基于Serverless Framework的跨语言无服务器架构设计源码

package com.serverless; import com.fasterxml.jackson.core.type.TypeReference; import com.fasterxml.jackson.databind.JsonNode; import com.fasterxml.jackson.databind.ObjectMapper; import java.beans.Introspector; import java.beans.PropertyDescriptor; import java.io.BufferedReader; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.File; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.lang.reflect.Method; import java.net.URL; import java.net.URLClassLoader; import java.util.HashMap; public class InvokeBridge { private File artifact; private String className; private String handlerName; private Object instance; private Class clazz; private InvokeBridge() { this.artifact = new File(new File("."), System.getProperty("artifactPath")); this.className = System.getProperty("className"); this.handlerName = System.getProperty("handlerName"); try { HashMap<String, Object> parsedInput = parseInput(getInput()); HashMap<String, Object> eventMap = (HashMap<String, Object>) parsedInput.get("event"); this.instance = this.getInstance(); Object output = this.invoke(eventMap, this.getContext(parsedInput)); String string = null; if(output != null) { if(output.getClass().isAssignableFrom(ByteArrayOutputStream.class)){ string = new String(((ByteArrayOutputStream)output).toByteArray()); }else { string = output.toString(); } } System.out.println(string); } catch (Exception e) { e.printStackTrace(); } } private Context getContext(HashMap<String, Object> parsedInput) { HashMap<String, Object> contextMap = (HashMap<String, Object>) parsedInput.get("context"); String name = (String) contextMap.getOrDefault("name", "functionName"); String version = (String) contextMap.getOrDefault("version", "LATEST"); String logGroupName = (String) contextMap.getOrDefault("logGroupName", "logGroup"); int timeout = Integer.parseInt(String.valueOf(contextMap.getOrDefault("timeout", 5))); return new Context(name, version, logGroupName, timeout); } private Object getInstance() throws Exception { URL[] urls = {this.artifact.toURI().toURL()}; URLClassLoader child = new URLClassLoader(urls, this.getClass().getClassLoader()); this.clazz = Class.forName(this.className, true, child); return this.clazz.newInstance(); } private Object invoke(HashMap<String, Object> event, Context context) throws Exception { Method method = findHandlerMethod(this.clazz, this.handlerName); Class requestClass = method.getParameterTypes()[0]; Object request = event; if (!requestClass.isAssignableFrom(event.getClass()) && !requestClass.isAssignableFrom(InputStream.class)) { request = requestClass.newInstance(); PropertyDescriptor[] properties = Introspector.getBeanInfo(requestClass).getPropertyDescriptors(); for(int i=0; i < properties.length; i++) { if (properties[i].getWriteMethod() == null) continue; String propertyName = properties[i].getName(); if (event.containsKey(propertyName)) { properties[i].getWriteMethod().invoke(request, event.get(propertyName)); } } } if (method.getParameterCount() == 1) { return method.invoke(this.instance, request); } else if (method.getParameterCount() == 2) { return method.invoke(this.instance, request, context); } else if (method.getParameterCount() == 3 && requestClass.isAssignableFrom(InputStream.class)) { ByteArrayOutputStream outputStream = new ByteArrayOutputStream(); ByteArrayInputStream inputStream = new ByteArrayInputStream(new ObjectMapper().writeValueAsBytes(event)); method.invoke(this.instance, inputStream, outputStream, context); return outputStream; } else { throw new NoSuchMethodException("Handler should take 1, 2, or 3 (com.amazonaws.services.lambda.runtime.RequestStreamHandler compatible handlers) arguments: " + method); } } private Method findHandlerMethod(Class clazz, String handlerName) throws Exception { Method candidateMethod = null; for(Method method: clazz.getMethods()) { if (method.getName().equals(handlerName) && !method.isBridge()) { // Select the method with the largest number of parameters // If two or more methods have the same number of parameters, AWS Lambda selects the method that has // the Context as the last parameter. // If none or all of these methods have the Context parameter, then the behavior is undefined. int paramCount = method.getParameterCount(); boolean lastParamIsContext = paramCount >= 1 && method.getParameterTypes()[paramCount-1].getName().equals("com.amazonaws.services.lambda.runtime.Context"); if (candidateMethod == null || paramCount > candidateMethod.getParameterCount() || (paramCount == candidateMethod.getParameterCount() && lastParamIsContext)) { candidateMethod = method; } } } if (candidateMethod == null) { throw new NoSuchMethodException("Could not find handler for " + handlerName + " in " + clazz.getName()); } return candidateMethod; } private HashMap<String, Object> parseInput(String input) throws IOException { TypeReference<HashMap<String,Object>> typeRef = new TypeReference<HashMap<String,Object>>() {}; ObjectMapper mapper = new ObjectMapper().findAndRegisterModules(); JsonNode jsonNode = mapper.readTree(input); return mapper.convertValue(jsonNode, typeRef); } private String getInput() throws IOException { BufferedReader streamReader = new BufferedReader(new InputStreamReader(System.in, "UTF-8")); StringBuilder inputStringBuilder = new StringBuilder(); String inputStr; while ((inputStr = streamReader.readLine()) != null) { inputStringBuilder.append(inputStr); } return inputStringBuilder.toString(); } public static void main(String[] args) { new InvokeBridge(); } }