Aurora.Workflows.Fluent 0.3.1.53

Aurora.Workflows.Fluent

A self-documenting, modern Fluent API for building Aurora Workflows in C#.
Design complex automation pipelines with readable, chainable syntax – including branching, loops, scopes, parallel execution, and error handling.

Installation

dotnet add package Aurora.Workflows.Fluent

The package targets .NET Standard 2.0 and works with .NET Framework 4.6.1+, .NET 6/7/8, and .NET Core 3.1+.

Quick Start

using Aurora.Workflows.Fluent;
using Aurora.Workflows.Tasks;

var workflow = FluentWorkflow
    .Create("Hello World")
    .TriggerOnce()
    .Print("Hello, Aurora Workflows!")
    .Build();

await workflow.StartAsync();

Core Concepts

API by Category

1. Workflow Creation & Metadata

var builder = FluentWorkflow
    .Create("My Workflow", loggerFactory)   // required entry point
    .WithName("Renamed Workflow")           // override name
    .WithTags("etl", "nightly")             // classification tags
    .ConfigureWorkflow(wf => { … });        // raw IWorkflow access

2. Triggers

builder
    .TriggerOnce()                                        // run immediately, once
    .TriggerPeriodic(TimeSpan.FromMinutes(5))             // recurring
    .TriggerOnSchedule("0 2 * * *", "Nightly")           // cron
    .TriggerOnFileChange(@"C:\Inbox", "*.csv", "CSV In") // file watcher
    .AddTrigger<MyCustomTrigger>(t => t.Param = "x");    // custom trigger type

3. Adding Tasks – Sequential (Do / Then)

.Do<T>() adds a child task under the implicit root StartTask and returns a new builder scoped to it. .Then is syntactic sugar that makes chaining more readable. You never need to create a StartTask manually – it is provided automatically by Create().

FluentWorkflow.Create("demo")
    .TriggerOnce()

    .ReadFile("data.csv", outputVariable: "raw")

    .Then.Set("clean", "context.Get<string>(\"raw\").Trim()")

    .Then.Print("Done!", ConsoleColor.Green)

    .Build();

4. Task Shortcuts

Common tasks have one-liner convenience methods so you don't need Do<T>() with a lambda:

// Variables
.Set("counter", "0")                              // alias for SetVariable()
.SetVariable("total", "a + b")

// File I/O
.ReadFile("input.csv", outputVariable: "raw")      // auto-quotes the path
.WriteFile("output.csv", inputVariable: "data")    // auto-quotes the path
.WriteFile("log.txt", append: true)                // append mode

// Expression-based variants (path evaluated at runtime)
.ReadFileExpression("context.Get<string>(\"dynamicPath\")")
.WriteFileExpression("config.OutputPath")

// Console output
.Print("Hello!", ConsoleColor.Cyan)                // static text
.PrintExpression("$\"Count: {myVar}\"")             // runtime expression

// Pause
.Wait(TimeSpan.FromSeconds(5))

All shortcuts return the task builder, so modifiers like .Retry(), .Named(), etc. chain naturally.

5. Branching – Parallel Siblings

.Do<StartTask>(t => t.Name = "Fan-Out")
    .Parallel(
        new ReadFileTask { Expression = "\"a.csv\"", Name = "Read A" },
        new ReadFileTask { Expression = "\"b.csv\"", Name = "Read B" })

    .Merge("Wait for all")           // AND-gate synchronization

    .Then.Print("All branches done")

6. Conditions – If / Else

The expression is evaluated at runtime by the Roslyn evaluator.

.If("context.Get<int>(\"count\") > 0",
    then:  t => t.Print("Has items",  ConsoleColor.Green),
    @else: e => e.Print("Empty list", ConsoleColor.Red),
    name: "Check Count")

7. Multi-way Branching – Switch

Chains nested ConditionQueryTask nodes (if / else-if / else).

.Switch(sw => sw
    .Case("score >= 90", b => b.Print("A"))
    .Case("score >= 70", b => b.Print("B"))
    .Case("score >= 50", b => b.Print("C"))
    .Default(            b => b.Print("F")),
    name: "Grade")

8. Loops

.Loop("context.Get<int>(\"i\") < 10", body => body
    .Do<SetVariableTask>(t =>
    {
        t.Expression = "context.Get<int>(\"i\") + 1";
        t.CustomOutputVariableName = "i";
    })
        .UseGlobalScopeForInput()
        .UseGlobalScopeForOutput(),
    name: "Count to 10")

9. Scopes – Throttle & OnChange

// Execute at most once per hour
.Throttle(TimeSpan.FromHours(1), body => body
    .Print("Throttled action"))

// Execute only when the config file changes
.OnChange("System.IO.File.ReadAllText(\"config.json\")", body => body
    .Print("Config changed – reloading!"))

10. Task Modifiers

Modifiers configure the current task and return this (no new builder is created).

.ReadFile("data.txt", outputVariable: "outputVar", name: "Load Data")
    .WithInput("inputVar")                       // bind input variable
    .Retry(TimeSpan.FromSeconds(3), maxRetries: 5)
    .IgnoreErrors()                              // continue on failure
    .WithErrorHandling(continueOnError: true, retryCount: 3)
    .WithDelay(before: TimeSpan.FromSeconds(1))
    .UseGlobalScopeForOutput()                   // variable scoping
    .UseParentScopeForInput()
    .BreakOnDebug()                              // debugger support
    .SkipOnDebug()

11. Extension Methods

Higher-order helpers available via FluentWorkflowExtensions:

// Chain pre-built tasks sequentially
.Chain(task1, task2, task3)

// Repeat a task N times
.Repeat<DebugOutputTask>(5, (t, i) => t.Expression = $"\"#{i}\"")

// ForEach over a collection
.ForEach<ReadFileTask, string>(files, (t, f) => t.Expression = $"\"{f}\"")

// Named group (container StartTask)
.Group("Cleanup", g => g.Print("Cleaning…").Then.Do<GcTask>())

// Build-time conditional (NOT runtime!)
.When(isDebug, b => b.Print("Debug info"))
.DoIf<DebugOutputTask>(isDebug, t => t.Expression = "\"dbg\"")

// Parallel with typed tasks
.Parallel<WorkerTask>(4, (t, i) => t.Name = $"Worker {i}")

12. Execution

// Option A: Build, then execute
var wf = builder.Build();
await wf.StartAsync();

// Option B: Shortcut – execute directly from builder
var ctx = await builder.ExecuteAsync();

// Option C: Synchronous (blocking)
var ctx = builder.Execute();

// Long-running with triggers
await builder.StartAsync();
// ... later ...
await builder.StopAsync();

// Pause / Resume
var json = await builder.PauseAsync();
await builder.ResumeAsync(json);

Complete Example – ETL Pipeline

var workflow = FluentWorkflow
    .Create("Customer ETL", loggerFactory)
    .WithTags("ETL", "Production")
    .TriggerOnSchedule("0 3 * * *", "Nightly ETL")

    // ── Extract ──
    .Group("Extract", g => g
            .Do<ReadFileTask>(t =>
            {
                t.Expression = "\"customers.csv\"";
                t.Name = "Read CSV";
            })
                .WithOutput("rawData")
                .Retry(TimeSpan.FromSeconds(5), maxRetries: 3))

        // ── Transform (parallel) ──
        .Group("Transform", g => g
            .Async("Parallel Transform")
                .Parallel(
                    new SetVariableTask { Expression = "rawData.ToUpper()", CustomOutputVariableName = "upper" },
                    new SetVariableTask { Expression = "rawData.Trim()",    CustomOutputVariableName = "trim"  })
                .Merge("Await transforms"))

        // ── Load ──
        .Group("Load", g => g
            .Do<WriteFileTask>(t =>
            {
                t.Expression = "\"customers_out.csv\"";
            })
                .WithInput("upper")
            .Then.Print("ETL complete ✓", ConsoleColor.Green))

        .Build();

await workflow.StartAsync();

Migration from Legacy API

All legacy method signatures are preserved as aliases – existing code continues to compile.

License

See LICENCE.MD in the package root. 6. Add Debug Output: Use Debug() and Print() during development 7. Configure Retry Logic: Add retry for network/external operations 8. Group Related Tasks: Use Group() to organize complex workflows

Migration from Old API

Old API:

var workflow = FluentWorkflow.Create("My Workflow");
var builder = workflow.SetupTasks();
builder.AddChildTask(new MyTask());
builder.SetOutputVariable("result");
var wf = builder.Commit().Get();

New API:

var workflow = FluentWorkflow
    .Create("My Workflow")
    .AddTask<MyTask>()
        .SetOutputVariable("result")
    .Build();

License

Copyright © Ben Wagner 2020+

See LICENCE.MD for details.