快速入门：从服务到组件的弹性

通过Dapr的状态管理API来了解其弹性功能

通过模拟系统故障来了解Dapr的弹性功能。在本快速入门中，您将：

运行一个微服务应用程序，该应用程序通过Dapr的状态管理API持续保存和检索状态。
通过模拟系统故障来触发弹性策略。
解决故障后，微服务应用程序将恢复。

在继续快速入门之前，请选择您偏好的Dapr SDK语言。

前提条件

对于此示例，您将需要：

Docker Desktop

步骤1：设置环境

克隆快速入门仓库中提供的示例。

git clone https://github.com/dapr/quickstarts.git

在终端窗口中，导航到order-processor目录。

cd ../state_management/python/sdk/order-processor

安装依赖项

pip3 install -r requirements.txt

步骤2：运行应用程序

在Dapr边车的支持下运行order-processor服务。然后，Dapr边车会加载位于资源目录中的弹性规范：

apiVersion: dapr.io/v1alpha1
kind: Resiliency
metadata:
  name: myresiliency
scopes:
  - order-processor

spec:
  policies:
    retries:
      retryForever:
        policy: constant
        duration: 5s
        maxRetries: -1

    circuitBreakers:
      simpleCB:
        maxRequests: 1
        timeout: 5s
        trip: consecutiveFailures >= 5

  targets:
    components:
      statestore:
        outbound:
          retry: retryForever
          circuitBreaker: simpleCB

dapr run --app-id order-processor --resources-path ../../../resources/ -- python3

应用程序启动后，order-processor服务会将orderId键值对写入和读取到statestore的Redis实例中在statestore.yaml组件中定义。

== APP == Saving Order:  { orderId: '1' }
== APP == Getting Order:  { orderId: '1' }
== APP == Saving Order:  { orderId: '2' }
== APP == Getting Order:  { orderId: '2' }
== APP == Saving Order:  { orderId: '3' }
== APP == Getting Order:  { orderId: '3' }
== APP == Saving Order:  { orderId: '4' }
== APP == Getting Order:  { orderId: '4' }

步骤3：引入故障

通过停止在开发机器上执行dapr init时初始化的Redis容器实例来模拟故障。一旦实例停止，来自order-processor服务的写入和读取操作将开始失败。

由于resiliency.yaml规范将statestore定义为组件目标，所有失败的请求将自动应用重试和断路器策略：

  targets:
    components:
      statestore:
        outbound:
          retry: retryForever
          circuitBreaker: simpleCB

在新的终端窗口中，运行以下命令以停止Redis：

docker stop dapr_redis

一旦Redis停止，请求开始失败，并应用名为retryForever的重试策略。以下输出显示了来自order-processor服务的日志：

INFO[0006] Error processing operation component[statestore] output. Retrying...

根据retryForever策略，重试将以5秒间隔无限期地继续每个失败的请求。

retryForever:
  policy: constant
  maxInterval: 5s
  maxRetries: -1

一旦5次连续重试失败，断路器策略simpleCB被触发，断路器打开，停止所有请求：

INFO[0026] Circuit breaker "simpleCB-statestore" changed state from closed to open

circuitBreakers:
  simpleCB:
  maxRequests: 1
  timeout: 5s 
  trip: consecutiveFailures >= 5

经过5秒后，断路器将切换到半开状态，允许一个请求通过以验证故障是否已解决。如果请求继续失败，断路器将再次触发回到打开状态。

INFO[0031] Circuit breaker "simpleCB-statestore" changed state from open to half-open  
INFO[0031] Circuit breaker "simpleCB-statestore" changed state from half-open to open 
INFO[0036] Circuit breaker "simpleCB-statestore" changed state from open to half-open  
INFO[0036] Circuit breaker "simpleCB-statestore" changed state from half-open to closed

只要Redis容器停止，这种半开/打开行为将继续。

步骤3：移除故障

当您在机器上重新启动Redis容器后，应用程序将无缝恢复并继续之前的操作。

docker start dapr_redis

INFO[0036] Recovered processing operation component[statestore] output.  
== APP == Saving Order:  { orderId: '5' }
== APP == Getting Order:  { orderId: '5' }
== APP == Saving Order:  { orderId: '6' }
== APP == Getting Order:  { orderId: '6' }
== APP == Saving Order:  { orderId: '7' }
== APP == Getting Order:  { orderId: '7' }
== APP == Saving Order:  { orderId: '8' }
== APP == Getting Order:  { orderId: '8' }
== APP == Saving Order:  { orderId: '9' }
== APP == Getting Order:  { orderId: '9' }

前提条件

对于此示例，您将需要：

Docker Desktop

步骤1：设置环境

克隆快速入门仓库中提供的示例。

git clone https://github.com/dapr/quickstarts.git

在终端窗口中，导航到order-processor目录。

cd ../state_management/javascript/sdk/order-processor

安装依赖项

npm install

步骤2：运行应用程序

在Dapr边车的支持下运行order-processor服务。然后，Dapr边车会加载位于资源目录中的弹性规范：

apiVersion: dapr.io/v1alpha1
kind: Resiliency
metadata:
  name: myresiliency
scopes:
  - checkout

spec:
  policies:
    retries:
      retryForever:
        policy: constant
        maxInterval: 5s
        maxRetries: -1 

    circuitBreakers:
      simpleCB:
        maxRequests: 1
        timeout: 5s 
        trip: consecutiveFailures >= 5

  targets:
    apps:
      order-processor:
        retry: retryForever
        circuitBreaker: simpleCB

dapr run --app-id order-processor --resources-path ../../../resources/ -- npm start

应用程序启动后，order-processor服务会将orderId键值对写入和读取到statestore的Redis实例中在statestore.yaml组件中定义。

== APP == Saving Order:  { orderId: '1' }
== APP == Getting Order:  { orderId: '1' }
== APP == Saving Order:  { orderId: '2' }
== APP == Getting Order:  { orderId: '2' }
== APP == Saving Order:  { orderId: '3' }
== APP == Getting Order:  { orderId: '3' }
== APP == Saving Order:  { orderId: '4' }
== APP == Getting Order:  { orderId: '4' }

步骤3：引入故障

通过停止在开发机器上执行dapr init时初始化的Redis容器实例来模拟故障。一旦实例停止，来自order-processor服务的写入和读取操作将开始失败。

由于resiliency.yaml规范将statestore定义为组件目标，所有失败的请求将自动应用重试和断路器策略：

  targets:
    components:
      statestore:
        outbound:
          retry: retryForever
          circuitBreaker: simpleCB

在新的终端窗口中，运行以下命令以停止Redis：

docker stop dapr_redis

一旦Redis停止，请求开始失败，并应用名为retryForever的重试策略。以下输出显示了来自order-processor服务的日志：

INFO[0006] Error processing operation component[statestore] output. Retrying...

根据retryForever策略，重试将以5秒间隔无限期地继续每个失败的请求。

retryForever:
  policy: constant
  maxInterval: 5s
  maxRetries: -1

一旦5次连续重试失败，断路器策略simpleCB被触发，断路器打开，停止所有请求：

INFO[0026] Circuit breaker "simpleCB-statestore" changed state from closed to open

circuitBreakers:
  simpleCB:
  maxRequests: 1
  timeout: 5s 
  trip: consecutiveFailures >= 5

经过5秒后，断路器将切换到半开状态，允许一个请求通过以验证故障是否已解决。如果请求继续失败，断路器将再次触发回到打开状态。

INFO[0031] Circuit breaker "simpleCB-statestore" changed state from open to half-open  
INFO[0031] Circuit breaker "simpleCB-statestore" changed state from half-open to open 
INFO[0036] Circuit breaker "simpleCB-statestore" changed state from open to half-open  
INFO[0036] Circuit breaker "simpleCB-statestore" changed state from half-open to closed

只要Redis容器停止，这种半开/打开行为将继续。

步骤3：移除故障

当您在机器上重新启动Redis容器后，应用程序将无缝恢复并继续之前的操作。

docker start dapr_redis

INFO[0036] Recovered processing operation component[statestore] output.  
== APP == Saving Order:  { orderId: '5' }
== APP == Getting Order:  { orderId: '5' }
== APP == Saving Order:  { orderId: '6' }
== APP == Getting Order:  { orderId: '6' }
== APP == Saving Order:  { orderId: '7' }
== APP == Getting Order:  { orderId: '7' }
== APP == Saving Order:  { orderId: '8' }
== APP == Getting Order:  { orderId: '8' }
== APP == Saving Order:  { orderId: '9' }
== APP == Getting Order:  { orderId: '9' }

前提条件

对于此示例，您将需要：

Docker Desktop

步骤1：设置环境

克隆快速入门仓库中提供的示例。

git clone https://github.com/dapr/quickstarts.git

在终端窗口中，导航到order-processor目录。

cd ../state_management/csharp/sdk/order-processor

安装依赖项

dotnet restore
dotnet build

步骤2：运行应用程序

在Dapr边车的支持下运行order-processor服务。然后，Dapr边车会加载位于资源目录中的弹性规范：

apiVersion: dapr.io/v1alpha1
kind: Resiliency
metadata:
  name: myresiliency
scopes:
  - checkout

spec:
  policies:
    retries:
      retryForever:
        policy: constant
        maxInterval: 5s
        maxRetries: -1 

    circuitBreakers:
      simpleCB:
        maxRequests: 1
        timeout: 5s 
        trip: consecutiveFailures >= 5

  targets:
    apps:
      order-processor:
        retry: retryForever
        circuitBreaker: simpleCB

dapr run --app-id order-processor --resources-path ../../../resources/ -- dotnet run

应用程序启动后，order-processor服务会将orderId键值对写入和读取到statestore的Redis实例中在statestore.yaml组件中定义。

== APP == Saving Order:  { orderId: '1' }
== APP == Getting Order:  { orderId: '1' }
== APP == Saving Order:  { orderId: '2' }
== APP == Getting Order:  { orderId: '2' }
== APP == Saving Order:  { orderId: '3' }
== APP == Getting Order:  { orderId: '3' }
== APP == Saving Order:  { orderId: '4' }
== APP == Getting Order:  { orderId: '4' }

步骤3：引入故障

通过停止在开发机器上执行dapr init时初始化的Redis容器实例来模拟故障。一旦实例停止，来自order-processor服务的写入和读取操作将开始失败。

由于resiliency.yaml规范将statestore定义为组件目标，所有失败的请求将自动应用重试和断路器策略：

  targets:
    components:
      statestore:
        outbound:
          retry: retryForever
          circuitBreaker: simpleCB

在新的终端窗口中，运行以下命令以停止Redis：

docker stop dapr_redis

一旦Redis停止，请求开始失败，并应用名为retryForever的重试策略。以下输出显示了来自order-processor服务的日志：

INFO[0006] Error processing operation component[statestore] output. Retrying...

根据retryForever策略，重试将以5秒间隔无限期地继续每个失败的请求。

retryForever:
  policy: constant
  maxInterval: 5s
  maxRetries: -1

一旦5次连续重试失败，断路器策略simpleCB被触发，断路器打开，停止所有请求：

INFO[0026] Circuit breaker "simpleCB-statestore" changed state from closed to open

circuitBreakers:
  simpleCB:
  maxRequests: 1
  timeout: 5s 
  trip: consecutiveFailures >= 5

经过5秒后，断路器将切换到半开状态，允许一个请求通过以验证故障是否已解决。如果请求继续失败，断路器将再次触发回到打开状态。

INFO[0031] Circuit breaker "simpleCB-statestore" changed state from open to half-open  
INFO[0031] Circuit breaker "simpleCB-statestore" changed state from half-open to open 
INFO[0036] Circuit breaker "simpleCB-statestore" changed state from open to half-open  
INFO[0036] Circuit breaker "simpleCB-statestore" changed state from half-open to closed

只要Redis容器停止，这种半开/打开行为将继续。

步骤3：移除故障

当您在机器上重新启动Redis容器后，应用程序将无缝恢复并继续之前的操作。

docker start dapr_redis

INFO[0036] Recovered processing operation component[statestore] output.  
== APP == Saving Order:  { orderId: '5' }
== APP == Getting Order:  { orderId: '5' }
== APP == Saving Order:  { orderId: '6' }
== APP == Getting Order:  { orderId: '6' }
== APP == Saving Order:  { orderId: '7' }
== APP == Getting Order:  { orderId: '7' }
== APP == Saving Order:  { orderId: '8' }
== APP == Getting Order:  { orderId: '8' }
== APP == Saving Order:  { orderId: '9' }
== APP == Getting Order:  { orderId: '9' }

前提条件

对于此示例，您将需要：

Dapr CLI和已初始化的环境。
Java JDK 17（或更高版本）：
- Oracle JDK，或
- OpenJDK
Apache Maven，版本3.x。

Docker Desktop

步骤1：设置环境

克隆快速入门仓库中提供的示例。

git clone https://github.com/dapr/quickstarts.git

在终端窗口中，导航到order-processor目录。

cd ../state_management/java/sdk/order-processor

安装依赖项

mvn clean install

步骤2：运行应用程序

在Dapr边车的支持下运行order-processor服务。然后，Dapr边车会加载位于资源目录中的弹性规范：

apiVersion: dapr.io/v1alpha1
kind: Resiliency
metadata:
  name: myresiliency
scopes:
  - checkout

spec:
  policies:
    retries:
      retryForever:
        policy: constant
        maxInterval: 5s
        maxRetries: -1 

    circuitBreakers:
      simpleCB:
        maxRequests: 1
        timeout: 5s 
        trip: consecutiveFailures >= 5

  targets:
    apps:
      order-processor:
        retry: retryForever
        circuitBreaker: simpleCB

dapr run --app-id order-processor --resources-path ../../../resources/ -- java -jar target/OrderProcessingService-0.0.1-SNAPSHOT.jar

应用程序启动后，order-processor服务会将orderId键值对写入和读取到statestore的Redis实例中在statestore.yaml组件中定义。

== APP == Saving Order:  { orderId: '1' }
== APP == Getting Order:  { orderId: '1' }
== APP == Saving Order:  { orderId: '2' }
== APP == Getting Order:  { orderId: '2' }
== APP == Saving Order:  { orderId: '3' }
== APP == Getting Order:  { orderId: '3' }
== APP == Saving Order:  { orderId: '4' }
== APP == Getting Order:  { orderId: '4' }

步骤3：引入故障

通过停止在开发机器上执行dapr init时初始化的Redis容器实例来模拟故障。一旦实例停止，来自order-processor服务的写入和读取操作将开始失败。

由于resiliency.yaml规范将statestore定义为组件目标，所有失败的请求将自动应用重试和断路器策略：

  targets:
    components:
      statestore:
        outbound:
          retry: retryForever
          circuitBreaker: simpleCB

在新的终端窗口中，运行以下命令以停止Redis：

docker stop dapr_redis

一旦Redis停止，请求开始失败，并应用名为retryForever的重试策略。以下输出显示了来自order-processor服务的日志：

INFO[0006] Error processing operation component[statestore] output. Retrying...

根据retryForever策略，重试将以5秒间隔无限期地继续每个失败的请求。

retryForever:
  policy: constant
  maxInterval: 5s
  maxRetries: -1

一旦5次连续重试失败，断路器策略simpleCB被触发，断路器打开，停止所有请求：

INFO[0026] Circuit breaker "simpleCB-statestore" changed state from closed to open

circuitBreakers:
  simpleCB:
  maxRequests: 1
  timeout: 5s 
  trip: consecutiveFailures >= 5

经过5秒后，断路器将切换到半开状态，允许一个请求通过以验证故障是否已解决。如果请求继续失败，断路器将再次触发回到打开状态。

INFO[0031] Circuit breaker "simpleCB-statestore" changed state from open to half-open  
INFO[0031] Circuit breaker "simpleCB-statestore" changed state from half-open to open 
INFO[0036] Circuit breaker "simpleCB-statestore" changed state from open to half-open  
INFO[0036] Circuit breaker "simpleCB-statestore" changed state from half-open to closed

只要Redis容器停止，这种半开/打开行为将继续。

步骤3：移除故障

当您在机器上重新启动Redis容器后，应用程序将无缝恢复并继续之前的操作。

docker start dapr_redis

INFO[0036] Recovered processing operation component[statestore] output.  
== APP == Saving Order:  { orderId: '5' }
== APP == Getting Order:  { orderId: '5' }
== APP == Saving Order:  { orderId: '6' }
== APP == Getting Order:  { orderId: '6' }
== APP == Saving Order:  { orderId: '7' }
== APP == Getting Order:  { orderId: '7' }
== APP == Saving Order:  { orderId: '8' }
== APP == Getting Order:  { orderId: '8' }
== APP == Saving Order:  { orderId: '9' }
== APP == Getting Order:  { orderId: '9' }

前提条件

对于此示例，您将需要：

Docker Desktop

步骤1：设置环境

克隆快速入门仓库中提供的示例。

git clone https://github.com/dapr/quickstarts.git

在终端窗口中，导航到order-processor目录。

cd ../state_management/go/sdk/order-processor

安装依赖项

go build .

步骤2：运行应用程序

在Dapr边车的支持下运行order-processor服务。然后，Dapr边车会加载位于资源目录中的弹性规范：

apiVersion: dapr.io/v1alpha1
kind: Resiliency
metadata:
  name: myresiliency
scopes:
  - checkout

spec:
  policies:
    retries:
      retryForever:
        policy: constant
        maxInterval: 5s
        maxRetries: -1 

    circuitBreakers:
      simpleCB:
        maxRequests: 1
        timeout: 5s 
        trip: consecutiveFailures >= 5

  targets:
    apps:
      order-processor:
        retry: retryForever
        circuitBreaker: simpleCB

dapr run --app-id order-processor --resources-path ../../../resources -- go run .

应用程序启动后，order-processor服务会将orderId键值对写入和读取到statestore的Redis实例中在statestore.yaml组件中定义。

== APP == Saving Order:  { orderId: '1' }
== APP == Getting Order:  { orderId: '1' }
== APP == Saving Order:  { orderId: '2' }
== APP == Getting Order:  { orderId: '2' }
== APP == Saving Order:  { orderId: '3' }
== APP == Getting Order:  { orderId: '3' }
== APP == Saving Order:  { orderId: '4' }
== APP == Getting Order:  { orderId: '4' }

步骤3：引入故障

通过停止在开发机器上执行dapr init时初始化的Redis容器实例来模拟故障。一旦实例停止，来自order-processor服务的写入和读取操作将开始失败。

由于resiliency.yaml规范将statestore定义为组件目标，所有失败的请求将自动应用重试和断路器策略：

  targets:
    components:
      statestore:
        outbound:
          retry: retryForever
          circuitBreaker: simpleCB

在新的终端窗口中，运行以下命令以停止Redis：

docker stop dapr_redis

一旦Redis停止，请求开始失败，并应用名为retryForever的重试策略。以下输出显示了来自order-processor服务的日志：

INFO[0006] Error processing operation component[statestore] output. Retrying...

根据retryForever策略，重试将以5秒间隔无限期地继续每个失败的请求。

retryForever:
  policy: constant
  maxInterval: 5s
  maxRetries: -1

一旦5次连续重试失败，断路器策略simpleCB被触发，断路器打开，停止所有请求：

INFO[0026] Circuit breaker "simpleCB-statestore" changed state from closed to open

circuitBreakers:
  simpleCB:
  maxRequests: 1
  timeout: 5s 
  trip: consecutiveFailures >= 5

经过5秒后，断路器将切换到半开状态，允许一个请求通过以验证故障是否已解决。如果请求继续失败，断路器将再次触发回到打开状态。

INFO[0031] Circuit breaker "simpleCB-statestore" changed state from open to half-open  
INFO[0031] Circuit breaker "simpleCB-statestore" changed state from half-open to open 
INFO[0036] Circuit breaker "simpleCB-statestore" changed state from open to half-open  
INFO[0036] Circuit breaker "simpleCB-statestore" changed state from half-open to closed

只要Redis容器停止，这种半开/打开行为将继续。

步骤3：移除故障

当您在机器上重新启动Redis容器后，应用程序将无缝恢复并继续之前的操作。

docker start dapr_redis

INFO[0036] Recovered processing operation component[statestore] output.  
== APP == Saving Order:  { orderId: '5' }
== APP == Getting Order:  { orderId: '5' }
== APP == Saving Order:  { orderId: '6' }
== APP == Getting Order:  { orderId: '6' }
== APP == Saving Order:  { orderId: '7' }
== APP == Getting Order:  { orderId: '7' }
== APP == Saving Order:  { orderId: '8' }
== APP == Getting Order:  { orderId: '8' }
== APP == Saving Order:  { orderId: '9' }
== APP == Getting Order:  { orderId: '9' }

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