Dapr Workflow构建块的.NET Demo

Dapr 1.10版本中带来了最有亮点的特性就是工作流构建块的的发布，虽然是Alpha 阶段，可以让我们尽早在应用系统中规划工作流， 在使用Dapr的系统中更好的编写负责的分布式应用系统。Dapr 工作流使你能够生成跨多个应用的长时间运行的持久进程或数据流。 Dapr 工作流可以与其他 Dapr API 构建基块结合使用。例如，工作流可以通过服务调用调用另一个服务、触发绑定或检索机密，从而使您能够编排和构建复杂的应用程序方案。

Dapr 工作流构建块的提案早在2022年的5月份提出，计划在 Dapr Runtime 中构建工作流引擎，社区反映非常积极。这个提案（https://github.com/dapr/dapr/issues/4576）内容比较长 ，敖小剑 有一个翻译的中文版：https://cn.dapr.io/post/202206-dapr-workflow-proposal/。在Alpha版本里完成了以下内容：

• 内置工作流引擎将作为初始预览功能提供 ，这个内置工作流引擎是Azure 上的 持久任务框架 （DTF），在在Azure 基础设施有大量的应用，它是用.NET 编写的。Dapr团队正在把这个实践抽象成工作流构建块，基于Dapr Actor构建块来实现。 Beta 版本会实现 Logic Apps 作为工作流引擎，当然还有更多的工作流引擎可以集成进入Dapr Workflow构建块里。
• API 将支持 3 种方法（启动、停止、获取状态）的工作流管理
• API 将作为 alpha 版发布
• 内置引擎的 API 支持
• 创作 SDK 将支持：.NET
• 管理 API SDK 将支持：.NET
• 文档，详细的介绍了Dapr Workflow构建块的工作原理等，推荐大家详细的看一看：https://docs.dapr.io/developing-applications/building-blocks/workflow/workflow-overview/
• 代码示例（.NET ），快速入门文档里包含了。

Dapr 工作流构建块目前是alpha版本，自然是有很多限制的，不推荐应用于生产环境中，至少等到beta版本时再考虑应用于生产，通常应用于生产环境的组件都是stable 版本的。Dapr Workflow 构建块让我们看到了他的潜力，Dapr Actor 模块基本上.NET圈子用的多，在其他java，go等用的很少，工作流模块组合上 Actor 构建块会让Dapr 上一个台阶，和其他类似框架的领先度进一步加大。我们常说“ 技术总是在短期内被高估，但是在长期又被低估。” 再来看看这句话，短期内被高估是因为在短期内的需求所迫，长期内被低估是因为技术的隐形需求要比实际上的业务务求多得多。

作为开发者，你需要考虑你将要投身的技术领域长期的隐形成本与试错成本。再者，投入到某个技术领域中其实不能走马观花，而要长期以往的进行深入研究与学习，才能获取更高的技术视野。Dapr 作为云原生时代的开发框架值得投入进去深入研究和学习。

在Dapr的 components-contrib 仓库里 也有一个 https://github.com/dapr/components-contrib/tree/master/workflows ，其中包含了一个分布式调度框架

Temporal https://github.com/temporalio/temporal 的一个组件实现。

现在 可以使用 .NET SDK 体验 Dapr 工作流，在Dapr 工作流的快速入门文档里包含了.NET 的示例，创建一个简单的控制台应用程序来演示 Dapr 的工作流编程模型和工作流管理 API。

控制台应用order-processor 启动并管理在状态存储中存储和检索数据的工作流的生命周期。工作流OrderProcessingWorkflow 由四个工作流活动或任务组成：

• NotifyActivity：利用记录器在整个工作流程中打印出消息
• ReserveInventoryActivity：检查状态存储以确保有足够的库存供购买
• ProcessPaymentActivity：处理和授权付款
• UpdateInventoryActivity：从状态存储中删除请求的物料，并使用新的剩余库存值更新存储

快速入门存储库中提供的示例代码。仓库地址： https://github.com/dapr/quickstarts.git ，我们把它克隆到本地，进入到示例代码目录 order-processor：

cd workflows/csharp/sdk/order-processor

在终端中，与 Dapr Sidecar 一起启动订单处理器应用：dapr run --app-id order-processor dotnet run ，下面是一次完整运行的输出：

❯❯ order-processor git:(master)[docker-desktop] 15:05 dapr run --app-id order-processor dotnet run
Starting Dapr with id order-processor. HTTP Port: 1599. gRPC Port: 1600
Checking if Dapr sidecar is listening on HTTP port 1599
time="2023-02-18T15:05:30.4699685+08:00" level=info msg="starting Dapr Runtime -- version 1.10.0 -- commit 029ec8cb7a1c88ec5d222bc2b0d1d53541217f19" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime type=log ver=1.10.0
time="2023-02-18T15:05:30.470968+08:00" level=info msg="log level set to: info" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime type=log ver=1.10.0
time="2023-02-18T15:05:30.4739685+08:00" level=info msg="metrics server started on :1601/" app_id=order-processor instance=geffzhang-laptop scope=dapr.metrics type=log ver=1.10.0
time="2023-02-18T15:05:30.4950736+08:00" level=info msg="Resiliency configuration loaded." app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime type=log ver=1.10.0
time="2023-02-18T15:05:30.5000719+08:00" level=info msg="standalone mode configured" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime type=log ver=1.10.0
time="2023-02-18T15:05:30.5000719+08:00" level=info msg="app id: order-processor" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime type=log ver=1.10.0
time="2023-02-18T15:05:30.5010762+08:00" level=info msg="mTLS is disabled. Skipping certificate request and tls validation" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime type=log ver=1.10.0
time="2023-02-18T15:05:30.5030734+08:00" level=info msg="Dapr trace sampler initialized: DaprTraceSampler(P=1.000000)" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime type=log ver=1.10.0
time="2023-02-18T15:05:30.5862994+08:00" level=info msg="local service entry announced: order-processor -> 192.168.1.6:1602" app_id=order-processor component="mdns (nameResolution/v1)" instance=geffzhang-laptop scope=dapr.contrib type=log ver=1.10.0
time="2023-02-18T15:05:30.5878674+08:00" level=info msg="Initialized name resolution to mdns" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime type=log ver=1.10.0
time="2023-02-18T15:05:30.5892504+08:00" level=info msg="loading components" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime type=log ver=1.10.0
time="2023-02-18T15:05:30.6287701+08:00" level=info msg="component loaded. name: pubsub, type: pubsub.redis/v1" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime type=log ver=1.10.0
time="2023-02-18T15:05:30.6291486+08:00" level=info msg="waiting for all outstanding components to be processed" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime type=log ver=1.10.0
time="2023-02-18T15:05:30.6400323+08:00" level=info msg="detected actor state store: statestore" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime type=log ver=1.10.0
time="2023-02-18T15:05:30.6400323+08:00" level=info msg="component loaded. name: statestore, type: state.redis/v1" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime type=log ver=1.10.0
time="2023-02-18T15:05:30.6400323+08:00" level=info msg="all outstanding components processed" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime type=log ver=1.10.0
time="2023-02-18T15:05:30.6405641+08:00" level=info msg="gRPC proxy enabled" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime type=log ver=1.10.0
time="2023-02-18T15:05:30.6426739+08:00" level=info msg="gRPC server listening on TCP address: :1600" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.grpc.api type=log ver=1.10.0
time="2023-02-18T15:05:30.6431919+08:00" level=info msg="Enabled gRPC tracing middleware" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.grpc.api type=log ver=1.10.0
time="2023-02-18T15:05:30.6437283+08:00" level=info msg="Enabled gRPC metrics middleware" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.grpc.api type=log ver=1.10.0
time="2023-02-18T15:05:30.6491391+08:00" level=info msg="configuring workflow engine gRPC endpoint" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.wfengine type=log ver=1.10.0
time="2023-02-18T15:05:30.6506026+08:00" level=info msg="API gRPC server is running on port 1600" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime type=log ver=1.10.0
time="2023-02-18T15:05:30.6570537+08:00" level=info msg="enabled metrics http middleware" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.http type=log ver=1.10.0
time="2023-02-18T15:05:30.6570537+08:00" level=info msg="enabled tracing http middleware" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.http type=log ver=1.10.0
time="2023-02-18T15:05:30.6575707+08:00" level=info msg="HTTP server listening on TCP address: :1599" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.http type=log ver=1.10.0
time="2023-02-18T15:05:30.6580969+08:00" level=info msg="http server is running on port 1599" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime type=log ver=1.10.0
time="2023-02-18T15:05:30.6586808+08:00" level=info msg="The request body size parameter is: 4" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime type=log ver=1.10.0
time="2023-02-18T15:05:30.6592257+08:00" level=info msg="gRPC server listening on TCP address: :1602" app_id=order-processor instance=geffzhang-lapance=geffzhang-laptop scope=dapr.runtime type=log ver=1.10.0
time="2023-02-18T15:05:30.6921456+08:00" level=info msg="dapr initialized. Status: Running. Init Elapsed 192ms" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime type=log ver=1.10.0
time="2023-02-18T15:05:30.7694178+08:00" level=info msg="placement tables updated, version: 0" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.actor.internal.placement type=log ver=1.10.0
Checking if Dapr sidecar is listening on GRPC port 1600Dapr sidecar is up and running.
Updating metadata for app command: dotnet runYou're up and running! Both Dapr and your app logs will appear here.

== APP == info: Microsoft.DurableTask[1]
== APP ==       Durable Task worker is connecting to sidecar at localhost:1600.
== APP == info: Microsoft.Hosting.Lifetime[0]
== APP ==       Application started. Press Ctrl+C to shut down.
== APP == info: Microsoft.Hosting.Lifetime[0]
== APP ==       Hosting environment: Production
== APP == info: Microsoft.Hosting.Lifetime[0]
== APP ==       Content root path: C:\Users\zsygz\Documents\GitHub\daprquickstarts\workflows\csharp\sdk\order-processor
== APP == Starting workflow 49caa2d7 purchasing 10 Cars
== APP == info: Microsoft.DurableTask.Client.Grpc.GrpcDurableTaskClient[40]
== APP ==       Scheduling new OrderProcessingWorkflow orchestration with instance ID '49caa2d7' and 47 bytes of input data.
time="2023-02-18T15:05:44.2802197+08:00" level=info msg="Error processing operation DaprBuiltInActorNotFoundRetries. Retrying in 1s…" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime type=log ver=1.10.0
== APP == info: Microsoft.DurableTask[4]
== APP ==       Sidecar work-item streaming connection established.
time="2023-02-18T15:05:44.3005331+08:00" level=info msg="work item stream established by user-agent: [grpc-dotnet/2.50.0 (.NET 6.0.13; CLR 6.0.13; net6.0; windows; x64)]" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.wfengine type=log ver=1.10.0
time="2023-02-18T15:05:44.3005331+08:00" level=info msg="worker started with backend dapr.actors/v1-alpha" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.wfengine type=log ver=1.10.0
time="2023-02-18T15:05:44.3010653+08:00" level=info msg="workflow engine started" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.wfengine type=log ver=1.10.0
time="2023-02-18T15:05:47.0119252+08:00" level=info msg="placement tables updated, version: 1" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.actor.internal.placement type=log ver=1.10.0
time="2023-02-18T15:05:47.2813299+08:00" level=info msg="Recovered processing operation DaprBuiltInActorNotFoundRetries." app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime type=log ver=1.10.0
time="2023-02-18T15:05:47.3016215+08:00" level=info msg="49caa2d7: starting new 'OrderProcessingWorkflow' instance." app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.wfengine type=log ver=1.10.0
time="2023-02-18T15:05:47.3980173+08:00" level=info msg="49caa2d7#0: loading activity state" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.wfengine type=log ver=1.10.0
time="2023-02-18T15:05:47.4054132+08:00" level=info msg="reminder \"start-6af4e78b\" was canceled by the actor" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.actor type=log ver=1.10.0
time="2023-02-18T15:05:47.4055923+08:00" level=info msg="Found reminder with key: dapr.internal.wfengine.workflow||49caa2d7||start-6af4e78b. Deleting reminder" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.actor type=log ver=1.10.0
== APP == info: WorkflowConsoleApp.Activities.NotifyActivity[0]
== APP ==       Received order 49caa2d7 for 10 Cars at $15000
time="2023-02-18T15:05:47.4244248+08:00" level=info msg="reminder \"run-activity\" was canceled by the actor" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.actor type=log ver=1.10.0
time="2023-02-18T15:05:47.4249645+08:00" level=info msg="Found reminder with key: dapr.internal.wfengine.activity||49caa2d7#0||run-activity. Deleting reminder" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.actor type=log ver=1.10.0
time="2023-02-18T15:05:47.4401806+08:00" level=info msg="49caa2d7#1: loading activity state" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.wfengine type=log ver=1.10.0
time="2023-02-18T15:05:47.4493286+08:00" level=info msg="reminder \"new-event-21a81b86\" was canceled by the actor" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.actor type=log ver=1.10.0
time="2023-02-18T15:05:47.4496796+08:00" level=info msg="Found reminder with key: dapr.internal.wfengine.workflow||49caa2d7||new-event-21a81b86. Deleting reminder" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.actor type=log ver=1.10.0
== APP == info: WorkflowConsoleApp.Activities.ReserveInventoryActivity[0]
== APP ==       Reserving inventory for order 49caa2d7 of 10 Cars
== APP == info: WorkflowConsoleApp.Activities.ReserveInventoryActivity[0]
== APP ==       There are: 100, Cars available for purchase
== APP == Your workflow has started. Here is the status of the workflow: Running
time="2023-02-18T15:05:49.4896663+08:00" level=info msg="reminder \"run-activity\" was canceled by the actor" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.actor type=log ver=1.10.0
time="2023-02-18T15:05:49.491597+08:00" level=info msg="Found reminder with key: dapr.internal.wfengine.activity||49caa2d7#1||run-activity. Deleting reminder" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.actor type=log ver=1.10.0
time="2023-02-18T15:05:49.5078761+08:00" level=info msg="49caa2d7#2: loading activity state" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.wfengine type=log ver=1.10.0
time="2023-02-18T15:05:49.5208857+08:00" level=info msg="reminder \"new-event-b34a7d49\" was canceled by the actor" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.actor type=log ver=1.10.0
time="2023-02-18T15:05:49.5276731+08:00" level=info msg="Found reminder with key: dapr.internal.wfengine.workflow||49caa2d7||new-event-b34a7d49. Deleting reminder" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.actor type=log ver=1.10.0
== APP == info: WorkflowConsoleApp.Activities.ProcessPaymentActivity[0]
== APP ==       Processing payment: 49caa2d7 for 10 Cars at $15000
== APP == info: WorkflowConsoleApp.Activities.ProcessPaymentActivity[0]
== APP ==       Payment for request ID '49caa2d7' processed successfully
time="2023-02-18T15:05:56.5412886+08:00" level=info msg="reminder \"run-activity\" was canceled by the actor" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.actor type=log ver=1.10.0
time="2023-02-18T15:05:56.5418687+08:00" level=info msg="49caa2d7#3: loading activity state" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.wfengine type=log ver=1.10.0
time="2023-02-18T15:05:56.5423941+08:00" level=info msg="Found reminder with key: dapr.internal.wfengine.activity||49caa2d7#2||run-activity. Deleting reminder" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.actor type=log ver=1.10.0
time="2023-02-18T15:05:56.551159+08:00" level=info msg="reminder \"new-event-ef938587\" was canceled by the actor" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.actor type=log ver=1.10.0
time="2023-02-18T15:05:56.5518012+08:00" level=info msg="Found reminder with key: dapr.internal.wfengine.workflow||49caa2d7||new-event-ef938587. Deleting reminder" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.actor type=log ver=1.10.0
== APP == info: WorkflowConsoleApp.Activities.UpdateInventoryActivity[0]
== APP ==       Checking Inventory for: Order# 49caa2d7 for 10 Cars
== APP == info: WorkflowConsoleApp.Activities.UpdateInventoryActivity[0]
== APP ==       There are now: 90 Cars left in stock
time="2023-02-18T15:06:01.5721469+08:00" level=info msg="reminder \"run-activity\" was canceled by the actor" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.actor type=log ver=1.10.0
time="2023-02-18T15:06:01.5727943+08:00" level=info msg="Found reminder with key: dapr.internal.wfengine.activity||49caa2d7#3||run-activity. Deleting reminder" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.actor type=log ver=1.10.0
time="2023-02-18T15:06:01.5741849+08:00" level=info msg="49caa2d7#4: loading activity state" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.wfengine type=log ver=1.10.0
== APP == info: WorkflowConsoleApp.Activities.NotifyActivity[0]
== APP ==       Order 49caa2d7 has completed!
time="2023-02-18T15:06:01.5835833+08:00" level=info msg="reminder \"new-event-d423d421\" was canceled by the actor" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.actor type=log ver=1.10.0
time="2023-02-18T15:06:01.5896839+08:00" level=info msg="Found reminder with key: dapr.internal.wfengine.workflow||49caa2d7||new-event-d423d421. Deleting reminder" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.actor type=log ver=1.10.0
time="2023-02-18T15:06:01.5919168+08:00" level=info msg="reminder \"run-activity\" was canceled by the actor" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.actor type=log ver=1.10.0
time="2023-02-18T15:06:01.597233+08:00" level=info msg="Found reminder with key: dapr.internal.wfengine.activity||49caa2d7#4||run-activity. Deleting reminder" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.actor type=log ver=1.10.0
time="2023-02-18T15:06:01.6004245+08:00" level=info msg="49caa2d7: 'OrderProcessingWorkflow' completed with a COMPLETED status." app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.wfengine type=log ver=1.10.0
time="2023-02-18T15:06:01.6048974+08:00" level=info msg="reminder \"new-event-61f53bff\" was canceled by the actor" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.actor type=log ver=1.10.0
time="2023-02-18T15:06:01.6054844+08:00" level=info msg="Found reminder with key: dapr.internal.wfengine.workflow||49caa2d7||new-event-61f53bff. Deleting reminder" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.actor type=log ver=1.10.0
== APP == Workflow Status: Completed
time="2023-02-18T15:06:03.434236+08:00" level=info msg="work item stream closed" app_id=order-processor instance=geffzhang-laptop scope=dapr.runtime.wfengine type=log ver=1.10.0
Exited App successfully

terminated signal received: shutting down
Exited Dapr successfully

这里面发生的事情大概如下：

1. 为工作流生成唯一的订单 ID（在上面的示例中为49caa2d7 ），并启动工作流。
2. 工作流活动NotifyActivity发送一条通知，指出已收到 10 辆汽车的订单。
3. 工作流活动ReserveInventoryActivity检查库存数据，确定您是否可以提供订购的物料，并使用库存中的汽车数量进行响应。
4. 您的工作流将启动并通知您其状态。
5. 工作流活动ProcessPaymentActivity开始处理订单49caa2d7 付款并确认是否成功。
6. 处理订单后，工作流活动UpdateInventoryActivity使用当前可用汽车更新库存。
7. 工作流活动NotifyActivity 发送一条通知，指出订单 49caa2d7 已完成。
8. 工作流在完成时终止。