DistributedWorkflowPatterns

Enterprise reference implementation of distributed workflow patterns in .NET.

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Overview

Distributed systems become challenging when multiple independent components need to coordinate reliable execution.

This project demonstrates reusable distributed workflow patterns instead of application-specific business logic.

The repository does not implement scenarios such as:

• Order Processing
• Payment
• Reservation
• Shopping Cart

Instead, it provides architectural building blocks for:

• Workflow orchestration
• Saga Pattern
• Message-driven communication
• Compensation
• Retry strategies
• Correlation
• Technology-independent messaging

RabbitMQ is the first transport implementation. The architecture is designed to allow future integration with Kafka, Azure Service Bus, or MassTransit without changing the core workflow engine.

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Architecture

The solution follows Clean Architecture principles.

                    API
                     |
                     v
              Application
              /        \
             v          v
        Domain     BuildingBlocks
                     |
                     v
             Infrastructure

Dependency direction always moves toward the core.

Infrastructure contains implementation details.

Domain contains workflow concepts without infrastructure dependencies.

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Solution Structure

DistributedWorkflowPatterns

src/

├── DistributedWorkflowPatterns.Api

├── DistributedWorkflowPatterns.Application

├── DistributedWorkflowPatterns.Domain

├── DistributedWorkflowPatterns.Infrastructure

├── DistributedWorkflowPatterns.Contracts

└── DistributedWorkflowPatterns.BuildingBlocks

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Core Responsibilities

Domain

Contains the core workflow model:

• Workflow
• Workflow Step
• Workflow State
• Workflow Execution
• Workflow Compensation

No dependency on external technologies.

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Application

Responsible for workflow coordination:

• Workflow execution
• Saga orchestration
• Compensation handling
• Application use cases

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BuildingBlocks

Contains reusable abstractions:

• Messaging abstractions
• Correlation concepts
• Retry contracts
• Compensation contracts

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Infrastructure

Contains external implementations:

• RabbitMQ transport
• OpenTelemetry configuration
• External adapters

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Contracts

Contains shared communication contracts:

• Commands
• Events
• Message definitions

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MVP Scope (Version 1)

Implemented:

• Workflow Definition
• Workflow Steps
• Workflow State Management
• Workflow Execution Model
• Messaging Abstractions
• Saga Orchestration
• Compensation Strategy
• RabbitMQ Transport
• Retry Abstractions
• Saga Choreography Contracts
• OpenTelemetry Integration
• Persistence Contract

Not included:

• Database implementation
• Authentication
• Dashboard
• Docker/Kubernetes deployment
• Event Sourcing

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Workflow Execution Flow

Client
 |
 v
Workflow Definition
 |
 v
Workflow Coordinator
 |
 v
Execute Workflow Step
 |
 v
Publish Message
 |
 v
External Component
 |
 +------------+
 | Success    |
 +------------+
 |
 v
Next Step


Failure:

Workflow Coordinator
 |
 v
Compensation Flow
 |
 v
Rollback Previous Steps

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Saga Orchestration Flow

Coordinator

    |
    v

Execute Step A

    |
    v

Execute Step B

    |
    v

Failure Occurs

    |
    v

Compensate Previous Steps

The orchestrator manages:

• Workflow state
• Executed steps
• Failure handling
• Compensation execution

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Development Roadmap

Phase 1 - Foundation

Completed:

• Solution structure
• Clean Architecture setup
• Domain modeling

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Phase 2 - Messaging Abstractions

Completed:

• IMessageBus abstraction
• Publisher/Subscriber contracts
• Message metadata concepts

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Phase 3 - RabbitMQ Transport

Completed:

• RabbitMQ adapter
• Connection handling
• Message publishing and consuming

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Phase 4 - Workflow Runtime

Completed:

• Workflow execution concepts
• Step management
• State transitions

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Phase 5 - Saga Orchestrator

Completed:

• Workflow coordination
• Saga execution flow
• Failure handling

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Phase 6 - Compensation Engine

Completed:

• Compensation contracts
• Recovery strategy

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Phase 7 - Retry Policies

Completed:

• Retry abstractions
• Transient failure handling

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Phase 8 - Saga Choreography

Completed:

• Event contracts
• Command contracts
• Decoupled communication model

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Phase 9 - OpenTelemetry Integration

Completed:

• OpenTelemetry setup
• Trace instrumentation foundation

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Phase 10 - Persistence Contract

Completed:

• Persistence abstraction
• Future database provider support

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Design Principles

The project follows:

• Clean Architecture
• Separation of Concerns
• Technology Independence
• Low Coupling
• High Cohesion
• Extensible Design
• Message-driven Architecture

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Technology Stack

• .NET 8
• ASP.NET Core
• C#
• Clean Architecture
• RabbitMQ
• OpenTelemetry

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Repository Status

Current Version:

v1.0.0

Status:

✅ MVP Completed

The first version focuses on architecture and reusable distributed workflow patterns.

Future versions will add:

• Executable workflow examples
• Automated tests
• Database providers
• Additional messaging transports
• Monitoring capabilities

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License

MIT License