}/src/main/groovy/org/springframework/cloud/contract/verifier/converter/StubGenerator.groovy[indent=0,lines=16..-1]
+include::{converters_path}/src/main/groovy/org/springframework/cloud/contract/verifier/converter/StubGenerator.java[indent=0,lines=16..-1]
 ----
 
 Again, you must provide a `spring.factories` file, such as the one shown in the following

samples/standalone/dsl/http-client/src/test/java/com/example/loan/GoodbyeWorldTests.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2013-2019 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 com.example.loan;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
+import org.springframework.cloud.contract.stubrunner.spring.AutoConfigureStubRunner;
+import org.springframework.cloud.contract.stubrunner.spring.StubRunnerPort;
+import org.springframework.cloud.contract.stubrunner.spring.StubRunnerProperties;
+import org.springframework.test.context.junit4.SpringRunner;
+import org.springframework.web.client.RestTemplate;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+// tag::autoconfigure_stubrunner[]
+@RunWith(SpringRunner.class)
+@SpringBootTest(webEnvironment = WebEnvironment.NONE)
+@AutoConfigureStubRunner(ids = {
+		"com.example:http-server-dsl"},
+		repositoryRoot = "stubs://classpath://contractsAtRuntime/",
+		stubsMode = StubRunnerProperties.StubsMode.LOCAL,
+		generateStubs = true)
+public class GoodbyeWorldTests {
+
+	// end::autoconfigure_stubrunner[]
+
+	@StubRunnerPort("http-server-dsl")
+	int port;
+
+	@Test
+	public void shouldGenerateStubsAtRuntime() {
+		// when:
+		String response = new RestTemplate().getForObject("http://localhost:" + this.port + "/goodbye", String.class);
+		// then:
+		assertThat(response)
+				.isEqualTo("Goodbye World!");
+	}
+
+}

samples/standalone/dsl/http-client/src/test/resources/contractsAtRuntime/goodbyeWorld.groovy

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2013-2019 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.
+ */
+
+import org.springframework.cloud.contract.spec.Contract
+
+Contract.make {
+	request {
+		url("/goodbye")
+		method(GET())
+	}
+	response {
+		status(OK())
+		body("Goodbye World!")
+	}
+}

spring-cloud-contract-stub-runner/pom.xml

@@ -22,6 +22,10 @@
 			<groupId>org.springframework.cloud</groupId>
 			<artifactId>spring-cloud-contract-shade</artifactId>
 		</dependency>
+		<dependency>
+			<groupId>org.springframework.cloud</groupId>
+			<artifactId>spring-cloud-contract-converters</artifactId>
+		</dependency>
 		<dependency>
 			<groupId>org.springframework.cloud</groupId>
 			<artifactId>spring-cloud-stream-test-support</artifactId>

spring-cloud-contract-stub-runner/src/main/java/org/springframework/cloud/contract/stubrunner/MappingGenerator.java

@@ -0,0 +1,82 @@
+/*
+ * Copyright 2013-2019 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.stubrunner;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Collection;
+import java.util.LinkedList;
+import java.util.Map;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import org.springframework.cloud.contract.spec.Contract;
+import org.springframework.cloud.contract.verifier.converter.StubGenerator;
+import org.springframework.cloud.contract.verifier.converter.StubGeneratorProvider;
+import org.springframework.cloud.contract.verifier.file.ContractMetadata;
+import org.springframework.util.StringUtils;
+
+final class MappingGenerator {
+
+	private static final Log log = LogFactory.getLog(MappingGenerator.class);
+
+	private MappingGenerator() {
+		throw new IllegalStateException("Can't instantiate utility class");
+	}
+
+	static Collection<Path> toMappings(File contractFile, Collection<Contract> contracts,
+			File mappingsFolder) {
+		StubGeneratorProvider provider = new StubGeneratorProvider();
+		Collection<StubGenerator> stubGenerators = provider
+				.converterForName(contractFile.getName());
+		if (log.isDebugEnabled()) {
+			log.debug("Found following matching stub generators " + stubGenerators);
+		}
+		Collection<Path> mappings = new LinkedList<>();
+		for (StubGenerator stubGenerator : stubGenerators) {
+			Map<Contract, String> map = stubGenerator.convertContents(
+					contractFile.getName(), new ContractMetadata(contractFile.toPath(),
+							false, contracts.size(), null, contracts));
+			for (Map.Entry<Contract, String> entry : map.entrySet()) {
+				String value = entry.getValue();
+				File mapping = new File(mappingsFolder,
+						StringUtils.stripFilenameExtension(contractFile.getName()) + "_"
+								+ Math.abs(entry.getKey().hashCode())
+								+ stubGenerator.fileExtension());
+				mappings.add(storeFile(mapping.toPath(), value.getBytes()));
+			}
+		}
+		return mappings;
+	}
+
+	private static Path storeFile(Path path, byte[] contents) {
+		try {
+			Path storedPath = Files.write(path, contents);
+			if (log.isDebugEnabled()) {
+				log.debug("Stored file [" + path.toString() + "]");
+			}
+			return storedPath;
+		}
+		catch (IOException e) {
+			throw new IllegalStateException(e);
+		}
+	}
+
+}

spring-cloud-contract-stub-runner/src/main/java/org/springframework/cloud/contract/stubrunner/StubRunnerFactory.java

@@ -17,7 +17,13 @@
 package org.springframework.cloud.contract.stubrunner;
 
 import java.io.File;
-import java.lang.invoke.MethodHandles;
+import java.io.IOException;
+import java.nio.file.FileVisitResult;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.SimpleFileVisitor;
+import java.nio.file.attribute.BasicFileAttributes;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Map;
@@ -25,7 +31,12 @@ import java.util.Map;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
+import org.springframework.cloud.contract.verifier.config.ContractVerifierConfigProperties;
+import org.springframework.cloud.contract.verifier.converter.RecursiveFilesConverter;
+import org.springframework.cloud.contract.verifier.converter.StubGenerator;
+import org.springframework.cloud.contract.verifier.converter.StubGeneratorProvider;
 import org.springframework.cloud.contract.verifier.messaging.MessageVerifier;
+import org.springframework.core.io.Resource;
 
 /**
  * Factory of StubRunners. Basing on the options and passed collaborators downloads the
@@ -33,8 +44,7 @@ import org.springframework.cloud.contract.verifier.messaging.MessageVerifier;
  */
 class StubRunnerFactory {
 
-	private static final Log log = LogFactory
-			.getLog(MethodHandles.lookup().lookupClass());
+	private static final Log log = LogFactory.getLog(StubRunnerFactory.class);
 
 	private final StubRunnerOptions stubRunnerOptions;
 
@@ -69,13 +79,93 @@ class StubRunnerFactory {
 						+ "] the downloaded entry is [" + entry + "]");
 			}
 			if (entry != null) {
-				result.add(createStubRunner(entry.getKey(), entry.getValue()));
+				Path path = resolvePath(entry.getValue());
+				File unpackedLocation = path.toFile();
+				if (this.stubRunnerOptions.isGenerateStubs()) {
+					if (log.isDebugEnabled()) {
+						log.debug(
+								"Flag to generate stubs at runtime was switched on. Will remove the current mappings and will generate new ones.");
+					}
+					generateMappingsAtRuntime(path);
+				}
+				result.add(createStubRunner(entry.getKey(), unpackedLocation));
 			}
-
 		}
 		return result;
 	}
 
+	private void generateMappingsAtRuntime(Path path) {
+		removeCurrentMappings(path);
+		generateNewMappings(path);
+	}
+
+	private Path resolvePath(File unpackedLocation) {
+		Resource resource = ResourceResolver.resource(unpackedLocation.getPath());
+		Path path = unpackedLocation.toPath();
+		if (resource != null) {
+			try {
+				return Paths.get(resource.getURI());
+			}
+			catch (IOException ex) {
+				return unpackedLocation.toPath();
+			}
+		}
+		return path;
+	}
+
+	private void removeCurrentMappings(Path path) {
+		try {
+			Files.walkFileTree(path, new SimpleFileVisitor<Path>() {
+
+				private final Log log = LogFactory.getLog(StubRunnerFactory.class);
+
+				private final StubGeneratorProvider provider = new StubGeneratorProvider();
+
+				@Override
+				public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) {
+					Collection<StubGenerator> stubGenerators = this.provider
+							.converterForName(file.toString());
+					if (!stubGenerators.isEmpty()) {
+						if (log.isDebugEnabled()) {
+							log.debug("Deleting file [" + file.toString()
+									+ "] since at least one stub generator would run it");
+						}
+						try {
+							Files.delete(file);
+						}
+						catch (IOException ex) {
+							log.warn("Failed to delete file [" + file.toString() + "]",
+									ex);
+						}
+					}
+					return FileVisitResult.CONTINUE;
+				}
+			});
+		}
+		catch (IOException ex) {
+			log.warn("Exception occurred while trying to delete mappings", ex);
+		}
+	}
+
+	private void generateNewMappings(Path path) {
+		File unpackedLocation = path.toFile();
+		ContractVerifierConfigProperties configProperties = new ContractVerifierConfigProperties();
+		configProperties
+				.setContractsDslDir(subfolderIfPresent(unpackedLocation, "contracts"));
+		configProperties
+				.setStubsOutputDir(subfolderIfPresent(unpackedLocation, "mappings"));
+		RecursiveFilesConverter converter = new RecursiveFilesConverter(configProperties);
+		converter.processFiles();
+	}
+
+	private File subfolderIfPresent(File unpackedLocation, String subfolder) {
+		File subfolderDir = new File(unpackedLocation, subfolder);
+		if (subfolderDir.exists()) {
+			return subfolderDir;
+		}
+		return unpackedLocation;
+	}
+
 	private StubRunner createStubRunner(StubConfiguration stubsConfiguration,
 			File unzipedStubDir) {
 		if (unzipedStubDir == null) {

spring-cloud-contract-stub-runner/src/main/java/org/springframework/cloud/contract/stubrunner/StubRunnerOptions.java

@@ -116,6 +116,12 @@ public class StubRunnerOptions {
 	 */
 	private boolean deleteStubsAfterTest;
 
+	/**
+	 * When enabled, this flag will tell stub runner to not load the generated stubs, but
+	 * convert the found contracts at runtime to a stub format and run those stubs.
+	 */
+	private boolean generateStubs;
+
 	/**
 	 * Map of properties that can be passed to custom
 	 * {@link org.springframework.cloud.contract.stubrunner.StubDownloaderBuilder}.
@@ -128,7 +134,8 @@ public class StubRunnerOptions {
 			Map<StubConfiguration, Integer> stubIdsToPortMapping, String username,
 			String password, final StubRunnerProxyOptions stubRunnerProxyOptions,
 			boolean stubsPerConsumer, String consumerName, String mappingsOutputFolder,
-			boolean deleteStubsAfterTest, Map<String, String> properties,
+			boolean deleteStubsAfterTest, boolean generateStubs,
+			Map<String, String> properties,
 			Class<? extends HttpServerStubConfigurer> httpServerStubConfigurer) {
 		this.minPortValue = minPortValue;
 		this.maxPortValue = maxPortValue;
@@ -145,6 +152,7 @@ public class StubRunnerOptions {
 		this.consumerName = consumerName;
 		this.mappingsOutputFolder = mappingsOutputFolder;
 		this.deleteStubsAfterTest = deleteStubsAfterTest;
+		this.generateStubs = generateStubs;
 		this.properties = properties;
 		this.httpServerStubConfigurer = httpServerStubConfigurer;
 	}
@@ -169,6 +177,8 @@ public class StubRunnerOptions {
 						System.getProperty("stubrunner.mappings-output-folder"))
 				.withDeleteStubsAfterTest(Boolean.parseBoolean(
 						System.getProperty("stubrunner.delete-stubs-after-test", "true")))
+				.withGenerateStubs(Boolean.parseBoolean(
+						System.getProperty("stubrunner.generate-stubs", "false")))
 				.withProperties(stubRunnerProps());
 		builder = httpStubConfigurer(builder);
 		String proxyHost = System.getProperty("stubrunner.proxy.host");
@@ -318,6 +328,10 @@ public class StubRunnerOptions {
 		this.deleteStubsAfterTest = deleteStubsAfterTest;
 	}
 
+	public boolean isGenerateStubs() {
+		return this.generateStubs;
+	}
+
 	public Map<String, String> getProperties() {
 		return this.properties;
 	}

spring-cloud-contract-stub-runner/src/main/java/org/springframework/cloud/contract/stubrunner/StubRunnerOptionsBuilder.java

@@ -69,6 +69,8 @@ public class StubRunnerOptionsBuilder {
 
 	private boolean deleteStubsAfterTest = true;
 
+	private boolean generateStubs;
+
 	private Map<String, String> properties = new HashMap<>();
 
 	private Class httpServerStubConfigurer = HttpServerStubConfigurer.NoOpHttpServerStubConfigurer.class;
@@ -194,6 +196,7 @@ public class StubRunnerOptionsBuilder {
 		this.stubIdsToPortMapping = options.stubIdsToPortMapping != null
 				? options.stubIdsToPortMapping : new LinkedHashMap<>();
 		this.deleteStubsAfterTest = options.isDeleteStubsAfterTest();
+		this.generateStubs = options.isGenerateStubs();
 		this.properties = options.getProperties();
 		this.httpServerStubConfigurer = options.getHttpServerStubConfigurer();
 		return this;
@@ -211,6 +214,11 @@ public class StubRunnerOptionsBuilder {
 		return this;
 	}
 
+	public StubRunnerOptionsBuilder withGenerateStubs(boolean generateStubs) {
+		this.generateStubs = generateStubs;
+		return this;
+	}
+
 	public StubRunnerOptionsBuilder withProperties(Map<String, String> properties) {
 		this.properties = properties;
 		return this;
@@ -228,7 +236,7 @@ public class StubRunnerOptionsBuilder {
 				buildDependencies(), this.stubIdsToPortMapping, this.username,
 				this.password, this.stubRunnerProxyOptions, this.stubsPerConsumer,
 				this.consumerName, this.mappingsOutputFolder, this.deleteStubsAfterTest,
-				this.properties, this.httpServerStubConfigurer);
+				this.generateStubs, this.properties, this.httpServerStubConfigurer);
 	}
 
 	private Collection<StubConfiguration> buildDependencies() {

spring-cloud-contract-stub-runner/src/main/java/org/springframework/cloud/contract/stubrunner/junit/StubRunnerExtension.java

@@ -252,6 +252,12 @@ public class StubRunnerExtension implements BeforeAllCallback, AfterAllCallback,
 		return new PortStubRunnerExtension(this.delegate);
 	}
 
+	@Override
+	public StubRunnerExtension withGenerateStubs(boolean generateStubs) {
+		builder().withGenerateStubs(generateStubs);
+		return new PortStubRunnerExtension(this.delegate);
+	}
+
 	@Override
 	public StubRunnerExtension withProperties(Map<String, String> properties) {
 		builder().withProperties(properties);

spring-cloud-contract-stub-runner/src/main/java/org/springframework/cloud/contract/stubrunner/junit/StubRunnerExtensionOptions.java

@@ -149,6 +149,13 @@ interface StubRunnerExtensionOptions {
 	 */
 	StubRunnerExtension withDeleteStubsAfterTest(boolean deleteStubsAfterTest);
 
+	/**
+	 * @param generateStubs If set to {@code true} will NOT load generated stubs but will
+	 * generate stubs from contract definitions at runtime.
+	 * @return the rule
+	 */
+	StubRunnerExtension withGenerateStubs(boolean generateStubs);
+
 	/**
 	 * @param properties Map of properties that can be passed to custom
 	 * {@link org.springframework.cloud.contract.stubrunner.StubDownloaderBuilder}

spring-cloud-contract-stub-runner/src/main/java/org/springframework/cloud/contract/stubrunner/junit/StubRunnerRule.java

@@ -190,6 +190,12 @@ public class StubRunnerRule implements TestRule, StubFinder, StubRunnerRuleOptio
 		return this.delegate;
 	}
 
+	@Override
+	public StubRunnerRule withGenerateStubs(boolean generateStubs) {
+		builder().withGenerateStubs(true);
+		return this.delegate;
+	}
+
 	@Override
 	public StubRunnerRule withProperties(Map<String, String> properties) {
 		builder().withProperties(properties);

spring-cloud-contract-stub-runner/src/main/java/org/springframework/cloud/contract/stubrunner/junit/StubRunnerRuleOptions.java

@@ -145,6 +145,13 @@ interface StubRunnerRuleOptions {
 	 */
 	StubRunnerRule withDeleteStubsAfterTest(boolean deleteStubsAfterTest);
 
+	/**
+	 * @param generateStubs If set to {@code true} will NOT load generated stubs but will
+	 * generate stubs from contract definitions at runtime.
+	 * @return the rule
+	 */
+	StubRunnerRule withGenerateStubs(boolean generateStubs);
+
 	/**
 	 * @param properties Map of properties that can be passed to custom
 	 * {@link org.springframework.cloud.contract.stubrunner.StubDownloaderBuilder}

spring-cloud-contract-stub-runner/src/main/java/org/springframework/cloud/contract/stubrunner/spring/AutoConfigureStubRunner.java

@@ -137,6 +137,13 @@ public @interface AutoConfigureStubRunner {
 	 */
 	boolean deleteStubsAfterTest() default true;
 
+	/**
+	 * @return When enabled, this flag will tell stub runner to not load the generated
+	 * stubs, but convert the found contracts at runtime to a stub format and run those
+	 * stubs.
+	 */
+	boolean generateStubs() default false;
+
 	/**
 	 * Configuration for an HTTP server stub.
 	 * @return class that allows to perform additional HTTP server stub configuration

spring-cloud-contract-stub-runner/src/main/java/org/springframework/cloud/contract/stubrunner/spring/StubRunnerConfiguration.java

@@ -101,6 +101,7 @@ public class StubRunnerConfiguration {
 				.withConsumerName(consumerName())
 				.withMappingsOutputFolder(this.props.getMappingsOutputFolder())
 				.withDeleteStubsAfterTest(this.props.isDeleteStubsAfterTest())
+				.withGenerateStubs(this.props.isGenerateStubs())
 				.withProperties(this.props.getProperties())
 				.withHttpServerStubConfigurer(this.props.getHttpServerStubConfigurer());
 	}

spring-cloud-contract-stub-runner/src/main/java/org/springframework/cloud/contract/stubrunner/spring/StubRunnerProperties.java

@@ -30,7 +30,6 @@ import org.springframework.util.StringUtils;
 
 /**
  * @author Dave Syer
- *
  */
 @ConfigurationProperties("stubrunner")
 public class StubRunnerProperties {
@@ -109,6 +108,12 @@ public class StubRunnerProperties {
 	 */
 	private boolean deleteStubsAfterTest = true;
 
+	/**
+	 * When enabled, this flag will tell stub runner to not load the generated stubs, but
+	 * convert the found contracts at runtime to a stub format and run those stubs.
+	 */
+	private boolean generateStubs;
+
 	/**
 	 * Map of properties that can be passed to custom
 	 * {@link org.springframework.cloud.contract.stubrunner.StubDownloaderBuilder}.
@@ -247,6 +252,14 @@ public class StubRunnerProperties {
 		}
 	}
 
+	public boolean isGenerateStubs() {
+		return this.generateStubs;
+	}
+
+	public void setGenerateStubs(boolean generateStubs) {
+		this.generateStubs = generateStubs;
+	}
+
 	public Class getHttpServerStubConfigurer() {
 		return this.httpServerStubConfigurer;
 	}

spring-cloud-contract-stub-runner/src/test/groovy/org/springframework/cloud/contract/stubrunner/StubRunnerOptionsBuilderSpec.groovy

@@ -231,7 +231,7 @@ class StubRunnerOptionsBuilderSpec extends Specification {
 		given:
 			StubRunnerOptionsBuilder builder = builder.withOptions(new StubRunnerOptions(1, 2, new FileSystemResource("root"), StubRunnerProperties.StubsMode.LOCAL,
 					"classifier", [new StubConfiguration("a:b:c")], [(new StubConfiguration("a:b:c")): 3], "foo", "bar",
-					new StubRunnerOptions.StubRunnerProxyOptions("host", 4), true, "consumer", "folder", false, [foo: "bar"], Foo))
+					new StubRunnerOptions.StubRunnerProxyOptions("host", 4), true, "consumer", "folder", false, true, [foo: "bar"], Foo))
 			builder.withStubs("foo:bar:baz")
 		when:
 			StubRunnerOptions options = builder.build()
@@ -251,6 +251,7 @@ class StubRunnerOptionsBuilderSpec extends Specification {
 			options.consumerName == "consumer"
 			options.mappingsOutputFolder == "folder"
 			options.deleteStubsAfterTest == false
+			options.generateStubs == true
 			options.properties == [foo: "bar"]
 			options.httpServerStubConfigurer == Foo
 	}
@@ -260,7 +261,7 @@ class StubRunnerOptionsBuilderSpec extends Specification {
 			StubRunnerOptionsBuilder builder = builder.withOptions(new StubRunnerOptions(1, 2, new FileSystemResource("root"),
 					StubRunnerProperties.StubsMode.CLASSPATH, "classifier",
 					[new StubConfiguration("a:b:c")], [(new StubConfiguration("a:b:c")): 3], "username123", "password123",
-					new StubRunnerOptions.StubRunnerProxyOptions("host", 4), true, "consumer", "folder", false, [:], Foo))
+					new StubRunnerOptions.StubRunnerProxyOptions("host", 4), true, "consumer", "folder", false, true, [:], Foo))
 			builder.withStubs("foo:bar:baz")
 		when:
 			String options = builder.build().toString()
@@ -290,6 +291,8 @@ class StubRunnerOptionsBuilderSpec extends Specification {
 			System.setProperty("stubrunner.properties.foo-bar", "bar")
 			System.setProperty("stubrunner.properties.foo-baz", "baz")
 			System.setProperty("stubrunner.properties.bar.bar", "foo")
+			System.setProperty("stubrunner.delete-stubs-after-test", "false")
+			System.setProperty("stubrunner.generate-stubs", "true")
 			System.setProperty("stubrunner.http-server-stub-configurer", "org.springframework.cloud.contract.stubrunner.Foo")
 		when:
 			StubRunnerOptions options = StubRunnerOptions.fromSystemProps()
@@ -305,6 +308,8 @@ class StubRunnerOptionsBuilderSpec extends Specification {
 			options.proxyOptions.proxyHost == "host"
 			options.proxyOptions.proxyPort == 4
 			options.stubsPerConsumer == true
+			options.deleteStubsAfterTest == false
+			options.generateStubs == true
 			options.consumerName == "consumer"
 			options.mappingsOutputFolder == "folder"
 			options.properties == ["foo-bar": "bar", "foo-baz": "baz", "bar.bar": "foo"]

spring-cloud-contract-stub-runner/src/test/groovy/org/springframework/cloud/contract/stubrunner/StubRunnerSpec.groovy

@@ -16,14 +16,21 @@
 
 package org.springframework.cloud.contract.stubrunner
 
+
 import spock.lang.Specification
 
+import org.springframework.cloud.contract.stubrunner.spring.StubRunnerProperties
+import org.springframework.cloud.contract.verifier.messaging.noop.NoOpStubMessages
+import org.springframework.util.SocketUtils
+
 class StubRunnerSpec extends Specification {
 
-	private static final int MIN_PORT = 8111
-	private static final int MAX_PORT = 8111
+	private static final int MIN_PORT = SocketUtils.findAvailableTcpPort()
+	private static final int MAX_PORT = MIN_PORT
 	private static final URL EXPECTED_STUB_URL = new URL("http://localhost:$MIN_PORT")
 
+	private static final URL generateStubs = StubRunnerSpec.getResource('/generateStubs/')
+
 	def 'should provide stub URL for provided groupid and artifactId'() {
 		given:
 			Arguments args = argumentsWithProjectDefinition()
@@ -50,10 +57,42 @@ class StubRunnerSpec extends Specification {
 			runner.close()
 	}
 
+
+	def 'should generate stubs at runtime'() {
+		given:
+			Arguments args = argumentsWithGenerateStubs()
+			StubDownloader downloader = new FileStubDownloader().build(args.stubRunnerOptions);
+			StubRunner runner = new StubRunnerFactory(args.stubRunnerOptions,
+					downloader, new NoOpStubMessages()).createStubsFromServiceConfiguration().first()
+		when:
+			runner.runStubs()
+		then:
+			URL url = runner.findStubUrl("groupId2", "artifactId2")
+			new URL(url.toString() + "/goodbye").text
+		when:
+			new URL(url.toString() + "/hello").text
+		then:
+			thrown(FileNotFoundException)
+		cleanup:
+			runner.close()
+	}
+
 	Arguments argumentsWithProjectDefinition() {
 		StubConfiguration stubConfiguration = new StubConfiguration("groupId", "artifactId", "classifier")
 		StubRunnerOptions stubRunnerOptions = new StubRunnerOptionsBuilder().withMinMaxPort(MIN_PORT, MAX_PORT).build()
 		return new Arguments(stubRunnerOptions, 'src/test/resources/repository', stubConfiguration)
 	}
 
+	Arguments argumentsWithGenerateStubs() {
+		StubConfiguration stubConfiguration = new StubConfiguration("groupId2", "artifactId2", "classifier2")
+		StubRunnerOptions stubRunnerOptions = new StubRunnerOptionsBuilder()
+				.withMinMaxPort(MIN_PORT, MAX_PORT)
+				.withGenerateStubs(true)
+				.withStubs(stubConfiguration.toString())
+				.withStubsMode(StubRunnerProperties.StubsMode.REMOTE)
+				.withStubRepositoryRoot("stubs://file://" + generateStubs.path)
+				.build()
+		return new Arguments(stubRunnerOptions, 'src/test/resources/generateStubs', stubConfiguration)
+	}
+
 }

spring-cloud-contract-stub-runner/src/test/resources/generateStubs/contracts/goodbye.groovy

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2013-2019 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.
+ */
+
+import org.springframework.cloud.contract.spec.Contract
+
+Contract.make {
+	request {
+		url("/goodbye")
+		method(GET())
+	}
+	response {
+		status(OK())
+		body("Goodbye World!")
+	}
+}

spring-cloud-contract-stub-runner/src/test/resources/generateStubs/mappings/hello.json

@@ -0,0 +1,13 @@
+{
+  "request": {
+    "method": "GET",
+    "url": "/hello"
+  },
+  "response": {
+    "status": 200,
+    "body": "Hello world!",
+    "headers": {
+      "Content-Type": "text/plain"
+    }
+  }
+}

spring-cloud-contract-tools/spring-cloud-contract-converters/src/main/groovy/org/springframework/cloud/contract/verifier/converter/StubGenerator.groovy

@@ -1,54 +0,0 @@
-/*
- * Copyright 2013-2019 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.converter
-
-import groovy.transform.CompileStatic
-
-import org.springframework.cloud.contract.spec.Contract
-import org.springframework.cloud.contract.verifier.file.ContractMetadata
-
-/**
- * Converts contracts into their stub representation.
- *
- * @since 1.1.0
- */
-@CompileStatic
-interface StubGenerator {
-
-	/**
-	 * @return {@code true} if the converter can handle the file to convert it into a stub.
-	 */
-	boolean canHandleFileName(String fileName)
-
-	/**
-	 * @return the collection of converted contracts into stubs. One contract can
-	 * result in multiple stubs.
-	 */
-	Map<Contract, String> convertContents(String rootName, ContractMetadata content)
-
-	/**
-	 * @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#name} 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)
-}

spring-cloud-contract-tools/spring-cloud-contract-converters/src/main/groovy/org/springframework/cloud/contract/verifier/converter/StubGenerator.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright 2013-2019 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.converter;
+
+import java.util.Map;
+
+import org.springframework.cloud.contract.spec.Contract;
+import org.springframework.cloud.contract.verifier.file.ContractMetadata;
+
+/**
+ * Converts contracts into their stub representation.
+ *
+ * @since 1.1.0
+ */
+public interface StubGenerator {
+
+	/**
+	 * @param fileName - file name
+	 * @return {@code true} if the converter can handle the file to convert it into a
+	 * stub.
+	 */
+	default boolean canHandleFileName(String fileName) {
+		return fileName.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);
+
+	/**
+	 * @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#name} 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 that this stub generator can handle.
+	 * @return string describing the file extension
+	 */
+	default String fileExtension() {
+		return ".json";
+	}
+
+}

spring-cloud-contract-tools/spring-cloud-contract-converters/src/main/groovy/org/springframework/cloud/contract/verifier/wiremock/DslToWireMockConverter.groovy

@@ -28,11 +28,6 @@ import org.springframework.cloud.contract.verifier.converter.StubGenerator
 @CompileStatic
 abstract class DslToWireMockConverter implements StubGenerator {
 
-	@Override
-	boolean canHandleFileName(String fileName) {
-		return fileName.endsWith('.groovy')
-	}
-
 	@Override
 	String generateOutputFileNameForInput(String inputFileName) {
 		return inputFileName.replaceAll(extension(inputFileName), 'json')

spring-cloud-contract-tools/spring-cloud-contract-maven-plugin/src/main/java/org/springframework/cloud/contract/maven/verifier/ConvertMojo.java

@@ -38,10 +38,10 @@ import org.springframework.cloud.contract.verifier.converter.RecursiveFilesConve
 import org.springframework.cloud.contract.verifier.converter.ToYamlConverter;
 
 /**
- * Convert Spring Cloud Contract Verifier contracts into WireMock stubs mappings.
+ * Convert Spring Cloud Contract Verifier contracts into stubs mappings.
  * <p>
  * This goal allows you to generate `stubs-jar` or execute `spring-cloud-contract:run`
- * with generated WireMock mappings.
+ * with generated mappings.
  *
  * @author Mariusz Smykula
  */

spring-cloud-contract-tools/spring-cloud-contract-pact/src/main/groovy/org/springframework/cloud/contract/stubrunner/PactStubDownloaderBuilder.java

@@ -47,9 +47,6 @@ import org.jetbrains.annotations.NotNull;
 
 import org.springframework.cloud.contract.spec.Contract;
 import org.springframework.cloud.contract.stubrunner.spring.StubRunnerProperties;
-import org.springframework.cloud.contract.verifier.converter.StubGenerator;
-import org.springframework.cloud.contract.verifier.converter.StubGeneratorProvider;
-import org.springframework.cloud.contract.verifier.file.ContractMetadata;
 import org.springframework.cloud.contract.verifier.spec.pact.PactContractConverter;
 import org.springframework.core.io.AbstractResource;
 import org.springframework.core.io.Resource;
@@ -216,32 +213,16 @@ class PactStubDownloader implements StubDownloader {
 			log.debug("Converted pact file [" + file + "] to [" + contracts.size()
 					+ "] contracts");
 		}
-		StubGeneratorProvider provider = new StubGeneratorProvider();
-		Collection<StubGenerator> stubGenerators = provider
-				.converterForName(ARTIFICIAL_NAME_ENDING_WITH_GROOVY);
-		if (log.isDebugEnabled()) {
-			log.debug("Found following matching stub generators " + stubGenerators);
-		}
-		for (StubGenerator stubGenerator : stubGenerators) {
-			Map<Contract, String> map = stubGenerator.convertContents(file.getName(),
-					new ContractMetadata(file.toPath(), false, contracts.size(), null,
-							contracts));
-			for (Map.Entry<Contract, String> entry : map.entrySet()) {
-				String value = entry.getValue();
-				File mapping = new File(mappingsFolder,
-						StringUtils.stripFilenameExtension(file.getName()) + "_"
-								+ Math.abs(entry.getKey().hashCode()) + ".json");
-				storeFile(mapping.toPath(), value.getBytes());
-			}
-		}
+		MappingGenerator.toMappings(file, contracts, mappingsFolder);
 	}
 
-	private void storeFile(Path path, byte[] contents) {
+	private Path storeFile(Path path, byte[] contents) {
 		try {
-			Files.write(path, contents);
+			Path storedPath = Files.write(path, contents);
 			if (log.isDebugEnabled()) {
 				log.debug("Stored file [" + path.toString() + "]");
 			}
+			return storedPath;
 		}
 		catch (IOException e) {
 			throw new IllegalStateException(e);