running ads on queue

main.go

package main

import (
	"fmt"
	"time"
)

func handleSpecificAd(wg *sync.WaitGroup, dId int) {
	defer wg.Done()

	count := 0
	for count < 2 {
		fmt.Println("handleSpecificAd", adId, count)
		time.Sleep(1 * time.Second)
		count++
	}
}

/**
this one will read from the DB, it will query for all the ads
that are in state in queued and the queue time ie before now.

for each ad we find, we can either run it on synchronously,
or we can run it in another goroutine.

I assume running synchronously will be simpler for now,
espcially as we dont have a lot of traffic now.
*/
func bgWorker() {
	count := 0
	for {
		fmt.Println("bgworker round")
		var wg sync.WaitGroup

		// fetch "n" items from DB
		fetchItems := fetchFromDb(limit: n)

		// each item will be sent to processing
		for item in fetchItems {
			wg.Add(1)
			go handleSpecificAd(&wg, fetchItems)
		}

		//wait until all items processing is done
		wg.Wait()
	}
}

/**
this one is out main app that currently serves the grpc app
+
calling the bg worker on a goroutine
*/
func main() {
	// this worker will handle the jobs
	go bgWorker()

	grpc()

	//this is the main app grpc
	for {
		time.Sleep(2 * time.Second)
		fmt.Println("main app stuff")
	}
}

We may want to split fetchItems to groups, and assign each group for func handleSpecificAd, instead of each item for func handleSpecificAd, to control the number of go gorountines.