Merge pull request #14 from xgodev/docs/hystrix-readme

Add README for Hystrix factory integration

Author: jpfaria

factory/contrib/afex/hystrix-go/v0/README.md

@@ -0,0 +1,132 @@
+# Hystrix Factory
+
+## Overview
+
+The Hystrix Factory provides integration with the [Hystrix-Go](https://github.com/afex/hystrix-go) library, implementing the circuit breaker pattern for Go applications within the Boost framework. This factory enables resilient and fault-tolerant systems by preventing cascading failures in distributed environments.
+
+## Features
+
+- **Command Configuration**: Easy configuration of Hystrix commands through Boost's configuration system
+- **Circuit Breaker Pattern**: Implementation of the circuit breaker pattern to handle failures gracefully
+- **Configurable Parameters**: Fine-grained control over timeout, concurrency, error thresholds, and recovery windows
+- **Logging Integration**: Seamless integration with Boost's logging system
+
+## Usage
+
+### Basic Configuration
+
+```go
+package main
+
+import (
+    "github.com/xgodev/boost"
+    "github.com/xgodev/boost/factory/contrib/afex/hystrix-go/v0"
+)
+
+func main() {
+    // Initialize Boost
+    boost.Start()
+    
+    // Configure a Hystrix command
+    hystrix.ConfigureCommand("my_command")
+    
+    // Use the command in your application
+    // ...
+}
+```
+
+### Configuring Multiple Commands
+
+```go
+// Configure multiple commands at once
+commands := []string{"database_query", "api_request", "authentication"}
+hystrix.ConfigureCommands(commands)
+```
+
+### Custom Configuration
+
+You can customize Hystrix command parameters through Boost's configuration system:
+
+```
+# In your configuration file or environment variables
+boost.factory.hystrix.commands.my_command.timeout=5000
+boost.factory.hystrix.commands.my_command.maxConcurrentRequests=10
+boost.factory.hystrix.commands.my_command.requestVolumeThreshold=20
+boost.factory.hystrix.commands.my_command.errorPercentThreshold=25
+boost.factory.hystrix.commands.my_command.sleepWindow=10000
+```
+
+## Configuration Parameters
+
+| Parameter | Description | Default |
+|-----------|-------------|---------|
+| `timeout` | How long to wait for command to complete (milliseconds) | 10000 |
+| `maxConcurrentRequests` | Maximum number of concurrent requests | 20 |
+| `requestVolumeThreshold` | Minimum requests needed before circuit can trip | 10 |
+| `errorPercentThreshold` | Error percentage to open the circuit | 5 |
+| `sleepWindow` | Time to wait after circuit opens before testing recovery (milliseconds) | 5000 |
+
+## Integration with Other Boost Components
+
+The Hystrix Factory integrates with:
+
+- **Config Wrapper**: For loading and managing configuration
+- **Log Wrapper**: For logging circuit breaker events and errors
+
+## Plugin System
+
+The factory supports plugins for extending functionality. Custom plugins can be added to the `plugins` directory and registered with the factory.
+
+## Example
+
+```go
+package main
+
+import (
+    "errors"
+    "github.com/afex/hystrix-go/hystrix"
+    hystrixfactory "github.com/xgodev/boost/factory/contrib/afex/hystrix-go/v0"
+    "github.com/xgodev/boost/wrapper/log"
+)
+
+func main() {
+    // Configure the command
+    hystrixfactory.ConfigureCommand("get_user_profile")
+    
+    // Use the command
+    err := hystrix.Do("get_user_profile", func() error {
+        // This function will be executed if the circuit is closed
+        return callExternalService()
+    }, func(err error) error {
+        // This function will be executed if the circuit is open
+        log.Errorf("Circuit open, using fallback: %v", err)
+        return getFallbackUserProfile()
+    })
+    
+    if err != nil {
+        log.Errorf("Error: %v", err)
+    }
+}
+
+func callExternalService() error {
+    // Actual implementation to call external service
+    return nil
+}
+
+func getFallbackUserProfile() error {
+    // Fallback implementation
+    return errors.New("using cached profile")
+}
+```
+
+## Best Practices
+
+1. **Command Naming**: Use descriptive names for commands that reflect their purpose
+2. **Timeout Configuration**: Set appropriate timeouts based on expected response times
+3. **Error Thresholds**: Adjust error thresholds based on your application's tolerance for failures
+4. **Monitoring**: Monitor circuit breaker states to understand system health
+
+## References
+
+- [Hystrix-Go GitHub Repository](https://github.com/afex/hystrix-go)
+- [Circuit Breaker Pattern](https://martinfowler.com/bliki/CircuitBreaker.html)