dns: don't skip getaddrino/getnameinfo when c-ares init fails

[bnoordhuis]

#8710 makes process.binding('cares_wrap') throw a JS exception instead of aborting when ares_library_init() or ares_init_options() fail.

Maybe we can do better. We can still bring up the bindings for getaddrinfo and getnameinfo because those don't depend on c-ares (although if c-ares fails, there is a goodly chance the others won't work either.)

Policy question: do we think it's better to quit or keep on trucking in a franken-init state?

[cjihrig]

do we think it's better to quit or keep on trucking in a franken-init state?

My vote is to quit. If people really need the franken-init state, perhaps we could add flag for it.

[weagle08]

i'd like some way around this. my set up is just setting up a LAN with a switch and letting windows assign an IP and Mask, however no DNS is set. The machines should still be able to communicate with no DNS set.

[Trott]

@bnoordhuis @cjihrig Should this remain open? If so, should we add help wanted and maybe even mentor available?

[mika-fischer]

We have a client server application with a C++/Qt UI and a NodeJS backend (running as a windows service). We've seen this bug only once but in that case it prevents our application (which needs only to listen on 127.0.0.1 and needs no DNS) from working.

So we would also be interested in a fix.

[bnoordhuis]

I'm on the fence myself but happy to review pull requests or answer questions. Labels added.

[mika-fischer]

Looks like this might be fixed in c-ares 1.13.0:
c-ares/c-ares@55bbe92
https://c-ares.haxx.se/mail/c-ares-archive-2017-06/0003.shtml

EDIT: Actually, looks like it should already be fixed in 1.12...

[ryzokuken]

It is fixed already? In that case, should this issue be closed?

[bnoordhuis]

Not fixed and no consensus on whether it should be fixed.

[mika-fischer]

@bnoordhuis I think this is actually two issues now:

1. What to do if ares_library_init() or ares_init_options() fail and
2. Updating c-ares so that ares_init_options() don't fail under benign circumstances (like network with no DNS configured).

I don't care much about 1) but I do care about 2). Do you mean to say that c-ares might never be updated in Node.js?

[bnoordhuis]

This issue is about (1), not (2). If you want to see c-ares updated, can you file a new issue?

[mika-fischer]

Actually, c-ares 1.13 it's already in Node 9, so 2) is not relevant anymore. Sorry for the noise!

[dhanushuUzumaki]

Hi, Is this available? I would like to work on this.

[bnoordhuis]

@dhanushuUzumaki See #8966 (comment). You're welcome to open a pull request but I can't promise it'll be accepted.

[refack]

Put into https://github.com/nodejs/node/projects/13 backlog