golang parallel async tasks, results via channel

main.go

package main

import (
	"fmt"
	"time"
)

type QueryResult struct {
	key    string
	result string
}

func main() {
	// runs taks in parallel,
	// publishes results to a channel,
	// loops to pull data from the channel, to collect results.
	start := time.Now()
	queries := map[string]string{
		"a": "...",
		"b": "...",
		"c": "...",
	}
	numQueries := len(queries)
	
	resultChan := make(chan QueryResult)
	
	for key, query := range queries {
		go func(k, q string) {
			fmt.Printf("Going to query for key %s...\n", k)
			// sleep to mock a long running task
			time.Sleep(time.Duration(2) * time.Second)

			res := QueryResult{ key: k, result: "result" }
			resultChan <- res
		}(key, query)
	}

	results := map[string]string{}
	
	for i := 0; i < numQueries; i++ {
		res := <-resultChan
		results[res.key] = res.result
	}
	
	fmt.Println("collected results:", results)
	fmt.Println("took", time.Since(start))
}