[tor-bugs] #9957 [Tor]: Tor should consider stderr output of transport proxies

[Tor Bug Tracker & Wiki]

#9957: Tor should consider stderr output of transport proxies
------------------------+--------------------------------
     Reporter:  wfn     |      Owner:
         Type:  defect  |     Status:  needs_review
     Priority:  minor   |  Milestone:  Tor: 0.2.6.x-final
    Component:  Tor     |    Version:
   Resolution:          |   Keywords:  tor-pt
Actual Points:          |  Parent ID:
       Points:          |
------------------------+--------------------------------

Comment (by wfn):

 Replying to [comment:11 asn]:
 > Replying to [comment:9 wfn]:
 > > Replying to [comment:7 asn]:
 > >
 > >
 > > > Patch looks plausible.
 > > >
 > > > Three comments:
 > >
 > > > Maybe we should just suggest people to look into INFO-level logs,
 since obfsproxy doesn't log to a file by default, and some times it
 doesn't have time to write a logfile when this error appears (in
 ImportErrors, etc.).
 > >
 > > I agree (that was indeed the original problem anyway.) Log message
 tells them that, maybe it should be more clear about it? But this notice
 is there.
 > >
 >
 > I wanted to say that maybe we shouldn't even suggest people to look at
 obfsproxy's log, because that might confuse them (they probably don't know
 if obfsproxy is logging or where. and obfsproxy does not log by default).
 We should only suggest people to look at Tor's info log.
 >
 > BTW, here is the current log message:
 > {{{
 >     log_notice(LD_GENERAL, "Managed proxy '%s' is giving some output
 over "
 >                "the standard error pipe. This usually means that it has
 "
 >                "encountered some error that I won't be able to
 understand. "
 >                "You should check its log, or enable INFO-level tor log
 to "
 >                "see what it is saying.", mp->argv[0]);
 > }}}
 >
 > What do you think?

 Ahh - of course, that makes sense, yeah. See rebased commit above
 (https://github.com/wfn/tor/commit/580516d37f4332da280a1cd5077f71285e6d75cc)
 - I considered including a very short notice about which keyword to use in
 torrc to enable INFO etc., but it would all come out too verbose, I think.
 So simply removed the 'look at PT proxy logs' part.

 > > > c) I wonder what PTs currently output to stderr. Maybe if we are
 serious about this, we should add another convention to `pt-spec.txt`
 asking PTs to not print stuff in stderr except if they have error messages
 that the user should see.
 > >
 > > Yeah, I was wondering if this could not cause any trouble in some
 other/future PTs. Adding an explicit clause makes sense. Also, it'd be
 nice to make sure all current PTs already stick to this practice
 (obfsproxy does, I guess.)
 >
 > Yeah, we should make sure of this.

 Should I try and produce a possible patch for `pt-spec.txt`? Not confident
 about wording things there re: this.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/9957#comment:13>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online