nix/tests/unit/libstore/worker-protocol.cc
Eelco Dolstra 3be7c0037e WorkerProto: Support fine-grained protocol feature negotiation
Currently, the worker protocol has a version number that we increment
whenever we change something in the protocol. However, this can cause
a collision between Nix PRs / forks that make protocol changes
(e.g. PR #9857 increments the version, which could collide with
another PR). So instead, the client and daemon now exchange a set of
protocol features (such as `auth-forwarding`). They will use the
intersection of the sets of features, i.e. the features they both
support.

Note that protocol features are completely distinct from
`ExperimentalFeature`s.
2024-07-24 16:23:37 +02:00

783 lines
25 KiB
C++

#include <regex>
#include <thread>
#include <nlohmann/json.hpp>
#include <gtest/gtest.h>
#include "worker-protocol.hh"
#include "worker-protocol-connection.hh"
#include "worker-protocol-impl.hh"
#include "derived-path.hh"
#include "build-result.hh"
#include "tests/protocol.hh"
#include "tests/characterization.hh"
namespace nix {
const char workerProtoDir[] = "worker-protocol";
struct WorkerProtoTest : VersionedProtoTest<WorkerProto, workerProtoDir>
{
/**
* For serializers that don't care about the minimum version, we
* used the oldest one: 1.10.
*/
WorkerProto::Version defaultVersion = 1 << 8 | 10;
};
VERSIONED_CHARACTERIZATION_TEST(
WorkerProtoTest,
string,
"string",
defaultVersion,
(std::tuple<std::string, std::string, std::string, std::string, std::string> {
"",
"hi",
"white rabbit",
"大白兔",
"oh no \0\0\0 what was that!",
}))
VERSIONED_CHARACTERIZATION_TEST(
WorkerProtoTest,
storePath,
"store-path",
defaultVersion,
(std::tuple<StorePath, StorePath> {
StorePath { "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-foo" },
StorePath { "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-foo-bar" },
}))
VERSIONED_CHARACTERIZATION_TEST(
WorkerProtoTest,
contentAddress,
"content-address",
defaultVersion,
(std::tuple<ContentAddress, ContentAddress, ContentAddress> {
ContentAddress {
.method = ContentAddressMethod::Raw::Text,
.hash = hashString(HashAlgorithm::SHA256, "Derive(...)"),
},
ContentAddress {
.method = ContentAddressMethod::Raw::Flat,
.hash = hashString(HashAlgorithm::SHA1, "blob blob..."),
},
ContentAddress {
.method = ContentAddressMethod::Raw::NixArchive,
.hash = hashString(HashAlgorithm::SHA256, "(...)"),
},
}))
VERSIONED_CHARACTERIZATION_TEST(
WorkerProtoTest,
derivedPath_1_29,
"derived-path-1.29",
1 << 8 | 29,
(std::tuple<DerivedPath, DerivedPath, DerivedPath> {
DerivedPath::Opaque {
.path = StorePath { "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-foo" },
},
DerivedPath::Built {
.drvPath = makeConstantStorePathRef(StorePath {
"g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-bar.drv",
}),
.outputs = OutputsSpec::All { },
},
DerivedPath::Built {
.drvPath = makeConstantStorePathRef(StorePath {
"g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-bar.drv",
}),
.outputs = OutputsSpec::Names { "x", "y" },
},
}))
VERSIONED_CHARACTERIZATION_TEST(
WorkerProtoTest,
derivedPath_1_30,
"derived-path-1.30",
1 << 8 | 30,
(std::tuple<DerivedPath, DerivedPath, DerivedPath, DerivedPath> {
DerivedPath::Opaque {
.path = StorePath { "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-foo" },
},
DerivedPath::Opaque {
.path = StorePath { "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-foo.drv" },
},
DerivedPath::Built {
.drvPath = makeConstantStorePathRef(StorePath {
"g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-bar.drv",
}),
.outputs = OutputsSpec::All { },
},
DerivedPath::Built {
.drvPath = makeConstantStorePathRef(StorePath {
"g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-bar.drv",
}),
.outputs = OutputsSpec::Names { "x", "y" },
},
}))
VERSIONED_CHARACTERIZATION_TEST(
WorkerProtoTest,
drvOutput,
"drv-output",
defaultVersion,
(std::tuple<DrvOutput, DrvOutput> {
{
.drvHash = Hash::parseSRI("sha256-FePFYIlMuycIXPZbWi7LGEiMmZSX9FMbaQenWBzm1Sc="),
.outputName = "baz",
},
DrvOutput {
.drvHash = Hash::parseSRI("sha256-b4afnqKCO9oWXgYHb9DeQ2berSwOjS27rSd9TxXDc/U="),
.outputName = "quux",
},
}))
VERSIONED_CHARACTERIZATION_TEST(
WorkerProtoTest,
realisation,
"realisation",
defaultVersion,
(std::tuple<Realisation, Realisation> {
Realisation {
.id = DrvOutput {
.drvHash = Hash::parseSRI("sha256-FePFYIlMuycIXPZbWi7LGEiMmZSX9FMbaQenWBzm1Sc="),
.outputName = "baz",
},
.outPath = StorePath { "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-foo" },
.signatures = { "asdf", "qwer" },
},
Realisation {
.id = {
.drvHash = Hash::parseSRI("sha256-FePFYIlMuycIXPZbWi7LGEiMmZSX9FMbaQenWBzm1Sc="),
.outputName = "baz",
},
.outPath = StorePath { "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-foo" },
.signatures = { "asdf", "qwer" },
.dependentRealisations = {
{
DrvOutput {
.drvHash = Hash::parseSRI("sha256-b4afnqKCO9oWXgYHb9DeQ2berSwOjS27rSd9TxXDc/U="),
.outputName = "quux",
},
StorePath { "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-foo" },
},
},
},
}))
VERSIONED_CHARACTERIZATION_TEST(
WorkerProtoTest,
buildResult_1_27,
"build-result-1.27",
1 << 8 | 27,
({
using namespace std::literals::chrono_literals;
std::tuple<BuildResult, BuildResult, BuildResult> t {
BuildResult {
.status = BuildResult::OutputRejected,
.errorMsg = "no idea why",
},
BuildResult {
.status = BuildResult::NotDeterministic,
.errorMsg = "no idea why",
},
BuildResult {
.status = BuildResult::Built,
},
};
t;
}))
VERSIONED_CHARACTERIZATION_TEST(
WorkerProtoTest,
buildResult_1_28,
"build-result-1.28",
1 << 8 | 28,
({
using namespace std::literals::chrono_literals;
std::tuple<BuildResult, BuildResult, BuildResult> t {
BuildResult {
.status = BuildResult::OutputRejected,
.errorMsg = "no idea why",
},
BuildResult {
.status = BuildResult::NotDeterministic,
.errorMsg = "no idea why",
},
BuildResult {
.status = BuildResult::Built,
.builtOutputs = {
{
"foo",
{
.id = DrvOutput {
.drvHash = Hash::parseSRI("sha256-b4afnqKCO9oWXgYHb9DeQ2berSwOjS27rSd9TxXDc/U="),
.outputName = "foo",
},
.outPath = StorePath { "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-foo" },
},
},
{
"bar",
{
.id = DrvOutput {
.drvHash = Hash::parseSRI("sha256-b4afnqKCO9oWXgYHb9DeQ2berSwOjS27rSd9TxXDc/U="),
.outputName = "bar",
},
.outPath = StorePath { "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-bar" },
},
},
},
},
};
t;
}))
VERSIONED_CHARACTERIZATION_TEST(
WorkerProtoTest,
buildResult_1_29,
"build-result-1.29",
1 << 8 | 29,
({
using namespace std::literals::chrono_literals;
std::tuple<BuildResult, BuildResult, BuildResult> t {
BuildResult {
.status = BuildResult::OutputRejected,
.errorMsg = "no idea why",
},
BuildResult {
.status = BuildResult::NotDeterministic,
.errorMsg = "no idea why",
.timesBuilt = 3,
.isNonDeterministic = true,
.startTime = 30,
.stopTime = 50,
},
BuildResult {
.status = BuildResult::Built,
.timesBuilt = 1,
.builtOutputs = {
{
"foo",
{
.id = DrvOutput {
.drvHash = Hash::parseSRI("sha256-b4afnqKCO9oWXgYHb9DeQ2berSwOjS27rSd9TxXDc/U="),
.outputName = "foo",
},
.outPath = StorePath { "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-foo" },
},
},
{
"bar",
{
.id = DrvOutput {
.drvHash = Hash::parseSRI("sha256-b4afnqKCO9oWXgYHb9DeQ2berSwOjS27rSd9TxXDc/U="),
.outputName = "bar",
},
.outPath = StorePath { "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-bar" },
},
},
},
.startTime = 30,
.stopTime = 50,
},
};
t;
}))
VERSIONED_CHARACTERIZATION_TEST(
WorkerProtoTest,
buildResult_1_37,
"build-result-1.37",
1 << 8 | 37,
({
using namespace std::literals::chrono_literals;
std::tuple<BuildResult, BuildResult, BuildResult> t {
BuildResult {
.status = BuildResult::OutputRejected,
.errorMsg = "no idea why",
},
BuildResult {
.status = BuildResult::NotDeterministic,
.errorMsg = "no idea why",
.timesBuilt = 3,
.isNonDeterministic = true,
.startTime = 30,
.stopTime = 50,
},
BuildResult {
.status = BuildResult::Built,
.timesBuilt = 1,
.builtOutputs = {
{
"foo",
{
.id = DrvOutput {
.drvHash = Hash::parseSRI("sha256-b4afnqKCO9oWXgYHb9DeQ2berSwOjS27rSd9TxXDc/U="),
.outputName = "foo",
},
.outPath = StorePath { "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-foo" },
},
},
{
"bar",
{
.id = DrvOutput {
.drvHash = Hash::parseSRI("sha256-b4afnqKCO9oWXgYHb9DeQ2berSwOjS27rSd9TxXDc/U="),
.outputName = "bar",
},
.outPath = StorePath { "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-bar" },
},
},
},
.startTime = 30,
.stopTime = 50,
.cpuUser = std::chrono::microseconds(500s),
.cpuSystem = std::chrono::microseconds(604s),
},
};
t;
}))
VERSIONED_CHARACTERIZATION_TEST(
WorkerProtoTest,
keyedBuildResult_1_29,
"keyed-build-result-1.29",
1 << 8 | 29,
({
using namespace std::literals::chrono_literals;
std::tuple<KeyedBuildResult, KeyedBuildResult/*, KeyedBuildResult*/> t {
KeyedBuildResult {
{
.status = KeyedBuildResult::OutputRejected,
.errorMsg = "no idea why",
},
/* .path = */ DerivedPath::Opaque {
StorePath { "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-xxx" },
},
},
KeyedBuildResult {
{
.status = KeyedBuildResult::NotDeterministic,
.errorMsg = "no idea why",
.timesBuilt = 3,
.isNonDeterministic = true,
.startTime = 30,
.stopTime = 50,
},
/* .path = */ DerivedPath::Built {
.drvPath = makeConstantStorePathRef(StorePath {
"g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-bar.drv",
}),
.outputs = OutputsSpec::Names { "out" },
},
},
};
t;
}))
VERSIONED_CHARACTERIZATION_TEST(
WorkerProtoTest,
unkeyedValidPathInfo_1_15,
"unkeyed-valid-path-info-1.15",
1 << 8 | 15,
(std::tuple<UnkeyedValidPathInfo, UnkeyedValidPathInfo> {
({
UnkeyedValidPathInfo info {
Hash::parseSRI("sha256-FePFYIlMuycIXPZbWi7LGEiMmZSX9FMbaQenWBzm1Sc="),
};
info.registrationTime = 23423;
info.narSize = 34878;
info;
}),
({
UnkeyedValidPathInfo info {
Hash::parseSRI("sha256-FePFYIlMuycIXPZbWi7LGEiMmZSX9FMbaQenWBzm1Sc="),
};
info.deriver = StorePath {
"g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-bar.drv",
};
info.references = {
StorePath {
"g1w7hyyyy1w7hy3qg1w7hy3qgqqqqy3q-foo.drv",
},
};
info.registrationTime = 23423;
info.narSize = 34878;
info;
}),
}))
VERSIONED_CHARACTERIZATION_TEST(
WorkerProtoTest,
validPathInfo_1_15,
"valid-path-info-1.15",
1 << 8 | 15,
(std::tuple<ValidPathInfo, ValidPathInfo> {
({
ValidPathInfo info {
StorePath {
"g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-bar",
},
UnkeyedValidPathInfo {
Hash::parseSRI("sha256-FePFYIlMuycIXPZbWi7LGEiMmZSX9FMbaQenWBzm1Sc="),
},
};
info.registrationTime = 23423;
info.narSize = 34878;
info;
}),
({
ValidPathInfo info {
StorePath {
"g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-bar",
},
UnkeyedValidPathInfo {
Hash::parseSRI("sha256-FePFYIlMuycIXPZbWi7LGEiMmZSX9FMbaQenWBzm1Sc="),
},
};
info.deriver = StorePath {
"g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-bar.drv",
};
info.references = {
// other reference
StorePath {
"g1w7hyyyy1w7hy3qg1w7hy3qgqqqqy3q-foo",
},
// self reference
StorePath {
"g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-bar",
},
};
info.registrationTime = 23423;
info.narSize = 34878;
info;
}),
}))
VERSIONED_CHARACTERIZATION_TEST(
WorkerProtoTest,
validPathInfo_1_16,
"valid-path-info-1.16",
1 << 8 | 16,
(std::tuple<ValidPathInfo, ValidPathInfo, ValidPathInfo> {
({
ValidPathInfo info {
StorePath {
"g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-bar",
},
UnkeyedValidPathInfo {
Hash::parseSRI("sha256-FePFYIlMuycIXPZbWi7LGEiMmZSX9FMbaQenWBzm1Sc="),
},
};
info.registrationTime = 23423;
info.narSize = 34878;
info.ultimate = true;
info;
}),
({
ValidPathInfo info {
StorePath {
"g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-bar",
},
UnkeyedValidPathInfo {
Hash::parseSRI("sha256-FePFYIlMuycIXPZbWi7LGEiMmZSX9FMbaQenWBzm1Sc="),
},
};
info.deriver = StorePath {
"g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-bar.drv",
};
info.references = {
// other reference
StorePath {
"g1w7hyyyy1w7hy3qg1w7hy3qgqqqqy3q-foo",
},
// self reference
StorePath {
"g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-bar",
},
};
info.registrationTime = 23423;
info.narSize = 34878;
info.sigs = {
"fake-sig-1",
"fake-sig-2",
},
info;
}),
({
ValidPathInfo info {
*LibStoreTest::store,
"foo",
FixedOutputInfo {
.method = FileIngestionMethod::NixArchive,
.hash = hashString(HashAlgorithm::SHA256, "(...)"),
.references = {
.others = {
StorePath {
"g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-bar",
},
},
.self = true,
},
},
Hash::parseSRI("sha256-FePFYIlMuycIXPZbWi7LGEiMmZSX9FMbaQenWBzm1Sc="),
};
info.registrationTime = 23423;
info.narSize = 34878;
info;
}),
}))
VERSIONED_CHARACTERIZATION_TEST(
WorkerProtoTest,
buildMode,
"build-mode",
defaultVersion,
(std::tuple<BuildMode, BuildMode, BuildMode> {
bmNormal,
bmRepair,
bmCheck,
}))
VERSIONED_CHARACTERIZATION_TEST(
WorkerProtoTest,
optionalTrustedFlag,
"optional-trusted-flag",
defaultVersion,
(std::tuple<std::optional<TrustedFlag>, std::optional<TrustedFlag>, std::optional<TrustedFlag>> {
std::nullopt,
std::optional { Trusted },
std::optional { NotTrusted },
}))
VERSIONED_CHARACTERIZATION_TEST(
WorkerProtoTest,
vector,
"vector",
defaultVersion,
(std::tuple<std::vector<std::string>, std::vector<std::string>, std::vector<std::string>, std::vector<std::vector<std::string>>> {
{ },
{ "" },
{ "", "foo", "bar" },
{ {}, { "" }, { "", "1", "2" } },
}))
VERSIONED_CHARACTERIZATION_TEST(
WorkerProtoTest,
set,
"set",
defaultVersion,
(std::tuple<std::set<std::string>, std::set<std::string>, std::set<std::string>, std::set<std::set<std::string>>> {
{ },
{ "" },
{ "", "foo", "bar" },
{ {}, { "" }, { "", "1", "2" } },
}))
VERSIONED_CHARACTERIZATION_TEST(
WorkerProtoTest,
optionalStorePath,
"optional-store-path",
defaultVersion,
(std::tuple<std::optional<StorePath>, std::optional<StorePath>> {
std::nullopt,
std::optional {
StorePath { "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-foo-bar" },
},
}))
VERSIONED_CHARACTERIZATION_TEST(
WorkerProtoTest,
optionalContentAddress,
"optional-content-address",
defaultVersion,
(std::tuple<std::optional<ContentAddress>, std::optional<ContentAddress>> {
std::nullopt,
std::optional {
ContentAddress {
.method = ContentAddressMethod::Raw::Flat,
.hash = hashString(HashAlgorithm::SHA1, "blob blob..."),
},
},
}))
VERSIONED_CHARACTERIZATION_TEST(
WorkerProtoTest,
clientHandshakeInfo_1_30,
"client-handshake-info_1_30",
1 << 8 | 30,
(std::tuple<WorkerProto::ClientHandshakeInfo> {
{},
}))
VERSIONED_CHARACTERIZATION_TEST(
WorkerProtoTest,
clientHandshakeInfo_1_33,
"client-handshake-info_1_33",
1 << 8 | 33,
(std::tuple<WorkerProto::ClientHandshakeInfo, WorkerProto::ClientHandshakeInfo> {
{
.daemonNixVersion = std::optional { "foo" },
},
{
.daemonNixVersion = std::optional { "bar" },
},
}))
VERSIONED_CHARACTERIZATION_TEST(
WorkerProtoTest,
clientHandshakeInfo_1_35,
"client-handshake-info_1_35",
1 << 8 | 35,
(std::tuple<WorkerProto::ClientHandshakeInfo, WorkerProto::ClientHandshakeInfo> {
{
.daemonNixVersion = std::optional { "foo" },
.remoteTrustsUs = std::optional { NotTrusted },
},
{
.daemonNixVersion = std::optional { "bar" },
.remoteTrustsUs = std::optional { Trusted },
},
}))
TEST_F(WorkerProtoTest, handshake_log)
{
CharacterizationTest::writeTest("handshake-to-client", [&]() -> std::string {
StringSink toClientLog;
Pipe toClient, toServer;
toClient.create();
toServer.create();
WorkerProto::Version clientResult;
auto thread = std::thread([&]() {
FdSink out { toServer.writeSide.get() };
FdSource in0 { toClient.readSide.get() };
TeeSource in { in0, toClientLog };
clientResult = std::get<0>(WorkerProto::BasicClientConnection::handshake(
out, in, defaultVersion, {}));
});
{
FdSink out { toClient.writeSide.get() };
FdSource in { toServer.readSide.get() };
WorkerProto::BasicServerConnection::handshake(
out, in, defaultVersion, {});
};
thread.join();
return std::move(toClientLog.s);
});
}
TEST_F(WorkerProtoTest, handshake_features)
{
Pipe toClient, toServer;
toClient.create();
toServer.create();
std::tuple<WorkerProto::Version, std::set<WorkerProto::Feature>> clientResult;
auto clientThread = std::thread([&]() {
FdSink out { toServer.writeSide.get() };
FdSource in { toClient.readSide.get() };
clientResult = WorkerProto::BasicClientConnection::handshake(
out, in, 123, {"bar", "aap", "mies", "xyzzy"});
});
FdSink out { toClient.writeSide.get() };
FdSource in { toServer.readSide.get() };
auto daemonResult = WorkerProto::BasicServerConnection::handshake(
out, in, 456, {"foo", "bar", "xyzzy"});
clientThread.join();
EXPECT_EQ(clientResult, daemonResult);
EXPECT_EQ(std::get<0>(clientResult), 123);
EXPECT_EQ(std::get<1>(clientResult), std::set<WorkerProto::Feature>({"bar", "xyzzy"}));
}
/// Has to be a `BufferedSink` for handshake.
struct NullBufferedSink : BufferedSink {
void writeUnbuffered(std::string_view data) override { }
};
TEST_F(WorkerProtoTest, handshake_client_replay)
{
CharacterizationTest::readTest("handshake-to-client", [&](std::string toClientLog) {
NullBufferedSink nullSink;
StringSource in { toClientLog };
auto clientResult = std::get<0>(WorkerProto::BasicClientConnection::handshake(
nullSink, in, defaultVersion, {}));
EXPECT_EQ(clientResult, defaultVersion);
});
}
TEST_F(WorkerProtoTest, handshake_client_truncated_replay_throws)
{
CharacterizationTest::readTest("handshake-to-client", [&](std::string toClientLog) {
for (size_t len = 0; len < toClientLog.size(); ++len) {
NullBufferedSink nullSink;
StringSource in {
// truncate
toClientLog.substr(0, len)
};
if (len < 8) {
EXPECT_THROW(
WorkerProto::BasicClientConnection::handshake(
nullSink, in, defaultVersion, {}),
EndOfFile);
} else {
// Not sure why cannot keep on checking for `EndOfFile`.
EXPECT_THROW(
WorkerProto::BasicClientConnection::handshake(
nullSink, in, defaultVersion, {}),
Error);
}
}
});
}
TEST_F(WorkerProtoTest, handshake_client_corrupted_throws)
{
CharacterizationTest::readTest("handshake-to-client", [&](const std::string toClientLog) {
for (size_t idx = 0; idx < toClientLog.size(); ++idx) {
// corrupt a copy
std::string toClientLogCorrupt = toClientLog;
toClientLogCorrupt[idx] *= 4;
++toClientLogCorrupt[idx];
NullBufferedSink nullSink;
StringSource in { toClientLogCorrupt };
if (idx < 4 || idx == 9) {
// magic bytes don't match
EXPECT_THROW(
WorkerProto::BasicClientConnection::handshake(
nullSink, in, defaultVersion, {}),
Error);
} else if (idx < 8 || idx >= 12) {
// Number out of bounds
EXPECT_THROW(
WorkerProto::BasicClientConnection::handshake(
nullSink, in, defaultVersion, {}),
SerialisationError);
} else {
auto ver = std::get<0>(WorkerProto::BasicClientConnection::handshake(
nullSink, in, defaultVersion, {}));
// `std::min` of this and the other version saves us
EXPECT_EQ(ver, defaultVersion);
}
}
});
}
}