Go routines, channels and wait group demo.

go_chan_wg.go

package main

import (
	"log"
	"math/rand"
	"sync"
	"time"
)

type Report struct {
	Type                   string `json:"type"`
	StartTime              string `json:"start_time"`
	EndTime                string `json:"end_time"`
	TotalRecords           int    `json:"num_of_records"`
	RecordsWithCoordinates int    `json:"records_with_coordinates"`
}

func Random() *rand.Rand {
	return rand.New(rand.NewSource(time.Now().UnixNano()))
}

func Execute(typeOfReport string, r chan Report) {
	rSecs := Random().Intn(10)
	log.Printf("Executing report %s and waiting for %d seconds...", typeOfReport, rSecs)
	time.Sleep(time.Duration(rSecs) * time.Second)

	report := Report{
		Type:                   typeOfReport,
		StartTime:              "2020-01-01T00:00:00Z",
		EndTime:                "2020-01-01T00:00:00Z",
		TotalRecords:           Random().Intn(100),
		RecordsWithCoordinates: Random().Intn(50),
	}

	r <- report
}

func main() {
	log.Println("Starting the program...")
	r := make(chan Report)

	var wg sync.WaitGroup

	wg.Add(3)

	scrapers := []string{"ScienceDaily", "CNN", "BBC"}

	for _, s := range scrapers {
		go func(s string) {
			log.Printf("Starting report %s...", s)
			Execute(s, r)
			wg.Done()
		}(s)
	}

	for i := 0; i < 3; i++ {
		report := <-r
		log.Printf("Report %s has been executed...", report.Type)
		log.Printf("Results for report %s: %v", report.Type, report)
	}

	wg.Wait()
	close(r)

	log.Println("End of the program")
}