I would like to run my program like this:
go run launch.go http://example.com --m=2 --strat=par
"http://example.com" gets interpreted as the first command line argument, which is ok, but the flags are not parsed after that and stay at the default value. If I put it like this:
go run launch.go --m=2 --strat=par http://example.com
then "--m=2" is interpreted as the first argument (which should be the URL).
I could also just remove the os.Args completely, but then I would have only optional flags and I want one (the URL) to be mandatory.
Here's my code:
package main
import (
"fmt"
"webcrawler/crawler"
"webcrawler/model"
"webcrawler/urlutils"
"os"
"flag"
)
func main() {
if len(os.Args) < 2 {
log.Fatal("Url must be provided as first argument")
}
strategy := flag.String("strat", "par", "par for parallel OR seq for sequential crawling strategy")
routineMultiplier := flag.Int("m", 1, "Goroutine multiplier. Default 1x logical CPUs. Only works in parallel strategy")
page := model.NewBasePage(os.Args[1])
urlutils.BASE_URL = os.Args[1]
flag.Parse()
pages := crawler.Crawl(&page, *strategy, *routineMultiplier)
fmt.Printf("Crawled: %d
", len(pages))
}
I am pretty sure that this should be possible, but I can't figure out how.
EDIT: Thanks justinas for the hint with the flag.Args(). I now adapted it like this and it works:
...
flag.Parse()
args := flag.Args()
if len(args) != 1 {
log.Fatal("Only one argument (URL) allowed.")
}
page := model.NewBasePage(args[0])
...