48 ms·

If you want DNS resolution to obey user/system preferences then you need to use the system provided API

• rwmj 1y ago
  For sure! The only problem is there should be a non-blocking system-provided API and there isn't.
  • foota 1y ago
    System provided is maybe a strange word to use here since getaddrinfo is a libc function, not a system call.
    • rwmj 1y ago
      POSIX as the system, of course.
    • froh 1y ago
      the system API is not syscalls but libc. so why does it feel strange?
• Seattle3503 1y ago
  In this case it isn't in the kernel, but in glibc. Could someone implement an equivalent alternative? Do any language runtimes re-implement DNS resolution?
  • NewJazz 1y ago
    I think most languages use the OS api by default, but there are plenty of libraries out there that bypass the system resolution.
  • bradfitz 1y ago
    Go does. And it supports timeouts and cancelation.
• tremon 1y ago
  The system-provided API for getting DNS user/system preferences on Unix systems is to read /etc/resolv.conf. Every application is free to implement their own lookup from that.
  • dcrazy 1y ago
    That is absolutely not the API on macOS, which is a certified UNIX.
  • Spivak 1y ago
    This isn't even correct on Linux as it won't work if your user has anything other than or in addition to the dns module in their nsswitch.conf. You must use glibc's resolution on Linux for correct behavior. If it's software on your own systems then do what you want but you'll piss off some sysadmins deploying your software if you don't. Even Go farms out to cgo to resolve names if it detects modules it doesn't recognize.