lix/src/libstore/builtins/fetchurl.cc
John Ericson f4a5913125 hashed-mirrors: Use parsed derivation output rather than reconstructing it
Now the derivation outputs are parsed up front, we can avoid a reparse
by doing it. Also, this just feels a bit better as the `output*` env
vars are more of a `libnixexpr` interface than `libnixstore` interface:
ultimately, it's the derivation outputs that decide whether the
derivation is fixed-output.

Yes, hashed mirrors might go away with #3689, but this bit of code would
be moved rather than deleted, so it's worth doing a cleanup anyways I
think.
2020-06-22 15:17:20 +00:00

82 lines
2.7 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 (output.hash && output.hash->method == FileIngestionMethod::Flat)
for (auto hashedMirror : settings.hashedMirrors.get())
try {
if (!hasSuffix(hashedMirror, "/")) hashedMirror += '/';
auto & h = output.hash->hash;
fetch(hashedMirror + printHashType(*h.type) + "/" + h.to_string(Base16, false));
return;
} catch (Error & e) {
debug(e.what());
}
/* Otherwise try the specified URL. */
fetch(mainUrl);
}
}