Discussion: Set a default value for NacosConfigProperties#serverAddr e.g. 127.0.0.1:8848

[ice2shell]

Spring Cloud Alibaba Version
2021.0.1.0

Which Component
Nacos Config

Describe what problem you have encountered
When using the following configuration，application failed to start due to an exception: com.alibaba.nacos.api.exception.NacosException: endpoint is blank.

Through debugging, I found that NacosConfigDataLocationResolver has loaded properties into NacosConfigProperties
before Spring instantiated the bean. Therefore, if spring.cloud.nacos is not configured, the property named serverAddr in NacosConfigProperties will be null.

So why not set a default value e.g.127.0.0.1:8848 for serverAddr as the method overrideFromEnv of NacosConfigProperties did. Is there any other consideration? I'll glad to make a pr for this if possible.

Here is the yaml configuration:

spring:
  application:
    name: demo1
  config:
    import:
      - optional:nacos:local-gateway-server.yaml
server:
  port: 8380

Here is the pom :

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <artifactId>spring-boot-starter-parent</artifactId>
        <groupId>org.springframework.boot</groupId>
        <version>2.6.8</version>
        <relativePath/>
    </parent>
    <groupId>com.example</groupId>
    <artifactId>sca-nacos-demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>sca-nacos-demo</name>
    <description>sca-nacos-demo</description>
    <properties>
        <java.version>11</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!-- Nacos注册中心 -->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
            <version>2021.0.4.0</version>
        </dependency>
        <!-- Nacos配置中心 -->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
            <version>2021.0.4.0</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

Here is the exception stack trace:

Connected to the target VM, address: '127.0.0.1:65440', transport: 'socket'
15:15:01.546 [main] DEBUG org.springframework.boot.diagnostics.LoggingFailureAnalysisReporter - Application failed to start due to an exception
com.alibaba.cloud.nacos.diagnostics.analyzer.NacosConnectionFailureException: java.lang.reflect.InvocationTargetException
	at com.alibaba.cloud.nacos.NacosConfigManager.createConfigService(NacosConfigManager.java:62)
	at com.alibaba.cloud.nacos.NacosConfigManager.<init>(NacosConfigManager.java:43)
	at com.alibaba.cloud.nacos.configdata.NacosConfigDataLocationResolver.registerConfigManager(NacosConfigDataLocationResolver.java:189)
	at com.alibaba.cloud.nacos.configdata.NacosConfigDataLocationResolver.resolveProfileSpecific(NacosConfigDataLocationResolver.java:149)
	at org.springframework.boot.context.config.ConfigDataLocationResolvers.lambda$resolve$2(ConfigDataLocationResolvers.java:120)
	at org.springframework.boot.context.config.ConfigDataLocationResolvers.resolve(ConfigDataLocationResolvers.java:126)
	at org.springframework.boot.context.config.ConfigDataLocationResolvers.resolve(ConfigDataLocationResolvers.java:119)
	at org.springframework.boot.context.config.ConfigDataLocationResolvers.resolve(ConfigDataLocationResolvers.java:107)
	at org.springframework.boot.context.config.ConfigDataImporter.resolve(ConfigDataImporter.java:105)
	at org.springframework.boot.context.config.ConfigDataImporter.resolve(ConfigDataImporter.java:97)
	at org.springframework.boot.context.config.ConfigDataImporter.resolveAndLoad(ConfigDataImporter.java:85)
	at org.springframework.boot.context.config.ConfigDataEnvironmentContributors.withProcessedImports(ConfigDataEnvironmentContributors.java:116)
	at org.springframework.boot.context.config.ConfigDataEnvironment.processWithProfiles(ConfigDataEnvironment.java:311)
	at org.springframework.boot.context.config.ConfigDataEnvironment.processAndApply(ConfigDataEnvironment.java:232)
	at org.springframework.boot.context.config.ConfigDataEnvironmentPostProcessor.postProcessEnvironment(ConfigDataEnvironmentPostProcessor.java:102)
	at org.springframework.boot.context.config.ConfigDataEnvironmentPostProcessor.postProcessEnvironment(ConfigDataEnvironmentPostProcessor.java:94)
	at org.springframework.boot.env.EnvironmentPostProcessorApplicationListener.onApplicationEnvironmentPreparedEvent(EnvironmentPostProcessorApplicationListener.java:102)
	at org.springframework.boot.env.EnvironmentPostProcessorApplicationListener.onApplicationEvent(EnvironmentPostProcessorApplicationListener.java:87)
	at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:176)
	at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:169)
	at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:143)
	at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:131)
	at org.springframework.boot.context.event.EventPublishingRunListener.environmentPrepared(EventPublishingRunListener.java:85)
	at org.springframework.boot.SpringApplicationRunListeners.lambda$environmentPrepared$2(SpringApplicationRunListeners.java:66)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1541)
	at org.springframework.boot.SpringApplicationRunListeners.doWithListeners(SpringApplicationRunListeners.java:120)
	at org.springframework.boot.SpringApplicationRunListeners.doWithListeners(SpringApplicationRunListeners.java:114)
	at org.springframework.boot.SpringApplicationRunListeners.environmentPrepared(SpringApplicationRunListeners.java:65)
	at org.springframework.boot.SpringApplication.prepareEnvironment(SpringApplication.java:339)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:297)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1312)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1301)
	at com.example.scanacosdemo.ScaNacosDemoApplication.main(ScaNacosDemoApplication.java:10)
Caused by: com.alibaba.nacos.api.exception.NacosException: java.lang.reflect.InvocationTargetException
	at com.alibaba.nacos.api.config.ConfigFactory.createConfigService(ConfigFactory.java:46)
	at com.alibaba.nacos.api.NacosFactory.createConfigService(NacosFactory.java:44)
	at com.alibaba.cloud.nacos.NacosConfigManager.createConfigService(NacosConfigManager.java:55)
	... 32 common frames omitted
Caused by: java.lang.reflect.InvocationTargetException: null
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490)
	at com.alibaba.nacos.api.config.ConfigFactory.createConfigService(ConfigFactory.java:43)
	... 34 common frames omitted
Caused by: com.alibaba.nacos.api.exception.NacosException: endpoint is blank
	at com.alibaba.nacos.client.config.impl.ServerListManager.<init>(ServerListManager.java:183)
	at com.alibaba.nacos.client.config.http.ServerHttpAgent.<init>(ServerHttpAgent.java:274)
	at com.alibaba.nacos.client.config.NacosConfigService.<init>(NacosConfigService.java:88)
	... 39 common frames omitted
15:15:01.548 [main] ERROR org.springframework.boot.diagnostics.LoggingFailureAnalysisReporter - 

***************************
APPLICATION FAILED TO START
***************************

Description:

Application failed to connect to Nacos server: "null"

Action:

Please check your Nacos server config

15:15:01.550 [Thread-1] WARN com.alibaba.nacos.common.http.HttpClientBeanHolder - [HttpClientBeanHolder] Start destroying common HttpClient
15:15:01.551 [Thread-1] WARN com.alibaba.nacos.common.http.HttpClientBeanHolder - [HttpClientBeanHolder] Destruction of the end
Disconnected from the target VM, address: '127.0.0.1:65440', transport: 'socket'

Process finished with exit code 1

Describe what information you have read
I have read the reference doc of Nacos

[steverao]

Good idea! I think we should set default value in com.alibaba.cloud.nacos.NacosConfigProperties#assembleConfigServiceProperties.

[ice2shell]

Yes, it can be solved like this. But i'm curious if there will be any problems if setting the default value directly.

[985492783]

@i will solve it@

[chickenlj]

According to the official documentation, we should add default address support:

https://docs.spring.io/spring-cloud-config/docs/current/reference/html/#config-data-import

[chickenlj]

According to the official documentation, we should add default address support:

https://docs.spring.io/spring-cloud-config/docs/current/reference/html/#config-data-import

application.properties

spring.config.import=optional:configserver:

This will connect to the Config Server at the default location of "http://localhost:8888".