Dapr Workflow .NET SDK on Dapr Docs

DaprWorkflowClient lifetime management and registration

Mon, 01 Jan 0001 00:00:00 +0000

Lifetime management

A DaprWorkflowClient holds access to networking resources in the form of TCP sockets used to communicate with the Dapr sidecar as well as other types used in the management and operation of Workflows. DaprWorkflowClient implements IAsyncDisposable to support eager cleanup of resources.

Dependency Injection

The AddDaprWorkflow() method will register the Dapr workflow services with ASP.NET Core dependency injection. This method requires an options delegate that defines each of the workflows and activities you wish to register and use in your application.

Workflow serialization in the .NET SDK

Mon, 01 Jan 0001 00:00:00 +0000

Overview

Starting with Dapr .NET SDK v1.17.0, Dapr.Workflow supports pluggable serialization. The SDK continues to use System.Text.Json by default, but you can now:

Override the default System.Text.Json settings.
Register a custom serializer (for example, MessagePack or BSON).

Serialization configuration is entirely client-side and does not require a specific Dapr runtime version.

Note

This feature requires Dapr .NET SDK v1.17.0 or later.

Compatibility and breaking changes

Warning

Changing serialization can be a breaking change for existing workflows. There is no supported migration path between serialization implementations.

Multi-application workflows in the .NET SDK

Mon, 01 Jan 0001 00:00:00 +0000

Overview

Dapr workflows can call activities or child workflows that are hosted in a different Dapr application. In .NET, multi-application workflows are supported starting with:

Dapr runtime v1.16.0+
Dapr .NET SDK v1.17.0+

Conceptual guidance and constraints are covered in Multi Application Workflows.

Requirements

Multi-application workflow calls require:

The target app ID must exist and must register the activity or workflow you invoke.
All participating app IDs must be in the same namespace.
All participating app IDs must use the same workflow (actor) state store.

Call an activity in another application

Set TargetAppId on WorkflowTaskOptions when calling an activity to execute it in another app:

Workflow management operations with DaprWorkflowClient

Mon, 01 Jan 0001 00:00:00 +0000

Workflow management operations with `DaprWorkflowClient`

The DaprWorkflowClient class provides methods to manage workflow instances. Below are the operations you can perform using the DaprWorkflowClient.

Schedule a new workflow instance

To start a new workflow instance, use the ScheduleNewWorkflowAsync method. This method requires the workflow type name and an input required by the workflow. The workflow instancedId is an optional argument; if not provided, a new GUID is generated by the DaprWorkflowClient. The final optional argument is a startTime of type DateTimeOffset which can be used to define when the workflow instance should start. The method returns the instanceId of the scheduled workflow which is used for other workflow management operations.

Workflow versioning in the .NET SDK

Mon, 01 Jan 0001 00:00:00 +0000

Overview

Dapr Workflow versioning lets you evolve workflows without breaking deterministic execution for in-flight instances. The .NET SDK supports two approaches:

Patch-based versioning: introduce conditional branches guarded by context.IsPatched("patch-name").
Name-based versioning: create a new workflow type name and let a versioning strategy select the newest version.

Use patch-based versioning for small, in-place changes. Use name-based versioning for larger refactors where you want a clean new workflow type.

Note

Workflow versioning requires Dapr .NET SDK v1.17.0 or later and Dapr runtime v1.17.0 or later.

When to use each approach

Patch-based versioning is a good fit when:

.NET Workflow Examples

Mon, 01 Jan 0001 00:00:00 +0000

Workflow tutorials in the Dapr Quickstarts repository

The Dapr Quickstarts repository on GitHub includes many workflow tutorials that showcase the various workflow patterns and how to use the workflow management operations. You can find these tutorials in the quickstarts/tutorials/workflow/csharp folder.

Workflow examples in the .NET SDK repository

The Dapr .NET SDK repository on GitHub contains several examples demonstrating how to use Dapr Workflows with .NET. You can find these examples in the examples/Workflow folder.