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‎README.md

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@@ -53,7 +53,7 @@ public class MyWorkflow : IWorkflow
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}
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```
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* Resilient service orchestration
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* Saga Transactions
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```c#
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public class MyWorkflow : IWorkflow
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}
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```
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```c#
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builder
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.StartWith<LogStart>()
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.Saga(saga => saga
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.StartWith<Task1>()
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.CompensateWith<UndoTask1>()
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.Then<Task2>()
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.CompensateWith<UndoTask2>()
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.Then<Task3>()
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.CompensateWith<UndoTask3>()
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)
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.OnError(Models.WorkflowErrorHandling.Retry, TimeSpan.FromMinutes(10))
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.Then<LogEnd>();
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```
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## Persistence
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Since workflows are typically long running processes, they will need to be persisted to storage between steps.
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* [Parallel Tasks](src/samples/WorkflowCore.Sample13)
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* [Saga Transactions (with compensation)](src/samples/WorkflowCore.Sample17)
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* [Scheduled Background Tasks](src/samples/WorkflowCore.Sample16)
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* [Recurring Background Tasks](src/samples/WorkflowCore.Sample14)

‎ReleaseNotes/1.6.0.md

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#### Specifying compensation steps for each component of a saga transaction
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In this sample, if `Task2` throws an exception, then `UndoTask2` and `UndoTask1` will be triggered.
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```c#
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builder
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.StartWith<SayHello>()
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#### Retrying a failed transaction
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This particular example will retry the entire saga every 5 seconds
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```c#
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builder
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.StartWith<SayHello>()
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#### Compensating the entire transaction
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You could also only specify a master compensation step, as follows
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```c#
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builder
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.StartWith<SayHello>()
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```c#
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builder
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.StartWith<SayHello>()
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.CompensateWith<CustomMessage>(compensate =>
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.CompensateWith<PrintMessage>(compensate =>
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{
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compensate.Input(step => step.Message, data => "undoing...");
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})

‎src/samples/WorkflowCore.Sample17/CompensatingWorkflow.cs

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@@ -15,26 +15,17 @@ class CompensatingWorkflow : IWorkflow
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public void Build(IWorkflowBuilder<object> builder)
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{
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builder
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.StartWith(context => Console.WriteLine("Hello"))
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.CompensateWith(context => Console.WriteLine("undo hello"))
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.StartWith(context => Console.WriteLine("Begin"))
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.Saga(saga => saga
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.StartWith(context => Console.WriteLine("1"))
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.CompensateWith(context => Console.WriteLine("undo 1"))
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.Then(context =>
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{
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Console.WriteLine("2");
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throw new Exception("boo");
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Console.WriteLine("2.5");
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})
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.CompensateWith<CustomMessage>(x => x.Input(step => step.Message, data => "undo 2"))
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.Then(context => Console.WriteLine("3"))
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)
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//.CompensateWithSequence(comp => comp
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// .StartWith(ctx => Console.WriteLine("fail saga1"))
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// .Then(ctx => Console.WriteLine("fail saga2"))
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// )
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.OnError(Models.WorkflowErrorHandling.Retry, TimeSpan.FromSeconds(5))
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.Then(context => Console.WriteLine("end"));
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.StartWith<Task1>()
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.CompensateWith<UndoTask1>()
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.Then<Task2>()
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.CompensateWith<UndoTask2>()
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.Then<Task3>()
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.CompensateWith<UndoTask3>()
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)
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.OnError(Models.WorkflowErrorHandling.Retry, TimeSpan.FromSeconds(5))
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.Then(context => Console.WriteLine("End"));
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}
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}
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}

‎src/samples/WorkflowCore.Sample17/Program.cs

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//setup dependency injection
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IServiceCollection services = new ServiceCollection();
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services.AddLogging();
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//services.AddWorkflow();
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services.AddWorkflow(x => x.UseMongoDB(@"mongodb://localhost:27017", "workflow"));
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services.AddWorkflow();
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//services.AddWorkflow(x => x.UseMongoDB(@"mongodb://localhost:27017", "workflow"));
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//services.AddWorkflow(x => x.UseSqlServer(@"Server=.;Database=WorkflowCore;Trusted_Connection=True;", true, true));
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//services.AddWorkflow(x => x.UsePostgreSQL(@"Server=127.0.0.1;Port=5432;Database=workflow;User Id=postgres;", true, true));
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‎src/samples/WorkflowCore.Sample17/README.md

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# Saga transaction with compensation sample
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Illustrates how to encapsulate a sequence of steps within a saga transaction and specify compensation steps for each.
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In the sample, `Task2` will throw an exception, then `UndoTask2` and `UndoTask1` will be triggered.
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```c#
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builder
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.StartWith(context => Console.WriteLine("Begin"))
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.Saga(saga => saga
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.StartWith<Task1>()
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.CompensateWith<UndoTask1>()
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.Then<Task2>()
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.CompensateWith<UndoTask2>()
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.Then<Task3>()
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.CompensateWith<UndoTask3>()
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)
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.OnError(Models.WorkflowErrorHandling.Retry, TimeSpan.FromSeconds(5))
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.Then(context => Console.WriteLine("End"));
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```
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## Retry policy for failed saga transaction
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This particular example will retry the saga every 5 seconds, but you could also simply fail completely, and process a master compensation task for the whole saga.
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```c#
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builder
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.StartWith(context => Console.WriteLine("Begin"))
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.Saga(saga => saga
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.StartWith<Task1>()
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.CompensateWith<UndoTask1>()
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.Then<Task2>()
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.CompensateWith<UndoTask2>()
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.Then<Task3>()
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.CompensateWith<UndoTask3>()
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)
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.CompensateWith<CleanUp>()
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.Then(context => Console.WriteLine("End"));
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```
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## Compensate entire saga transaction
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You could also only specify a master compensation step, as follows
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```c#
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builder
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.StartWith(context => Console.WriteLine("Begin"))
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.Saga(saga => saga
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.StartWith<Task1>()
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.Then<Task2>()
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.Then<Task3>()
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)
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.CompensateWith<UndoEverything>()
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.Then(context => Console.WriteLine("End"));
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```
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## Passing parameters to compensation steps
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Parameters can be passed to a compensation step as follows
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```c#
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builder
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.StartWith<SayHello>()
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.CompensateWith<PrintMessage>(compensate =>
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{
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compensate.Input(step => step.Message, data => "undoing...");
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})
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```
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## Expressing a saga in JSON
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A saga transaction can be expressed in JSON, by using the `WorkflowCore.Primitives.Sequence` step and setting the `Saga` parameter to `true`.
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The compensation steps can be defined by specifying the `CompensateWith` parameter.
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```json
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{
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"Id": "Saga-Sample",
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"Version": 1,
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"DataType": "MyApp.MyDataClass, MyApp",
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"Steps": [
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{
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"Id": "Hello",
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"StepType": "MyApp.HelloWorld, MyApp",
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"NextStepId": "MySaga"
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},
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{
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"Id": "MySaga",
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"StepType": "WorkflowCore.Primitives.Sequence, WorkflowCore",
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"NextStepId": "Bye",
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"Saga": true,
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"Do": [
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[
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{
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"Id": "do1",
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"StepType": "MyApp.Task1, MyApp",
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"NextStepId": "do2",
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"CompensateWith": [
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{
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"Id": "undo1",
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"StepType": "MyApp.UndoTask1, MyApp"
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}
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]
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},
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{
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"Id": "do2",
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"StepType": "MyApp.Task2, MyApp",
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"CompensateWith": [
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{
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"Id": "undo2-1",
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"NextStepId": "undo2-2",
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"StepType": "MyApp.UndoTask2, MyApp"
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},
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{
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"Id": "undo2-2",
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"StepType": "MyApp.DoSomethingElse, MyApp"
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}
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]
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}
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]
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]
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},
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{
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"Id": "Bye",
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"StepType": "MyApp.GoodbyeWorld, MyApp"
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}
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]
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}
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```

‎src/samples/WorkflowCore.Sample17/Steps/Task1.cs

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using System;
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using WorkflowCore.Interface;
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using WorkflowCore.Models;
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namespace WorkflowCore.Sample17.Steps
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{
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public class Task1 : StepBody
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{
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public override ExecutionResult Run(IStepExecutionContext context)
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{
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Console.WriteLine("Doing Task 1");
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return ExecutionResult.Next();
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}
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}
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}

‎src/samples/WorkflowCore.Sample17/Steps/Task2.cs

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using System;
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using WorkflowCore.Interface;
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using WorkflowCore.Models;
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namespace WorkflowCore.Sample17.Steps
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{
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public class Task2 : StepBody
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{
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public override ExecutionResult Run(IStepExecutionContext context)
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{
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Console.WriteLine("Doing Task 2");
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throw new Exception();
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}
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}
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}

‎src/samples/WorkflowCore.Sample17/Steps/Task3.cs

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using System;
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using WorkflowCore.Interface;
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using WorkflowCore.Models;
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namespace WorkflowCore.Sample17.Steps
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{
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public class Task3 : StepBody
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{
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public override ExecutionResult Run(IStepExecutionContext context)
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{
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Console.WriteLine("Doing Task 3");
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return ExecutionResult.Next();
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}
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}
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}

‎src/samples/WorkflowCore.Sample17/Steps/UndoTask1.cs

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using System;
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using WorkflowCore.Interface;
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using WorkflowCore.Models;
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namespace WorkflowCore.Sample17.Steps
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{
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public class UndoTask1 : StepBody
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{
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public override ExecutionResult Run(IStepExecutionContext context)
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{
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Console.WriteLine("Undoing Task 1");
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return ExecutionResult.Next();
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}
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}
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}

‎src/samples/WorkflowCore.Sample17/Steps/UndoTask2.cs

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using System;
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using WorkflowCore.Interface;
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using WorkflowCore.Models;
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namespace WorkflowCore.Sample17.Steps
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{
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public class UndoTask2 : StepBody
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{
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public override ExecutionResult Run(IStepExecutionContext context)
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{
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Console.WriteLine("Undoing Task 2");
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return ExecutionResult.Next();
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}
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}
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}

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