spring-cloud-bootstrap

Intend to demo spring cloud usage by some demo code and instruction. There'll be one branch for each demo

Base on spring cloud bootstrap guide and code
Upgrade spring cloud to Hoxton.SR1 and spring boot to 2.2.1

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Demo 1 Bootstrap - Config server + Eureka + Zull + 2 servies

Demonstrate basic configuration for those services
Demonstrate ribbon client-side load balancer embedded in spring Zuul component

Steps

codebase

1. Import project into IDE such as Intellij or Eclipse
2. Start ConfigApp.java
   Please note default configuration repository path is application-config in project root folder
   Intellij will replace ${user.dir} to spring-cloud-bootstrapping path, while in Eclipse it should be spring-cloud-bootstrapping/cloud-config folder, please replace ${user.dir} to correct path to load configuration properly

You should start Eureka(below step) as soon as possible to make config server registered

3. Start EurekaApp.java
4. Start GatewayApp.java
5. Start RatingserviceApp.java
6. Start BookserviceApp.java twice, one with 'peer1' profile, the other with 'peer2' profile

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Alternately we can run mvn command to startup all services, navigate to project root folder:
mvn spring-boot:run -f cloud-config/pom.xml
timeout /t 10 /nobreak
mvn spring-boot:run -f cloud-eureka/pom.xml
mvn spring-boot:run -f cloud-gateway/pom.xml
mvn spring-boot:run -f cloud-bookservice/pom.xml -Dspring.profiles.include=peer1
mvn spring-boot:run -f cloud-bookservice/pom.xml -Dspring.profiles.include=peer2

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7. Verification
   If all services start correctly, you should have services run in Intellij as below
   If any error, please check service log, such as port confliction, configuration path wrongness should make the problem
   

Access below url several times, it should show you two port number of BookserviceApp in turn
http://localhost:18080/bookservice/books/port

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Review flexible configuration in config server

Refer to quick start

/{application}/{profile}[/{label}]
/{application}-{profile}.yml
/{label}/{application}-{profile}.yml
/{application}-{profile}.properties
/{label}/{application}-{profile}.properties

The 1st endpoint is more powerful, it's default endpoints for spring cloud component to retrieve config of several config name and profile combination, extended usage as below:

/{appliction}[,{application}...]/{profile}[,{profile}...][/{label}]

But it cannot support several labels at one call

File based repository config

Base on above config server characteristics, I prefer below file based repository config:

Native:
file:${user.dir}/application-config,file:${user.dir}/application-config/{profile},file:${user.dir}/application-config/{profile}/{application},file:${user.dir}/application-config/{profile}/{application}/{label},file:${user.dir}/application-config/{label},file:${user.dir}/application-config/{label}/{application},file:${user.dir}/application-config/{label}/{application}/{profile}

Git:
application-config,application-config/{profile},application-config/{profile}/{application},application-config/{profile}/{application}/{label},application-config/{label},application-config/{label}/{application},application-config/{label}/{application}/{profile}

Config folder purpose by design:

/: Global level configuration, refer to how to share configuration for all application

/{profile}: Common profiled configuration shared across different environment

/{profile}/{application}: Common profiled configuration of particular application shared across different environment

/{label}: Use label as environment identifier, such as prod for production, env1 for UAT environment 1, env2 for UAT environment 2 etc, so under this folder to define environment level common configuration
/{label}/{application}: Application level setting of particular environment

/{label}/{appication}/{profile}: Application leve setting of particular profile under specific environment

Demo 2 Eureka multiple zones

codebase

Steps to demo:

1. Create virtual hostname by editing local DNS mapping
   Linux: /etc/hosts
   MacOS: /etc/hosts
   Window: C:\Windows\System32\drivers\etc\hosts

Append below lines:
127.0.0.1 peer1
127.0.0.1 peer2

2. Navigate to project root folder and run commands:
   mvn spring-boot:run -f cloud-config/pom.xml -Dspring.profiles.include=peer1
   mvn spring-boot:run -f cloud-config/pom.xml -Dspring.profiles.include=peer2
   timeout /t 10 /nobreak
   mvn spring-boot:run -f cloud-eureka/pom.xml -Dspring.profiles.include=peer1
   mvn spring-boot:run -f cloud-eureka/pom.xml -Dspring.profiles.include=peer2
   mvn spring-boot:run -f cloud-gateway/pom.xml -Dspring.profiles.include=peer1
   mvn spring-boot:run -f cloud-gateway/pom.xml -Dspring.profiles.include=peer2
   mvn spring-boot:run -f cloud-bookservice/pom.xml -Dspring.profiles.include=peer1
   mvn spring-boot:run -f cloud-bookservice/pom.xml -Dspring.profiles.include=peer2

3. Eureka instances
   Accessing http://localhost:18010/, can see all services with two instances distributing in two zones

4. Verification Accessing below url several times, it show you consistent port number, that's because by default gateway forward request to the same zone(zone1), and we have only one bookservice at zone1
   http://localhost:18081/bookservice/books/port
   Accessing below url several times, it show you another consistent port number, that's bookservice port number in zone2