GlitchMesh 🧪

GlitchMesh is a lightweight, developer-focused proxy tool designed for testing microservice resilience. It allows you to simulate network faults like latency, errors, and dropped requests, making it easier to validate the robustness of distributed systems, all without touching production code.

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⚠️ Note: This project is under active development. Many features are still being implemented, and things may change frequently. Feedback and contributions are highly appreciated!

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🚀 Current Features

Core Proxy Functionality

• Intelligent Request Routing - Single-port proxy that routes requests to appropriate backend services based on URL patterns (/redirect/{service-name}/{endpoint})
• YAML Configuration - Simple, declarative configuration using YAML files for service definitions and fault rules
• HTTP Proxy - Full HTTP request/response proxying with header preservation and query parameter support

Fault Injection Capabilities

Latency Injection - Add configurable artificial delays to simulate slow downstream services

• Configurable delay in milliseconds
• Per-service latency configuration

Error Simulation - Simulate service failures and HTTP errors

• Configurable HTTP status codes (500, 503, etc.)
• Custom error messages
• Request termination on error injection

Configuration & Control

• Priority-Based Fault Application - Define fault execution order with priority arrays (priority: ["error", "latency"])
• Service-Specific Configuration - Apply different fault profiles to different services
• Enable/Disable Faults - Toggle fault injection on/off per service configuration

Observability

• Request Logging - Comprehensive logging of all proxied requests with timing information
• Fault Logging - Transparent logging of all injected faults for debugging and monitoring

Current Configuration Format

service:
  - name: "service-one"
    url: "http://localhost:8080/"
    fault:
      enabled: true
      priority: ["error", "latency"]
      types:
        latency:
          delay: 5000  # 5 second delay
        error:
          statuscode: 500
          message: "something went really wrong!!"

Usage

# Start the proxy server on port 9000
go run ./cmd/glitchmesh/main.go start server

# Make requests through the proxy
curl http://localhost:9000/redirect/service-one/api/users

Upcoming Features

Network Faults

• Connection Timeouts - Simulate services that accept connections but never respond
• Connection Drop - Randomly Dropping connections mid request
• Bandwidth Throttling - Limiting throughput to simulate network congestion

Response Manupulation

• Partial response corruption - Corrupt random bytes in response bodies

Advanced Simulations

• Circuit breaker simulation - Fail fast after consecutive failures

Other Features

• Hot reloading of configs - reloading configs without restarts
• Sidecar Mode for transparent proxy (mainly for K8s)
• API Based control - to enable/disable faults using API endpoints
• Percentage Based Faults - Apply faults to only X% of the requests