Re: [Gnu-arch-users] [BUG] tla cat-archive-log downloads .listing files unnecessarily

[Aaron Bentley]

Since tla has no exception handling mechanism, the only way to prevent 
http 404/IO_PANIC etc. messages from being displayed is to verify that 
user-supplied revision names actually exist before attempting to use them.

Matthieu Moy wrote:
> It seems that tla downloads unnecessary .listing files when running
> cat-archive-log:
>
> $ strace tla cat-archive-log
> address@hidden/xtla--jet--0.2--patch-100 | & grep GET
> fcntl64(3, F_GETFD)                     = 0

This part looks like the initial connection setup:
> write(3, "GET /arch/xtla/.listing HTTP/1.1"..., 134) = 134
> write(3, "GET /arch/xtla/.listing HTTP/1.1"..., 134) = 134
> write(3, "GET /arch/xtla/=meta-info/mirror"..., 143) = 143
> write(3, "GET /arch/xtla/=meta-info/name H"..., 141) = 141
> write(3, "GET /arch/xtla/=meta-info/http-b"..., 147) = 147
> write(3, "GET /arch/xtla/=meta-info/signed"..., 151) = 151

What version of tla is this?  It looks like earlier than 1.2.1.  1.2.1 
and later shoul be a bit better than this.,

Make sure the category  exists
> write(3, "GET /arch/xtla/.listing HTTP/1.1"..., 134) = 134
> write(3, "GET /arch/xtla/.listing HTTP/1.1"..., 134) = 134

make sure the branch exists
> write(3, "GET /arch/xtla/xtla/.listing HTT"..., 139) = 139
> write(3, "GET /arch/xtla/xtla/xtla--jet/.l"..., 149) = 149

make sure the version exists
> write(3, "GET /arch/xtla/.listing HTTP/1.1"..., 134) = 134
> write(3, "GET /arch/xtla/xtla/xtla--jet/xt"..., 174) = 174
> write(3, "GET /arch/xtla/xtla/xtla--jet/xt"..., 174) = 174
> write(3, "GET /arch/xtla/xtla/xtla--jet/xt"..., 183) = 183
> write(3, "GET /arch/xtla/xtla/xtla--jet/xt"..., 169) = 169
>
> tla knows exactly the location of the file.  One single GET should be
> sufficient here. (possibly followed by others in case of failure, to
> get the diagnosis)
>
> Since tla has no (yet) HTTP pipelining, this results in a considerable
> performance loss: tla cat-archive-log takes 5 seconds to execute where
> a wget on the right URL takes only 0.60 seconds!

If you screw up the URL, wget can only tell you 404.  Arch will tell you 
whether the revision, version, category or branch was wrong.

Aaron
--
Aaron Bentley
Director of Technology
Panometrics, Inc.