Workflow Engine Core

A powerful, framework-agnostic workflow engine for PHP applications. This core library provides comprehensive workflow definition, execution, and state management capabilities without any framework dependencies.

⚠️ WARNING: DEVELOPMENT STATUS⚠️

This package is currently under active development and is NOT READY FOR PRODUCTION USE.

Features may be incomplete, APIs might change, and there could be breaking changes. Use at your own risk in development environments only.

📋 Requirements

• PHP 8.3+ - Leverages modern PHP features for type safety and performance
• Composer - For dependency management
• No framework dependencies - Works with any PHP project

✨ Features

• 🚀 Framework Agnostic: Works with any PHP framework or standalone applications
• 🔒 Type Safe: Full PHP 8.3+ type safety with strict typing and generics
• 🔧 Extensible: Plugin architecture for custom actions and storage adapters
• 📊 State Management: Robust workflow instance state tracking and persistence
• ⚡ Performance: Optimized for high-throughput workflow execution
• 🛡️ Error Handling: Comprehensive exception handling with detailed context
• 🔄 Retry Logic: Built-in retry mechanisms with configurable strategies
• ⏱️ Timeouts: Step-level timeout controls for reliable execution
• 📋 Conditions: Conditional workflow execution based on runtime data
• 🎯 Events: Rich event system for monitoring and integration
• 🧪 Well Tested: Comprehensive test suite with 93 tests and 224+ assertions

📦 Installation

For Production Use

composer require solution-forest/workflow-engine-core

For Development

# Clone the repository
git clone https://github.com/solution-forest/workflow-engine-core.git
cd workflow-engine-core

# Install dependencies
composer install

# Run quality checks
composer ci

🚀 Quick Start

Basic Workflow Definition

use SolutionForest\WorkflowEngine\Core\WorkflowBuilder;
use SolutionForest\WorkflowEngine\Core\WorkflowEngine;
use SolutionForest\WorkflowEngine\Core\WorkflowContext;
use SolutionForest\WorkflowEngine\Core\ActionResult;
use SolutionForest\WorkflowEngine\Actions\BaseAction;

// Define custom actions
class ValidateOrderAction extends BaseAction
{
    public function execute(WorkflowContext $context): ActionResult
    {
        $orderId = $context->getData('order_id');

        // Your validation logic here
        if ($this->isValidOrder($orderId)) {
            return ActionResult::success(['validated' => true]);
        }

        return ActionResult::failure('Invalid order');
    }
}

// Build a workflow definition
$definition = WorkflowBuilder::create('order-processing')
    ->description('Process customer orders')
    ->addStep('validate', ValidateOrderAction::class)
    ->addStep('payment', ProcessPaymentAction::class, timeout: 300, retryAttempts: 3)
    ->addStep('fulfillment', FulfillOrderAction::class)
    ->build();

// Create engine with storage adapter and event dispatcher
$engine = new WorkflowEngine($storageAdapter, $eventDispatcher);

// Start and run the workflow
$instanceId = $engine->start(
    'order-processing',
    $definition->toArray(),
    ['order_id' => 123, 'customer_id' => 456]
);

// Check the result
$instance = $engine->getInstance($instanceId);
echo $instance->getState()->value; // "completed"

Advanced Workflow Builder

use SolutionForest\WorkflowEngine\Core\WorkflowBuilder;

$workflow = WorkflowBuilder::create('order-flow')
    ->description('Process customer orders')
    ->addStep('validate', ValidateOrderAction::class)
    ->when('order.total > 1000', function ($builder) {
        $builder->addStep('fraud_check', FraudCheckAction::class);
    })
    ->addStep('payment', ProcessPaymentAction::class, timeout: 300, retryAttempts: 3)
    ->email('order-confirmation', 'customer@example.com', 'Order Confirmed')
    ->build();

// Quick templates for common patterns
$workflow = WorkflowBuilder::quick()->userOnboarding();
$workflow = WorkflowBuilder::quick()->orderProcessing();
$workflow = WorkflowBuilder::quick()->documentApproval();

PHP 8.3+ Attributes

Note: Attributes are currently metadata annotations for documentation and tooling. They are not yet auto-parsed by the engine at runtime — use the builder API (timeout:, retryAttempts:, when()) or step config to apply these behaviors. Attribute-driven execution is planned for a future release.

Use native PHP attributes to annotate actions with retry, timeout, and conditions:

Retry Logic

use SolutionForest\WorkflowEngine\Attributes\Retry;

#[Retry(attempts: 3, backoff: 'exponential', delay: 1000)]
class ReliableApiAction extends BaseAction
{
    public function execute(WorkflowContext $context): ActionResult
    {
        // Retries up to 3 times with exponential backoff starting at 1s
        return ActionResult::success();
    }
}

Timeouts

use SolutionForest\WorkflowEngine\Attributes\Timeout;

#[Timeout(seconds: 30)]
class TimedAction extends BaseAction
{
    public function execute(WorkflowContext $context): ActionResult
    {
        // Will timeout after 30 seconds
        return ActionResult::success();
    }
}

Conditional Execution

use SolutionForest\WorkflowEngine\Attributes\Condition;

#[Condition('order.amount > 100')]
class PremiumProcessingAction extends BaseAction
{
    public function execute(WorkflowContext $context): ActionResult
    {
        // Only executes when order.amount > 100
        return ActionResult::success();
    }
}

Step Metadata

use SolutionForest\WorkflowEngine\Attributes\WorkflowStep;

#[WorkflowStep(id: 'send_email', name: 'Send Welcome Email', description: 'Sends a welcome email to the new user')]
class SendWelcomeEmailAction extends BaseAction
{
    public function execute(WorkflowContext $context): ActionResult
    {
        return ActionResult::success();
    }
}

Retry, Timeout & Conditions via Builder

These features can also be configured through the fluent builder API:

// Steps with retry and timeout configured via builder
$workflow = WorkflowBuilder::create('reliable-flow')
    ->addStep('fetch_data', FetchDataAction::class, timeout: 30, retryAttempts: 3)
    ->addStep('process', ProcessAction::class, timeout: 60)
    ->build();

// Conditional steps evaluated at runtime
$workflow = WorkflowBuilder::create('conditional-flow')
    ->addStep('validate', ValidateAction::class)
    ->when('order.total > 1000', function ($builder) {
        $builder->addStep('fraud_check', FraudCheckAction::class);
    })
    ->addStep('complete', CompleteAction::class)
    ->build();

Workflow Lifecycle Management

// Start, resume, cancel
$instanceId = $engine->start('my-workflow', $definition->toArray(), ['key' => 'value']);
$instance = $engine->getInstance($instanceId);
$engine->resume($instanceId);
$engine->cancel($instanceId, 'No longer needed');

// Track progress
$progress = $instance->getProgress(); // 0.0 to 100.0
$summary = $instance->getStatusSummary();

// Query instances with filters
$instances = $engine->getInstances([
    'state' => 'running',
    'definition_name' => 'order-processing',
    'created_after' => new \DateTime('-7 days'),
    'limit' => 50,
    'offset' => 0,
]);

SimpleWorkflow Helper

For quick workflow execution without manual engine setup:

use SolutionForest\WorkflowEngine\Support\SimpleWorkflow;

$simple = new SimpleWorkflow($storageAdapter);

// Run actions sequentially
$instanceId = $simple->sequential('user-onboarding', [
    SendWelcomeEmailAction::class,
    CreateUserProfileAction::class,
    AssignDefaultRoleAction::class,
], ['user_id' => 123]);

// Run a single action as a workflow
$instanceId = $simple->runAction(SendEmailAction::class, [
    'to' => 'user@example.com',
    'subject' => 'Welcome!',
]);

// Execute from a builder
$builder = WorkflowBuilder::create('custom-flow')
    ->addStep('validate', ValidateAction::class)
    ->addStep('process', ProcessAction::class);
$instanceId = $simple->executeBuilder($builder, $context);

// Check status
$status = $simple->getStatus($instanceId);
// Returns: id, state, current_step, progress, completed_steps, failed_steps, error_message, ...

🏗️ Architecture

The workflow engine follows a clean architecture with clear separation of concerns:

WorkflowBuilder → WorkflowDefinition → WorkflowEngine → Executor → Actions
                                              ↓
                                        StateManager → StorageAdapter
                                              ↓
                                        EventDispatcher

Core Components

Component	Purpose
WorkflowBuilder	Fluent API for constructing workflow definitions with addStep(), when(), email(), delay(), http()
WorkflowDefinition	Immutable blueprint containing steps, transitions, conditions, and metadata
WorkflowEngine	Central orchestrator — start(), resume(), cancel(), getInstance(), getInstances(), getStatus()
Executor	Runs steps sequentially with retry logic, timeout enforcement, and condition evaluation
StateManager	Coordinates persistence through StorageAdapter
EventDispatcher	Broadcasts 7 event types during workflow lifecycle

State Machine

PENDING → RUNNING → COMPLETED
    ↓         ↓ ↑
  FAILED   WAITING
    ↑         ↓ ↑
  FAILED ← PAUSED
    ↑
CANCELLED ← (any non-terminal state)

Valid transitions:

• PENDING → RUNNING, FAILED, CANCELLED
• RUNNING → WAITING, PAUSED, COMPLETED, FAILED, CANCELLED
• WAITING → RUNNING, FAILED, CANCELLED
• PAUSED → RUNNING, FAILED, CANCELLED
• Terminal states (COMPLETED, FAILED, CANCELLED) → no further transitions

State transitions are validated at runtime — invalid transitions throw InvalidWorkflowStateException.

Namespace Map

Namespace	Contents
Core\	WorkflowEngine, WorkflowBuilder, Executor, StateManager, WorkflowInstance, WorkflowDefinition, WorkflowContext, ActionResult, Step, DefinitionParser, ActionResolver
Actions\	BaseAction, LogAction, EmailAction, HttpAction, DelayAction, ConditionAction
Contracts\	WorkflowAction, StorageAdapter, EventDispatcher, Logger
Attributes\	WorkflowStep, Retry, Timeout, Condition
Events\	WorkflowStartedEvent, WorkflowCompletedEvent, WorkflowFailedEvent, WorkflowCancelledEvent, StepCompletedEvent, StepFailedEvent, StepRetriedEvent
Exceptions\	WorkflowException, InvalidWorkflowDefinitionException, InvalidWorkflowStateException, ActionNotFoundException, StepExecutionException, WorkflowInstanceNotFoundException
Support\	NullLogger, NullEventDispatcher, SimpleWorkflow, Uuid, Timeout, ConditionEvaluator, Arr

Built-in Actions

Six ready-to-use actions are included:

Action	Purpose	Config Keys
LogAction	Log messages with placeholder replacement ({user.name})	message, level (debug/info/warning/error)
EmailAction	Mock email sending with template support	to, subject, body, template
HttpAction	HTTP requests with {{ variable }} template variables	url, method, headers, body
DelayAction	Pause execution for a specified duration	seconds, minutes, hours
ConditionAction	Evaluate boolean expressions and branch (on_true/on_false)	condition, on_true, on_false
BaseAction	Abstract base class for custom actions	—

WorkflowState Helpers

The WorkflowState enum provides utility methods for UI and logic:

$state = $instance->getState();

$state->isActive();        // true for PENDING, RUNNING, WAITING, PAUSED
$state->isFinished();      // true for COMPLETED, FAILED, CANCELLED
$state->isSuccessful();    // true for COMPLETED
$state->isError();         // true for FAILED
$state->label();           // "Running"
$state->description();     // "The workflow is actively executing steps..."
$state->color();           // "blue" (gray, blue, yellow, orange, green, red, purple)
$state->icon();            // "▶️"
$state->canTransitionTo(WorkflowState::COMPLETED); // bool
$state->getValidTransitions(); // [WorkflowState::WAITING, ...]

🔧 Configuration

Storage Adapters

Implement the StorageAdapter interface for custom persistence:

use SolutionForest\WorkflowEngine\Contracts\StorageAdapter;

class DatabaseStorageAdapter implements StorageAdapter
{
    public function save(WorkflowInstance $instance): void { /* ... */ }
    public function load(string $id): WorkflowInstance { /* ... */ }
    public function findInstances(array $criteria = []): array { /* ... */ }
    public function delete(string $id): void { /* ... */ }
    public function exists(string $id): bool { /* ... */ }
    public function updateState(string $id, array $updates): void { /* ... */ }
}

Event Handling

Listen to workflow events — 7 event types are dispatched during execution:

use SolutionForest\WorkflowEngine\Contracts\EventDispatcher;
use SolutionForest\WorkflowEngine\Events\WorkflowStartedEvent;
use SolutionForest\WorkflowEngine\Events\WorkflowCompletedEvent;
use SolutionForest\WorkflowEngine\Events\WorkflowFailedEvent;
use SolutionForest\WorkflowEngine\Events\WorkflowCancelledEvent;
use SolutionForest\WorkflowEngine\Events\StepCompletedEvent;
use SolutionForest\WorkflowEngine\Events\StepFailedEvent;
use SolutionForest\WorkflowEngine\Events\StepRetriedEvent;

class CustomEventDispatcher implements EventDispatcher
{
    public function dispatch(object $event): void
    {
        match ($event::class) {
            WorkflowStartedEvent::class => $this->onWorkflowStarted($event),
            WorkflowCompletedEvent::class => $this->onWorkflowCompleted($event),
            WorkflowFailedEvent::class => $this->onWorkflowFailed($event),
            StepCompletedEvent::class => $this->onStepCompleted($event),
            StepFailedEvent::class => $this->onStepFailed($event),
            StepRetriedEvent::class => $this->onStepRetried($event),
            default => null,
        };
    }
}

Logging

Provide a custom logging implementation (PSR-3 style):

use SolutionForest\WorkflowEngine\Contracts\Logger;

class CustomLogger implements Logger
{
    public function info(string $message, array $context = []): void { /* ... */ }
    public function warning(string $message, array $context = []): void { /* ... */ }
    public function error(string $message, array $context = []): void { /* ... */ }
    public function debug(string $message, array $context = []): void { /* ... */ }
}

🧪 Development

Testing

Run the test suite:

# Run all tests
composer test

# Run tests with coverage
composer test:coverage

# Run specific test file
vendor/bin/pest tests/Unit/WorkflowEngineTest.php

# Run tests with detailed output
vendor/bin/pest --verbose

Code Quality

We use several tools to maintain high code quality:

# Static analysis with PHPStan
composer analyze

# Code formatting with Laravel Pint
composer pint

# Check code formatting without making changes
composer pint --test

# Run all quality checks
composer pint && composer analyze && composer test

Development Tools

• Pest - Testing framework with expressive syntax
• Pest Architecture Testing - Architectural constraints and code quality rules
• PHPStan - Static analysis tool for catching bugs
• Laravel Pint - Code style fixer built on PHP-CS-Fixer
• Framework-agnostic - No Laravel dependencies in the core library

Configuration Files

• phpstan.neon.dist - PHPStan configuration for static analysis
• pint.json - Laravel Pint configuration for code formatting
• phpunit.xml.dist - PHPUnit configuration for testing
• .github/workflows/run-tests.yml - CI/CD pipeline configuration

Quality Standards

We maintain high code quality through:

• 100% PHPStan Level 6 - Static analysis with zero errors across 46 source files
• Laravel Pint - Consistent code formatting following Laravel standards
• Comprehensive Testing - 93 tests with 224+ assertions covering unit, integration, and real-world scenarios
• Architecture Tests - Automated checks preventing debug functions in source code
• State Transition Validation - Runtime enforcement of valid workflow state transitions
• Type Safety - Full PHP 8.3+ type declarations throughout
• Continuous Integration - Automated quality checks on every commit (PHP 8.3/8.4 matrix)

📚 Framework Integrations

This core library is framework-agnostic. For specific framework integrations:

• Laravel: Use solution-forest/workflow-engine-laravel
• Symfony: Coming soon
• Other frameworks: Easily integrate using the provided interfaces

🤝 Contributing

We welcome contributions! Please see CONTRIBUTING.md for details.

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

🙏 Credits

• Solution Forest Team - Initial development and maintenance
• Contributors - Thank you to all contributors who have helped improve this project

🔗 Links

• Issues
• Changelog
• Laravel Integration