快速入门:服务到服务弹性

通过服务调用 API 开始使用 Dapr 的弹性功能

通过模拟系统故障来观察 Dapr 弹性功能。在本快速入门中,您将:

  • 运行两个微服务应用程序:checkoutorder-processorcheckout 将持续向 order-processor 发起 Dapr 服务调用请求。
  • 通过模拟系统故障来触发弹性规范。
  • 移除故障,使微服务应用程序能够恢复。
Diagram showing the resiliency applied to Dapr APIs

在继续快速入门之前,选择您偏好的特定语言的 Dapr SDK。

前置条件

对于此示例,您需要:

步骤 1:设置环境

克隆 Quickstarts 仓库中提供的示例

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

步骤 2:运行 order-processor 服务

在终端窗口中,从快速入门目录的根目录导航到 order-processor 目录。

cd service_invocation/python/http/order-processor

安装依赖:

pip3 install -r requirements.txt

运行 order-processor 服务以及 Dapr 边车。

dapr run --app-port 8001 --app-id order-processor --resources-path ../../../resources/ --app-protocol http --dapr-http-port 3501 -- python3 app.py

步骤 3:运行 checkout 服务应用程序

在新的终端窗口中,从快速入门目录的根目录导航到 checkout 目录。

cd service_invocation/python/http/checkout

安装依赖:

pip3 install -r requirements.txt

运行 checkout 服务以及 Dapr 边车。

dapr run --app-id checkout --resources-path ../../../resources/ --app-protocol http --dapr-http-port 3500 -- python3 app.py

然后 Dapr 边车将加载位于 resources 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

步骤 4:查看服务调用输出

当两个服务和边车都在运行时,注意订单是如何使用 Dapr 服务调用从 checkout 服务传递到 order-processor 服务的。

checkout 服务输出:

== APP == Order passed: {"orderId": 1}
== APP == Order passed: {"orderId": 2}
== APP == Order passed: {"orderId": 3}
== APP == Order passed: {"orderId": 4}

order-processor 服务输出:

== APP == Order received: {"orderId": 1}
== APP == Order received: {"orderId": 2}
== APP == Order received: {"orderId": 3}
== APP == Order received: {"orderId": 4}

步骤 5:引入故障

通过停止 order-processor 服务来模拟故障。一旦实例停止,来自 checkout 服务的服务调用操作将开始失败。

由于 resiliency.yaml 规范将 order-processor 服务定义为弹性目标,所有失败的请求都将应用重试和断路器策略:

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

order-processor 窗口中,停止服务:

CMD + C
CTRL + C

一旦第一个请求失败,将应用名为 retryForever 的重试策略:

INFO[0005] Error processing operation endpoint[order-processor, order-processor:orders]. Retrying...  

对于每个失败的请求,重试将以 5 秒的间隔无限期继续。

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

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

INFO[0025] Circuit breaker "order-processor:orders" changed state from closed to open  
circuitBreakers:
  simpleCB:
  maxRequests: 1
  timeout: 5s 
  trip: consecutiveFailures >= 5

超过 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,电路将跳闸回到打开状态。

INFO[0030] Circuit breaker "order-processor:orders" changed state from open to half-open  
INFO[0030] Circuit breaker "order-processor:orders" changed state from half-open to open   
INFO[0030] Circuit breaker "order-processor:orders" changed state from open to half-open  
INFO[0030] Circuit breaker "order-processor:orders" changed state from half-open to open     

只要 order-processor 服务停止,这种半开/打开行为就会持续下去。

步骤 6:移除故障

重新启动 order-processor 服务后,应用程序将无缝恢复,从中断的地方继续接受订单请求。

order-processor 服务终端中,重新启动应用程序:

dapr run --app-port 8001 --app-id order-processor --app-protocol http --dapr-http-port 3501 -- python3 app.py

checkout 服务输出:

== APP == Order passed: {"orderId": 5}
== APP == Order passed: {"orderId": 6}
== APP == Order passed: {"orderId": 7}
== APP == Order passed: {"orderId": 8}
== APP == Order passed: {"orderId": 9}
== APP == Order passed: {"orderId": 10}

order-processor 服务输出:

== APP == Order received: {"orderId": 5}
== APP == Order received: {"orderId": 6}
== APP == Order received: {"orderId": 7}
== APP == Order received: {"orderId": 8}
== APP == Order received: {"orderId": 9}
== APP == Order received: {"orderId": 10}

前置条件

对于此示例,您需要:

步骤 1:设置环境

克隆 Quickstarts 仓库中提供的示例

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

步骤 2:运行 order-processor 服务

在终端窗口中,从快速入门目录的根目录导航到 order-processor 目录。

cd service_invocation/javascript/http/order-processor

安装依赖:

npm install

运行 order-processor 服务以及 Dapr 边车。

dapr run --app-port 5001 --app-id order-processor --resources-path ../../../resources/ --app-protocol http --dapr-http-port 3501 -- npm start

步骤 3:运行 checkout 服务应用程序

在新的终端窗口中,从快速入门目录的根目录导航到 checkout 目录。

cd service_invocation/javascript/http/checkout

安装依赖:

npm install

运行 checkout 服务以及 Dapr 边车。

dapr run --app-id checkout --resources-path ../../../resources/ --app-protocol http --dapr-http-port 3500 -- npm start

然后 Dapr 边车将加载位于 resources 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

步骤 4:查看服务调用输出

当两个服务和边车都在运行时,注意订单是如何使用 Dapr 服务调用从 checkout 服务传递到 order-processor 服务的。

checkout 服务输出:

== APP == Order passed: {"orderId": 1}
== APP == Order passed: {"orderId": 2}
== APP == Order passed: {"orderId": 3}
== APP == Order passed: {"orderId": 4}

order-processor 服务输出:

== APP == Order received: {"orderId": 1}
== APP == Order received: {"orderId": 2}
== APP == Order received: {"orderId": 3}
== APP == Order received: {"orderId": 4}

步骤 5:引入故障

通过停止 order-processor 服务来模拟故障。一旦实例停止,来自 checkout 服务的服务调用操作将开始失败。

由于 resiliency.yaml 规范将 order-processor 服务定义为弹性目标,所有失败的请求都将应用重试和断路器策略:

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

order-processor 窗口中,停止服务:

CMD + C
CTRL + C

一旦第一个请求失败,将应用名为 retryForever 的重试策略:

INFO[0005] Error processing operation endpoint[order-processor, order-processor:orders]. Retrying...  

对于每个失败的请求,重试将以 5 秒的间隔无限期继续。

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

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

INFO[0025] Circuit breaker "order-processor:orders" changed state from closed to open  
circuitBreakers:
  simpleCB:
  maxRequests: 1
  timeout: 5s 
  trip: consecutiveFailures >= 5

超过 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,电路将跳闸回到打开状态。

INFO[0030] Circuit breaker "order-processor:orders" changed state from open to half-open  
INFO[0030] Circuit breaker "order-processor:orders" changed state from half-open to open   
INFO[0030] Circuit breaker "order-processor:orders" changed state from open to half-open  
INFO[0030] Circuit breaker "order-processor:orders" changed state from half-open to open     

只要 Redis 容器停止,这种半开/打开行为就会持续下去。

步骤 6:移除故障

重新启动 order-processor 服务后,应用程序将无缝恢复,从中断的地方继续。

order-processor 服务终端中,重新启动应用程序:

dapr run --app-port 5001 --app-id order-processor --resources-path ../../../resources/ --app-protocol http --dapr-http-port 3501 -- npm start

checkout 服务输出:

== APP == Order passed: {"orderId": 5}
== APP == Order passed: {"orderId": 6}
== APP == Order passed: {"orderId": 7}
== APP == Order passed: {"orderId": 8}
== APP == Order passed: {"orderId": 9}
== APP == Order passed: {"orderId": 10}

order-processor 服务输出:

== APP == Order received: {"orderId": 5}
== APP == Order received: {"orderId": 6}
== APP == Order received: {"orderId": 7}
== APP == Order received: {"orderId": 8}
== APP == Order received: {"orderId": 9}
== APP == Order received: {"orderId": 10}

前置条件

对于此示例,您需要:

步骤 1:设置环境

克隆 Quickstarts 仓库中提供的示例

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

步骤 2:运行 order-processor 服务

在终端窗口中,从快速入门目录的根目录导航到 order-processor 目录。

cd service_invocation/csharp/http/order-processor

安装依赖:

dotnet restore
dotnet build

运行 order-processor 服务以及 Dapr 边车。

dapr run --app-port 7001 --app-id order-processor --resources-path ../../../resources/ --app-protocol http --dapr-http-port 3501 -- dotnet run

步骤 3:运行 checkout 服务应用程序

在新的终端窗口中,从快速入门目录的根目录导航到 checkout 目录。

cd service_invocation/csharp/http/checkout

安装依赖:

dotnet restore
dotnet build

运行 checkout 服务以及 Dapr 边车。

dapr run --app-id checkout --resources-path ../../../resources/ --app-protocol http --dapr-http-port 3500 -- dotnet run

然后 Dapr 边车将加载位于 resources 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

步骤 4:查看服务调用输出

当两个服务和边车都在运行时,注意订单是如何使用 Dapr 服务调用从 checkout 服务传递到 order-processor 服务的。

checkout 服务输出:

== APP == Order passed: {"orderId": 1}
== APP == Order passed: {"orderId": 2}
== APP == Order passed: {"orderId": 3}
== APP == Order passed: {"orderId": 4}

order-processor 服务输出:

== APP == Order received: {"orderId": 1}
== APP == Order received: {"orderId": 2}
== APP == Order received: {"orderId": 3}
== APP == Order received: {"orderId": 4}

步骤 5:引入故障

通过停止 order-processor 服务来模拟故障。一旦实例停止,来自 checkout 服务的服务调用操作将开始失败。

由于 resiliency.yaml 规范将 order-processor 服务定义为弹性目标,所有失败的请求都将应用重试和断路器策略:

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

order-processor 窗口中,停止服务:

CMD + C
CTRL + C

一旦第一个请求失败,将应用名为 retryForever 的重试策略:

INFO[0005] Error processing operation endpoint[order-processor, order-processor:orders]. Retrying...  

对于每个失败的请求,重试将以 5 秒的间隔无限期继续。

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

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

INFO[0025] Circuit breaker "order-processor:orders" changed state from closed to open  
circuitBreakers:
  simpleCB:
  maxRequests: 1
  timeout: 5s 
  trip: consecutiveFailures >= 5

超过 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,电路将跳闸回到打开状态。

INFO[0030] Circuit breaker "order-processor:orders" changed state from open to half-open  
INFO[0030] Circuit breaker "order-processor:orders" changed state from half-open to open   
INFO[0030] Circuit breaker "order-processor:orders" changed state from open to half-open  
INFO[0030] Circuit breaker "order-processor:orders" changed state from half-open to open     

只要 Redis 容器停止,这种半开/打开行为就会持续下去。

步骤 6:移除故障

重新启动 order-processor 服务后,应用程序将无缝恢复,从中断的地方继续。

order-processor 服务终端中,重新启动应用程序:

dapr run --app-port 7001 --app-id order-processor --app-protocol http --dapr-http-port 3501 -- dotnet run

checkout 服务输出:

== APP == Order passed: {"orderId": 5}
== APP == Order passed: {"orderId": 6}
== APP == Order passed: {"orderId": 7}
== APP == Order passed: {"orderId": 8}
== APP == Order passed: {"orderId": 9}
== APP == Order passed: {"orderId": 10}

order-processor 服务输出:

== APP == Order received: {"orderId": 5}
== APP == Order received: {"orderId": 6}
== APP == Order received: {"orderId": 7}
== APP == Order received: {"orderId": 8}
== APP == Order received: {"orderId": 9}
== APP == Order received: {"orderId": 10}

前置条件

对于此示例,您需要:

步骤 1:设置环境

克隆 Quickstarts 仓库中提供的示例

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

步骤 2:运行 order-processor 服务

在终端窗口中,从快速入门目录的根目录导航到 order-processor 目录。

cd service_invocation/java/http/order-processor

安装依赖:

mvn clean install

运行 order-processor 服务以及 Dapr 边车。

dapr run --app-id order-processor --resources-path ../../../resources/ --app-port 9001 --app-protocol http --dapr-http-port 3501 -- java -jar target/OrderProcessingService-0.0.1-SNAPSHOT.jar

步骤 3:运行 checkout 服务应用程序

在新的终端窗口中,从快速入门目录的根目录导航到 checkout 目录。

cd service_invocation/java/http/checkout

安装依赖:

mvn clean install

运行 checkout 服务以及 Dapr 边车。

dapr run --app-id checkout --resources-path ../../../resources/ --app-protocol http --dapr-http-port 3500 -- java -jar target/CheckoutService-0.0.1-SNAPSHOT.jar

然后 Dapr 边车将加载位于 resources 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

步骤 4:查看服务调用输出

当两个服务和边车都在运行时,注意订单是如何使用 Dapr 服务调用从 checkout 服务传递到 order-processor 服务的。

checkout 服务输出:

== APP == Order passed: {"orderId": 1}
== APP == Order passed: {"orderId": 2}
== APP == Order passed: {"orderId": 3}
== APP == Order passed: {"orderId": 4}

order-processor 服务输出:

== APP == Order received: {"orderId": 1}
== APP == Order received: {"orderId": 2}
== APP == Order received: {"orderId": 3}
== APP == Order received: {"orderId": 4}

步骤 5:引入故障

通过停止 order-processor 服务来模拟故障。一旦实例停止,来自 checkout 服务的服务调用操作将开始失败。

由于 resiliency.yaml 规范将 order-processor 服务定义为弹性目标,所有失败的请求都将应用重试和断路器策略:

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

order-processor 窗口中,停止服务:

CMD + C
CTRL + C

一旦第一个请求失败,将应用名为 retryForever 的重试策略:

INFO[0005] Error processing operation endpoint[order-processor, order-processor:orders]. Retrying...  

对于每个失败的请求,重试将以 5 秒的间隔无限期继续。

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

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

INFO[0025] Circuit breaker "order-processor:orders" changed state from closed to open  
circuitBreakers:
  simpleCB:
  maxRequests: 1
  timeout: 5s 
  trip: consecutiveFailures >= 5

超过 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,电路将跳闸回到打开状态。

INFO[0030] Circuit breaker "order-processor:orders" changed state from open to half-open  
INFO[0030] Circuit breaker "order-processor:orders" changed state from half-open to open   
INFO[0030] Circuit breaker "order-processor:orders" changed state from open to half-open  
INFO[0030] Circuit breaker "order-processor:orders" changed state from half-open to open     

只要 Redis 容器停止,这种半开/打开行为就会持续下去。

步骤 6:移除故障

重新启动 order-processor 服务后,应用程序将无缝恢复,从中断的地方继续。

order-processor 服务终端中,重新启动应用程序:

dapr run --app-id order-processor --resources-path ../../../resources/ --app-port 9001 --app-protocol http --dapr-http-port 3501 -- java -jar target/OrderProcessingService-0.0.1-SNAPSHOT.jar

checkout 服务输出:

== APP == Order passed: {"orderId": 5}
== APP == Order passed: {"orderId": 6}
== APP == Order passed: {"orderId": 7}
== APP == Order passed: {"orderId": 8}
== APP == Order passed: {"orderId": 9}
== APP == Order passed: {"orderId": 10}

order-processor 服务输出:

== APP == Order received: {"orderId": 5}
== APP == Order received: {"orderId": 6}
== APP == Order received: {"orderId": 7}
== APP == Order received: {"orderId": 8}
== APP == Order received: {"orderId": 9}
== APP == Order received: {"orderId": 10}

前置条件

对于此示例,您需要:

步骤 1:设置环境

克隆 Quickstarts 仓库中提供的示例

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

步骤 2:运行 order-processor 服务

在终端窗口中,从快速入门目录的根目录导航到 order-processor 目录。

cd service_invocation/go/http/order-processor

安装依赖:

go build .

运行 order-processor 服务以及 Dapr 边车。

dapr run --app-port 6001 --app-id order-processor --resources-path ../../../resources/ --app-protocol http --dapr-http-port 3501 -- go run .

步骤 3:运行 checkout 服务应用程序

在新的终端窗口中,从快速入门目录的根目录导航到 checkout 目录。

cd service_invocation/go/http/checkout

安装依赖:

go build .

运行 checkout 服务以及 Dapr 边车。

dapr run --app-id checkout --resources-path ../../../resources/ --app-protocol http --dapr-http-port 3500 -- go run .

然后 Dapr 边车将加载位于 resources 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

步骤 4:查看服务调用输出

当两个服务和边车都在运行时,注意订单是如何使用 Dapr 服务调用从 checkout 服务传递到 order-processor 服务的。

checkout 服务输出:

== APP == Order passed: {"orderId": 1}
== APP == Order passed: {"orderId": 2}
== APP == Order passed: {"orderId": 3}
== APP == Order passed: {"orderId": 4}

order-processor 服务输出:

== APP == Order received: {"orderId": 1}
== APP == Order received: {"orderId": 2}
== APP == Order received: {"orderId": 3}
== APP == Order received: {"orderId": 4}

步骤 5:引入故障

通过停止 order-processor 服务来模拟故障。一旦实例停止,来自 checkout 服务的服务调用操作将开始失败。

由于 resiliency.yaml 规范将 order-processor 服务定义为弹性目标,所有失败的请求都将应用重试和断路器策略:

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

order-processor 窗口中,停止服务:

CMD + C
CTRL + C

一旦第一个请求失败,将应用名为 retryForever 的重试策略:

INFO[0005] Error processing operation endpoint[order-processor, order-processor:orders]. Retrying...  

对于每个失败的请求,重试将以 5 秒的间隔无限期继续。

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

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

INFO[0025] Circuit breaker "order-processor:orders" changed state from closed to open  
circuitBreakers:
  simpleCB:
  maxRequests: 1
  timeout: 5s 
  trip: consecutiveFailures >= 5

超过 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,电路将跳闸回到打开状态。

INFO[0030] Circuit breaker "order-processor:orders" changed state from open to half-open  
INFO[0030] Circuit breaker "order-processor:orders" changed state from half-open to open   
INFO[0030] Circuit breaker "order-processor:orders" changed state from open to half-open  
INFO[0030] Circuit breaker "order-processor:orders" changed state from half-open to open     

只要 Redis 容器停止,这种半开/打开行为就会持续下去。

步骤 6:移除故障

重新启动 order-processor 服务后,应用程序将无缝恢复,从中断的地方继续。

order-processor 服务终端中,重新启动应用程序:

dapr run --app-port 6001 --app-id order-processor --resources-path ../../../resources/ --app-protocol http --dapr-http-port 3501 -- go run .

checkout 服务输出:

== APP == Order passed: {"orderId": 5}
== APP == Order passed: {"orderId": 6}
== APP == Order passed: {"orderId": 7}
== APP == Order passed: {"orderId": 8}
== APP == Order passed: {"orderId": 9}
== APP == Order passed: {"orderId": 10}

order-processor 服务输出:

== APP == Order received: {"orderId": 5}
== APP == Order received: {"orderId": 6}
== APP == Order received: {"orderId": 7}
== APP == Order received: {"orderId": 8}
== APP == Order received: {"orderId": 9}
== APP == Order received: {"orderId": 10}

告诉我们您的想法!

我们正在不断努力改进我们的快速入门示例,重视您的反馈。您觉得这个快速入门有帮助吗?您有改进建议吗?

加入我们的 discord 频道 进行讨论。

下一步

访问 此链接 以获取有关 Dapr 弹性的更多信息。

探索 Dapr 教程 >>