memgraph/tests/unit/rpc.cpp
Matej Ferencevic 53c405c699 Throw exceptions on RPC failure and Distributed error handling
Summary:
This diff changes the RPC layer to directly return `TResponse` to the user when
issuing a `Call<...>` RPC call. The call throws an exception on failure
(instead of the previous return `nullopt`).

All servers (network, RPC and distributed) are set to have explicit `Shutdown`
methods so that a controlled shutdown can always be performed. The object
destructors now have `CHECK`s to enforce that the `AwaitShutdown` methods were
called.

The distributed memgraph is changed that none of the binaries (master/workers)
crash when there is a communication failure. Instead, the whole cluster starts
a graceful shutdown when a persistent communication error is detected.
Transient errors are allowed during execution. The transaction that errored out
will be aborted on the whole cluster. The cluster state is managed using a new
Heartbeat RPC call.

Reviewers: buda, teon.banek, msantl

Reviewed By: teon.banek

Subscribers: pullbot

Differential Revision: https://phabricator.memgraph.io/D1604
2018-09-27 16:27:40 +02:00

208 lines
5.0 KiB
C++

#include <thread>
#include "capnp/serialize.h"
#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include "communication/rpc/client.hpp"
#include "communication/rpc/client_pool.hpp"
#include "communication/rpc/messages.hpp"
#include "communication/rpc/server.hpp"
#include "utils/timer.hpp"
using namespace communication::rpc;
using namespace std::literals::chrono_literals;
struct SumReq {
using Capnp = ::capnp::AnyPointer;
static const MessageType TypeInfo;
SumReq() {} // Needed for serialization.
SumReq(int x, int y) : x(x), y(y) {}
int x;
int y;
void Save(::capnp::AnyPointer::Builder *builder) const {
auto list_builder = builder->initAs<::capnp::List<int>>(2);
list_builder.set(0, x);
list_builder.set(1, y);
}
void Load(const ::capnp::AnyPointer::Reader &reader) {
auto list_reader = reader.getAs<::capnp::List<int>>();
x = list_reader[0];
y = list_reader[1];
}
};
const MessageType SumReq::TypeInfo{0, "SumReq"};
struct SumRes {
using Capnp = ::capnp::AnyPointer;
static const MessageType TypeInfo;
SumRes() {} // Needed for serialization.
SumRes(int sum) : sum(sum) {}
int sum;
void Save(::capnp::AnyPointer::Builder *builder) const {
auto list_builder = builder->initAs<::capnp::List<int>>(1);
list_builder.set(0, sum);
}
void Load(const ::capnp::AnyPointer::Reader &reader) {
auto list_reader = reader.getAs<::capnp::List<int>>();
sum = list_reader[0];
}
};
const MessageType SumRes::TypeInfo{1, "SumRes"};
using Sum = RequestResponse<SumReq, SumRes>;
struct EchoMessage {
using Capnp = ::capnp::AnyPointer;
static const MessageType TypeInfo;
EchoMessage() {} // Needed for serialization.
EchoMessage(const std::string &data) : data(data) {}
std::string data;
void Save(::capnp::AnyPointer::Builder *builder) const {
auto list_builder = builder->initAs<::capnp::List<::capnp::Text>>(1);
list_builder.set(0, data);
}
void Load(const ::capnp::AnyPointer::Reader &reader) {
auto list_reader = reader.getAs<::capnp::List<::capnp::Text>>();
data = list_reader[0];
}
};
const MessageType EchoMessage::TypeInfo{2, "EchoMessage"};
using Echo = RequestResponse<EchoMessage, EchoMessage>;
TEST(Rpc, Call) {
Server server({"127.0.0.1", 0});
server.Register<Sum>([](const auto &req_reader, auto *res_builder) {
SumReq req;
req.Load(req_reader);
SumRes res(req.x + req.y);
res.Save(res_builder);
});
std::this_thread::sleep_for(100ms);
Client client(server.endpoint());
auto sum = client.Call<Sum>(10, 20);
EXPECT_EQ(sum.sum, 30);
server.Shutdown();
server.AwaitShutdown();
}
TEST(Rpc, Abort) {
Server server({"127.0.0.1", 0});
server.Register<Sum>([](const auto &req_reader, auto *res_builder) {
SumReq req;
req.Load(req_reader);
std::this_thread::sleep_for(500ms);
SumRes res(req.x + req.y);
res.Save(res_builder);
});
std::this_thread::sleep_for(100ms);
Client client(server.endpoint());
std::thread thread([&client]() {
std::this_thread::sleep_for(100ms);
LOG(INFO) << "Shutting down the connection!";
client.Abort();
});
utils::Timer timer;
EXPECT_THROW(client.Call<Sum>(10, 20),
communication::rpc::RpcFailedException);
EXPECT_LT(timer.Elapsed(), 200ms);
thread.join();
server.Shutdown();
server.AwaitShutdown();
}
TEST(Rpc, ClientPool) {
Server server({"127.0.0.1", 0});
server.Register<Sum>([](const auto &req_reader, auto *res_builder) {
SumReq req;
req.Load(req_reader);
std::this_thread::sleep_for(100ms);
SumRes res(req.x + req.y);
res.Save(res_builder);
});
std::this_thread::sleep_for(100ms);
Client client(server.endpoint());
/* these calls should take more than 400ms because we're using a regular
* client */
auto get_sum_client = [&client](int x, int y) {
auto sum = client.Call<Sum>(x, y);
EXPECT_EQ(sum.sum, x + y);
};
utils::Timer t1;
std::vector<std::thread> threads;
for (int i = 0; i < 4; ++i) {
threads.emplace_back(get_sum_client, 2 * i, 2 * i + 1);
}
for (int i = 0; i < 4; ++i) {
threads[i].join();
}
threads.clear();
EXPECT_GE(t1.Elapsed(), 400ms);
ClientPool pool(server.endpoint());
/* these calls shouldn't take much more that 100ms because they execute in
* parallel */
auto get_sum = [&pool](int x, int y) {
auto sum = pool.Call<Sum>(x, y);
EXPECT_EQ(sum.sum, x + y);
};
utils::Timer t2;
for (int i = 0; i < 4; ++i) {
threads.emplace_back(get_sum, 2 * i, 2 * i + 1);
}
for (int i = 0; i < 4; ++i) {
threads[i].join();
}
EXPECT_LE(t2.Elapsed(), 200ms);
server.Shutdown();
server.AwaitShutdown();
}
TEST(Rpc, LargeMessage) {
Server server({"127.0.0.1", 0});
server.Register<Echo>([](const auto &req_reader, auto *res_builder) {
EchoMessage res;
res.Load(req_reader);
res.Save(res_builder);
});
std::this_thread::sleep_for(100ms);
std::string testdata(100000, 'a');
Client client(server.endpoint());
auto echo = client.Call<Echo>(testdata);
EXPECT_EQ(echo.data, testdata);
server.Shutdown();
server.AwaitShutdown();
}