[tor-bugs] #14784 [Tor]: Implement status/fresh-relay-descs controller command

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#14784: Implement status/fresh-relay-descs controller command
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     Reporter:  Sebastian    |      Owner:
         Type:  enhancement  |     Status:  new
     Priority:  normal       |  Milestone:  Tor: 0.2.7.x-final
    Component:  Tor          |    Version:
   Resolution:               |   Keywords:
Actual Points:               |  Parent ID:
       Points:               |
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Comment (by Sebastian):

 Replying to [comment:3 atagar]:
 > Lets have separate methods for getting the server and extrainfo
 descriptor. Unless I'm missing something there's no reason for 'GETINFO
 status/fresh-relay-descs' to return both. Maybe...
 >
 > {{{
 > GETINFO status/fresh-descriptor/desc
 > GETINFO status/fresh-descriptor/extra-info
 > }}}
 >
 > Just picking 'desc' here to be consistent with the earlier methods.
 Don't really care much about the name. :P

 I thought this too at first, but it's not possible to use this because the
 descriptors are temporary. To generate the relay descriptor, we have to
 generate the extra-info document too (to reference it from the
 descriptor). I could be convinced to add a method to just fetch the
 descriptor without extrainfo.

 > Nitpick but we're pretty inconsistent with descriptor naming...
 >
 >  * 'GETINFO desc/*' and Stem call the main self-published descriptors
 'server descriptors'.
 >  * The dir-spec calls them 'router descriptors'... usually. It opts for
 'server descriptor' in section 6.2.
 >  * CollecTor calls them 'relay descriptors'.
 >
 > It looks like you're opting for 'relay descriptors' here. That's fine,
 just pointing out that we're inconsistent. Maybe we should have another
 ticket to settle on a name? The specs and CollecTor can easily change, but
 Stem's classes would be a problem since we vend those.

 I think this is for another ticket, another time

 >
 > {{{
 > + DOC("status/fresh-relay-descs",
 > + "A fresh relay/ei descriptor pair for Tor's current state. Not
 stored."),
 > }}}
 >
 > I'm guessing the "/ei" is a typo?

 No, but extrainfo should be spelled out

 > {{{
 > if (router_build_fresh_descriptor(&r, &e) < 0) {
 > }}}
 >
 > I don't know Tor's conventions but maybe != 0 is safer? In practice I
 know this is fine (presently it only returns negative or zero statuses)
 but not sure if this is like exit status codes where any non-zero
 indicates failure.

 Imo that's fine.

 > {{{
 > + if (e) {
 > + size += e->cache_info.signed_descriptor_len + 1;
 > + }
 > }}}
 >
 > Do you know the use cases where a server descriptor can be generated but
 an extrainfo can't? Didn't know that was possible.

 There's a code path. I don't know if there's any kind of way to trigger it
 in practice in current Tor. I don't think it is possible, but it's
 currently allowed.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/14784#comment:4>
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