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Como se conectar a uma instância do Redis a partir de uma VM do Compute Engine

É possível se conectar à sua instância do Redis a partir de instâncias de VMs do Compute Engine que usam a mesma rede autorizada que a instância do Redis.

Configuração

Se você já tiver instalado a CLI do Google Cloud, criado uma instância do Redis e um bucket do Cloud Storage, pule essas etapas.

Instale a CLI gcloud e inicialize:
```
gcloud init
```
Siga o Guia de início rápido para criar uma instância do Redis. Anote a zona, o endereço IP e a porta da instância do Redis.
Crie um bucket do Cloud Storage em que o artefato do aplicativo para este aplicativo de amostra será carregado. Para mais informações, consulte Criar buckets.

Como definir as configurações do gcloud para o aplicativo de amostra

Defina o projeto padrão do gcloud como seu projeto de aplicativo de amostra.
```
gcloud config set project [PROJECT_ID]
```

Exemplo de aplicativo

Este aplicativo de servidor HTTP de amostra estabelece uma conexão com uma instância do Redis usando uma instância de VM do Compute Engine.

Clone o repositório da linguagem de programação pretendida e navegue até a pasta que contém o código de amostra:

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

Este aplicativo de amostra incrementa um contador do Redis sempre que o endpoint / é acessado.

Go

Este aplicativo usa o cliente github.com/gomodule/redigo/redis. Instale-o executando o comando a seguir:

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

Esta aplicação é baseada em servlets do Jet 3.1.

Ele usa a biblioteca Jedis (em inglês):

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

A classe AppServletContextListener é usada para criar um pool de conexão Redis de longa duração:


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
      }
    }
  }
}

A classe VisitCounterServlet é um servlet da Web que incrementa um contador do Redis:


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

Este aplicativo usa o módulo redis (em inglês).

{
  "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

Este aplicativo usa o Flask para veiculação na Web e o pacote redis-py (links em inglês) para se comunicar com a instância do Redis.

Flask==3.0.3
gunicorn==22.0.0
redis==5.0.1
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)

Como implantar o aplicativo em uma VM do Compute Engine

Navegue até o diretório gce_deployment:

cd gce_deployment

Com o script de implantação, é feito o upload do artefato para o caminho do Cloud Storage. Em seguida, é lançada uma instância do Compute Engine e um firewall é criado para expor a porta 8080. Com o script de inicialização a instância é preparada.

Defina as variáveis de ambiente REDISHOST e REDISPORT:

   export REDISHOST=[REDISHOST]
   export REDISPORT=[REDISPORT]

em que:

REDISHOST é o IP da instância gerenciada do Redis.
REDISPORT é a porta da instância Redis gerenciada por padrão, 6379.

Defina a variável de ambiente GCS_BUCKET_NAME:

     export GCS_BUCKET_NAME=[BUCKET_NAME]/[PATH]

em que:

BUCKET_NAME é o nome do bucket do Cloud Storage.
PATH é um caminho opcional para o diretório em que você quer armazenar o artefato do aplicativo.

Veja uma amostra de script de implantação com que é implantado esse aplicativo em uma nova instância de VM do Compute Engine.

Go

if [ -z "$REDISHOST" ]; then
  echo "Must set \$REDISHOST. For example: REDISHOST=127.0.0.1"
  exit 1
fi

if [ -z "$REDISPORT" ]; then
  echo "Must set \$REDISPORT. For example: REDISPORT=6379"
  exit 1
fi

if [ -z "$GCS_BUCKET_NAME" ]; then
  echo "Must set \$GCS_BUCKET_NAME. For example: GCS_BUCKET_NAME=my-bucket"
  exit 1
fi

if [ -z "$ZONE" ]; then
  ZONE=$(gcloud config get-value compute/zone -q)
  echo "$ZONE"
fi


# Cross compile the app for linux/amd64
GOOS=linux GOARCH=amd64 go build -v -o app ../main.go
# Add the app binary
tar -cvf app.tar app
# Copy to GCS bucket
gsutil cp app.tar gs://"$GCS_BUCKET_NAME"/gce/

# Create an instance
gcloud compute instances create my-instance \
    --image-family=debian-9 \
    --image-project=debian-cloud \
    --machine-type=g1-small \
    --scopes cloud-platform \
    --metadata-from-file startup-script=startup-script.sh \
    --metadata gcs-bucket="$GCS_BUCKET_NAME",redis-host="$REDISHOST",redis-port="$REDISPORT" \
    --zone "$ZONE" \
    --tags http-server

gcloud compute firewall-rules create allow-http-server-8080 \
    --allow tcp:8080 \
    --source-ranges 0.0.0.0/0 \
    --target-tags http-server \
    --description "Allow port 8080 access to http-server"

Java

if [ -z "$GCS_BUCKET_NAME" ]; then
    echo "Must set \$GCS_BUCKET_NAME. For example: GCS_BUCKET_NAME=my-bucket"
    exit 1
fi

if [ -z "$ZONE" ]; then
  ZONE=$(gcloud config get-value compute/zone -q)
  echo $ZONE
fi

if [ -z "$WAR" ]; then
  WAR=visitcounter-1.0-SNAPSHOT.war
fi

#Build the WAR package
cd ..
mvn clean package

#Copy the WAR artifact to the GCS bucket location
gsutil cp -r target/${WAR} gs://"$GCS_BUCKET_NAME"/gce/

cd gce_deployment

# Create an instance
gcloud compute instances create my-instance \
    --image-family=debian-9 \
    --image-project=debian-cloud \
    --machine-type=g1-small \
    --scopes cloud-platform \
    --metadata-from-file startup-script=startup-script.sh \
    --metadata gcs-bucket=$GCS_BUCKET_NAME,app-war=$WAR \
    --zone $ZONE \
    --tags http-server

gcloud compute firewall-rules create allow-http-server-8080 \
    --allow tcp:8080 \
    --source-ranges 0.0.0.0/0 \
    --target-tags http-server \
    --description "Allow port 8080 access to http-server"

Node.js

if [ -z "$REDISHOST" ]; then
  echo "Must set \$REDISHOST. For example: REDISHOST=127.0.0.1"
  exit 1
fi

if [ -z "$REDISPORT" ]; then
  echo "Must set \$REDISPORT. For example: REDISPORT=6379"
  exit 1
fi

if [ -z "$GCS_BUCKET_NAME" ]; then
  echo "Must set \$GCS_BUCKET_NAME. For example: GCS_BUCKET_NAME=my-bucket"
  exit 1
fi

if [ -z "$ZONE" ]; then
  ZONE=$(gcloud config get-value compute/zone -q)
  echo $ZONE
fi

#Upload the tar to GCS
tar -cvf app.tar -C .. package.json server.js
gsutil cp app.tar gs://"$GCS_BUCKET_NAME"/gce/

# Create an instance
gcloud compute instances create my-instance \
    --image-family=debian-9 \
    --image-project=debian-cloud \
    --machine-type=g1-small \
    --scopes cloud-platform \
    --metadata-from-file startup-script=startup-script.sh \
    --metadata gcs-bucket=$GCS_BUCKET_NAME,redis-host=$REDISHOST,redis-port=$REDISPORT \
    --zone $ZONE \
    --tags http-server

gcloud compute firewall-rules create allow-http-server-8080 \
    --allow tcp:8080 \
    --source-ranges 0.0.0.0/0 \
    --target-tags http-server \
    --description "Allow port 8080 access to http-server"

Python

if [ -z "$REDISHOST" ]; then
  echo "Must set \$REDISHOST. For example: REDISHOST=127.0.0.1"
  exit 1
fi

if [ -z "$REDISPORT" ]; then
  echo "Must set \$REDISPORT. For example: REDISPORT=6379"
  exit 1
fi

if [ -z "$GCS_BUCKET_NAME" ]; then
  echo "Must set \$GCS_BUCKET_NAME. For example: GCS_BUCKET_NAME=my-bucket"
  exit 1
fi

if [ -z "$ZONE" ]; then
  ZONE=$(gcloud config get-value compute/zone -q)
  echo $ZONE
fi

#Upload the tar to GCS
tar -cvf app.tar -C .. requirements.txt main.py
# Copy to GCS bucket
gsutil cp app.tar gs://"$GCS_BUCKET_NAME"/gce/

# Create an instance
gcloud compute instances create my-instance \
    --image-family=debian-11 \
    --image-project=debian-cloud \
    --machine-type=g1-small \
    --scopes cloud-platform \
    --metadata-from-file startup-script=startup-script.sh \
    --metadata gcs-bucket=$GCS_BUCKET_NAME,redis-host=$REDISHOST,redis-port=$REDISPORT \
    --zone $ZONE \
    --tags http-server

gcloud compute firewall-rules create allow-http-server-8080 \
    --allow tcp:8080 \
    --source-ranges 0.0.0.0/0 \
    --target-tags http-server \
    --description "Allow port 8080 access to http-server"

Execute o script de implantação:

     chmod +x deploy.sh
     ./deploy.sh

Script de inicialização do aplicativo

Esse script de inicialização é usado na amostra de script de implantação para preparar a instância. Para mais informações sobre scripts de inicialização e sobre como visualizar registros de execução de scripts de inicialização, consulte Como executar scripts de inicialização.

Go

set -ex

# Talk to the metadata server to get the project id and location of application binary.
PROJECTID=$(curl -s "http://metadata.google.internal/computeMetadata/v1/project/project-id" -H "Metadata-Flavor: Google")
export PROJECTID
GCS_BUCKET_NAME=$(curl -s "http://metadata.google.internal/computeMetadata/v1/instance/attributes/gcs-bucket" -H "Metadata-Flavor: Google")
REDISHOST=$(curl -s "http://metadata.google.internal/computeMetadata/v1/instance/attributes/redis-host" -H "Metadata-Flavor: Google")
REDISPORT=$(curl -s "http://metadata.google.internal/computeMetadata/v1/instance/attributes/redis-port" -H "Metadata-Flavor: Google")

# Install dependencies from apt
apt-get update
apt-get install -yq ca-certificates supervisor

# Install logging monitor. The monitor will automatically pickup logs send to
# syslog.
curl "https://storage.googleapis.com/signals-agents/logging/google-fluentd-install.sh" --output google-fluentd-install.sh
checksum=$(sha256sum google-fluentd-install.sh | awk '{print $1;}')
if [ "$checksum" != "ec78e9067f45f6653a6749cf922dbc9d79f80027d098c90da02f71532b5cc967" ]; then
    echo "Checksum does not match"
    exit 1
fi
chmod +x google-fluentd-install.sh && ./google-fluentd-install.sh
service google-fluentd restart &

gsutil cp gs://"$GCS_BUCKET_NAME"/gce/app.tar /app.tar
mkdir -p /app
tar -x -f /app.tar -C /app
chmod +x /app/app

# Create a goapp user. The application will run as this user.
getent passwd goapp || useradd -m -d /home/goapp goapp
chown -R goapp:goapp /app

# Configure supervisor to run the Go app.
cat >/etc/supervisor/conf.d/goapp.conf << EOF
[program:goapp]
directory=/app
environment=HOME="/home/goapp",USER="goapp",REDISHOST=$REDISHOST,REDISPORT=$REDISPORT
command=/app/app
autostart=true
autorestart=true
user=goapp
stdout_logfile=syslog
stderr_logfile=syslog
EOF

supervisorctl reread
supervisorctl update

Java

set -ex

# Talk to the metadata server to get the project id and location of application binary.
PROJECTID=$(curl -s "http://metadata.google.internal/computeMetadata/v1/project/project-id" -H "Metadata-Flavor: Google")
GCS_BUCKET_NAME=$(curl -s "http://metadata.google.internal/computeMetadata/v1/instance/attributes/gcs-bucket" -H "Metadata-Flavor: Google")
WAR=$(curl -s "http://metadata.google.internal/computeMetadata/v1/instance/attributes/app-war" -H "Metadata-Flavor: Google")

gsutil cp gs://"$GCS_BUCKET_NAME"/gce/"$WAR" .

# Install dependencies from apt
apt-get update
apt-get install -qq openjdk-8-jdk-headless

# Make Java8 the default
update-alternatives --set java /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java

# Jetty Setup
mkdir -p /opt/jetty/temp
mkdir -p /var/log/jetty

# Get Jetty
curl -L https://repo1.maven.org/maven2/org/eclipse/jetty/jetty-distribution/9.4.10.v20180503/jetty-distribution-9.4.10.v20180503.tar.gz -o jetty9.tgz
tar xf jetty9.tgz  --strip-components=1 -C /opt/jetty

# Add a Jetty User
useradd --user-group --shell /bin/false --home-dir /opt/jetty/temp jetty

cd /opt/jetty
# Add running as "jetty"
java -jar /opt/jetty/start.jar --add-to-startd=setuid
cd /

# very important - by renaming the war to root.war, it will run as the root servlet.
mv $WAR /opt/jetty/webapps/root.war

# Make sure "jetty" owns everything.
chown --recursive jetty /opt/jetty

# Configure the default paths for the Jetty service
cp /opt/jetty/bin/jetty.sh /etc/init.d/jetty
echo "JETTY_HOME=/opt/jetty" > /etc/default/jetty
{
  echo "JETTY_BASE=/opt/jetty"
  echo "TMPDIR=/opt/jetty/temp"
  echo "JAVA_OPTIONS=-Djetty.http.port=8080"
  echo "JETTY_LOGS=/var/log/jetty"
} >> /etc/default/jetty


# Reload daemon to pick up new service
systemctl daemon-reload

# Install logging monitor. The monitor will automatically pickup logs sent to syslog.
curl -s "https://storage.googleapis.com/signals-agents/logging/google-fluentd-install.sh" | bash
service google-fluentd restart &

service jetty start
service jetty check

echo "Startup Complete"

Node.js

set -ex

# Talk to the metadata server to get the project id and location of application binary.
PROJECTID=$(curl -s "http://metadata.google.internal/computeMetadata/v1/project/project-id" -H "Metadata-Flavor: Google")
GCS_BUCKET_NAME=$(curl -s "http://metadata.google.internal/computeMetadata/v1/instance/attributes/gcs-bucket" -H "Metadata-Flavor: Google")
REDISHOST=$(curl -s "http://metadata.google.internal/computeMetadata/v1/instance/attributes/redis-host" -H "Metadata-Flavor: Google")
REDISPORT=$(curl -s "http://metadata.google.internal/computeMetadata/v1/instance/attributes/redis-port" -H "Metadata-Flavor: Google")

# Install dependencies from apt
apt-get update
# Install Node.js 9
curl -sL https://deb.nodesource.com/setup_9.x | sudo -E bash -
apt-get install -yq ca-certificates supervisor nodejs build-essential


# Install logging monitor. The monitor will automatically pickup logs send to
# syslog.
curl -s "https://storage.googleapis.com/signals-agents/logging/google-fluentd-install.sh" | bash
service google-fluentd restart &

gsutil cp gs://"$GCS_BUCKET_NAME"/gce/app.tar /app.tar
mkdir -p /app
tar -x -f /app.tar -C /app
cd /app
# Install the app dependencies
npm install

# Create a nodeapp user. The application will run as this user.
getent passwd nodeapp || useradd -m -d /home/nodeapp nodeapp
chown -R nodeapp:nodeapp /app

# Configure supervisor to run the Go app.
cat >/etc/supervisor/conf.d/nodeapp.conf << EOF
[program:nodeapp]
directory=/app
environment=HOME="/home/nodeapp",USER="nodeapp",REDISHOST=$REDISHOST,REDISPORT=$REDISPORT
command=node server.js
autostart=true
autorestart=true
user=nodeapp
stdout_logfile=syslog
stderr_logfile=syslog
EOF

supervisorctl reread
supervisorctl update

Python

set -v

# Talk to the metadata server to get the project id and location of application binary.
PROJECTID=$(curl -s "http://metadata.google.internal/computeMetadata/v1/project/project-id" -H "Metadata-Flavor: Google")
GCS_BUCKET_NAME=$(curl -s "http://metadata.google.internal/computeMetadata/v1/instance/attributes/gcs-bucket" -H "Metadata-Flavor: Google")
REDISHOST=$(curl -s "http://metadata.google.internal/computeMetadata/v1/instance/attributes/redis-host" -H "Metadata-Flavor: Google")
REDISPORT=$(curl -s "http://metadata.google.internal/computeMetadata/v1/instance/attributes/redis-port" -H "Metadata-Flavor: Google")

# Install dependencies from apt
apt-get update
apt-get install -yq \
    git build-essential supervisor python python-dev python-pip libffi-dev \
    libssl-dev

# Install logging monitor. The monitor will automatically pickup logs send to
# syslog.
curl -s "https://storage.googleapis.com/signals-agents/logging/google-fluentd-install.sh" | bash
service google-fluentd restart &

gsutil cp gs://"$GCS_BUCKET_NAME"/gce/app.tar /app.tar
mkdir -p /app
tar -x -f /app.tar -C /app
cd /app

# Install the app dependencies
pip install --upgrade pip virtualenv
virtualenv /app/env
/app/env/bin/pip install -r /app/requirements.txt

# Create a pythonapp user. The application will run as this user.
getent passwd pythonapp || useradd -m -d /home/pythonapp pythonapp
chown -R pythonapp:pythonapp /app

# Configure supervisor to run the app.
cat >/etc/supervisor/conf.d/pythonapp.conf << EOF
[program:pythonapp]
directory=/app
environment=HOME="/home/pythonapp",USER="pythonapp",REDISHOST=$REDISHOST,REDISPORT=$REDISPORT
command=/app/env/bin/gunicorn main:app --bind 0.0.0:8080
autostart=true
autorestart=true
user=pythonapp
stdout_logfile=syslog
stderr_logfile=syslog
EOF

supervisorctl reread
supervisorctl update

Pode levar vários minutos para que o aplicativo de amostra seja implantado na recém-criada instância do Compute Engine.

Quando a instância estiver pronta e o script de inicialização tiver concluído a execução, acesse a página de instâncias do Compute Engine e copie o endereço IP externo.

Para ver o aplicativo de amostra implantado, visite http://[EXTERNAL-IP]:8080

Use o script teardown.sh para excluir a instância e o firewall criados pelo script de implantação:

gcloud compute instances delete my-instance

gcloud compute firewall-rules delete allow-http-server-8080