从 App Engine 标准环境应用连接到 Redis 实例

您可以使用无服务器 VPC 访问通道从 App Engine 标准环境连接到 Redis 实例。

设置

如果您已安装 Google Cloud CLI 且已创建 Redis 实例，则可以跳过这些步骤。

1. 安装 gcloud CLI 并初始化：

   gcloud init
   

2. 按照快速入门指南创建一个 Redis 实例。记下该 Redis 实例的地区、IP 地址和端口。

配置无服务器 VPC 访问通道

要从 App Engine 应用连接到 Redis 实例的授权 VPC 网络，您必须设置无服务器 VPC 访问通道。

1. 通过运行以下命令查找 Redis 实例的授权网络：

   gcloud beta redis instances describe [INSTANCE_ID] --region [REGION]
   

2. 按照创建连接器中的说明创建无服务器 VPC 访问通道连接器。请务必在应用所在的区域中创建连接器，并确保该连接器已连接到 Redis 实例的授权 VPC 网络。记下连接器的名称。

示例应用

此示例 HTTP 服务器应用通过 App Engine 标准环境应用建立与 Redis 实例的连接。

克隆您所需编程语言的代码库，并转到包含示例代码的文件夹：

Go

git clone https://github.com/GoogleCloudPlatform/golang-samples
cd golang-samples/memorystore/redis

Java

git clone https://github.com/GoogleCloudPlatform/java-docs-samples
cd java-docs-samples/memorystore/redis

Node.js

git clone https://github.com/GoogleCloudPlatform/nodejs-docs-samples
cd nodejs-docs-samples/memorystore/redis

Python

git clone https://github.com/GoogleCloudPlatform/python-docs-samples
cd python-docs-samples/memorystore/redis

每次访问 / 端点时，此示例应用都会增加一个 Redis 计数器。

Go

此应用使用 github.com/gomodule/redigo/redis 客户端。通过运行以下命令进行安装：

go get github.com/gomodule/redigo/redis

// Command redis is a basic app that connects to a managed Redis instance.
package main

import (
	"fmt"
	"log"
	"net/http"
	"os"

	"github.com/gomodule/redigo/redis"
)

var redisPool *redis.Pool

func incrementHandler(w http.ResponseWriter, r *http.Request) {
	conn := redisPool.Get()
	defer conn.Close()

	counter, err := redis.Int(conn.Do("INCR", "visits"))
	if err != nil {
		http.Error(w, "Error incrementing visitor counter", http.StatusInternalServerError)
		return
	}
	fmt.Fprintf(w, "Visitor number: %d", counter)
}

func main() {
	redisHost := os.Getenv("REDISHOST")
	redisPort := os.Getenv("REDISPORT")
	redisAddr := fmt.Sprintf("%s:%s", redisHost, redisPort)

	const maxConnections = 10
	redisPool = &redis.Pool{
		MaxIdle: maxConnections,
		Dial:    func() (redis.Conn, error) { return redis.Dial("tcp", redisAddr) },
	}

	http.HandleFunc("/", incrementHandler)

	port := os.Getenv("PORT")
	if port == "" {
		port = "8080"
	}
	log.Printf("Listening on port %s", port)
	if err := http.ListenAndServe(":"+port, nil); err != nil {
		log.Fatal(err)
	}
}

Java

此应用基于 Jetty 3.1 servlet。

它使用 Jedis 库：

<dependency>
  <groupId>redis.clients</groupId>
  <artifactId>jedis</artifactId>
  <version>5.1.0</version>
</dependency>

AppServletContextListener 类用于创建长效 Redis 连接池：

package com.example.redis;

import java.io.IOException;
import java.util.Properties;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.annotation.WebListener;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.JedisPoolConfig;

@WebListener
public class AppServletContextListener implements ServletContextListener {

  private Properties config = new Properties();

  private JedisPool createJedisPool() throws IOException {
    String host;
    Integer port;
    config.load(
        Thread.currentThread()
            .getContextClassLoader()
            .getResourceAsStream("application.properties"));
    host = config.getProperty("redis.host");
    port = Integer.valueOf(config.getProperty("redis.port", "6379"));

    JedisPoolConfig poolConfig = new JedisPoolConfig();
    // Default : 8, consider how many concurrent connections into Redis you will need under load
    poolConfig.setMaxTotal(128);

    return new JedisPool(poolConfig, host, port);
  }

  @Override
  public void contextDestroyed(ServletContextEvent event) {
    JedisPool jedisPool = (JedisPool) event.getServletContext().getAttribute("jedisPool");
    if (jedisPool != null) {
      jedisPool.destroy();
      event.getServletContext().setAttribute("jedisPool", null);
    }
  }

  // Run this before web application is started
  @Override
  public void contextInitialized(ServletContextEvent event) {
    JedisPool jedisPool = (JedisPool) event.getServletContext().getAttribute("jedisPool");
    if (jedisPool == null) {
      try {
        jedisPool = createJedisPool();
        event.getServletContext().setAttribute("jedisPool", jedisPool);
      } catch (IOException e) {
        // handle exception
      }
    }
  }
}

VisitCounterServlet 类是一个网络 Servlet，用于增加 Redis 计数器。

package com.example.redis;

import java.io.IOException;
import java.net.SocketException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;

@WebServlet(name = "Track visits", value = "")
public class VisitCounterServlet extends HttpServlet {

  @Override
  public void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
    try {
      JedisPool jedisPool = (JedisPool) req.getServletContext().getAttribute("jedisPool");

      if (jedisPool == null) {
        throw new SocketException("Error connecting to Jedis pool");
      }
      Long visits;

      try (Jedis jedis = jedisPool.getResource()) {
        visits = jedis.incr("visits");
      }

      resp.setStatus(HttpServletResponse.SC_OK);
      resp.getWriter().println("Visitor counter: " + String.valueOf(visits));
    } catch (Exception e) {
      resp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, e.getMessage());
    }
  }
}

Node.js

此应用使用 redis 模块。

{
  "name": "memorystore-redis",
  "description": "An example of using Memorystore(Redis) with Node.js",
  "version": "0.0.1",
  "private": true,
  "license": "Apache Version 2.0",
  "author": "Google Inc.",
  "engines": {
    "node": ">=16.0.0"
  },
  "dependencies": {
    "redis": "^4.0.0"
  }
}

'use strict';
const http = require('http');
const redis = require('redis');

const REDISHOST = process.env.REDISHOST || 'localhost';
const REDISPORT = process.env.REDISPORT || 6379;

const client = redis.createClient(REDISPORT, REDISHOST);
client.on('error', err => console.error('ERR:REDIS:', err));

// create a server
http
  .createServer((req, res) => {
    // increment the visit counter
    client.incr('visits', (err, reply) => {
      if (err) {
        console.log(err);
        res.status(500).send(err.message);
        return;
      }
      res.writeHead(200, {'Content-Type': 'text/plain'});
      res.end(`Visitor number: ${reply}\n`);
    });
  })
  .listen(8080);

Python

此应用使用 Flask 进行网络服务，并使用 redis-py 软件包与 Redis 实例进行通信。

Flask==3.0.3
gunicorn==23.0.0
redis==5.2.1
Werkzeug==3.0.3

import logging
import os

from flask import Flask
import redis

app = Flask(__name__)

redis_host = os.environ.get("REDISHOST", "localhost")
redis_port = int(os.environ.get("REDISPORT", 6379))
redis_client = redis.StrictRedis(host=redis_host, port=redis_port)


@app.route("/")
def index():
    value = redis_client.incr("counter", 1)
    return f"Visitor number: {value}"


@app.errorhandler(500)
def server_error(e):
    logging.exception("An error occurred during a request.")
    return (
        """
    An internal error occurred: <pre>{}</pre>
    See logs for full stacktrace.
    """.format(
            e
        ),
        500,
    )


if __name__ == "__main__":
    # This is used when running locally. Gunicorn is used to run the
    # application on Google App Engine and Cloud Run.
    # See entrypoint in app.yaml or Dockerfile.
    app.run(host="127.0.0.1", port=8080, debug=True)

准备应用进行部署

要访问 Redis 实例，App Engine 应用必须配置为使用无服务器 VPC 访问通道连接器，并且您必须提供 Redis 实例的连接详细信息。

1. 如果您还没有 App Engine 应用，请创建一个。

2. 更新应用的配置以指定无服务器 VPC 访问通道连接器以及 Redis 实例的 IP 地址和端口：

   Go

   更新 gae_standard_deployment/app.yaml 文件。

   runtime: go111
   
   # Update with Redis instance details
   env_variables:
     REDISHOST: '<REDIS_IP>'
     REDISPORT: '6379'
   
   # Update with Serverless VPC Access connector details
   vpc_access_connector:
     name: 'projects/<PROJECT_ID>/locations/<REGION>/connectors/<CONNECTOR_NAME>'

   如需了解详情，请参阅 app.yaml 配置文件。

   Java

   注意：此示例使用 Java 8 运行时。要了解如何迁移到 Java 11 运行时，请参阅将 App Engine 应用从 Java 8 迁移到 Java 11。

   更新 gae_standard_deployment/appengine-web.xml 文件以指定无服务器 VPC 访问通道连接器：

   <appengine-web-app xmlns="http://appengine.google.com/ns/1.0">
     <runtime>java8</runtime>
     <threadsafe>true</threadsafe>
     <vpc-access-connector>
       <name>projects/[PROJECT_ID]/locations/[REGION]/connectors/[CONNECTOR_NAME]</name>
     </vpc-access-connector>
   </appengine-web-app>

   并使用 Redis 实例的 IP 地址和端口更新 src/main/resources/application.properties 文件：

   redis.host=REDIS_HOST_IP
   redis.port=6379

   如需详细了解如何配置应用，请参阅 appengine-web.xml 参考。

   Node.js

   更新 gae_standard_deployment/app.yaml 文件。

   runtime: nodejs10
   
   # Update with Redis instance details
   env_variables:
     REDISHOST: '<REDIS_IP>'
     REDISPORT: '6379'
   
   # Update with Serverless VPC Access connector details
   vpc_access_connector:
     name: 'projects/<PROJECT_ID>/locations/<REGION>/connectors/<CONNECTOR_NAME>'

   如需了解详情，请参阅 app.yaml 配置文件。

   Python

   更新 gae_standard_deployment/app.yaml 文件。

   runtime: python37
   entrypoint: gunicorn -b :$PORT main:app
   
   # Update with Redis instance details
   env_variables:
     REDISHOST: '<REDIS_IP>'
     REDISPORT: '6379'
   
   # Update with Serverless VPC Access connector details
   vpc_access_connector:
     name: 'projects/<PROJECT_ID>/locations/<REGION>/connectors/<CONNECTOR_NAME>'

   如需了解详情，请参阅 app.yaml 配置文件。

将应用部署到 App Engine 标准环境

如需部署应用，请执行以下操作：

1. 将必要的配置文件复制到来源目录中：

   Go

   将 app.yaml 和 go.mod 文件复制到源目录中：

   cp gae_standard_deployment/{app.yaml,go.mod} .
   

   Java

   将 appengine-web.xml 文件复制到来源目录中：

   mkdir -p src/main/webapp/WEB-INF
   cp gae_standard_deployment/appengine-web.xml src/main/webapp/WEB-INF/
   

   Node.js

   将 app.yaml 文件复制到来源目录中：

   cp gae_standard_deployment/app.yaml .
   

   Python

   将 app.yaml 文件复制到来源目录中：

   cp gae_standard_deployment/app.yaml .
   

2. 运行 deploy 命令：

   Go

   gcloud app deploy
   

   Java

   mvn package appengine:stage
   gcloud app deploy target/appengine-staging/app.yaml
   

   Node.js

   gcloud app deploy
   

   Python

   gcloud app deploy
   

部署完成后，该命令将输出供您访问应用的网址。如果您访问此网址，就会看到每次加载页面时 Redis 实例上的计数都会增加。