advanced patterns with Go's goroutines and channel closing in a rate-limited API client
I just started working with I'm testing a new approach and I'm not sure how to approach I'm sure I'm missing something obvious here, but I'm implementing a rate-limited API client in Go using goroutines and channels, but I'm running into an scenario where it seems some goroutines are attempting to send data on a closed channel, causing a panic. I have set up a simple worker pool that processes requests based on a rate limit, but I think my channel management might be flawed. Here’s a simplified version of my implementation: ```go package main import ( "fmt" "sync" "time" ) func main() { rateLimit := time.Tick(1 * time.Second) // Limit to 1 request per second requests := make(chan int, 5) var wg sync.WaitGroup // Start worker goroutines for i := 0; i < 5; i++ { wg.Add(1) go worker(requests, rateLimit, &wg) } // Simulating sending requests for i := 0; i < 10; i++ { requests <- i } close(requests) // Closing the channel after all requests are sent wg.Wait() // Wait for all workers to finish } func worker(requests <-chan int, rateLimit <-chan time.Time, wg *sync.WaitGroup) { defer wg.Done() for req := range requests { <-rateLimit // Wait for the rate limit fmt.Printf("Processing request %d\n", req) } } ``` I expected the program to process each request without a question, but I'm getting a panic message like this: ``` panic: send on closed channel goroutine 5 [running]: main.worker(0x0, 0x0, 0x0) ``` It seems that the `worker` goroutine is still trying to process requests even after the `requests` channel has been closed. I've confirmed that I close the channel only after sending all the requests. I'm not sure if the question lies in how I manage goroutines or how the channel is being closed. I've tried adding a check to ensure I'm not reading from a closed channel, but I need to seem to get it right. What is the best way to handle this situation to avoid a panic due to sending on a closed channel? Am I misusing the `sync.WaitGroup` or is there another pattern I should consider? I'm using Go version 1.18. Any advice on best practices for this scenario would be greatly appreciated! Any help would be greatly appreciated! Thanks for any help you can provide! This is happening in both development and production on CentOS. Am I missing something obvious?