Added a json schema definition and added it to the docs

fixes gh-1250

docs/pom.xml

@@ -14,6 +14,7 @@
 	<name>Spring Cloud Contract Docs</name>
 	<description>Spring Cloud Docs</description>
 	<properties>
+		<jackson-module-jsonSchema.version>2.10.0</jackson-module-jsonSchema.version>
 		<docs.main>spring-cloud-contract</docs.main>
 		<main.basedir>${basedir}/..</main.basedir>
 		<maven.plugin.plugin.version>3.4</maven.plugin.plugin.version>
@@ -29,6 +30,40 @@
 					<skip>true</skip>
 				</configuration>
 			</plugin>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-compiler-plugin</artifactId>
+				<executions>
+					<execution>
+						<id>schema-test-compilation</id>
+						<phase>generate-test-resources</phase>
+						<goals>
+							<goal>testCompile</goal>
+						</goals>
+					</execution>
+				</executions>
+			</plugin>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-surefire-plugin</artifactId>
+				<executions>
+					<execution>
+						<id>schema-generation</id>
+						<phase>generate-test-resources</phase>
+						<goals>
+							<goal>test</goal>
+						</goals>
+						<configuration>
+							<includes>
+								<include>**/*Tests.*</include>
+								<include>**/*Test.*</include>
+							</includes>
+							<reportFormat>plain</reportFormat>
+							<failIfNoTests>true</failIfNoTests>
+						</configuration>
+					</execution>
+				</executions>
+			</plugin>
 		</plugins>
 	</build>
 	<dependencies>
@@ -40,6 +75,12 @@
 			<groupId>${project.groupId}</groupId>
 			<artifactId>spring-cloud-starter-contract-verifier</artifactId>
 		</dependency>
+		<dependency>
+			<groupId>com.fasterxml.jackson.module</groupId>
+			<artifactId>jackson-module-jsonSchema</artifactId>
+			<version>${jackson-module-jsonSchema.version}</version>
+			<scope>test</scope>
+		</dependency>
 	</dependencies>
 	<profiles>
 		<profile>

docs/src/main/asciidoc/_project-features-contract.adoc

@@ -164,6 +164,11 @@ IMPORTANT: Remember that, inside the Kotlin Script file, you have to provide the
 Generally you would use its contract function like this: `org.springframework.cloud.contract.spec.ContractDsl.contract { ... }`.
 You can also provide an import to the `contract` function (`import org.springframework.cloud.contract.spec.ContractDsl.Companion.contract`) and then call `contract { ... }`.
 
+[[contract-yml]]
+=== Contract DSL in YML
+
+In order to see a schema of a YAML contract, you can check out the link:yml-schema.html[YML Schema] page.
+
 [[contract-limitations]]
 === Limitations
 

docs/src/main/asciidoc/yml-schema.adoc

@@ -0,0 +1,12 @@
+[[yml-schema]]
+== YML Schema
+include::_attributes.adoc[]
+
+Below you can find a JSON schema definition of a YAML contract.
+
+====
+[source,json,indent=0]
+----
+include::{project-root}/docs/target/contract_schema.json[indent=0]
+----
+====

docs/src/test/java/org/springframework/cloud/contract/docs/JsonSchemaTests.java

@@ -0,0 +1,120 @@
+/*
+ * 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.docs;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.util.Collection;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializationFeature;
+import com.fasterxml.jackson.module.jsonSchema.JsonSchema;
+import com.fasterxml.jackson.module.jsonSchema.JsonSchemaGenerator;
+import org.assertj.core.api.BDDAssertions;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.cloud.contract.spec.Contract;
+import org.springframework.cloud.contract.verifier.converter.YamlContract;
+import org.springframework.cloud.contract.verifier.converter.YamlContractConverter;
+
+class JsonSchemaTests {
+
+	// @formatter:off
+	private static final String CONTRACT = "description: Some description\n"
+			+ "name: some name\n"
+			+ "priority: 8\n"
+			+ "ignored: true\n"
+			+ "inProgress: true\n"
+			+ "request:\n"
+			+ "  method: PUT\n"
+			+ "  url: /foo\n"
+			+ "  queryParameters:\n"
+			+ "    a: b\n"
+			+ "    b: c\n"
+			+ "  headers:\n"
+			+ "    foo: bar\n"
+			+ "    fooReq: baz\n"
+			+ "  cookies:\n"
+			+ "    foo: bar\n"
+			+ "    fooReq: baz\n"
+			+ "  body:\n"
+			+ "    foo: bar\n"
+			+ "  matchers:\n"
+			+ "    body:\n"
+			+ "      - path: $.foo\n"
+			+ "        type: by_regex\n"
+			+ "        value: bar\n"
+			+ "    headers:\n"
+			+ "      - key: foo\n"
+			+ "        regex: bar\n"
+			+ "response:\n"
+			+ "  status: 200\n"
+			+ "  fixedDelayMilliseconds: 1000\n"
+			+ "  headers:\n"
+			+ "    foo2: bar\n"
+			+ "    foo3: foo33\n"
+			+ "    fooRes: baz\n"
+			+ "  body:\n"
+			+ "    foo2: bar\n"
+			+ "    foo3: baz\n"
+			+ "    nullValue: null\n"
+			+ "  matchers:\n"
+			+ "    body:\n"
+			+ "      - path: $.foo2\n"
+			+ "        type: by_regex\n"
+			+ "        value: bar\n"
+			+ "      - path: $.foo3\n"
+			+ "        type: by_command\n"
+			+ "        value: executeMe($it)\n"
+			+ "      - path: $.nullValue\n"
+			+ "        type: by_null\n"
+			+ "        value: null\n"
+			+ "    headers:\n"
+			+ "      - key: foo2\n"
+			+ "        regex: bar\n"
+			+ "      - key: foo3\n"
+			+ "        command: andMeToo($it)\n"
+			+ "    cookies:\n"
+			+ "      - key: foo2\n"
+			+ "        regex: bar\n"
+			+ "      - key: foo3\n"
+			+ "        predefined:\n";
+	// @formatter:on
+
+	@Test
+	void should_produce_a_json_schema_of_a_yaml_model() throws IOException {
+		ObjectMapper mapper = new ObjectMapper();
+		mapper.enable(SerializationFeature.INDENT_OUTPUT);
+		JsonSchemaGenerator schemaGen = new JsonSchemaGenerator(mapper);
+		JsonSchema schema = schemaGen.generateSchema(YamlContract.class);
+		String schemaString = mapper.writeValueAsString(schema);
+		File schemaFile = new File("target/contract_schema.json");
+		Files.write(schemaFile.toPath(), schemaString.getBytes());
+	}
+
+	@Test
+	void should_convert_yaml_to_contract() throws IOException {
+		File ymlFile = new File("target/contract.yml");
+		Files.write(ymlFile.toPath(), CONTRACT.getBytes());
+
+		Collection<Contract> contracts = new YamlContractConverter().convertFrom(ymlFile);
+
+		BDDAssertions.then(contracts).isNotEmpty();
+	}
+
+}

docs/src/test/resources/contract.yml

@@ -0,0 +1,59 @@
+description: Some description
+name: some name
+priority: 8
+ignored: true
+inProgress: true
+request:
+  method: PUT
+  url: /foo
+  queryParameters:
+    a: b
+    b: c
+  headers:
+    foo: bar
+    fooReq: baz
+  cookies:
+    foo: bar
+    fooReq: baz
+  body:
+    foo: bar
+  matchers:
+    body:
+      - path: $.foo
+        type: by_regex
+        value: bar
+    headers:
+      - key: foo
+        regex: bar
+response:
+  status: 200
+  fixedDelayMilliseconds: 1000
+  headers:
+    foo2: bar
+    foo3: foo33
+    fooRes: baz
+  body:
+    foo2: bar
+    foo3: baz
+    nullValue: null
+  matchers:
+    body:
+      - path: $.foo2
+        type: by_regex
+        value: bar
+      - path: $.foo3
+        type: by_command
+        value: executeMe($it)
+      - path: $.nullValue
+        type: by_null
+        value: null
+    headers:
+      - key: foo2
+        regex: bar
+      - key: foo3
+        command: andMeToo($it)
+    cookies:
+      - key: foo2
+        regex: bar
+      - key: foo3
+        predefined: