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  • OpenFaaS实战之三:Java函数

本篇概览

  1. 本文是《OpenFaaS实战》系列的第三篇,经过前文实战,咱们掌握了函数开发和部署的要领,作为一名Java程序员,当然迫切的希望用Java编写OpenFaaS函数,于是就有了本文;
  2. 本文开发一个Java函数,功能是解析请求body中的JSON字符串,再加上JVM进程ID、IP地址、当前时间一起拼成字符串,包装在JSON中返回;
  3. 平时写java代码会用到各种二方库,这里引入jackson的库,作为OpenFaaS添加依赖的参考;

源码下载

  • 本篇实战中的源码可在GitHub下载到,地址和链接信息如下表所示(https://github.com/zq2599/blog_demos):
名称 链接 备注
项目主页 https://github.com/zq2599/blog_demos 该项目在GitHub上的主页
git仓库地址(https) https://github.com/zq2599/blog_demos.git 该项目源码的仓库地址,https协议
git仓库地址(ssh) git@github.com:zq2599/blog_demos.git 该项目源码的仓库地址,ssh协议
  • 这个git项目中有多个文件夹,本章的应用在openfaas文件夹下,如下图红框所示:

在这里插入图片描述

  • openfaas里面有多个子文件夹,本篇的源码在currenttime中,如下图红框:

在这里插入图片描述

创建函数

  1. 执行以下命令,即可创建名为faas-currenttime的函数,此函数的镜像前缀是bolingcavalry,语言类型为java11
faas-cli new faas-currenttime --lang java11 -p bolingcavalry
  1. 控制台响应如下:
[root@node1 20]# faas-cli new faas-currenttime --lang java11 -p bolingcavalry
2020/11/20 15:47:50 No templates found in current directory.
2020/11/20 15:47:50 Attempting to expand templates from https://github.com/openfaas/templates.git

2020/11/20 15:47:56 Fetched 12 template(s) : [csharp dockerfile go java11 java11-vert-x node node12 php7 python python3 python3-debian ruby] from https://github.com/openfaas/templates.git
Folder: faas-currenttime created.
  ___                   _____           ____
 / _ \ _ __   ___ _ __ |  ___|_ _  __ _/ ___|
| | | | '_ \ / _ \ '_ \| |_ / _` |/ _` \___ \
| |_| | |_) |  __/ | | |  _| (_| | (_| |___) |
 \___/| .__/ \___|_| |_|_|  \__,_|\__,_|____/
      |_|


Function created in folder: faas-currenttime
Stack file written: faas-currenttime.yml

Notes:
You have created a function using the java11 template which uses an LTS
version of the OpenJDK.
  1. 当前目录已经新增了文件faas-currenttime.yml和文件夹faas-currenttime
  2. 文件夹faas-currenttime的内容如下,可见是个gradle工程:
faas-currenttime
├── build.gradle
├── gradle
│   └── wrapper
│       ├── gradle-wrapper.jar
│       └── gradle-wrapper.properties
├── gradlew
├── gradlew.bat
├── settings.gradle
└── src
    ├── main
    │   └── java
    │       └── com
    │           └── openfaas
    │               └── function
    │                   └── Handler.java
    └── test
        └── java
            └── HandlerTest.java
  1. 打开build.gradle文件,添加下图红框中的内容,即jacksoncommon库的依赖:

在这里插入图片描述

  1. 进入文件夹faas-currenttime/src/main/java/com/openfaas/function/,可见已创建了默认的业务功能类Handler.java,打开看看OpenFaaS给的默认代码啥样的,如下所示:
package com.openfaas.function;

import com.openfaas.model.IHandler;
import com.openfaas.model.IResponse;
import com.openfaas.model.IRequest;
import com.openfaas.model.Response;

public class Handler extends com.openfaas.model.AbstractHandler {

    public IResponse Handle(IRequest req) {
        Response res = new Response();
            res.setBody("Hello, world!");

            return res;
    }
}
  1. 把Handler.java的内容用以下代码替换掉,替换后的函数,其功能是取得请求参数,再把当前JVM的进程ID、IP地址、当前时间都拼接到一个字符串中返回,需要重点关注的有两点:将请求参数反序列化成Map实例,以及将Map序列化成JSON字符串返回:
package com.openfaas.function;

import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.openfaas.model.IRequest;
import com.openfaas.model.IResponse;
import com.openfaas.model.Response;
import org.apache.commons.lang3.StringUtils;

import java.lang.management.ManagementFactory;
import java.net.Inet4Address;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;

public class Handler extends com.openfaas.model.AbstractHandler {

    private static final String PARAM_USER_NAME = "name";


    private static final String RESPONSE_TEMPLETE = "Hello %s, response from [%s], PID [%s], %s";

    private ObjectMapper mapper = new ObjectMapper();


    /**
     * 获取本机IP地址
     * @return
     */
    public static String getIpAddress() {
        try {
            Enumeration<NetworkInterface> allNetInterfaces = NetworkInterface.getNetworkInterfaces();
            InetAddress ip = null;
            while (allNetInterfaces.hasMoreElements()) {
                NetworkInterface netInterface = (NetworkInterface) allNetInterfaces.nextElement();
                if (netInterface.isLoopback() || netInterface.isVirtual() || !netInterface.isUp()) {
                    continue;
                } else {
                    Enumeration<InetAddress> addresses = netInterface.getInetAddresses();
                    while (addresses.hasMoreElements()) {
                        ip = addresses.nextElement();
                        if (ip != null && ip instanceof Inet4Address) {
                            return ip.getHostAddress();
                        }
                    }
                }
            }
        } catch (Exception e) {
            System.err.println("IP地址获取失败" + e.toString());
        }
        return "";
    }

    /**
     * 返回当前进程ID
     * @return
     */
    private static String getPID() {
        return ManagementFactory
                .getRuntimeMXBean()
                .getName()
                .split("@")[0];
    }


    private String getUserName(IRequest req) {
        // 如果从请求body中取不到userName,就用
        String userName = null;

        try {
            Map<String, Object> mapFromStr = mapper.readValue(req.getBody(),
                    new TypeReference<Map<String, Object>>() {});

            if(null!=mapFromStr && mapFromStr.containsKey(PARAM_USER_NAME)) {
                userName = String.valueOf(mapFromStr.get(PARAM_USER_NAME));
            }

        } catch (Exception e) {
            e.printStackTrace();
        }

        // 如果从请求body中取不到userName,就给个默认值
        if(StringUtils.isBlank(userName)) {
            userName = "anonymous";
        }

        return userName;
    }

    public IResponse Handle(IRequest req) {

        String userName = getUserName(req);

        System.out.println("1. ---" + userName);

        // 返回信息带上当前JVM所在机器的IP、进程号、时间
        String message = String.format(RESPONSE_TEMPLETE,
                userName,
                getIpAddress(),
                getPID(),
                new SimpleDateFormat( "yyyy-MM-dd hh:mm:ss" ).format(new Date()));

        System.out.println("2. ---" + message);

        // 响应内容也是JSON格式,所以先存入map,然后再序列化
        Map<String, Object> rlt = new HashMap<>();
        rlt.put("success", true);
        rlt.put("message", message);

        String rltStr = null;

        try {
            rltStr = mapper.writeValueAsString(rlt);
        } catch (Exception e) {
            e.printStackTrace();
        }

        Response res = new Response();
        res.setContentType("application/json;charset=utf-8");
        res.setBody(rltStr);

	    return res;
    }
}
  • 至此编码完成,接下来是制作镜像和部署;

部署

  1. faas-currenttime.yml所在目录执行以下命令,即可开始制作镜像,制作过程中会有gradle的编译过程,如果编译失败会中断镜像制作:
faas-cli build -f ./faas-currenttime.yml
  1. 镜像制作成功时,控制台输出类似如下信息:
Step 27/30 : ENV fprocess="java -XX:+UseContainerSupport com.openfaas.entrypoint.App"
---> Running in 0f50636cc747
Removing intermediate container 0f50636cc747
---> 54a5c9a193c8
Step 28/30 : EXPOSE 8080
---> Running in 3252f165af15
Removing intermediate container 3252f165af15
---> c05afc826ec5
Step 29/30 : HEALTHCHECK --interval=5s CMD [ -e /tmp/.lock ] || exit 1
---> Running in 4106410be0a2
Removing intermediate container 4106410be0a2
---> 6d95b73b5f33
Step 30/30 : CMD ["fwatchdog"]
---> Running in 1606dbcd7003
Removing intermediate container 1606dbcd7003
---> 99a519ab82fd
Successfully built 99a519ab82fd
Successfully tagged bolingcavalry/faas-currenttime:latest
Image: bolingcavalry/faas-currenttime:latest built.
[0] < Building faas-currenttime done in 34.94s.
[0] Worker done.


Total build time: 34.94s
  1. 将镜像推送到镜像仓库,以便Kubernetes可以下载到此镜像,我这里用的是hub.docker.com,因为我的ID是bolingcavalry,所执行以下命令即可推送成功:
docker push bolingcavalry/faas-currenttime:latest
  1. 执行以下命令部署函数到OpenFaaS:
faas-cli deploy -f faas-currenttime.yml
  1. 控制台响应如下,可见部署已经开始,并且给出了endpoint:
[root@node1 20]# faas-cli deploy -f faas-currenttime.yml
Deploying: faas-currenttime.
WARNING! Communication is not secure, please consider using HTTPS. Letsencrypt.org offers free SSL/TLS certificates.

Deployed. 202 Accepted.
URL: http://192.168.133.187:31112/function/faas-currenttime.openfaas-fn
  1. 打开web端,在页面上可见新增的函数,验证操作如下图所示,可见入参的JSON内容可以被正常解析:

在这里插入图片描述

  1. 也可以在控制台用curl命令测试:
[root@node1 20]# curl \
> -H "Content-Type: application/json" \
> -X POST \
> --data '{"name":"Jerry}' \
> http://192.168.133.187:31112/function/faas-currenttime
{"success":true,"message":"Hello anonymous, response from [10.233.90.79], PID [11], 2020-11-20 02:14:46"}
  1. 执行命令faas-cli deploy -f faas-currenttime.yml开始部署,控制台已经接受了部署请求,并给出了函数的endpoint:
[root@node1 20]# faas-cli deploy -f faas-currenttime.yml
Deploying: faas-currenttime.
WARNING! Communication is not secure, please consider using HTTPS. Letsencrypt.org offers free SSL/TLS certificates.

Deployed. 202 Accepted.
URL: http://192.168.133.187:31112/function/faas-currenttime.openfaas-fn

清理

  • 删除函数的命令如下,依旧是faas-currenttime.yml所在目录:
faas-cli remove -f faas-currenttime.yml
  • 至此,最基本的Java函数的开发、部署、验证都已经完成,如果您也打算用Java开发OpenFaaS函数,希望本文能给您一些参考;

出处:https://www.cnblogs.com/bolingcavalry/p/15068687.html

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