Add Kotlin suspend function support

Use suspendCoroutineUninterceptedOrReturn to avoid using not fully implemented Function2.reflect()

Mapping of Function, Consumer and Supplier to kotlin suspend flow lambda

Fix MR review

Resolves #655

spring-cloud-function-kotlin/src/test/java/org/springframework/cloud/function/kotlin/ContextFunctionCatalogAutoConfigurationKotlinSuspendTests.java

@@ -0,0 +1,126 @@
+/*
+ * Copyright 2019-2021 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.function.kotlin;
+
+import java.lang.reflect.ParameterizedType;
+import java.util.function.Consumer;
+import java.util.function.Function;
+import java.util.function.Supplier;
+
+import kotlin.jvm.functions.Function2;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.TestInstance;
+
+import org.springframework.beans.factory.BeanCreationException;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.builder.SpringApplicationBuilder;
+import org.springframework.cloud.function.context.FunctionCatalog;
+import org.springframework.cloud.function.context.catalog.FunctionTypeUtils;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.support.GenericApplicationContext;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+/**
+ * @author Adrien Poupard
+ */
+@TestInstance(TestInstance.Lifecycle.PER_CLASS)
+public class ContextFunctionCatalogAutoConfigurationKotlinSuspendTests {
+
+	private GenericApplicationContext context;
+
+	private FunctionCatalog catalog;
+
+	@AfterEach
+	public void close() {
+		if (this.context != null) {
+			this.context.close();
+		}
+	}
+
+	@Test
+	public void typeDiscoveryTests() {
+		create(new Class[] { KotlinSuspendFlowLambdasConfiguration.class,
+			ContextFunctionCatalogAutoConfigurationKotlinTests.SimpleConfiguration.class });
+
+		Object function = this.context.getBean("kotlinFunction");
+		ParameterizedType functionType = (ParameterizedType) FunctionTypeUtils.discoverFunctionType(function, "kotlinFunction", this.context);
+		assertThat(functionType.getRawType().getTypeName()).isEqualTo(Function.class.getName());
+		assertThat(functionType.getActualTypeArguments().length).isEqualTo(2);
+		assertThat(functionType.getActualTypeArguments()[0].getTypeName()).isEqualTo("reactor.core.publisher.Flux<java.lang.String>");
+		assertThat(functionType.getActualTypeArguments()[1].getTypeName()).isEqualTo("reactor.core.publisher.Flux<java.lang.String>");
+
+		function = this.context.getBean("kotlinConsumer");
+		functionType = (ParameterizedType) FunctionTypeUtils.discoverFunctionType(function, "kotlinConsumer", this.context);
+		assertThat(functionType.getRawType().getTypeName()).isEqualTo(Consumer.class.getName());
+		assertThat(functionType.getActualTypeArguments().length).isEqualTo(1);
+		assertThat(functionType.getActualTypeArguments()[0].getTypeName()).isEqualTo("reactor.core.publisher.Flux<java.lang.String>");
+
+		function = this.context.getBean("kotlinSupplier");
+		functionType = (ParameterizedType) FunctionTypeUtils.discoverFunctionType(function, "kotlinSupplier", this.context);
+		assertThat(functionType.getRawType().getTypeName()).isEqualTo(Supplier.class.getName());
+		assertThat(functionType.getActualTypeArguments().length).isEqualTo(1);
+		assertThat(functionType.getActualTypeArguments()[0].getTypeName()).isEqualTo("reactor.core.publisher.Flux<java.lang.String>");
+
+		function = this.context.getBean("kotlinPojoFunction");
+		functionType = (ParameterizedType) FunctionTypeUtils.discoverFunctionType(function, "kotlinPojoFunction", this.context);
+		assertThat(functionType.getRawType().getTypeName()).isEqualTo(Function.class.getName());
+		assertThat(functionType.getActualTypeArguments().length).isEqualTo(2);
+		assertThat(functionType.getActualTypeArguments()[0].getTypeName()).isEqualTo("reactor.core.publisher.Flux<org.springframework.cloud.function.kotlin.Person>");
+		assertThat(functionType.getActualTypeArguments()[1].getTypeName()).isEqualTo("reactor.core.publisher.Flux<java.lang.String>");
+	}
+
+	@Test
+	public void shouldNotLoadKotlinSuspendLambasNotUsingFlow() {
+		create(new Class[] { KotlinSuspendLambdasConfiguration.class,
+			ContextFunctionCatalogAutoConfigurationKotlinTests.SimpleConfiguration.class });
+
+		assertThat(this.context.getBean("kotlinFunction")).isInstanceOf(Function2.class);
+		assertThatThrownBy(() -> {
+			this.catalog.lookup(Function.class, "kotlinFunction");
+		}).isInstanceOf(BeanCreationException.class);
+
+		assertThatThrownBy(() -> {
+			this.catalog.lookup(Function.class, "kotlinConsumer");
+		}).isInstanceOf(BeanCreationException.class);
+
+		assertThatThrownBy(() -> {
+			this.catalog.lookup(Supplier.class, "kotlinSupplier");
+		}).isInstanceOf(BeanCreationException.class);
+
+	}
+
+	private void create(Class<?>[] types, String... props) {
+		this.context = (GenericApplicationContext) new SpringApplicationBuilder(types).properties(props).run();
+		this.catalog = this.context.getBean(FunctionCatalog.class);
+	}
+
+	@EnableAutoConfiguration
+	@Configuration
+	protected static class SimpleConfiguration {
+
+		@Bean
+		public Function<String, String> function2() {
+			return value -> value + "function2";
+		}
+
+	}
+
+}

spring-cloud-function-kotlin/src/test/kotlin/org/springframework/cloud/function/kotlin/KotlinLambdasConfiguration.kt

@@ -32,7 +32,7 @@ class KotlinLambdasConfiguration {
 	fun kotlinFunction(): (String) -> String {
 		return { it.toUpperCase() }
 	}
-	
+
 	@Bean
 	fun kotlinPojoFunction(): (Person) -> String {
 		return { it.name.toString()}
@@ -52,4 +52,5 @@ class KotlinLambdasConfiguration {
 	fun javaFunction(): Function<String, String> {
 		return Function { x -> x }
 	}
+
 }

spring-cloud-function-kotlin/src/test/kotlin/org/springframework/cloud/function/kotlin/KotlinSuspendFlowLambdasConfiguration.kt

@@ -0,0 +1,64 @@
+/*
+ * Copyright 2012-2019 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.function.kotlin
+
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.collect
+import kotlinx.coroutines.flow.flow
+import kotlinx.coroutines.flow.map
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration
+import org.springframework.context.annotation.Bean
+import org.springframework.context.annotation.Configuration
+import reactor.core.publisher.Flux
+import java.util.function.Function
+
+/**
+ * @author Adrien Poupard
+ *
+ */
+@EnableAutoConfiguration
+@Configuration
+class KotlinSuspendFlowLambdasConfiguration {
+
+	@Bean
+	fun kotlinFunction(): suspend (Flow<String>) -> Flow<String> =  { flow ->
+		flow.map { value -> value.toUpperCase() }
+	}
+	
+	@Bean
+	fun kotlinPojoFunction(): suspend (Flow<Person>) -> Flow<String> = { flow ->
+		flow.map(Person::toString)
+	}
+
+	@Bean
+	fun kotlinConsumer(): suspend (Flow<String>) -> Unit = { flow ->
+		flow.collect(::println)
+	}
+
+	@Bean
+	fun kotlinSupplier(): suspend () -> Flow<String>  = {
+		flow {
+			emit("Hello")
+		}
+	}
+
+	@Bean
+	fun javaFunction(): Function<Flux<String>, Flux<String>> {
+		return Function { x -> x }
+	}
+
+}

spring-cloud-function-kotlin/src/test/kotlin/org/springframework/cloud/function/kotlin/KotlinSuspendLambdasConfiguration.kt

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2012-2019 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.function.kotlin
+
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration
+import org.springframework.context.annotation.Bean
+import org.springframework.context.annotation.Configuration
+
+/**
+ * @author Adrien Poupard
+ *
+ */
+@EnableAutoConfiguration
+@Configuration
+class KotlinSuspendLambdasConfiguration {
+
+	@Bean
+	fun kotlinFunction(): suspend (Person) -> String {
+		return { it.name.toString()}
+	}
+
+	@Bean
+	fun kotlinConsumer(): suspend (String) -> Unit {
+		return { println(it) }
+	}
+
+	@Bean
+	fun kotlinSupplier(): suspend () -> String {
+		return { "Hello" }
+	}
+
+}

spring-cloud-function-kotlin/src/test/kotlin/org/springframework/cloud/function/kotlin/web/HeadersToMessageSuspendTests.kt

@@ -0,0 +1,108 @@
+/*
+ * Copyright 2012-2019 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.function.kotlin.web
+
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.map
+import org.assertj.core.api.Assertions
+import org.junit.jupiter.api.Test
+import org.springframework.beans.factory.annotation.Autowired
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration
+import org.springframework.boot.test.context.SpringBootTest
+import org.springframework.boot.test.context.SpringBootTest.WebEnvironment
+import org.springframework.boot.test.web.client.TestRestTemplate
+import org.springframework.cloud.function.web.RestApplication
+import org.springframework.context.annotation.Bean
+import org.springframework.http.MediaType
+import org.springframework.http.RequestEntity
+import org.springframework.messaging.Message
+import org.springframework.messaging.support.MessageBuilder
+import org.springframework.test.context.ContextConfiguration
+import java.net.URI
+
+/**
+ * @author Adrien Poupard
+ */
+@SpringBootTest(
+	webEnvironment = WebEnvironment.RANDOM_PORT,
+	properties = ["spring.cloud.function.web.path=/functions", "spring.main.web-application-type=reactive"]
+)
+@ContextConfiguration(classes = [RestApplication::class, HeadersToMessageSuspendTests.TestConfiguration::class])
+class HeadersToMessageSuspendTests {
+	@Autowired
+	private val rest: TestRestTemplate? = null
+	@Test
+	@Throws(Exception::class)
+	fun testBodyAndCustomHeaderFromMessagePropagation() {
+		// test POJO paylod
+		var postForEntity = rest!!
+			.exchange(
+				RequestEntity.post(URI("/functions/employeeSuspend"))
+					.contentType(MediaType.APPLICATION_JSON)
+					.body("[{\"name\":\"Bob\",\"age\":25}]"), String::class.java
+			)
+
+		Assertions.assertThat(postForEntity.body).isEqualTo("[{\"name\":\"Bob\",\"age\":25}]")
+		Assertions.assertThat(postForEntity.headers.containsKey("x-content-type")).isTrue
+		Assertions.assertThat(postForEntity.headers["x-content-type"]!![0])
+			.isEqualTo("application/xml")
+		Assertions.assertThat(postForEntity.headers["foo"]!![0]).isEqualTo("bar")
+
+		// test simple type payload
+		postForEntity = rest.postForEntity(
+			URI("/functions/stringSuspend"),
+			"HELLO", String::class.java
+		)
+		Assertions.assertThat(postForEntity.body).isEqualTo("[\"HELLO\"]")
+		Assertions.assertThat(postForEntity.headers.containsKey("x-content-type")).isTrue
+		Assertions.assertThat(postForEntity.headers["x-content-type"]!![0])
+			.isEqualTo("application/xml")
+		Assertions.assertThat(postForEntity.headers["foo"]!![0]).isEqualTo("bar")
+	}
+
+	@EnableAutoConfiguration
+	@org.springframework.boot.test.context.TestConfiguration
+	class TestConfiguration {
+		@Bean("stringSuspend")
+		fun functiono():suspend (employee: Flow<Message<String>>) -> Flow<Message<String>> = { flow: Flow<Message<String>> ->
+			flow.map { request ->
+				val message =
+					MessageBuilder.withPayload(request.payload)
+						.setHeader("X-Content-Type", "application/xml")
+						.setHeader("foo", "bar").build()
+				message
+			}
+		}
+
+		@Bean("employeeSuspend")
+		fun function1(): suspend (employee: Flow<Message<Employee>>) -> Flow<Message<Employee>> = { flow ->
+			flow.map { request ->
+				val message =
+					MessageBuilder
+						.withPayload(request.payload)
+						.setHeader("X-Content-Type", "application/xml")
+						.setHeader("foo", "bar")
+						.build()
+				message
+			}
+		}
+	}
+
+	class Employee {
+		var name: String? = null
+		var age = 0
+	}
+}

spring-cloud-function-kotlin/src/test/kotlin/org/springframework/cloud/function/kotlin/web/HeadersToMessageTests.kt

@@ -0,0 +1,103 @@
+/*
+ * Copyright 2012-2019 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.function.kotlin.web
+
+import org.assertj.core.api.Assertions
+import org.junit.jupiter.api.Test
+import org.springframework.beans.factory.annotation.Autowired
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration
+import org.springframework.boot.test.context.SpringBootTest
+import org.springframework.boot.test.context.SpringBootTest.WebEnvironment
+import org.springframework.boot.test.web.client.TestRestTemplate
+import org.springframework.cloud.function.web.RestApplication
+import org.springframework.context.annotation.Bean
+import org.springframework.http.MediaType
+import org.springframework.http.RequestEntity
+import org.springframework.messaging.Message
+import org.springframework.messaging.support.MessageBuilder
+import org.springframework.test.context.ContextConfiguration
+import java.lang.Exception
+import java.net.URI
+
+/**
+ * @author Dave Syer
+ * @author Oleg Zhurakousky
+ */
+@SpringBootTest(
+	webEnvironment = WebEnvironment.RANDOM_PORT,
+	properties = ["spring.cloud.function.web.path=/functions", "spring.main.web-application-type=reactive"]
+)
+@ContextConfiguration(classes = [RestApplication::class, HeadersToMessageTests.TestConfiguration::class])
+class HeadersToMessageTests {
+	@Autowired
+	private val rest: TestRestTemplate? = null
+	@Test
+	@Throws(Exception::class)
+	fun testBodyAndCustomHeaderFromMessagePropagation() {
+		// test POJO paylod
+		var postForEntity = rest!!
+			.exchange(
+				RequestEntity.post(URI("/functions/employee"))
+					.contentType(MediaType.APPLICATION_JSON)
+					.body("{\"name\":\"Bob\",\"age\":25}"), String::class.java
+			)
+		Assertions.assertThat(postForEntity.body).isEqualTo("{\"name\":\"Bob\",\"age\":25}")
+		Assertions.assertThat(postForEntity.headers.containsKey("x-content-type")).isTrue
+		Assertions.assertThat(postForEntity.headers["x-content-type"]!![0])
+			.isEqualTo("application/xml")
+		Assertions.assertThat(postForEntity.headers["foo"]!![0]).isEqualTo("bar")
+
+		// test simple type payload
+		postForEntity = rest.postForEntity(
+			URI("/functions/string"),
+			"{\"name\":\"Bob\",\"age\":25}", String::class.java
+		)
+		Assertions.assertThat(postForEntity.body).isEqualTo("{\"name\":\"Bob\",\"age\":25}")
+		Assertions.assertThat(postForEntity.headers.containsKey("x-content-type")).isTrue
+		Assertions.assertThat(postForEntity.headers["x-content-type"]!![0])
+			.isEqualTo("application/xml")
+		Assertions.assertThat(postForEntity.headers["foo"]!![0]).isEqualTo("bar")
+	}
+
+	@EnableAutoConfiguration
+	@org.springframework.boot.test.context.TestConfiguration
+	class TestConfiguration {
+		@Bean("string")
+		fun functiono(): (message: Message<String?>) -> Message<String> = { request: Message<String?> ->
+			val message =
+				MessageBuilder.withPayload(request.payload)
+					.setHeader("X-Content-Type", "application/xml")
+					.setHeader("foo", "bar").build()
+			message
+		}
+
+		@Bean("employee")
+		fun function1(): (employee: Message<Employee>) -> Message<Employee> = { request ->
+			val message =
+				MessageBuilder
+					.withPayload(request.payload)
+					.setHeader("X-Content-Type", "application/xml")
+					.setHeader("foo", "bar").build()
+			message
+		}
+	}
+
+	// used by json converter
+	class Employee {
+		var name: String? = null
+		var age = 0
+	}
+}