lix/src/libstore/builtins/fetchurl.cc
Matthew Bauer 8e0d0689be Only store hash of fixed derivation output
we don’t need a full storepath for a fixedoutput derivation. So just
putting the ingestion method + the hash is sufficient.
2020-07-08 19:11:39 -04:00

85 lines
2.8 KiB
C++

#include "builtins.hh"
#include "filetransfer.hh"
#include "store-api.hh"
#include "archive.hh"
#include "compression.hh"
namespace nix {
void builtinFetchurl(const BasicDerivation & drv, const std::string & netrcData)
{
/* Make the host's netrc data available. Too bad curl requires
this to be stored in a file. It would be nice if we could just
pass a pointer to the data. */
if (netrcData != "") {
settings.netrcFile = "netrc";
writeFile(settings.netrcFile, netrcData, 0600);
}
auto getAttr = [&](const string & name) {
auto i = drv.env.find(name);
if (i == drv.env.end()) throw Error("attribute '%s' missing", name);
return i->second;
};
Path storePath = getAttr("out");
auto mainUrl = getAttr("url");
bool unpack = get(drv.env, "unpack").value_or("") == "1";
/* Note: have to use a fresh fileTransfer here because we're in
a forked process. */
auto fileTransfer = makeFileTransfer();
auto fetch = [&](const std::string & url) {
auto source = sinkToSource([&](Sink & sink) {
/* No need to do TLS verification, because we check the hash of
the result anyway. */
FileTransferRequest request(url);
request.verifyTLS = false;
request.decompress = false;
auto decompressor = makeDecompressionSink(
unpack && hasSuffix(mainUrl, ".xz") ? "xz" : "none", sink);
fileTransfer->download(std::move(request), *decompressor);
decompressor->finish();
});
if (unpack)
restorePath(storePath, *source);
else
writeFile(storePath, *source);
auto executable = drv.env.find("executable");
if (executable != drv.env.end() && executable->second == "1") {
if (chmod(storePath.c_str(), 0755) == -1)
throw SysError("making '%1%' executable", storePath);
}
};
/* We always have one output, and if it's a fixed-output derivation (as
checked below) it must be the only output */
auto & output = drv.outputs.begin()->second;
/* Try the hashed mirrors first. */
if (auto hash = std::get_if<DerivationOutputFixed>(&output.output)) {
if (hash->hash.method == FileIngestionMethod::Flat) {
for (auto hashedMirror : settings.hashedMirrors.get()) {
try {
if (!hasSuffix(hashedMirror, "/")) hashedMirror += '/';
fetch(hashedMirror + printHashType(*hash->hash.hash.type) + "/" + hash->hash.hash.to_string(Base16, false));
return;
} catch (Error & e) {
debug(e.what());
}
}
}
}
/* Otherwise try the specified URL. */
fetch(mainUrl);
}
}