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| author | Eelco Dolstra <edolstra@gmail.com> | 2017-12-07 00:50:46 +0100 |
|---|---|---|
| committer | Eelco Dolstra <edolstra@gmail.com> | 2017-12-07 01:07:07 +0100 |
| commit | 2df9cbeb47177d6a21606b4b509ebcf6bd0437a6 (patch) | |
| tree | 14edcd7742a582cdaf5245ae86cb914748b0ebf4 /src/libstore/remote-fs-accessor.hh | |
| parent | 338f29dbd4ee04f2de4c747eadb8c106a98f885c (diff) | |
Provide random access to cached NARs
E.g.
$ time nix cat-store --store https://cache.nixos.org?local-nar-cache=/tmp/nars \
/nix/store/b0w2hafndl09h64fhb86kw6bmhbmnpm1-blender-2.79/share/icons/hicolor/scalable/apps/blender.svg > /dev/null
real 0m4.139s
$ time nix cat-store --store https://cache.nixos.org?local-nar-cache=/tmp/nars \
/nix/store/b0w2hafndl09h64fhb86kw6bmhbmnpm1-blender-2.79/share/icons/hicolor/scalable/apps/blender.svg > /dev/null
real 0m0.024s
(Before, the second call took ~0.220s.)
This will use a NAR listing in
/tmp/nars/b0w2hafndl09h64fhb86kw6bmhbmnpm1.ls containing all metadata,
including the offsets of regular files inside the NAR. Thus, we don't
need to read the entire NAR. (We do read the entire listing, but
that's generally pretty small. We could use a SQLite DB by borrowing
some more code from nixos-channel-scripts/file-cache.hh.)
This is primarily useful when Hydra is serving files from an S3 binary
cache, in particular when you have giant NARs. E.g. we had some 12 GiB
NARs, so accessing individuals files was pretty slow.
Diffstat (limited to 'src/libstore/remote-fs-accessor.hh')
| -rw-r--r-- | src/libstore/remote-fs-accessor.hh | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/src/libstore/remote-fs-accessor.hh b/src/libstore/remote-fs-accessor.hh index 2a3fc01ef..4afb3be95 100644 --- a/src/libstore/remote-fs-accessor.hh +++ b/src/libstore/remote-fs-accessor.hh @@ -18,9 +18,10 @@ class RemoteFSAccessor : public FSAccessor friend class BinaryCacheStore; - Path makeCacheFile(const Path & storePath); + Path makeCacheFile(const Path & storePath, const std::string & ext); - void addToCache(const Path & storePath, const std::string & nar); + void addToCache(const Path & storePath, const std::string & nar, + ref<FSAccessor> narAccessor); public: |