DavidHuie/quartz

package main

import (
    "net"

    "github.com/DavidHuie/quartz/go/quartz"
)

type Resolver struct{}

type FindIPsArgs struct {
    Hostnames []string
}

type FindIPsResponse struct {
    HostnameToIPs map[string][]net.IP
}

// Concurrently resolves all hostnames in the input struct
// to IPs.
func (r *Resolver) FindIPs(args FindIPsArgs, response *FindIPsResponse) error {
    *response = FindIPsResponse{}
    response.HostnameToIPs = make(map[string][]net.IP)
    c := make(chan bool)

    for _, hostname := range args.Hostnames {
        go func(h string) {
            addrs, err := net.LookupIP(h)
            if err != nil {
                panic(err)
            }

            response.HostnameToIPs[h] = addrs

            c <- true
        }(hostname)
    }

    for i := 0; i < len(args.Hostnames); i++ {
        <-c
    }

    return nil
}

func main() {
    resolver := &Resolver{}
    quartz.RegisterName("resolver", resolver)
    quartz.Start()
}