lix/src/nix/make-content-addressable.cc

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Allow content-addressable paths to have references This adds a command 'nix make-content-addressable' that rewrites the specified store paths into content-addressable paths. The advantage of such paths is that 1) they can be imported without signatures; 2) they can enable deduplication in cases where derivation changes do not cause output changes (apart from store path hashes). For example, $ nix make-content-addressable -r nixpkgs.cowsay rewrote '/nix/store/g1g31ah55xdia1jdqabv1imf6mcw0nb1-glibc-2.25-49' to '/nix/store/48jfj7bg78a8n4f2nhg269rgw1936vj4-glibc-2.25-49' ... rewrote '/nix/store/qbi6rzpk0bxjw8lw6azn2mc7ynnn455q-cowsay-3.03+dfsg1-16' to '/nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16' We can then copy the resulting closure to another store without signatures: $ nix copy --trusted-public-keys '' ---to ~/my-nix /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16 In order to support self-references in content-addressable paths, these paths are hashed "modulo" self-references, meaning that self-references are zeroed out during hashing. Somewhat annoyingly, this means that the NAR hash stored in the Nix database is no longer necessarily equal to the output of "nix hash-path"; for content-addressable paths, you need to pass the --modulo flag: $ nix path-info --json /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16 | jq -r .[].narHash sha256:0ri611gdilz2c9rsibqhsipbfs9vwcqvs811a52i2bnkhv7w9mgw $ nix hash-path --type sha256 --base32 /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16 1ggznh07khq0hz6id09pqws3a8q9pn03ya3c03nwck1kwq8rclzs $ nix hash-path --type sha256 --base32 /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16 --modulo iq6g2x4q62xp7y7493bibx0qn5w7xz67 0ri611gdilz2c9rsibqhsipbfs9vwcqvs811a52i2bnkhv7w9mgw
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#include "command.hh"
#include "store-api.hh"
#include "make-content-addressed.hh"
#include "common-args.hh"
#include "json.hh"
Allow content-addressable paths to have references This adds a command 'nix make-content-addressable' that rewrites the specified store paths into content-addressable paths. The advantage of such paths is that 1) they can be imported without signatures; 2) they can enable deduplication in cases where derivation changes do not cause output changes (apart from store path hashes). For example, $ nix make-content-addressable -r nixpkgs.cowsay rewrote '/nix/store/g1g31ah55xdia1jdqabv1imf6mcw0nb1-glibc-2.25-49' to '/nix/store/48jfj7bg78a8n4f2nhg269rgw1936vj4-glibc-2.25-49' ... rewrote '/nix/store/qbi6rzpk0bxjw8lw6azn2mc7ynnn455q-cowsay-3.03+dfsg1-16' to '/nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16' We can then copy the resulting closure to another store without signatures: $ nix copy --trusted-public-keys '' ---to ~/my-nix /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16 In order to support self-references in content-addressable paths, these paths are hashed "modulo" self-references, meaning that self-references are zeroed out during hashing. Somewhat annoyingly, this means that the NAR hash stored in the Nix database is no longer necessarily equal to the output of "nix hash-path"; for content-addressable paths, you need to pass the --modulo flag: $ nix path-info --json /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16 | jq -r .[].narHash sha256:0ri611gdilz2c9rsibqhsipbfs9vwcqvs811a52i2bnkhv7w9mgw $ nix hash-path --type sha256 --base32 /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16 1ggznh07khq0hz6id09pqws3a8q9pn03ya3c03nwck1kwq8rclzs $ nix hash-path --type sha256 --base32 /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16 --modulo iq6g2x4q62xp7y7493bibx0qn5w7xz67 0ri611gdilz2c9rsibqhsipbfs9vwcqvs811a52i2bnkhv7w9mgw
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using namespace nix;
struct CmdMakeContentAddressable : StorePathsCommand, MixJSON
Allow content-addressable paths to have references This adds a command 'nix make-content-addressable' that rewrites the specified store paths into content-addressable paths. The advantage of such paths is that 1) they can be imported without signatures; 2) they can enable deduplication in cases where derivation changes do not cause output changes (apart from store path hashes). For example, $ nix make-content-addressable -r nixpkgs.cowsay rewrote '/nix/store/g1g31ah55xdia1jdqabv1imf6mcw0nb1-glibc-2.25-49' to '/nix/store/48jfj7bg78a8n4f2nhg269rgw1936vj4-glibc-2.25-49' ... rewrote '/nix/store/qbi6rzpk0bxjw8lw6azn2mc7ynnn455q-cowsay-3.03+dfsg1-16' to '/nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16' We can then copy the resulting closure to another store without signatures: $ nix copy --trusted-public-keys '' ---to ~/my-nix /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16 In order to support self-references in content-addressable paths, these paths are hashed "modulo" self-references, meaning that self-references are zeroed out during hashing. Somewhat annoyingly, this means that the NAR hash stored in the Nix database is no longer necessarily equal to the output of "nix hash-path"; for content-addressable paths, you need to pass the --modulo flag: $ nix path-info --json /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16 | jq -r .[].narHash sha256:0ri611gdilz2c9rsibqhsipbfs9vwcqvs811a52i2bnkhv7w9mgw $ nix hash-path --type sha256 --base32 /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16 1ggznh07khq0hz6id09pqws3a8q9pn03ya3c03nwck1kwq8rclzs $ nix hash-path --type sha256 --base32 /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16 --modulo iq6g2x4q62xp7y7493bibx0qn5w7xz67 0ri611gdilz2c9rsibqhsipbfs9vwcqvs811a52i2bnkhv7w9mgw
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{
CmdMakeContentAddressable()
{
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realiseMode = Realise::Outputs;
Allow content-addressable paths to have references This adds a command 'nix make-content-addressable' that rewrites the specified store paths into content-addressable paths. The advantage of such paths is that 1) they can be imported without signatures; 2) they can enable deduplication in cases where derivation changes do not cause output changes (apart from store path hashes). For example, $ nix make-content-addressable -r nixpkgs.cowsay rewrote '/nix/store/g1g31ah55xdia1jdqabv1imf6mcw0nb1-glibc-2.25-49' to '/nix/store/48jfj7bg78a8n4f2nhg269rgw1936vj4-glibc-2.25-49' ... rewrote '/nix/store/qbi6rzpk0bxjw8lw6azn2mc7ynnn455q-cowsay-3.03+dfsg1-16' to '/nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16' We can then copy the resulting closure to another store without signatures: $ nix copy --trusted-public-keys '' ---to ~/my-nix /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16 In order to support self-references in content-addressable paths, these paths are hashed "modulo" self-references, meaning that self-references are zeroed out during hashing. Somewhat annoyingly, this means that the NAR hash stored in the Nix database is no longer necessarily equal to the output of "nix hash-path"; for content-addressable paths, you need to pass the --modulo flag: $ nix path-info --json /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16 | jq -r .[].narHash sha256:0ri611gdilz2c9rsibqhsipbfs9vwcqvs811a52i2bnkhv7w9mgw $ nix hash-path --type sha256 --base32 /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16 1ggznh07khq0hz6id09pqws3a8q9pn03ya3c03nwck1kwq8rclzs $ nix hash-path --type sha256 --base32 /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16 --modulo iq6g2x4q62xp7y7493bibx0qn5w7xz67 0ri611gdilz2c9rsibqhsipbfs9vwcqvs811a52i2bnkhv7w9mgw
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}
std::string description() override
{
return "rewrite a path or closure to content-addressed form";
Allow content-addressable paths to have references This adds a command 'nix make-content-addressable' that rewrites the specified store paths into content-addressable paths. The advantage of such paths is that 1) they can be imported without signatures; 2) they can enable deduplication in cases where derivation changes do not cause output changes (apart from store path hashes). For example, $ nix make-content-addressable -r nixpkgs.cowsay rewrote '/nix/store/g1g31ah55xdia1jdqabv1imf6mcw0nb1-glibc-2.25-49' to '/nix/store/48jfj7bg78a8n4f2nhg269rgw1936vj4-glibc-2.25-49' ... rewrote '/nix/store/qbi6rzpk0bxjw8lw6azn2mc7ynnn455q-cowsay-3.03+dfsg1-16' to '/nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16' We can then copy the resulting closure to another store without signatures: $ nix copy --trusted-public-keys '' ---to ~/my-nix /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16 In order to support self-references in content-addressable paths, these paths are hashed "modulo" self-references, meaning that self-references are zeroed out during hashing. Somewhat annoyingly, this means that the NAR hash stored in the Nix database is no longer necessarily equal to the output of "nix hash-path"; for content-addressable paths, you need to pass the --modulo flag: $ nix path-info --json /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16 | jq -r .[].narHash sha256:0ri611gdilz2c9rsibqhsipbfs9vwcqvs811a52i2bnkhv7w9mgw $ nix hash-path --type sha256 --base32 /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16 1ggznh07khq0hz6id09pqws3a8q9pn03ya3c03nwck1kwq8rclzs $ nix hash-path --type sha256 --base32 /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16 --modulo iq6g2x4q62xp7y7493bibx0qn5w7xz67 0ri611gdilz2c9rsibqhsipbfs9vwcqvs811a52i2bnkhv7w9mgw
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}
std::string doc() override
{
return
#include "make-content-addressable.md"
;
}
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void run(ref<Store> store, StorePaths && storePaths) override
Allow content-addressable paths to have references This adds a command 'nix make-content-addressable' that rewrites the specified store paths into content-addressable paths. The advantage of such paths is that 1) they can be imported without signatures; 2) they can enable deduplication in cases where derivation changes do not cause output changes (apart from store path hashes). For example, $ nix make-content-addressable -r nixpkgs.cowsay rewrote '/nix/store/g1g31ah55xdia1jdqabv1imf6mcw0nb1-glibc-2.25-49' to '/nix/store/48jfj7bg78a8n4f2nhg269rgw1936vj4-glibc-2.25-49' ... rewrote '/nix/store/qbi6rzpk0bxjw8lw6azn2mc7ynnn455q-cowsay-3.03+dfsg1-16' to '/nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16' We can then copy the resulting closure to another store without signatures: $ nix copy --trusted-public-keys '' ---to ~/my-nix /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16 In order to support self-references in content-addressable paths, these paths are hashed "modulo" self-references, meaning that self-references are zeroed out during hashing. Somewhat annoyingly, this means that the NAR hash stored in the Nix database is no longer necessarily equal to the output of "nix hash-path"; for content-addressable paths, you need to pass the --modulo flag: $ nix path-info --json /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16 | jq -r .[].narHash sha256:0ri611gdilz2c9rsibqhsipbfs9vwcqvs811a52i2bnkhv7w9mgw $ nix hash-path --type sha256 --base32 /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16 1ggznh07khq0hz6id09pqws3a8q9pn03ya3c03nwck1kwq8rclzs $ nix hash-path --type sha256 --base32 /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16 --modulo iq6g2x4q62xp7y7493bibx0qn5w7xz67 0ri611gdilz2c9rsibqhsipbfs9vwcqvs811a52i2bnkhv7w9mgw
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{
auto remappings = makeContentAddressed(*store, *store,
StorePathSet(storePaths.begin(), storePaths.end()));
if (json) {
JSONObject jsonRoot(std::cout);
JSONObject jsonRewrites(jsonRoot.object("rewrites"));
for (auto & path : storePaths) {
auto i = remappings.find(path);
assert(i != remappings.end());
jsonRewrites.attr(store->printStorePath(path), store->printStorePath(i->second));
}
} else {
for (auto & path : storePaths) {
auto i = remappings.find(path);
assert(i != remappings.end());
notice("rewrote '%s' to '%s'",
store->printStorePath(path),
store->printStorePath(i->second));
Allow content-addressable paths to have references This adds a command 'nix make-content-addressable' that rewrites the specified store paths into content-addressable paths. The advantage of such paths is that 1) they can be imported without signatures; 2) they can enable deduplication in cases where derivation changes do not cause output changes (apart from store path hashes). For example, $ nix make-content-addressable -r nixpkgs.cowsay rewrote '/nix/store/g1g31ah55xdia1jdqabv1imf6mcw0nb1-glibc-2.25-49' to '/nix/store/48jfj7bg78a8n4f2nhg269rgw1936vj4-glibc-2.25-49' ... rewrote '/nix/store/qbi6rzpk0bxjw8lw6azn2mc7ynnn455q-cowsay-3.03+dfsg1-16' to '/nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16' We can then copy the resulting closure to another store without signatures: $ nix copy --trusted-public-keys '' ---to ~/my-nix /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16 In order to support self-references in content-addressable paths, these paths are hashed "modulo" self-references, meaning that self-references are zeroed out during hashing. Somewhat annoyingly, this means that the NAR hash stored in the Nix database is no longer necessarily equal to the output of "nix hash-path"; for content-addressable paths, you need to pass the --modulo flag: $ nix path-info --json /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16 | jq -r .[].narHash sha256:0ri611gdilz2c9rsibqhsipbfs9vwcqvs811a52i2bnkhv7w9mgw $ nix hash-path --type sha256 --base32 /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16 1ggznh07khq0hz6id09pqws3a8q9pn03ya3c03nwck1kwq8rclzs $ nix hash-path --type sha256 --base32 /nix/store/iq6g2x4q62xp7y7493bibx0qn5w7xz67-cowsay-3.03+dfsg1-16 --modulo iq6g2x4q62xp7y7493bibx0qn5w7xz67 0ri611gdilz2c9rsibqhsipbfs9vwcqvs811a52i2bnkhv7w9mgw
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}
}
}
};
static auto rCmdMakeContentAddressable = registerCommand2<CmdMakeContentAddressable>({"store", "make-content-addressable"});