On 13 November 2017 at 04:46, Chad Granum <exodi...@gmail.com> wrote: > Kent, (or anyone really) > > Can you point to any documentation that covers these env vars, and the best > practices you layed out? I have never even heard of the NO_NETWORK_TESTING > var, and considering what modules I maibtain that is worrysome. > > I am not asking out of doubt, I want to educate myself, and make these vars > clearly documented along with when to use them in Test-Simple and related > modules.
Its more an emerging convention that is gaining adoption, than an official strategy. I started an email to this list a few years back, https://www.nntp.perl.org/group/perl.cpan.workers/2014/06/msg1117.html and this network variable ended up being rolled out in a few places as a result. The rationale as to why this approach is warranted is spelled out in that thread, but the gist of it is its not always safe to use sniffing to determine network availability, doing so can get given false-positives through network sandboxes and weird routing configurations, and syscall sandboxing can result in network calls tripping a SIGKILL on your process. Hence the application of an ENV var that states "Do not under any circumstances attempt to access the internet" serves as a decent gate keeper. This ENV var is still far from ubiquitous, but it is far more applied across CPAN than its competition these days. And for what its worth, NO_NETWORK_TESTING is employed by default when Gentoo builds and tests packages, unless the user explicitly opts to enable network tests, and anything that respects that ENV var automatically benefits. ( Because from a security standpoint, the machine which fetches the .tar.gz's and the machine that installs and tests a package need not be the same machine, nor need be the same security level, and so the default approach is to ensure the build environment is tightly locked down, but this can cause spurious test failures when tests try to dial out to nowhere. Sometimes things as innocuous as trying to resolve "localhost" can get you having problems )
