How to limit the number of polling worker calls if the API is paid?

To limit the number of polling worker calls when working with a paid API, several approaches can be used:

1. Token Bucket or Rate Limiter

   • Store a call counter and the time of the last reset.
   • Check before each call whether the limit has been exceeded.

2. Scheduling calls with delays

   • Use timers or sleep to maintain the required interval between calls.

3. Storing state in memory or external storage

   • If the worker is distributed, the limit state should be stored in Redis or a database.

Example in Go with a simple rate limiter:

package main

import (
    "fmt"
    "time"
)

func main() {
    maxCalls := 5
    interval := time.Minute
    calls := 0
    resetTime := time.Now().Add(interval)

    for {
        now := time.Now()
        if now.After(resetTime) {
            calls = 0
            resetTime = now.Add(interval)
        }

        if calls < maxCalls {
            // API call
            fmt.Println("Calling API")
            calls++
        } else {
            fmt.Println("Rate limit reached, waiting...")
            time.Sleep(time.Until(resetTime))
            continue
        }

        // Wait between calls if needed
        time.Sleep(10 * time.Second)
    }
}

This approach allows controlling the number of requests and not exceeding the limits of the paid API.