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Murphy for Delphi - Documentation

Welcome to the Murphy for Delphi documentation! Murphy is a comprehensive Chaos Engineering library for Delphi that provides ready-to-use implementations of nine common resilience and fault-tolerance patterns.

Important

Warning: some of this documentation was generated or reworked with an LLM tool (Claude). It may therefore contain errors and/or inaccuracies. If you encounter any, please report the issue or propose a fix by submitting a pull request.

Table of Contents

Getting Started

• Introduction - What is Murphy and why use it
• Getting Started - Installation and first steps
• Chaos Engineering Basics - Understanding Chaos Engineering principles

Core Concepts

• Architecture - Design principles and internal architecture

API Reference

• API Reference Index
  • Base Policy - Core interfaces and base classes
  • Retry Policy - Retry pattern API
  • Circuit Breaker Policy - Circuit Breaker pattern API
  • Fallback Policy - Fallback pattern API
  • Rate Limit Policy - Rate Limit pattern API
  • Timeout Policy - Timeout pattern API
  • Bulkhead Policy - Bulkhead pattern API
  • Cache Policy - Cache pattern API
  • Hedging Policy - Hedging pattern API
  • Policy Wrap - Policy composition API

Pattern Guides

• Retry Pattern - Automatic retry with configurable delays
• Circuit Breaker Pattern - Prevent cascading failures
• Fallback Pattern - Provide alternative results on failure
• Rate Limit Pattern - Control operation rate
• Timeout Pattern - Abort operations that take too long
• Bulkhead Pattern - Isolate resources by limiting concurrency
• Cache Pattern - Cache expensive results, serve stale data on failure
• Hedging Pattern - Reduce tail latency with parallel attempts
• Policy Wrap - Combine multiple policies into one
• Combining Patterns - Advanced: Using multiple patterns together

Advanced Topics

• Testing with Murphy - Unit testing and test mode
• Best Practices - Recommendations and common pitfalls
• Contributing - How to contribute to Murphy

Quick Links

Installation

# Using Blocks package manager
blocks install marcobreveglieri.murphy-delphi

Quick Example

uses Murphy.Policy.Retry;

var
  RetryPolicy: IRetryPolicy;
begin
  // Create a retry policy
  RetryPolicy := TRetryBuilder.Create
    .Handle(EIdHTTPProtocolException)
    .Retry(3)
    .Wait(TTimeSpan.FromSeconds(1))
    .Build;

  // Execute code with automatic retry
  RetryPolicy.Execute(
    procedure
    begin
      // Your code here - will be retried on failure
      MakeHttpRequest;
    end);
end;

Supported Patterns

Pattern	Purpose	Use Case
Retry	Automatically retry failed operations	Transient network errors, temporary service unavailability
Circuit Breaker	Prevent cascading failures	Protect against persistent downstream failures
Fallback	Provide alternative results	Return cached data, default values, or degraded functionality
Rate Limit	Control operation rate	Prevent API throttling, protect resource consumption
Timeout	Abort operations that take too long	Slow network calls, unresponsive services, enforcing SLAs
Bulkhead	Limit concurrent executions	Protect connection pools, isolate workloads, cap parallel work
Cache	Cache expensive results for a duration	Expensive lookups, remote configuration, reducing backend load
Hedging	Launch parallel attempts, return the first success	Tail-latency reduction, replicated services, flaky endpoints
Policy Wrap	Combine multiple policies into one	Sophisticated resilience strategies, combining retry/timeout/circuit breaker

Requirements

• Delphi 11 Alexandria or later
• Supports Windows (Win32, Win64)

License

Murphy for Delphi is released under the MIT License. See the LICENSE file for details.

Contributing

We welcome contributions! Please see our Contributing Guide for details on how to get started.

Support

• Issues: GitHub Issues
• Discussions: GitHub Discussions

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Next Steps: Start with the Introduction to learn more about Murphy, or jump straight to Getting Started to begin using the library.