v3.1.0

Workflow Core 3.1.0

Decision Branching

You can define multiple independent branches within your workflow and select one based on an expression value.

For the fluent API, we define our branches with the CreateBranch() method on the workflow builder. We can then select a branch using the Branch method.

The select expressions will be matched to the branch listed via the Branch method, and the matching next step(s) will be scheduled to execute next.

This workflow will select branch1 if the value of data.Value1 is one, and branch2 if it is two.

var branch1 = builder.CreateBranch()
    .StartWith<PrintMessage>()
        .Input(step => step.Message, data => "hi from 1")
    .Then<PrintMessage>()
        .Input(step => step.Message, data => "bye from 1");

var branch2 = builder.CreateBranch()
    .StartWith<PrintMessage>()
        .Input(step => step.Message, data => "hi from 2")
    .Then<PrintMessage>()
        .Input(step => step.Message, data => "bye from 2");


builder
    .StartWith<HelloWorld>()
    .Decide(data => data.Value1)
        .Branch((data, outcome) => data.Value1 == "one", branch1)
        .Branch((data, outcome) => data.Value1 == "two", branch2);

The JSON representation would look somthing like this.

{
  "Id": "DecisionWorkflow",
  "Version": 1,
  "DataType": "MyApp.MyData, MyApp",
  "Steps": [
    {
      "Id": "decide",
      "StepType": "...",
      "SelectNextStep":
      {
        "Print1": "data.Value1 == \"one\"",
        "Print2": "data.Value1 == \"two\""
      }
    },
    {
      "Id": "Print1",
      "StepType": "MyApp.PrintMessage, MyApp",
      "Inputs": 
	  { 
		"Message": "\"Hello from 1\"" 
	  }
    },
    {
      "Id": "Print2",
      "StepType": "MyApp.PrintMessage, MyApp",
      "Inputs": 
	  { 
	    "Message": "\"Hello from 2\"" 
	  }
    }
  ]
}

Outcomes for JSON workflows

You can now specify OutcomeSteps for a step in JSON and YAML workflow definitions.

"SelectNextStep":
{
	"<<Step1 Id>>": "<<expression>>",
	"<<Step2 Id>>": "<<expression>>"
}

If the outcome of a step matches a particular expression, that step would be scheduled as the next step to execute.

v3.0.0

Workflow Core 3.0.0

Support for PostgeSQL is delayed because of this issue with upstream libraries

Split DSL into own package

The JSON and YAML definition features into their own package.

Migration required for existing projects:

• Install the WorkflowCore.DSL package from nuget.
• Call AddWorkflowDSL() on your service collection.

Activities

An activity is defined as an item on an external queue of work, that a workflow can wait for.

In this example the workflow will wait for activity-1, before proceeding. It also passes the value of data.Value1 to the activity, it then maps the result of the activity to data.Value2.

Then we create a worker to process the queue of activity items. It uses the GetPendingActivity method to get an activity and the data that a workflow is waiting for.

public class ActivityWorkflow : IWorkflow<MyData>
{
    public void Build(IWorkflowBuilder<MyData> builder)
    {
        builder                
            .StartWith<HelloWorld>()
            .Activity("activity-1", (data) => data.Value1)
                .Output(data => data.Value2, step => step.Result)
            .Then<PrintMessage>()
                .Input(step => step.Message, data => data.Value2);
    }
             
}
...

var activity = host.GetPendingActivity("activity-1", "worker1", TimeSpan.FromMinutes(1)).Result;

if (activity != null)
{
    Console.WriteLine(activity.Parameters);
    host.SubmitActivitySuccess(activity.Token, "Some response data");
}

The JSON representation of this step would look like this

{
    "Id": "activity-step",
    "StepType": "WorkflowCore.Primitives.Activity, WorkflowCore",
    "Inputs": 
    {
        "ActivityName": "\"activity-1\"",
        "Parameters": "data.Value1" 
    },
    "Outputs": { "Value2": "step.Result" }
}

v2.1.2

Workflow Core 2.1.2

• Adds a feature to purge old workflows from the persistence store.

New IWorkflowPurger service that can be injected from the IoC container

Task PurgeWorkflows(WorkflowStatus status, DateTime olderThan)

Implementations are currently only for SQL Server, Postgres and MongoDB

v2.1.0

Workflow Core 2.1.0

• Adds the SyncWorkflowRunner service that enables workflows to be executed synchronously, you can also avoid persisting the state to the persistence store entirely

usage

var runner = serviceProvider.GetService<ISyncWorkflowRunner>();
...
var worfklow = await runner.RunWorkflowSync("my-workflow", 1, data, TimeSpan.FromSeconds(10));

v2.0.0

Workflow Core 2.0.0

Upgrade notes

Existing JSON definitions will be loaded as follows

using WorkflowCore.Services.DefinitionStorage;
...
DefinitionLoader.LoadDefinition(json, Deserializers.Json);

• Targets .NET Standard 2.0

  The core library now targets .NET Standard 2.0, in order to leverage newer features.

• Support for YAML definitions

  Added support for YAML workflow definitions, which can be loaded as follows

  using WorkflowCore.Services.DefinitionStorage;
  ...
  DefinitionLoader.LoadDefinition(json, Deserializers.Yaml);

  Existing JSON definitions will be loaded as follows

  using WorkflowCore.Services.DefinitionStorage;
  ...
  DefinitionLoader.LoadDefinition(json, Deserializers.Json);

• Object graphs and inline expressions on input properties

  You can now pass object graphs to step inputs as opposed to just scalar values

  "inputs": 
  {    
    "Body": {
        "Value1": 1,
        "Value2": 2
    },
    "Headers": {
        "Content-Type": "application/json"
    }
  },
  

  If you want to evaluate an expression for a given property of your object, simply prepend and @ and pass an expression string

  "inputs": 
  {    
    "Body": {
        "@Value1": "data.MyValue * 2",
        "Value2": 5
    },
    "Headers": {
        "Content-Type": "application/json"
    }
  },
  

• Support for enum values on input properties

  If your step has an enum property, you can now just pass the string representation of the enum value and it will be automatically converted.

• Environment variables available in input expressions

  You can now access environment variables from within input expressions.
  usage:

  environment["VARIABLE_NAME"]
  

v1.9.3

Workflow Core 1.9.3

• Fixes the order of processing for multiple events with same name/key
• Adds UseMaxConcurrentWorkflows to WorkflowOptions to allow overriding the max number of concurrent workflows for a given node

v1.9.2

Workflow Core 1.9.2

Changes the default retry behavior for steps within a saga to bubble up to the saga container.
This means you do not have to explicitly set each step within the saga to Compensate.

v1.8.3

• Added Attach and Id to fluent API
  This will enable one to attach the flow from a step to any other step with an Id
  Control structure scope will be preserved

    .StartWith<Step1>()
        .Id("step1")
    .Then<Step2>()
    .Attach("step1")    

• Added index queue ahead of upcoming feature for async indexing
• Various performance improvements

v1.8.1

Workflow Core 1.8.1

Thank you to @MarioAndron

This release adds a feature where a DI scope is created around the construction of steps that are registered with your IoC container.

This enables steps to consume services registered as scoped.

v1.8

Workflow Core 1.8

Elasticsearch plugin for Workflow Core

A search index plugin for Workflow Core backed by Elasticsearch, enabling you to index your workflows and search against the data and state of them.

Configuration

Use the .UseElasticsearch extension method on IServiceCollection when building your service provider

using Nest;
...
services.AddWorkflow(cfg =>
{
	...
	cfg.UseElasticsearch(new ConnectionSettings(new Uri("http://localhost:9200")), "index_name");
});

Usage

Inject the ISearchIndex service into your code and use the Search method.

Search(string terms, int skip, int take, params SearchFilter[] filters)

terms

A whitespace separated string of search terms, an empty string will match everything.
This will do a full text search on the following default fields

• Reference
• Description
• Status
• Workflow Definition

In addition you can search data within your own custom data object if it implements ISearchable

using WorkflowCore.Interfaces;
...
public class MyData : ISearchable
{
   public string StrValue1 { get; set; }
   public string StrValue2 { get; set; }

   public IEnumerable<string> GetSearchTokens()
   {
       return new List<string>()
       {
           StrValue1,
           StrValue2
       };    
   }
}

Examples

Search all fields for "puppies"

searchIndex.Search("puppies", 0, 10);

skip & take

Use skip and take to page your search results. Where skip is the result number to start from and take is the page size.

filters

You can also supply a list of filters to apply to the search, these can be applied to both the standard fields as well as any field within your custom data objects.
There is no need to implement ISearchable on your data object in order to use filters against it.

The following filter types are available

• ScalarFilter
• DateRangeFilter
• NumericRangeFilter
• StatusFilter

These exist in the WorkflowCore.Models.Search namespace.

Examples

Filtering by reference

using WorkflowCore.Models.Search;
...

searchIndex.Search("", 0, 10, ScalarFilter.Equals(x => x.Reference, "My Reference"));

Filtering by workflows started after a date

searchIndex.Search("", 0, 10, DateRangeFilter.After(x => x.CreateTime, startDate));

Filtering by workflows completed within a period

searchIndex.Search("", 0, 10, DateRangeFilter.Between(x => x.CompleteTime, startDate, endDate));

Filtering by workflows in a state

searchIndex.Search("", 0, 10, StatusFilter.Equals(WorkflowStatus.Complete));

Filtering against your own custom data class

class MyData
{
   public string Value1 { get; set; }
   public int Value2 { get; set; }
}

searchIndex.Search("", 0, 10, ScalarFilter.Equals<MyData>(x => x.Value1, "blue moon"));
searchIndex.Search("", 0, 10, NumericRangeFilter.LessThan<MyData>(x => x.Value2, 5))

Action Inputs / Outputs

Added the action Input & Output overloads on the fluent step builder.

Input(Action<TStepBody, TData> action);

This will allow one to manipulate properties on the step before it executes and properties on the data object after it executes, for example

Input((step, data) => step.Value1 = data.Value1)

.Output((step, data) => data["Value3"] = step.Output)

.Output((step, data) => data.MyCollection.Add(step.Output))

Breaking changes

The existing ability to assign values to entries in dictionaries or dynamic objects on .Output was problematic,
since it broke the ability to pass collections on the Output mappings.

.Output(data => data["Value3"], step => step.Output)

This feature has been removed, and it is advised to use the action Output API instead, for example

.Output((step, data) => data["Value3"] = step.Output)

This functionality remains intact for JSON defined workflows.