lix/src/libstore/legacy-ssh-store.cc
Eelco Dolstra ea7fa88131
LegacySSHStore: Provide a faster implementation of computeFSClosure()
This avoids the latency of the standard implementation, which can make
a huge difference (e.g. 16.5s -> 0.5s on a NixOS system closure).
2017-03-16 11:44:52 +01:00

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#include "archive.hh"
#include "pool.hh"
#include "remote-store.hh"
#include "serve-protocol.hh"
#include "store-api.hh"
#include "worker-protocol.hh"
#include "ssh.hh"
namespace nix {
static std::string uriScheme = "legacy-ssh://";
struct LegacySSHStore : public Store
{
struct Connection
{
std::unique_ptr<SSHMaster::Connection> sshConn;
FdSink to;
FdSource from;
};
std::string host;
ref<Pool<Connection>> connections;
SSHMaster master;
LegacySSHStore(const string & host, const Params & params)
: Store(params)
, host(host)
, connections(make_ref<Pool<Connection>>(
std::max(1, std::stoi(get(params, "max-connections", "1"))),
[this]() { return openConnection(); },
[](const ref<Connection> & r) { return true; }
))
, master(
host,
get(params, "ssh-key", ""),
// Use SSH master only if using more than 1 connection.
connections->capacity() > 1,
get(params, "compress", "") == "true")
{
}
ref<Connection> openConnection()
{
auto conn = make_ref<Connection>();
conn->sshConn = master.startCommand("nix-store --serve --write");
conn->to = FdSink(conn->sshConn->in.get());
conn->from = FdSource(conn->sshConn->out.get());
int remoteVersion;
try {
conn->to << SERVE_MAGIC_1 << SERVE_PROTOCOL_VERSION;
conn->to.flush();
unsigned int magic = readInt(conn->from);
if (magic != SERVE_MAGIC_2)
throw Error("protocol mismatch with nix-store --serve on %s", host);
remoteVersion = readInt(conn->from);
if (GET_PROTOCOL_MAJOR(remoteVersion) != 0x200)
throw Error("unsupported nix-store --serve protocol version on %s", host);
} catch (EndOfFile & e) {
throw Error("cannot connect to %1%", host);
}
return conn;
};
string getUri() override
{
return uriScheme + host;
}
void queryPathInfoUncached(const Path & path,
std::function<void(std::shared_ptr<ValidPathInfo>)> success,
std::function<void(std::exception_ptr exc)> failure) override
{
sync2async<std::shared_ptr<ValidPathInfo>>(success, failure, [&]() -> std::shared_ptr<ValidPathInfo> {
auto conn(connections->get());
debug("querying remote host %s for info on %s", host, path);
conn->to << cmdQueryPathInfos << PathSet{path};
conn->to.flush();
auto info = std::make_shared<ValidPathInfo>();
conn->from >> info->path;
if (info->path.empty()) return nullptr;
assert(path == info->path);
PathSet references;
conn->from >> info->deriver;
info->references = readStorePaths<PathSet>(*this, conn->from);
readLongLong(conn->from); // download size
info->narSize = readLongLong(conn->from);
auto s = readString(conn->from);
assert(s == "");
return info;
});
}
void addToStore(const ValidPathInfo & info, const ref<std::string> & nar,
bool repair, bool dontCheckSigs,
std::shared_ptr<FSAccessor> accessor) override
{
debug("adding path %s to remote host %s", info.path, host);
auto conn(connections->get());
conn->to
<< cmdImportPaths
<< 1;
conn->to(*nar);
conn->to
<< exportMagic
<< info.path
<< info.references
<< info.deriver
<< 0
<< 0;
conn->to.flush();
if (readInt(conn->from) != 1)
throw Error("failed to add path %s to remote host %s, info.path, host");
}
void narFromPath(const Path & path, Sink & sink) override
{
auto conn(connections->get());
conn->to << cmdDumpStorePath << path;
conn->to.flush();
/* FIXME: inefficient. */
ParseSink parseSink; /* null sink; just parse the NAR */
TeeSource savedNAR(conn->from);
parseDump(parseSink, savedNAR);
sink(*savedNAR.data);
}
/* Unsupported methods. */
[[noreturn]] void unsupported()
{
throw Error("operation not supported on SSH stores");
}
PathSet queryAllValidPaths() override { unsupported(); }
void queryReferrers(const Path & path, PathSet & referrers) override
{ unsupported(); }
PathSet queryDerivationOutputs(const Path & path) override
{ unsupported(); }
StringSet queryDerivationOutputNames(const Path & path) override
{ unsupported(); }
Path queryPathFromHashPart(const string & hashPart) override
{ unsupported(); }
Path addToStore(const string & name, const Path & srcPath,
bool recursive, HashType hashAlgo,
PathFilter & filter, bool repair) override
{ unsupported(); }
Path addTextToStore(const string & name, const string & s,
const PathSet & references, bool repair) override
{ unsupported(); }
void buildPaths(const PathSet & paths, BuildMode buildMode) override
{ unsupported(); }
BuildResult buildDerivation(const Path & drvPath, const BasicDerivation & drv,
BuildMode buildMode) override
{ unsupported(); }
void ensurePath(const Path & path) override
{ unsupported(); }
void addTempRoot(const Path & path) override
{ unsupported(); }
void addIndirectRoot(const Path & path) override
{ unsupported(); }
Roots findRoots() override
{ unsupported(); }
void collectGarbage(const GCOptions & options, GCResults & results) override
{ unsupported(); }
ref<FSAccessor> getFSAccessor() override
{ unsupported(); }
void addSignatures(const Path & storePath, const StringSet & sigs) override
{ unsupported(); }
bool isTrusted() override
{ return true; }
void computeFSClosure(const PathSet & paths,
PathSet & out, bool flipDirection = false,
bool includeOutputs = false, bool includeDerivers = false) override
{
if (flipDirection || includeDerivers) {
Store::computeFSClosure(paths, out, flipDirection, includeOutputs, includeDerivers);
return;
}
auto conn(connections->get());
conn->to
<< cmdQueryClosure
<< includeOutputs
<< paths;
conn->to.flush();
auto res = readStorePaths<PathSet>(*this, conn->from);
out.insert(res.begin(), res.end());
}
};
static RegisterStoreImplementation regStore([](
const std::string & uri, const Store::Params & params)
-> std::shared_ptr<Store>
{
if (std::string(uri, 0, uriScheme.size()) != uriScheme) return 0;
return std::make_shared<LegacySSHStore>(std::string(uri, uriScheme.size()), params);
});
}