Write a Flow

Now that you have created your flow library, it's time to create your first Flow. We will create a simple flow called QuickstartFlow.

What is a flow?

A Flow is Didact's term for a background job. The flow consists of both metadata and orchestration behavior configurations as well as the actual background job logic.

KISS

See Flows Overview to learn more.

Create flow class

First, create a new C# class called QuickstartFlow.

Implement IFlow interface

Next, add a reference to the DidactCore.Flows namespace and implement the IFlow interface onto your class:

using DidactCore.Flows;

public class QuickstartFlow : IFlow

The interface requires two method implementations to complete a flow definition:

• ConfigureAsync for setting up the flow's metadata and orchestration behavior.
• ExecuteAsync for defining the flow's background job logic.

ConfigureAsync

The configure method sets up important metadata and orchestration behavior for the flow. This method is executed by Didact Engine when it absorbs a flow library deployment.

The method is provided a context object with several utilies, the most important of which is the IFlowConfigurationContext.Configurator. The flow's metadata and and orchestration behavior is set by calling fluent API methods against this provided configurator object.

The most important and minimally-essential metadata to define is the flow's Name using the .WithName() method on the configurator:

public class QuickstartFlow : IFlow
{
    public Task ConfigureAsync(IFlowConfigurationContext context)
    {
        context.Configurator
            .WithName("quickstart-flow");

        return Task.CompletedTask;
    }
}

Don't forget the name!

Flow names are absolutely required and must be unique per Didact environment.

ExecuteAsync

The execute method defines the actual background job code for the flow. Similar to the configure method, it is provided its own context object. The context object comes with useful tools like read-only metadata, an ILogger, and a CancellationToken, among other utilities.

To keep QuickstartFlow simple, let's use the context logger and simulate work being done:

public class QuickstartFlow : IFlow
{
    public async Task ExecuteAsync(IFlowExecutionContext context)
    {
        context.Logger.LogInformation("Simulating work...");
        await Task.Delay(1000);
    }
}

Complete definition

Now let's combine both code snippets to create a fully-formed flow:

public class QuickstartFlow : IFlow
{
    public Task ConfigureAsync(IFlowConfigurationContext context)
    {
        context.Configurator
            .WithName("some-flow");

        return Task.CompletedTask;
    }

    public async Task ExecuteAsync(IFlowExecutionContext context)
    {
        context.Logger.LogInformation("Simulating work...");
        await Task.Delay(1000);
    }
}