DTF Determinism Analyzer

A production-ready Roslyn analyzer that validates Durable Task Framework (DTF) orchestration code for determinism constraints. Ensures your orchestrator functions follow replay-safe patterns required by Azure Durable Functions and Durable Task Framework.

🚀 Quick Start

Installation

<PackageReference Include="DtfDeterminismAnalyzer" PrivateAssets="all" />

or

dotnet add package DtfDeterminismAnalyzer

Automatic Detection

The analyzer automatically detects determinism violations in orchestrator functions:

Azure Durable Functions:

[FunctionName("MyOrchestrator")]
public static async Task<string> RunOrchestrator([OrchestrationTrigger] IDurableOrchestrationContext context)
{
    var time = DateTime.Now; // ⚠️ DFA0001: Use context.CurrentUtcDateTime instead
    var id = Guid.NewGuid(); // ⚠️ DFA0002: Use context.NewGuid() instead
    
    // ✅ Corrected automatically with code fixes
    var safeTime = context.CurrentUtcDateTime;
    var safeId = context.NewGuid();
}

Durable Task Framework:

public static async Task<string> RunOrchestrationAsync(TaskOrchestrationContext context, string input)
{
    var time = DateTime.Now; // ⚠️ DFA0001: Use context.CurrentUtcDateTime instead
    var id = Guid.NewGuid(); // ⚠️ DFA0002: Use context.NewGuid() instead
    
    // ✅ Corrected automatically with code fixes
    var safeTime = context.CurrentUtcDateTime;
    var safeId = context.NewGuid();
}

Code Fixes

Press Ctrl+. (Windows) or Cmd+. (macOS) to apply automatic fixes for common violations.

📖 Documentation

Topic	Link
📦 Installation & Setup	Installation Guide
📋 All Rules & Examples	Complete Rules Documentation
⚙️ Configuration	Configuration Guide
🔧 Troubleshooting	Troubleshooting Guide
� Code Fixes	Code Fixes Guide
�💡 Code Examples	Complete Examples
🛠️ Local Development	Local Development Guide

✅ Supported Rules

Rule	Description	Auto-Fix
DFA0001	DateTime.Now, DateTime.UtcNow, Stopwatch	✅
DFA0002	Guid.NewGuid() calls	✅
DFA0003	Random without deterministic seed	❌
DFA0004	Direct I/O operations	❌
DFA0005	Environment variable access	❌
DFA0006	Static mutable state access	❌
DFA0007	Thread.Sleep and blocking operations	✅
DFA0008	Non-durable async operations	❌
DFA0009	Threading APIs (Task.Run, Thread)	❌
DFA0010	Non-durable input bindings	❌

🎯 Supported Frameworks

Azure Durable Functions (.NET 6+)

[FunctionName("Orchestrator")]
public static async Task<string> Run([OrchestrationTrigger] IDurableOrchestrationContext context)

Durable Task Framework (.NET Framework 4.6.1+, .NET Core 2.1+)

public class MyOrchestration : TaskOrchestration<string, string>
{
    public override async Task<string> RunTask(OrchestrationContext context, string input)
}

🛠️ IDE Support

• Visual Studio 2019+ (16.3+) and 2022
• VS Code with C# extension
• JetBrains Rider 2020.3+

⚙️ Quick Configuration

Create or update .editorconfig:

[*.cs]
# Critical determinism violations
dotnet_diagnostic.DFA0001.severity = error
dotnet_diagnostic.DFA0002.severity = error
dotnet_diagnostic.DFA0006.severity = error

# Important but non-breaking
dotnet_diagnostic.DFA0004.severity = warning
dotnet_diagnostic.DFA0007.severity = warning

📦 Sample Projects

Explore working examples in the repository:

• Azure Functions Sample - Complete Azure Functions project with 40+ violations for learning
• DTF Sample - Pure Durable Task Framework implementation

🤝 Contributing

We welcome contributions! See our Contributing Guidelines for details.

Development Setup:

git clone https://github.com/kokosda/dtf-determinism-analyzer.git
cd dtf-determinism-analyzer

Quick start with automated script (cross-platform):

.\scripts\test-codefixes.ps1

Manual setup:

dotnet build
dotnet test

For comprehensive development workflows, code fix testing, and cross-platform setup instructions, see the Local Development Guide.

📋 Project Status

• ✅ 200+ Unit Tests covering all analyzer rules and code fixes
• ✅ Automated CI/CD pipeline with GitHub Actions
• ✅ NuGet Package published and maintained
• ✅ Security Scanning with Dependabot and CodeQL

📚 Learn More

• Durable Functions Code Constraints - Microsoft Documentation
• Understanding Replay Behavior - Why determinism matters

📄 License

This project is licensed under the MIT License.

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Made with ❤️ for the DTF community