GH-422 Add initial set of Cloud Event samples

This commit adds initial set of samples and tests demonstrating various ways of how cloud event can be consumed (i.e., structured, bindary, pojo etc)

spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/config/CloudEventJsonMessageConverter.java

@@ -17,7 +17,6 @@
 package org.springframework.cloud.function.context.config;
 
 import java.lang.reflect.Type;
-import java.util.Collection;
 import java.util.Map;
 
 import org.springframework.cloud.function.json.JsonMapper;
@@ -34,7 +33,7 @@
  *
  * @author Oleg Zhurakousky
  *
- * @since 3.1.0
+ * @since 3.1
  */
 public class CloudEventJsonMessageConverter extends JsonMessageConverter {
 
@@ -47,12 +46,17 @@ public CloudEventJsonMessageConverter(JsonMapper jsonMapper) {
 
 	@Override
 	protected Object convertFromInternal(Message<?> message, Class<?> targetClass, @Nullable Object conversionHint) {
-		Type convertToType = conversionHint == null ? targetClass : (Type) conversionHint;
-		String jsonString = (String) message.getPayload();
-		Map<String, Object> mapEvent = this.mapper.fromJson(jsonString, Map.class);
-		Object payload = this.mapper.fromJson(this.mapper.toJson(mapEvent.get("data")), convertToType);
-		mapEvent.remove("data");
-		return MessageBuilder.withPayload(payload).copyHeaders(mapEvent).build();
+		if (this.isBinary(message)) {
+			return super.convertFromInternal(message, targetClass, conversionHint);
+		}
+		else {
+			Type convertToType = conversionHint == null ? targetClass : (Type) conversionHint;
+			String jsonString = (String) message.getPayload();
+			Map<String, Object> mapEvent = this.mapper.fromJson(jsonString, Map.class);
+			Object payload = this.mapper.fromJson(this.mapper.toJson(mapEvent.get("data")), convertToType);
+			mapEvent.remove("data");
+			return MessageBuilder.withPayload(payload).copyHeaders(mapEvent).build();
+		}
 	}
 
 	@Override
@@ -61,4 +65,8 @@ protected Object convertToInternal(Object payload, @Nullable MessageHeaders head
 		throw new UnsupportedOperationException("Temporarily not supported as this converter is work in progress");
 	}
 
+	private boolean isBinary(Message<?> message) {
+		Map<String, Object> headers = message.getHeaders();
+		return headers.containsKey("source") && headers.containsKey("specversion") && headers.containsKey("type");
+	}
 }

spring-cloud-function-samples/function-sample-cloudevent/.gitignore

@@ -0,0 +1,33 @@
+HELP.md
+target/
+!.mvn/wrapper/maven-wrapper.jar
+!**/src/main/**/target/
+!**/src/test/**/target/
+
+### STS ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+
+### IntelliJ IDEA ###
+.idea
+*.iws
+*.iml
+*.ipr
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+build/
+!**/src/main/**/build/
+!**/src/test/**/build/
+
+### VS Code ###
+.vscode/

spring-cloud-function-samples/function-sample-cloudevent/.mvn/wrapper/MavenWrapperDownloader.java

@@ -0,0 +1,117 @@
+/*
+ * Copyright 2007-present 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 java.net.*;
+import java.io.*;
+import java.nio.channels.*;
+import java.util.Properties;
+
+public class MavenWrapperDownloader {
+
+    private static final String WRAPPER_VERSION = "0.5.6";
+    /**
+     * Default URL to download the maven-wrapper.jar from, if no 'downloadUrl' is provided.
+     */
+    private static final String DEFAULT_DOWNLOAD_URL = "https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/"
+        + WRAPPER_VERSION + "/maven-wrapper-" + WRAPPER_VERSION + ".jar";
+
+    /**
+     * Path to the maven-wrapper.properties file, which might contain a downloadUrl property to
+     * use instead of the default one.
+     */
+    private static final String MAVEN_WRAPPER_PROPERTIES_PATH =
+            ".mvn/wrapper/maven-wrapper.properties";
+
+    /**
+     * Path where the maven-wrapper.jar will be saved to.
+     */
+    private static final String MAVEN_WRAPPER_JAR_PATH =
+            ".mvn/wrapper/maven-wrapper.jar";
+
+    /**
+     * Name of the property which should be used to override the default download url for the wrapper.
+     */
+    private static final String PROPERTY_NAME_WRAPPER_URL = "wrapperUrl";
+
+    public static void main(String args[]) {
+        System.out.println("- Downloader started");
+        File baseDirectory = new File(args[0]);
+        System.out.println("- Using base directory: " + baseDirectory.getAbsolutePath());
+
+        // If the maven-wrapper.properties exists, read it and check if it contains a custom
+        // wrapperUrl parameter.
+        File mavenWrapperPropertyFile = new File(baseDirectory, MAVEN_WRAPPER_PROPERTIES_PATH);
+        String url = DEFAULT_DOWNLOAD_URL;
+        if(mavenWrapperPropertyFile.exists()) {
+            FileInputStream mavenWrapperPropertyFileInputStream = null;
+            try {
+                mavenWrapperPropertyFileInputStream = new FileInputStream(mavenWrapperPropertyFile);
+                Properties mavenWrapperProperties = new Properties();
+                mavenWrapperProperties.load(mavenWrapperPropertyFileInputStream);
+                url = mavenWrapperProperties.getProperty(PROPERTY_NAME_WRAPPER_URL, url);
+            } catch (IOException e) {
+                System.out.println("- ERROR loading '" + MAVEN_WRAPPER_PROPERTIES_PATH + "'");
+            } finally {
+                try {
+                    if(mavenWrapperPropertyFileInputStream != null) {
+                        mavenWrapperPropertyFileInputStream.close();
+                    }
+                } catch (IOException e) {
+                    // Ignore ...
+                }
+            }
+        }
+        System.out.println("- Downloading from: " + url);
+
+        File outputFile = new File(baseDirectory.getAbsolutePath(), MAVEN_WRAPPER_JAR_PATH);
+        if(!outputFile.getParentFile().exists()) {
+            if(!outputFile.getParentFile().mkdirs()) {
+                System.out.println(
+                        "- ERROR creating output directory '" + outputFile.getParentFile().getAbsolutePath() + "'");
+            }
+        }
+        System.out.println("- Downloading to: " + outputFile.getAbsolutePath());
+        try {
+            downloadFileFromURL(url, outputFile);
+            System.out.println("Done");
+            System.exit(0);
+        } catch (Throwable e) {
+            System.out.println("- Error downloading");
+            e.printStackTrace();
+            System.exit(1);
+        }
+    }
+
+    private static void downloadFileFromURL(String urlString, File destination) throws Exception {
+        if (System.getenv("MVNW_USERNAME") != null && System.getenv("MVNW_PASSWORD") != null) {
+            String username = System.getenv("MVNW_USERNAME");
+            char[] password = System.getenv("MVNW_PASSWORD").toCharArray();
+            Authenticator.setDefault(new Authenticator() {
+                @Override
+                protected PasswordAuthentication getPasswordAuthentication() {
+                    return new PasswordAuthentication(username, password);
+                }
+            });
+        }
+        URL website = new URL(urlString);
+        ReadableByteChannel rbc;
+        rbc = Channels.newChannel(website.openStream());
+        FileOutputStream fos = new FileOutputStream(destination);
+        fos.getChannel().transferFrom(rbc, 0, Long.MAX_VALUE);
+        fos.close();
+        rbc.close();
+    }
+
+}

spring-cloud-function-samples/function-sample-cloudevent/.mvn/wrapper/maven-wrapper.properties

@@ -0,0 +1,2 @@
+distributionUrl=https://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.6.3/apache-maven-3.6.3-bin.zip
+wrapperUrl=https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/0.5.6/maven-wrapper-0.5.6.jar