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Enable -fno-exceptions support (#261) 

Resolves #259

Signed-off-by: Tao He <sighingnow@gmail.com>
This commit is contained in:
Tao He 2023-12-20 09:18:10 +08:00 committed by GitHub
parent 5aff57cce5
commit b82efea7a9
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GPG Key ID: 4AEE18F83AFDEB23
14 changed files with 192 additions and 68 deletions
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16
CMakeLists.txt
View File

@ -26,6 +26,7 @@ if(NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
)
endif()
option(BUILD_WITH_NO_EXCEPTIONS "Build etcd-cpp-apiv3 with disabling exception handling, i.e., -fno-exceptions" OFF)
option(BUILD_SHARED_LIBS "Build etcd-cpp-apiv3 shared libraries" ON)
option(BUILD_ETCD_CORE_ONLY "Build etcd-cpp-apiv3 core library (the synchronous runtime) only" OFF)
option(BUILD_ETCD_TESTS "Build etcd-cpp-apiv3 test cases" OFF)
@ -88,6 +89,21 @@ macro(use_cxx target)
endif()
endmacro(use_cxx)
macro(set_exceptions target)
if(BUILD_NO_EXCEPTIONS)
if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
target_compile_options(${target} PRIVATE "-fno-exceptions")
elseif(CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
target_compile_options(${target} PRIVATE "-fno-exceptions")
elseif(CMAKE_CXX_COMPILER_ID STREQUAL "AppleClang")
target_compile_options(${target} PRIVATE "-fno-exceptions")
elseif(CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
target_compile_options(${target} PRIVATE "/EHs-c-")
endif()
target_compile_definitions(${target} PUBLIC -D_ETCD_NO_EXCEPTIONS)
endif()
endmacro(set_exceptions)
if(APPLE)
# If we're on OS X check for Homebrew's copy of OpenSSL instead of Apple's
if(NOT OpenSSL_DIR)

12
README.md
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@ -863,6 +863,8 @@ Without handler, the internal state can be checked via `KeepAlive::Check()` and
the async exception when there are errors during keeping the lease alive.
Note that even with `handler`, the `KeepAlive::Check()` still rethrow if there's an async exception.
When the library is built with `-fno-exceptions`, the `handler` argument and the `Check()` method
will abort the program when there are errors during keeping the lease alive.
### Etcd transactions
@ -960,7 +962,15 @@ The observer stream will be canceled when been destructed.
for more details, please refer to [etcd/Client.hpp](./etcd/Client.hpp) and [tst/ElectionTest.cpp](./tst/ElectionTest.cpp).
### TODO
## `-fno-exceptions`
The _etcd-cpp-apiv3_ library supports to be built with `-fno-exceptions` flag, controlled by the
cmake option `BUILD_WITH_NO_EXCEPTIONS=ON/OFF` (defaults to `OFF`).
When building with `-fno-exceptions`, the library will abort the program under certain circumstances,
e.g., when calling `.Check()` method of `KeepAlive` and there are errors during keeping the lease alive,
## TODO
1. Cancellation of asynchronous calls(except for watch)

8
etcd/KeepAlive.hpp
View File

@ -85,10 +85,10 @@ class KeepAlive {
~KeepAlive();
protected:
// automatically refresh loop
void refresh();
// refresh once immediately
void refresh_once();
// automatically refresh loop, returns the error message if failed
std::string refresh();
// refresh once immediately, returns the error message if failed
std::string refresh_once();
struct EtcdServerStubs;
struct EtcdServerStubsDeleter {

2
etcd/Response.hpp
View File

@ -34,7 +34,7 @@ class KeepAlive;
class Watcher;
/**
* The Reponse object received for the requests of etcd::Client
* The Response object received for the requests of etcd::Client
*/
class Response {
public:

4
etcd/v3/AsyncGRPC.hpp
View File

@ -269,7 +269,7 @@ class AsyncLeaseKeepAliveAction : public etcdv3::Action {
stream;
LeaseKeepAliveRequest req;
bool isCancelled;
std::atomic_bool isCancelled;
std::recursive_mutex protect_is_cancelled;
friend class etcd::KeepAlive;
@ -330,7 +330,7 @@ class AsyncObserveAction : public etcdv3::Action {
LeaderResponse reply;
std::unique_ptr<ClientAsyncReader<LeaderResponse>> response_reader;
std::atomic_bool isCancelled;
std::mutex protect_is_cancalled;
std::mutex protect_is_cancelled;
};
class AsyncProclaimAction : public etcdv3::Action {

3
src/CMakeLists.txt
View File

@ -19,6 +19,7 @@ file(GLOB_RECURSE CPP_CLIENT_CORE_SRC
add_library(etcd-cpp-api-core-objects OBJECT ${CPP_CLIENT_CORE_SRC} ${PROTOBUF_GENERATES})
use_cxx(etcd-cpp-api-core-objects)
set_exceptions(etcd-cpp-api-core-objects)
add_dependencies(etcd-cpp-api-core-objects protobuf_generates)
include_generated_protobuf_files(etcd-cpp-api-core-objects)
target_link_libraries(etcd-cpp-api-core-objects PUBLIC
@ -35,6 +36,7 @@ if(BUILD_ETCD_CORE_ONLY)
# add the core library, includes the sycnhronous client only
add_library(etcd-cpp-api-core $<TARGET_OBJECTS:etcd-cpp-api-core-objects>)
use_cxx(etcd-cpp-api-core)
set_exceptions(etcd-cpp-api-core)
target_link_libraries(etcd-cpp-api-core PUBLIC
${OPENSSL_LIBRARIES}
${GRPC_LIBRARIES}
@ -50,6 +52,7 @@ else()
add_library(etcd-cpp-api $<TARGET_OBJECTS:etcd-cpp-api-core-objects>
"${CMAKE_CURRENT_SOURCE_DIR}/Client.cpp")
use_cxx(etcd-cpp-api)
set_exceptions(etcd-cpp-api)
target_link_libraries(etcd-cpp-api PUBLIC
${CPPREST_LIB} # n.b.: the asynchronous client requires pplx in cpprestsdk
${OPENSSL_LIBRARIES}

72
src/KeepAlive.cpp
View File

@ -46,6 +46,7 @@ etcd::KeepAlive::KeepAlive(SyncClient const& client, int ttl, int64_t lease_id)
stubs->call.reset(new etcdv3::AsyncLeaseKeepAliveAction(std::move(params)));
refresh_task_ = std::thread([this]() {
#ifndef _ETCD_NO_EXCEPTIONS
try {
// start refresh
this->refresh();
@ -53,6 +54,12 @@ etcd::KeepAlive::KeepAlive(SyncClient const& client, int ttl, int64_t lease_id)
// propagate the exception
eptr_ = std::current_exception();
}
#else
const std::string err = this->refresh();
if (!err.empty()) {
eptr_ = std::make_exception_ptr(std::runtime_error(err));
}
#endif
});
}
@ -99,15 +106,22 @@ etcd::KeepAlive::KeepAlive(
stubs->call.reset(new etcdv3::AsyncLeaseKeepAliveAction(std::move(params)));
refresh_task_ = std::thread([this]() {
#ifndef _ETCD_NO_EXCEPTIONS
try {
// start refresh
this->refresh();
} catch (...) {
// propogate the exception
// propagate the exception
eptr_ = std::current_exception();
if (handler_) {
handler_(eptr_);
}
#else
const std::string err = this->refresh();
if (!err.empty()) {
eptr_ = std::make_exception_ptr(std::runtime_error(err));
}
#endif
if (eptr_ && handler_) {
handler_(eptr_);
}
});
}
@ -149,6 +163,7 @@ void etcd::KeepAlive::Check() {
std::rethrow_exception(eptr_);
}
// issue an refresh to make sure it still alive
#ifndef _ETCD_NO_EXCEPTIONS
try {
this->refresh_once();
} catch (...) {
@ -158,19 +173,35 @@ void etcd::KeepAlive::Check() {
// propagate the exception, as we throw in `Check()`, the `handler` won't be
// touched
eptr_ = std::current_exception();
if (handler_) {
}
#else
const std::string err = this->refresh_once();
if (!err.empty()) {
// run canceller first
this->Cancel();
// propagate the exception, as we throw in `Check()`, the `handler` won't be
// touched
eptr_ = std::make_exception_ptr(std::runtime_error(err));
}
#endif
if (eptr_ && handler_) {
handler_(eptr_);
}
#ifndef _ETCD_NO_EXCEPTIONS
if (eptr_) {
// rethrow in `Check()` to keep the consistent semantics
std::rethrow_exception(eptr_);
}
#endif
return;
}
void etcd::KeepAlive::refresh() {
std::string etcd::KeepAlive::refresh() {
while (true) {
if (!continue_next.load()) {
return;
return std::string{};
}
// minimal resolution: 1 second
int keepalive_ttl = std::max(ttl - 1, 1);
@ -179,7 +210,7 @@ void etcd::KeepAlive::refresh() {
if (cv_for_refresh_.wait_for(lock, std::chrono::seconds(keepalive_ttl)) ==
std::cv_status::no_timeout) {
if (!continue_next.load()) {
return;
return std::string{};
}
#ifndef NDEBUG
std::cerr
@ -191,24 +222,37 @@ void etcd::KeepAlive::refresh() {
}
// execute refresh
this->refresh_once();
const std::string err = this->refresh_once();
if (!err.empty()) {
return err;
}
}
return std::string{};
}
void etcd::KeepAlive::refresh_once() {
std::string etcd::KeepAlive::refresh_once() {
std::lock_guard<std::mutex> scope_lock(mutex_for_refresh_);
if (!continue_next.load()) {
return;
return std::string{};
}
this->stubs->call->mutable_parameters().grpc_timeout = this->grpc_timeout;
auto resp = this->stubs->call->Refresh();
if (!resp.is_ok()) {
throw std::runtime_error("Failed to refresh lease: error code: " +
const std::string err = "Failed to refresh lease: error code: " +
std::to_string(resp.error_code()) +
", message: " + resp.error_message());
", message: " + resp.error_message();
#ifndef _ETCD_NO_EXCEPTIONS
throw std::runtime_error(err);
#endif
return err;
}
if (resp.value().ttl() == 0) {
throw std::out_of_range(
"Failed to refresh lease due to expiration: the new TTL is 0.");
const std::string err =
"Failed to refresh lease due to expiration: the new TTL is 0.";
#ifndef _ETCD_NO_EXCEPTIONS
throw std::out_of_range(err);
#endif
return err;
}
return std::string{};
}

6
src/SyncClient.cpp
View File

@ -288,7 +288,11 @@ class etcd::SyncClient::TokenAuthenticator {
// auth
if (!etcd::detail::authenticate(this->channel_, username_, password_,
token_)) {
throw std::invalid_argument("Etcd authentication failed: " + token_);
// n.b.: no throw here as the failure of auth will be propagated
// to client when it is asked to issue requests.
//
// throw std::invalid_argument("Etcd authentication failed: " +
// token_);
}
}
}

47
src/v3/AsyncGRPC.cpp
View File

@ -512,7 +512,10 @@ etcdv3::AsyncLeaseKeepAliveAction::AsyncLeaseKeepAliveAction(
got_tag == (void*) etcdv3::KEEPALIVE_CREATE) {
// ok
} else {
throw std::runtime_error("Failed to create a lease keep-alive connection");
status = grpc::Status(grpc::StatusCode::CANCELLED,
"Failed to create a lease keep-alive connection");
// cannot continue for further refresh
isCancelled.store(true);
}
}
@ -534,7 +537,7 @@ etcd::Response etcdv3::AsyncLeaseKeepAliveAction::Refresh() {
std::lock_guard<std::recursive_mutex> scope_lock(this->protect_is_cancelled);
auto start_timepoint = std::chrono::high_resolution_clock::now();
if (isCancelled) {
if (isCancelled.load()) {
status = grpc::Status::CANCELLED;
return etcd::Response(ParseResponse(),
etcd::detail::duration_till_now(start_timepoint));
@ -621,9 +624,7 @@ etcd::Response etcdv3::AsyncLeaseKeepAliveAction::Refresh() {
void etcdv3::AsyncLeaseKeepAliveAction::CancelKeepAlive() {
std::lock_guard<std::recursive_mutex> scope_lock(this->protect_is_cancelled);
if (isCancelled == false) {
isCancelled = true;
if (!isCancelled.exchange(true)) {
void* got_tag = nullptr;
bool ok = false;
@ -658,7 +659,7 @@ void etcdv3::AsyncLeaseKeepAliveAction::CancelKeepAlive() {
}
bool etcdv3::AsyncLeaseKeepAliveAction::Cancelled() const {
return isCancelled;
return isCancelled.load();
}
etcdv3::ActionParameters&
@ -782,7 +783,10 @@ etcdv3::AsyncObserveAction::AsyncObserveAction(
got_tag == (void*) etcdv3::ELECTION_OBSERVE_CREATE) {
// n.b.: leave the issue of `Read` to the `waitForResponse`
} else {
throw std::runtime_error("failed to create a observe connection");
status = grpc::Status(grpc::StatusCode::CANCELLED,
"failed to create a observe connection");
// cannot continue for further observing
isCancelled.store(true);
}
}
@ -810,7 +814,7 @@ void etcdv3::AsyncObserveAction::waitForResponse() {
}
void etcdv3::AsyncObserveAction::CancelObserve() {
std::lock_guard<std::mutex> scope_lock(this->protect_is_cancalled);
std::lock_guard<std::mutex> scope_lock(this->protect_is_cancelled);
if (!isCancelled.exchange(true)) {
void* got_tag;
bool ok = false;
@ -1130,7 +1134,14 @@ etcdv3::AsyncWatchAction::AsyncWatchAction(etcdv3::ActionParameters&& params)
got_tag == (void*) etcdv3::WATCH_CREATE) {
stream->Write(watch_req, (void*) etcdv3::WATCH_WRITE);
} else {
throw std::runtime_error("failed to create a watch connection");
status = grpc::Status(grpc::StatusCode::CANCELLED,
"failed to create a watch connection");
// cannot continue for further watching
isCancelled.store(true);
}
if (!status.ok()) {
return;
}
// wait "write" (WatchCreateRequest) success, and start to read the first
@ -1138,7 +1149,10 @@ etcdv3::AsyncWatchAction::AsyncWatchAction(etcdv3::ActionParameters&& params)
if (cq_.Next(&got_tag, &ok) && ok && got_tag == (void*) etcdv3::WATCH_WRITE) {
stream->Read(&reply, (void*) this);
} else {
throw std::runtime_error("failed to write WatchCreateRequest to server");
status = grpc::Status(grpc::StatusCode::CANCELLED,
"failed to write WatchCreateRequest to server");
// cannot continue for further watching
isCancelled.store(true);
}
}
@ -1164,6 +1178,11 @@ void etcdv3::AsyncWatchAction::waitForResponse() {
bool ok = false;
bool the_final_round = false;
// failed to create the watcher
if (!status.ok()) {
return;
}
while (true) {
if (!the_final_round) {
if (!cq_.Next(&got_tag, &ok)) {
@ -1256,6 +1275,14 @@ void etcdv3::AsyncWatchAction::waitForResponse(
bool ok = false;
bool the_final_round = false;
// failed to create the watcher
if (!status.ok()) {
auto resp = ParseResponse();
auto duration = std::chrono::duration_cast<std::chrono::microseconds>(
std::chrono::high_resolution_clock::now() - start_timepoint);
callback(etcd::Response(resp, duration));
}
while (true) {
if (!the_final_round) {
if (!cq_.Next(&got_tag, &ok)) {

1
tst/CMakeLists.txt
View File

@ -19,6 +19,7 @@ foreach(testfile ${TEST_FILES})
add_executable(${test_name} EXCLUDE_FROM_ALL ${CMAKE_CURRENT_SOURCE_DIR}/${testfile})
endif()
use_cxx(${test_name})
set_exceptions(${test_name})
add_test(NAME ${test_name} COMMAND $<TARGET_FILE:${test_name}>)
target_include_directories(${test_name} PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/../proto/gen)

6
tst/KeepAliveTest.cpp
View File

@ -31,7 +31,9 @@ TEST_CASE("keepalive revoke and check if alive") {
std::this_thread::sleep_for(std::chrono::seconds(1));
// expect keep_alive->Check() to throw exception
#ifndef _ETCD_NO_EXCEPTIONS
REQUIRE_THROWS(keepalive->Check());
#endif
}
TEST_CASE("keepalive won't expire") {
@ -45,6 +47,7 @@ TEST_CASE("keepalive won't expire") {
auto lease_id = resp.value().lease();
etcd.add(key, meta_str, lease_id);
#ifndef _ETCD_NO_EXCEPTIONS
std::function<void(std::exception_ptr)> handler =
[](std::exception_ptr eptr) {
try {
@ -57,6 +60,9 @@ TEST_CASE("keepalive won't expire") {
std::cerr << "Lease expiry \"" << e.what() << "\"\n";
}
};
#else
std::function<void(std::exception_ptr)> handler;
#endif
etcd::KeepAlive keepalive(etcd, handler, ttl, lease_id);
std::this_thread::sleep_for(std::chrono::seconds(5));
}

4
tst/LockTest.cpp
View File

@ -117,6 +117,7 @@ TEST_CASE("lock using lease") {
bool failed = false;
#ifndef _ETCD_NO_EXCEPTIONS
std::function<void(std::exception_ptr)> handler =
[&failed](std::exception_ptr eptr) {
try {
@ -128,6 +129,9 @@ TEST_CASE("lock using lease") {
failed = true;
}
};
#else
std::function<void(std::exception_ptr)> handler;
#endif
// with handler
{

14
tst/MemLeakTest.cpp
View File

@ -24,7 +24,6 @@ class DistributedLock {
DistributedLock::DistributedLock(const std::string& lock_name, uint timeout) {
_etcd_client = std::unique_ptr<etcd::Client>(new etcd::Client(etcd_url));
try {
if (timeout == 0) {
etcd::Response resp = _etcd_client->lock(lock_name).get();
if (resp.is_ok()) {
@ -32,14 +31,12 @@ DistributedLock::DistributedLock(const std::string& lock_name, uint timeout) {
_acquired = true;
}
} else {
std::future<etcd::Response> future =
std::async(std::launch::async, [&]() {
std::future<etcd::Response> future = std::async(std::launch::async, [&]() {
etcd::Response resp = _etcd_client->lock(lock_name).get();
return resp;
});
std::future_status status =
future.wait_for(std::chrono::seconds(timeout));
std::future_status status = future.wait_for(std::chrono::seconds(timeout));
if (status == std::future_status::ready) {
auto resp = future.get();
if (resp.is_ok()) {
@ -53,9 +50,6 @@ DistributedLock::DistributedLock(const std::string& lock_name, uint timeout) {
std::cerr << "failed to acquire distributed lock" << std::endl;
}
}
} catch (std::exception& e) {
std::cerr << "failed to construct: " << e.what() << std::endl;
}
}
DistributedLock::~DistributedLock() noexcept {
@ -63,14 +57,10 @@ DistributedLock::~DistributedLock() noexcept {
return;
}
try {
auto resp = _etcd_client->unlock(_lock_key).get();
if (!resp.is_ok()) {
std::cout << resp.error_code() << std::endl;
}
} catch (std::exception& e) {
std::cerr << "failed to destruct: " << e.what() << std::endl;
}
}
int main() {

19
tst/RewatchTest.cpp
View File

@ -37,6 +37,7 @@ void print_response(etcd::Response const& resp) {
void wait_for_connection(std::string endpoints) {
// wait until the client connects to etcd server
while (true) {
#ifndef _ETCD_NO_EXCEPTIONS
try {
etcd::Client client(endpoints);
if (client.head().get().is_ok()) {
@ -45,6 +46,12 @@ void wait_for_connection(std::string endpoints) {
} catch (...) {
// pass
}
#else
etcd::Client client(endpoints);
if (client.head().get().is_ok()) {
break;
}
#endif
sleep(1);
}
}
@ -85,6 +92,7 @@ TEST_CASE("watch should can be re-established") {
// issue some changes to see if the watcher works
for (int round = 0; round < 100000; ++round) {
#ifndef _ETCD_NO_EXCEPTIONS
try {
etcd::Client client(etcd_url);
auto response =
@ -92,6 +100,11 @@ TEST_CASE("watch should can be re-established") {
} catch (...) {
// pass
}
#else
etcd::Client client(etcd_url);
auto response =
client.set(my_prefix + "/foo", "bar-" + std::to_string(round)).get();
#endif
std::this_thread::sleep_for(std::chrono::seconds(2));
}
@ -101,6 +114,7 @@ TEST_CASE("watch should can be re-established") {
// the watcher has been cancelled and shouldn't work anymore
for (int round = 10; round < 20; ++round) {
#ifndef _ETCD_NO_EXCEPTIONS
try {
etcd::Client client(etcd_url);
auto response =
@ -108,6 +122,11 @@ TEST_CASE("watch should can be re-established") {
} catch (...) {
// pass
}
#else
etcd::Client client(etcd_url);
auto response =
client.set(my_prefix + "/foo", "bar-" + std::to_string(round)).get();
#endif
std::this_thread::sleep_for(std::chrono::seconds(2));
}