nacos does service configuration and server discovery

1. Create a project

1. Create a spring-boot project
2. Create three modules: file, system, and gateway modules
3. file and system configure startup information respectively, and create a simple controller
```
server.port=9000
spring.application.name=file
server.servlet.context-path=/file
```

4. Introduce dependencies in the root directory

<properties>
    <java.version>1.8</java.version>
    <spring-cloud.version>2021.0.8</spring-cloud.version>
</properties>

...
<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-dependencies</artifactId>
            <version>${spring-cloud.version}</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

5. Introduce dependency packages into the gateway module

<dependencies>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-gateway</artifactId>
    </dependency>
</dependencies>

6. application.properties configuration of gateway module

server.port=8000
spring.application.name=gateway
server.servlet.context-path=/gateway
spring.main.web-application-type=reactive

# Register a service
spring.cloud.gateway.routes[0].id=system
spring.cloud.gateway.routes[0].uri.=http://localhost:9001
spring.cloud.gateway.routes[0].predicates[0].name=Path
spring.cloud.gateway.routes[0].predicates[0].args[0]=/system/**
# Register a service
spring.cloud.gateway.routes[1].id=file
spring.cloud.gateway.routes[1].uri.=http://localhost:9000
spring.cloud.gateway.routes[1].predicates[0].name=Path
spring.cloud.gateway.routes[1].predicates[0].args[0]=/file/**

7. Start three projects respectively to test whether individual interface requests and routing requests using the gateway are passed.
- http://localhost:9000/file/hello
- http://localhost:9001/system/hello1
- http://localhost:8000/file/hello
- http://localhost:9000/system/hello1

2. Installation of `nacos`

1. Download from the official website address. Download different packages according to different computer systems. Unzip and enter the bin directory. The prerequisite is that jdk must be installed on the computer.
```
# This is a window computer
startup.cmd -m standalone
```

2. Install using docker

docker search nacos
docker pull nacos/nacos-server

mkdir -p /home/docker/nacos/conf
mkdir -p /home/docker/nacos/data
mkdir -p /home/docker/nacos/logs
chmod a + w /home/docker/nacos

docker run -it --name nacos \
-p 8848:8848 \
-e MODE=standalone \
-v /home/docker/nacos/conf/data:/home/nacos/conf/data \
-v /home/docker/nacos/conf/logs:/home/nacos/conf/logs \
-d nacos/nacos-server

If authentication is required, please add the application.properties file

docker run -it --name nacos \
-p 8848:8848 \
-e MODE=standalone \
-v /home/docker/nacos/conf/application.properties:/home/nacos/conf/application.properties \
-v /home/docker/nacos/conf/data:/home/nacos/conf/data \
-v /home/docker/nacos/conf/logs:/home/nacos/conf/logs \
-d nacos/nacos-server

3. Use `nacos` as configuration center

1. Add dependency packages to the project that needs to obtain nacos

 <!-- nacos configuration -->
<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
    <version>2.2.3.RELEASE</version>
</dependency>

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-bootstrap</artifactId>
</dependency>

2. Here we introduce the system module and create a bootstrap.properties file in the resources directory.

# The name of the registration center
spring.application.name=system
# Start the environment, nacos will read different configurations according to the environment dataId:system-dev.properties
spring.profiles.active=dev
# The address of nacos
spring.cloud.nacos.config.server-addr=localhost:8848
#Configure center file suffix name
spring.cloud.nacos.config.file-extension=properties

3. Create a configuration file on the nacos control panel
```
test.nacos=hello1234566
```

4. Add the configuration of test.nacos in the project’s application.properties. The value is arbitrary.

server.port=9001
#spring.application.name=system
server.servlet.context-path=/system

test.nacos=hello

5. Get the configuration file from the controller of system

package com.example.controller;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RefreshScope
public class HelloController {<!-- -->
    @Value("${test.nacos}")
    private String nacosName;

    @GetMapping("hello1")
    public String hello() {<!-- -->
        System.out.println(nacosName + "=====");
        return "System Hello";
    }
}

6. Modify the configuration file on nacos to see if the latest configuration data is obtained.

4. Multi-environment configuration

1. Manually add startup variables
2. Configure production startup
```
-Dspring.profiles.active=prod
```
3. Copy a production configuration file in nacos
4. Modify the data of system-prod.properties and start the system project

5. Request the interface to see if the configuration file read is the production configuration file.

5. Namespace

1. Maybe you only have one project in a company, so you can directly use the default namespace of public in nacos. If a company has multiple projects, each project There are different configuration files. At this time, namespaces must be used. To simply understand, a project is a namespace.
2. For example, I create a namespace of test1 and create 2 configuration files in it

3. Use the namespace in the spring-boot project to read the configuration file

# The name of the registration center
spring.application.name=system
# Start the environment, nacos will read different configurations according to the environment dataId:system-dev.properties
spring.profiles.active=dev
# The address of nacos
spring.cloud.nacos.config.server-addr=localhost:8848
#Configure center file suffix name
spring.cloud.nacos.config.file-extension=properties
# Read namespace configuration
spring.cloud.nacos.config.namespace=test1

6. Use `nacos` to implement the registration center

1. Because all modules must be registered in nacos, dependency packages are directly introduced under the module. All dependencies in the configuration center above can also be imported into the module.

<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
    <version>2.2.3.RELEASE</version>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-bootstrap</artifactId>
</dependency>

2. Just add the following 2 lines of code to the bootstrap.properties file

# Service registration
spring.cloud.nacos.discovery.server-addr=localhost:8848
spring.cloud.nacos.discovery.namespace=test1

3. If it is currently a gateway module, you need to add an additional load balancing dependency.

<dependencies>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-gateway</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-loadbalancer</artifactId>
    </dependency>
</dependencies>

4. Start the service and view the nacos control panel
5. To start one more system project, just change the startup port number when starting.

6. At this time, you can modify the gateway address from the previous localhost to lb

server.port=8000
spring.application.name=gateway
server.servlet.context-path=/gateway
spring.main.web-application-type=reactive

# Register a service
spring.cloud.gateway.routes[0].id=system
#spring.cloud.gateway.routes[0].uri.=http://localhost:9001
spring.cloud.gateway.routes[0].uri=lb://system
spring.cloud.gateway.routes[0].predicates[0].name=Path
spring.cloud.gateway.routes[0].predicates[0].args[0]=/system/**
# Register a service
spring.cloud.gateway.routes[1].id=file
#spring.cloud.gateway.routes[1].uri.=http://localhost:9000
spring.cloud.gateway.routes[1].uri=lb://file
spring.cloud.gateway.routes[1].predicates[0].name=Path
spring.cloud.gateway.routes[1].predicates[0].args[0]=/file/**

7. Test whether it is possible to use the gateway request

7. Improve `openfeig`

1. Use openfeig to request other services

2. Change from the previous writing method to the following writing method

@FeignClient(name = "system", url = "http://localhost:9001/system")
public interface FeignSystemHello {<!-- -->
    /**
     * When the hell1 method is called elsewhere, the http://localhost:9001/system/hello route will be called.
     * @return
     */
    @GetMapping("hello1")
    String hello1();
}

@FeignClient("system")
public interface FeignSystemHello {<!-- -->
    @GetMapping("system/hello1")
    String hello1();
}

3. Test request address http://localhost:8000/file/systemHello

4. The above may report an error, and you need to exclude something in the pom.xml in the root directory.

<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
    <version>2.2.3.RELEASE</version>
    <exclusions>
        <exclusion>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
        </exclusion>
    </exclusions>
</dependency>

5. Use environment variables in the test controller of system to obtain the current port.

@RestController
@RefreshScope
public class HelloController {<!-- -->
    @Value("${test.nacos}")
    private String nacosName;

    @Autowired
    Environment environment;

    @GetMapping("hello1")
    public String hello() {<!-- -->
        String port = environment.getProperty("local.server.port");
        System.out.println(nacosName + "=====");
        return "System Hello" + port;
    }
}

8. Modify `nacos` to log in using account and password

1. Modify /nacos/conf/application.properties

2. But to enable the login function, you need to configure the following values, online tool

nacos.core.auth.caching.enabled=true

nacos.core.auth.server.identity.key=nacos
nacos.core.auth.server.identity.value=nacos

nacos.core.auth.plugin.nacos.token.secret.key=OGQ2ZTNmMDQ4MjVjNGQ0OTg4YzZjMGE1NDE4MDgwMTE=

3. Enter the desktop and modify the account and password.

1. Create a project

2. Installation of nacos

3. Use nacos as configuration center