lix/src/libstore/binary-cache-store.cc
Eelco Dolstra 451ebf24ce Cache path info lookups in SQLite
This re-implements the binary cache database in C++, allowing it to be
used by other Store backends, in particular the S3 backend.
2016-04-20 14:12:38 +02:00

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#include "archive.hh"
#include "binary-cache-store.hh"
#include "compression.hh"
#include "derivations.hh"
#include "fs-accessor.hh"
#include "globals.hh"
#include "nar-info.hh"
#include "sync.hh"
#include "worker-protocol.hh"
#include "nar-accessor.hh"
#include <chrono>
namespace nix {
BinaryCacheStore::BinaryCacheStore(std::shared_ptr<Store> localStore,
const Path & secretKeyFile)
: localStore(localStore)
{
if (secretKeyFile != "") {
secretKey = std::unique_ptr<SecretKey>(new SecretKey(readFile(secretKeyFile)));
publicKeys = std::unique_ptr<PublicKeys>(new PublicKeys);
publicKeys->emplace(secretKey->name, secretKey->toPublicKey());
}
StringSink sink;
sink << narVersionMagic1;
narMagic = *sink.s;
}
void BinaryCacheStore::init()
{
std::string cacheInfoFile = "nix-cache-info";
if (!fileExists(cacheInfoFile))
upsertFile(cacheInfoFile, "StoreDir: " + settings.nixStore + "\n");
}
void BinaryCacheStore::notImpl()
{
throw Error("operation not implemented for binary cache stores");
}
Path BinaryCacheStore::narInfoFileFor(const Path & storePath)
{
assertStorePath(storePath);
return storePathToHash(storePath) + ".narinfo";
}
void BinaryCacheStore::addToCache(const ValidPathInfo & info,
const string & nar)
{
auto narInfoFile = narInfoFileFor(info.path);
if (fileExists(narInfoFile)) return;
assert(nar.compare(0, narMagic.size(), narMagic) == 0);
auto narInfo = make_ref<NarInfo>(info);
narInfo->narSize = nar.size();
narInfo->narHash = hashString(htSHA256, nar);
if (info.narHash && info.narHash != narInfo->narHash)
throw Error(format("refusing to copy corrupted path %1% to binary cache") % info.path);
/* Compress the NAR. */
narInfo->compression = "xz";
auto now1 = std::chrono::steady_clock::now();
string narXz = compressXZ(nar);
auto now2 = std::chrono::steady_clock::now();
narInfo->fileHash = hashString(htSHA256, narXz);
narInfo->fileSize = narXz.size();
auto duration = std::chrono::duration_cast<std::chrono::milliseconds>(now2 - now1).count();
printMsg(lvlTalkative, format("copying path %1% (%2% bytes, compressed %3$.1f%% in %4% ms) to binary cache")
% narInfo->path % narInfo->narSize
% ((1.0 - (double) narXz.size() / nar.size()) * 100.0)
% duration);
/* Atomically write the NAR file. */
narInfo->url = "nar/" + printHash32(narInfo->fileHash) + ".nar.xz";
if (!fileExists(narInfo->url)) {
stats.narWrite++;
upsertFile(narInfo->url, narXz);
} else
stats.narWriteAverted++;
stats.narWriteBytes += nar.size();
stats.narWriteCompressedBytes += narXz.size();
stats.narWriteCompressionTimeMs += duration;
/* Atomically write the NAR info file.*/
if (secretKey) narInfo->sign(*secretKey);
upsertFile(narInfoFile, narInfo->to_string());
{
auto state_(state.lock());
state_->pathInfoCache.upsert(narInfo->path, std::shared_ptr<NarInfo>(narInfo));
}
stats.narInfoWrite++;
}
bool BinaryCacheStore::isValidPathUncached(const Path & storePath)
{
// FIXME: this only checks whether a .narinfo with a matching hash
// part exists. So f4kb...-foo matches f4kb...-bar, even
// though they shouldn't. Not easily fixed.
return fileExists(narInfoFileFor(storePath));
}
void BinaryCacheStore::narFromPath(const Path & storePath, Sink & sink)
{
auto info = queryPathInfo(storePath).cast<const NarInfo>();
auto nar = getFile(info->url);
if (!nar) throw Error(format("file %s missing from binary cache") % info->url);
stats.narRead++;
stats.narReadCompressedBytes += nar->size();
/* Decompress the NAR. FIXME: would be nice to have the remote
side do this. */
if (info->compression == "none")
;
else if (info->compression == "xz")
nar = decompressXZ(*nar);
else
throw Error(format("unknown NAR compression type %1%") % nar);
stats.narReadBytes += nar->size();
printMsg(lvlTalkative, format("exporting path %1% (%2% bytes)") % storePath % nar->size());
assert(nar->size() % 8 == 0);
sink((unsigned char *) nar->c_str(), nar->size());
}
void BinaryCacheStore::exportPath(const Path & storePath, bool sign, Sink & sink)
{
assert(!sign);
auto res = queryPathInfo(storePath);
narFromPath(storePath, sink);
// FIXME: check integrity of NAR.
sink << exportMagic << storePath << res->references << res->deriver << 0;
}
Paths BinaryCacheStore::importPaths(bool requireSignature, Source & source,
std::shared_ptr<FSAccessor> accessor)
{
assert(!requireSignature);
Paths res;
while (true) {
unsigned long long n = readLongLong(source);
if (n == 0) break;
if (n != 1) throw Error("input doesn't look like something created by nix-store --export");
res.push_back(importPath(source, accessor));
}
return res;
}
struct TeeSource : Source
{
Source & readSource;
ref<std::string> data;
TeeSource(Source & readSource)
: readSource(readSource)
, data(make_ref<std::string>())
{
}
size_t read(unsigned char * data, size_t len)
{
size_t n = readSource.read(data, len);
this->data->append((char *) data, n);
return n;
}
};
struct NopSink : ParseSink
{
};
std::shared_ptr<ValidPathInfo> BinaryCacheStore::queryPathInfoUncached(const Path & storePath)
{
auto narInfoFile = narInfoFileFor(storePath);
auto data = getFile(narInfoFile);
if (!data) return 0;
auto narInfo = make_ref<NarInfo>(*data, narInfoFile);
if (narInfo->path != storePath)
throw Error(format("NAR info file for store path %1% does not match %2%") % narInfo->path % storePath);
stats.narInfoRead++;
if (publicKeys) {
if (!narInfo->checkSignatures(*publicKeys))
throw Error(format("no good signature on NAR info file %1%") % narInfoFile);
}
return std::shared_ptr<NarInfo>(narInfo);
}
void BinaryCacheStore::querySubstitutablePathInfos(const PathSet & paths,
SubstitutablePathInfos & infos)
{
PathSet left;
if (!localStore) return;
for (auto & storePath : paths) {
try {
auto info = localStore->queryPathInfo(storePath);
SubstitutablePathInfo sub;
sub.references = info->references;
sub.downloadSize = 0;
sub.narSize = info->narSize;
infos.emplace(storePath, sub);
} catch (InvalidPath &) {
left.insert(storePath);
}
}
if (settings.useSubstitutes)
localStore->querySubstitutablePathInfos(left, infos);
}
Path BinaryCacheStore::addToStore(const string & name, const Path & srcPath,
bool recursive, HashType hashAlgo, PathFilter & filter, bool repair)
{
// FIXME: some cut&paste from LocalStore::addToStore().
/* Read the whole path into memory. This is not a very scalable
method for very large paths, but `copyPath' is mainly used for
small files. */
StringSink sink;
Hash h;
if (recursive) {
dumpPath(srcPath, sink, filter);
h = hashString(hashAlgo, *sink.s);
} else {
auto s = readFile(srcPath);
dumpString(s, sink);
h = hashString(hashAlgo, s);
}
ValidPathInfo info;
info.path = makeFixedOutputPath(recursive, hashAlgo, h, name);
if (repair || !isValidPath(info.path))
addToCache(info, *sink.s);
return info.path;
}
Path BinaryCacheStore::addTextToStore(const string & name, const string & s,
const PathSet & references, bool repair)
{
ValidPathInfo info;
info.path = computeStorePathForText(name, s, references);
info.references = references;
if (repair || !isValidPath(info.path)) {
StringSink sink;
dumpString(s, sink);
addToCache(info, *sink.s);
}
return info.path;
}
void BinaryCacheStore::buildPaths(const PathSet & paths, BuildMode buildMode)
{
for (auto & storePath : paths) {
assert(!isDerivation(storePath));
if (isValidPath(storePath)) continue;
if (!localStore)
throw Error(format("don't know how to realise path %1% in a binary cache") % storePath);
localStore->addTempRoot(storePath);
if (!localStore->isValidPath(storePath))
localStore->ensurePath(storePath);
auto info = localStore->queryPathInfo(storePath);
for (auto & ref : info->references)
if (ref != storePath)
ensurePath(ref);
StringSink sink;
dumpPath(storePath, sink);
addToCache(*info, *sink.s);
}
}
void BinaryCacheStore::ensurePath(const Path & path)
{
buildPaths({path});
}
/* Given requests for a path /nix/store/<x>/<y>, this accessor will
first download the NAR for /nix/store/<x> from the binary cache,
build a NAR accessor for that NAR, and use that to access <y>. */
struct BinaryCacheStoreAccessor : public FSAccessor
{
ref<BinaryCacheStore> store;
std::map<Path, ref<FSAccessor>> nars;
BinaryCacheStoreAccessor(ref<BinaryCacheStore> store)
: store(store)
{
}
std::pair<ref<FSAccessor>, Path> fetch(const Path & path_)
{
auto path = canonPath(path_);
auto storePath = toStorePath(path);
std::string restPath = std::string(path, storePath.size());
if (!store->isValidPath(storePath))
throw Error(format("path %1% is not a valid store path") % storePath);
auto i = nars.find(storePath);
if (i != nars.end()) return {i->second, restPath};
StringSink sink;
store->exportPath(storePath, false, sink);
auto accessor = makeNarAccessor(sink.s);
nars.emplace(storePath, accessor);
return {accessor, restPath};
}
Stat stat(const Path & path) override
{
auto res = fetch(path);
return res.first->stat(res.second);
}
StringSet readDirectory(const Path & path) override
{
auto res = fetch(path);
return res.first->readDirectory(res.second);
}
std::string readFile(const Path & path) override
{
auto res = fetch(path);
return res.first->readFile(res.second);
}
std::string readLink(const Path & path) override
{
auto res = fetch(path);
return res.first->readLink(res.second);
}
};
ref<FSAccessor> BinaryCacheStore::getFSAccessor()
{
return make_ref<BinaryCacheStoreAccessor>(ref<BinaryCacheStore>(
std::dynamic_pointer_cast<BinaryCacheStore>(shared_from_this())));
}
Path BinaryCacheStore::importPath(Source & source, std::shared_ptr<FSAccessor> accessor)
{
/* FIXME: some cut&paste of LocalStore::importPath(). */
/* Extract the NAR from the source. */
TeeSource tee(source);
NopSink sink;
parseDump(sink, tee);
uint32_t magic = readInt(source);
if (magic != exportMagic)
throw Error("Nix archive cannot be imported; wrong format");
ValidPathInfo info;
info.path = readStorePath(source);
info.references = readStorePaths<PathSet>(source);
readString(source); // deriver, don't care
bool haveSignature = readInt(source) == 1;
assert(!haveSignature);
addToCache(info, *tee.data);
auto accessor_ = std::dynamic_pointer_cast<BinaryCacheStoreAccessor>(accessor);
if (accessor_)
accessor_->nars.emplace(info.path, makeNarAccessor(tee.data));
return info.path;
}
}