From 1511aa9f488ba0762c2da0bf8ab61b5fde47305d Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Fri, 17 Jul 2015 17:57:40 +0200 Subject: Allow remote builds without sending the derivation closure Previously, to build a derivation remotely, we had to copy the entire closure of the .drv file to the remote machine, even though we only need the top-level derivation. This is very wasteful: the closure can contain thousands of store paths, and in some Hydra use cases, include source paths that are very large (e.g. Git/Mercurial checkouts). So now there is a new operation, StoreAPI::buildDerivation(), that performs a build from an in-memory representation of a derivation (BasicDerivation) rather than from a on-disk .drv file. The only files that need to be in the Nix store are the sources of the derivation (drv.inputSrcs), and the needed output paths of the dependencies (as described by drv.inputDrvs). "nix-store --serve" exposes this interface. Note that this is a privileged operation, because you can construct a derivation that builds any store path whatsoever. Fixing this will require changing the hashing scheme (i.e., the output paths should be computed from the other fields in BasicDerivation, allowing them to be verified without access to other derivations). However, this would be quite nice because it would allow .drv-free building (e.g. "nix-env -i" wouldn't have to write any .drv files to disk). Fixes #173. --- src/libstore/derivations.hh | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) (limited to 'src/libstore/derivations.hh') diff --git a/src/libstore/derivations.hh b/src/libstore/derivations.hh index 8d5e4d05d469..f0842045f86b 100644 --- a/src/libstore/derivations.hh +++ b/src/libstore/derivations.hh @@ -40,15 +40,21 @@ typedef std::map DerivationInputs; typedef std::map StringPairs; -struct Derivation +struct BasicDerivation { DerivationOutputs outputs; /* keyed on symbolic IDs */ - DerivationInputs inputDrvs; /* inputs that are sub-derivations */ PathSet inputSrcs; /* inputs that are sources */ string platform; Path builder; Strings args; StringPairs env; + + virtual ~BasicDerivation() { }; +}; + +struct Derivation : BasicDerivation +{ + DerivationInputs inputDrvs; /* inputs that are sub-derivations */ }; @@ -89,6 +95,12 @@ Path makeDrvPathWithOutputs(const Path & drvPath, const std::set & outpu bool wantOutput(const string & output, const std::set & wanted); -PathSet outputPaths(const Derivation & drv); +PathSet outputPaths(const BasicDerivation & drv); + +struct Source; +struct Sink; + +Source & operator >> (Source & in, BasicDerivation & drv); +Sink & operator << (Sink & out, const BasicDerivation & drv); } -- cgit 1.4.1