The clients package provides utility features for building robust and resilient client implementations in Go. This package includes support for retry handling and circuit breaker patterns, which are essential for creating fault-tolerant applications.
To install the package, use the following command:
go get github.com/nandlabs/golly/clientsThe RetryHandler feature allows you to configure retry logic for your client operations. This is useful for handling transient errors and ensuring that your client can recover from temporary failures.
To use the RetryHandler, you need to define the retry configuration using the RetryInfo struct.
package main
import (
"fmt"
"time"
"github.com/nandlabs/golly/clients"
)
func main() {
retryInfo := clients.RetryInfo{
MaxRetries: 3,
Wait: 1000, // Wait time in milliseconds
}
for i := 0; i < retryInfo.MaxRetries; i++ {
err := performOperation()
if err == nil {
fmt.Println("Operation succeeded")
break
}
fmt.Printf("Operation failed: %v. Retrying...\n", err)
time.Sleep(time.Duration(retryInfo.Wait) * time.Millisecond)
}
}
func performOperation() error {
// Simulate an operation that may fail
return fmt.Errorf("simulated error")
}The CircuitBreaker feature helps you to prevent cascading failures and improve the resilience of your client by stopping requests to a failing service. It transitions between different states (closed, open, half-open) based on the success or failure of requests.
To use the CircuitBreaker, you need to create an instance of the CircuitBreaker struct with the desired configuration.
package main
import (
"fmt"
"github.com/nandlabs/golly/clients"
)
func main() {
breakerInfo := &clients.BreakerInfo{
FailureThreshold: 3,
SuccessThreshold: 3,
MaxHalfOpen: 5,
Timeout: 300, // Timeout in seconds
}
cb := clients.NewCB(breakerInfo)
for i := 0; i < 10; i++ {
err := cb.CanExecute()
if err != nil {
fmt.Println("Circuit breaker is open. Cannot execute operation.")
continue
}
err = performOperation()
cb.OnExecution(err == nil)
if err != nil {
fmt.Printf("Operation failed: %v\n", err)
} else {
fmt.Println("Operation succeeded")
}
}
}
func performOperation() error {
// Simulate an operation that may fail
return fmt.Errorf("simulated error")
}circuitClosed: The circuit is closed, and requests can flow through.circuitHalfOpen: The circuit is partially open and allows limited requests for testing.circuitOpen: The circuit is open, and requests are blocked.
FailureThreshold: Number of consecutive failures required to open the circuit.SuccessThreshold: Number of consecutive successes required to close the circuit.MaxHalfOpen: Maximum number of requests allowed in the half-open state.Timeout: Timeout duration for the circuit to transition from open to half-open state.