I'm downloading a large number of urls and the result is expected to have failure reasons, DNS lookup failed being one.
calling lookup manually would solve my issue, I suppose. Just wanted to make sure that I'm not missing any obvious solutions. 1. lookup DNS and if it succeeds, 2. try http.Get - which calles Lookup again (also maybe DNS server went down now - improbable but not impossible?) On Monday, November 28, 2016 at 1:05:25 PM UTC+1, Dave Cheney wrote: > > What specifically do you want to handle about DNS errors ? > > If you have a set of possible dns names and you don't know if some of them > are valid, you could use net.LookupHost to check which ones are valid > before calling http.Get. > > On Monday, 28 November 2016 22:44:37 UTC+11, mb.dha...@gmail.com wrote: >> >> But AFIU, err.Temporary() could be true for other kind of errors that >> might happen, isn't that a problem if I only want to handle DNS errors? >> >> >> On Friday, November 25, 2016 at 6:35:59 PM UTC+1, Victor Vrantchan wrote: >>> >>> In Go, you can check if a type satisfies a particular behavior by >>> declaring an interface, and then checking if the type satisfies that >>> interface. >>> In your case, you can check if the error is `Temporrary()` or not. >>> >>> See this snippet as an example: https://I don't >>> thinplay.golang.org/p/Ffyg61iDpB <https://play.golang.org/p/Ffyg61iDpB> >>> >>> I recommend >>> https://dave.cheney.net/2016/04/27/dont-just-check-errors-handle-them-gracefully >>> >>> and.or the GopherCon talk https://www.youtube.com/watch?v=lsBF58Q-DnY >>> by Dave Cheney for a more in-depth presentation of this idea. >>> >>> On Friday, November 25, 2016 at 12:00:06 PM UTC-5, mb.dha...@gmail.com >>> wrote: >>>> >>>> This is a question about the net/http API, Googling was not very >>>> helpful. >>>> >>>> _, err := http.Get("https://random_non_existing_domain.com";) >>>> >>>> >>>> Following code will obviously fail, but how can I check if it failed >>>> because of DNS error not because a billion other things that might have >>>> gone wrong? >>>> >>>> I tried this, (mostly as a shot in the dark) >>>> >>>> if e, ok := err.(net.Error); ok { >>>> fmt.Println("dial error", e.Temporary()) >>>> } >>>> if e, ok := err.(*net.AddrError); ok { >>>> fmt.Println("addr rror", e.Temporary()) >>>> } >>>> if e, ok := err.(*net.DNSError); ok { >>>> fmt.Println(e) >>>> >>>> and it seems to print >>>> >>>> dial error false >>>> >>>> Is there any easy way to do what I'm trying to achieve? >>>> >>>> - >>>> dbalan >>>> @notmycommit >>>> >>>> >>>> -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
