loadparseprint.go

package main

import (
	"bufio"
	"fmt"
	"log"
	"net"
	"os"
	"strings"
	"sync"

	geoip2 "github.com/oschwald/geoip2-golang"
)

var (
	// embedded values are generated by init.sh in init.go
	dbASN     = newgeoip2Reader(embeddedASN)
	dbCountry = newgeoip2Reader(embeddedCountry)
)

// newgeoip2Reader wrapper from []byte to *geoip2.Reader
func newgeoip2Reader(Asset []byte) *geoip2.Reader {
	db, err := geoip2.FromBytes(Asset)
	if err != nil {
		log.Fatal("ERR geoip2.FromBytes() ", err)
	}
	return db
}

// parseandprint return string with ASN and Country from ip string
func parseandprint(ips string) string {
	const format = "%s (%s / AS%d %s)"
	return parseandprintgen(ips, format)
}

// parseandprint return string with ASN and Country from ip string for SED format
func parseandprintSED(ips string) string {
	const format = "s/\"%s\"/\"%s AS%d %s\"/g"
	return parseandprintgen(ips, format)
}

// parseandprint return string with ASN and Country from ip string for JSON format
func parseandprintJSON(ips string) string {
	// const format = "{\"ip\":\"%s\",\"country\":\"%s\",\"AS\":\"AS%d %s\"}"
	const format = "{ \"ip\":\"%s\", \"geoip\": { \"country\":\"%s\",\"AS\":\"AS%d %s\"} }"

	// better ?
	// { ip: "91.67.155.106" ,
	//  	"geoip": {	"country":"Germany",
	// 			"AS":"AS3209 Vodafone GmbH", },
	// }

	// {"user":"aurelie.goyenvalle@uvsq.fr","ip":"176.134.198.13"}

	return parseandprintgen(ips, format)
}

// Generic parseandprint with format as argument
func parseandprintgen(ips, format string) string {

	ip := net.ParseIP(ips)
	if ip == nil {
		return fmt.Sprintf(format,
			ips, "ERROR", 0, "Error net.parseIP")
	}

	record, err := dbCountry.Country(ip)
	if err != nil || record.Country.Names["en"] == "" {
		return fmt.Sprintf(format,
			ips, "ERROR", 0, "Error db.Country")
	}

	ASN, err := dbASN.ASN(ip)
	if err != nil {
		return fmt.Sprintf(format,
			ips, "ERROR", 0, "Error db.ASN")
	}

	// special caracters are problematic for JSON output
	change := strings.NewReplacer("&", " and ",
		"'", " ",
		"\\", " ")
	properASN := change.Replace(ASN.AutonomousSystemOrganization)

	return fmt.Sprintf(format,
		ips, record.Country.Names["en"],
		ASN.AutonomousSystemNumber, properASN)

}

// Trying ot pass a generic ParsePrint function to readandprintbulk
type FuncStringtoString func(string) string

// readandprintbulk read stdin and printout results
// channel was used when old parseandprint resolved ip to name
// wg was used to limit concurrent requests
func readandprintbulk(doit FuncStringtoString) {
	var line string
	var wg sync.WaitGroup
	var limitChan = make(chan bool, maxrequests)
	cached := make(map[string]bool)

	scanner := bufio.NewScanner(os.Stdin)

	for scanner.Scan() {
		line = strings.TrimSpace(scanner.Text())
		if cached[line] {
			continue
		}
		cached[line] = true
		wg.Add(1)
		limitChan <- true // will block after maxrequests

		go func(myline string, mywg *sync.WaitGroup, mychan chan bool) {
			out := doit(myline)
			if len(out) > 0 {
				fmt.Printf("%s\n", out)
			}
			<-mychan
			mywg.Done()
		}(line, &wg, limitChan)

	}
	wg.Wait()
}