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Posted to dev@brpc.apache.org by GitBox <gi...@apache.org> on 2020/09/16 02:07:40 UTC
[GitHub] [incubator-brpc] feng-y opened a new issue #1243: brpc::Join(CallId id) 支持带超时的等待
feng-y opened a new issue #1243:
URL: https://github.com/apache/incubator-brpc/issues/1243
**Describe the solution you'd like (描述你期望的解决方法)**
`brpc::Join(CallId id) ` 增加一个参数支持，最长等待时间， `brpc::Join(CallId id, int64_t int64_t waiting_us) `
**Describe alternatives you've considered (描述你想到的折衷方案)**
`
index 23046b25..caf99b40 100644
--- a/src/bthread/id.cpp
+++ b/src/bthread/id.cpp
@@ -510,6 +510,10 @@ int bthread_id_cancel(bthread_id_t id) {
}
int bthread_id_join(bthread_id_t id) {
+ return bthread_id_join(id, 0);
+}
+
+int bthread_id_join(bthread_id_t id, int64_t us) {
const bthread::IdResourceId slot = bthread::get_slot(id);
bthread::Id* const meta = address_resource(slot);
if (!meta) {
@@ -526,9 +530,17 @@ int bthread_id_join(bthread_id_t id) {
if (!has_ver) {
break;
}
- if (bthread::butex_wait(join_butex, expected_ver, NULL) < 0 &&
- errno != EWOULDBLOCK && errno != EINTR) {
+ if (us > 0) {
+ timespec abstime = butil::microseconds_to_timespec(us + butil::gettimeofday_ns());
+ if (bthread::butex_wait(join_butex, expected_ver, &abstime) < 0 &&
+ errno != EWOULDBLOCK && errno != EINTR) {
return errno;
+ }
+ } else {
+ if (bthread::butex_wait(join_butex, expected_ver, NULL) < 0 &&
+ errno != EWOULDBLOCK && errno != EINTR) {
+ return errno;
+ }
}
}
return 0;`
**Additional context/screenshots (更多上下文/截图)**
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[GitHub] [incubator-brpc] zyearn commented on issue #1243: brpc::Join(CallId id) 支持带超时的等待
Posted by GitBox <gi...@apache.org>.
zyearn commented on issue #1243:
URL: https://github.com/apache/incubator-brpc/issues/1243#issuecomment-693444506
> 一个不太靠谱的基于future的实现
> callback 里面设置 future
>
> ```
> void HandleEchoResponse(
> brpc::Controller* cntl,
> example::EchoResponse* response,
> std::shared_ptr<std::promise<bool>> waiter) {
> waiter->set_value(true);
> }
> ```
>
> 等待的时候不join， 等future ，如果futre 不成功就 cancel 请求
>
> ```
> std::shared_ptr<std::promise<bool>> waiter(std::make_shared<std::promise<bool>>());
>
> // Because `done'(last parameter) is NULL, this function waits until
> // the response comes back or error occurs(including timedout).
> google::protobuf::Closure* done = brpc::NewCallback(
> &HandleEchoResponse, &cntl, &response, waiter);
>
> auto call_id = cntl.call_id();
> stub.Echo(&cntl, &request, &response, done);
> LOG(INFO) << "waiting Join:" << errno << ", " << EINVAL;
> // brpc::Join(call_id);
> if (waiter->get_future().wait_for(std::chrono::microseconds(1)) != std::future_status::ready) {
> LOG(INFO) << "timeout";
> brpc::StartCancel(call_id);
> } else {
> .......
> }
> ```
这里用future来实现不太合适，future.wait会阻塞brpc的worker线程。
Join的语义暗含的意思是当Join返回的时候，被Join的对象已经处于一个结束的状态，这里加个timeout会有点破坏语义。
这个需求也可以通过bthread::CountdownEvent来实现，在原来future set_value的地方改成signal，在Join的地方改成timed_wait。
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[GitHub] [incubator-brpc] feng-y commented on issue #1243: brpc::Join(CallId id) 支持带超时的等待
Posted by GitBox <gi...@apache.org>.
feng-y commented on issue #1243:
URL: https://github.com/apache/incubator-brpc/issues/1243#issuecomment-693173569
SB服务的超时依赖于SA的响应，所以SB的超时是不好控制的
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[GitHub] [incubator-brpc] feng-y edited a comment on issue #1243: brpc::Join(CallId id) 支持带超时的等待
Posted by GitBox <gi...@apache.org>.
feng-y edited a comment on issue #1243:
URL: https://github.com/apache/incubator-brpc/issues/1243#issuecomment-693219844
一个不太靠谱的基于future的实现
```
void HandleEchoResponse(
brpc::Controller* cntl,
example::EchoResponse* response,
std::shared_ptr<std::promise<bool>> waiter) {
waiter->set_value(true);
}
std::shared_ptr<std::promise<bool>> waiter(std::make_shared<std::promise<bool>>());
// Because `done'(last parameter) is NULL, this function waits until
// the response comes back or error occurs(including timedout).
google::protobuf::Closure* done = brpc::NewCallback(
&HandleEchoResponse, &cntl, &response, waiter);
auto call_id = cntl.call_id();
stub.Echo(&cntl, &request, &response, done);
LOG(INFO) << "waiting Join:" << errno << ", " << EINVAL;
// brpc::Join(call_id);
if (waiter->get_future().wait_for(std::chrono::microseconds(1)) != std::future_status::ready) {
LOG(INFO) << "timeout";
brpc::StartCancel(call_id);
} else {
.......
}
```
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[GitHub] [incubator-brpc] gydong commented on issue #1243: brpc::Join(CallId id) 支持带超时的等待
Posted by GitBox <gi...@apache.org>.
gydong commented on issue #1243:
URL: https://github.com/apache/incubator-brpc/issues/1243#issuecomment-693776704
我们内部有个类似实现，仅供参考：
```cpp
// This class is NOT thread safe.
class BthreadGroup {
public:
class Task;
BthreadGroup();
~BthreadGroup();
// Always return true if call it before "Start()", return false otherwise.
bool AddOneTask(std::unique_ptr<Task>&& task);
void Start(int timeout_us = 0);
// The signature of TCallable is " void (Task*)".
// Note: if u start the group with a timeout, then use this function to
// retrieve your tasks, or there is a race condition.
template <typename TCallable>
void ForeachFinishedTask(const TCallable& func);
private:
struct SharedPart;
void StartBthread();
// Ihis just set a "stop flag" simply, and the user logic should stop
// according to Task::ShouldStop().
void NotifyStop();
bool is_started_ = false;
std::shared_ptr<SharedPart> sp_;
std::vector<std::unique_ptr<Task>> tasks_;
};
class BthreadGroup::Task {
public:
Task();
virtual ~Task();
virtual void Run() = 0;
protected:
// User should stop the task if this function return true. User can also
// ignore this function, and then this task will stop and delete itself.
bool ShouldStop() const;
private:
friend class BthreadGroup;
static void* InternalRun(void* data);
std::atomic<bool> is_finished_{false};
std::atomic<bool> should_stop_{false};
bthread_t bthread_ = INVALID_BTHREAD;
std::weak_ptr<BthreadGroup::SharedPart> sp_;
};
template <typename TCallable>
void BthreadGroup::ForeachFinishedTask(const TCallable& func) {
for (std::unique_ptr<Task>& task : tasks_) {
if (task && task->is_finished_.exchange(true, std::memory_order_seq_cst)) {
func(task.get());
} else {
task.release();
}
}
}
```
```cpp
namespace {
bvar::Adder<int> g_bthread_groups("bthread_group_count");
bvar::Adder<int> g_bthread_group_timeout_count("bthread_group_timeout_count");
bvar::Adder<int> g_bthread_group_tasks("bthread_group_task_count");
} // namespace
struct BthreadGroup::SharedPart {
SharedPart() : ce(0) { }
bthread::CountdownEvent ce;
};
BthreadGroup::BthreadGroup() : sp_(std::make_shared<SharedPart>()) {
g_bthread_groups << 1;
}
bool BthreadGroup::AddOneTask(std::unique_ptr<Task>&& task) {
if (is_started_) {
return false;
}
task->sp_ = sp_;
tasks_.emplace_back(std::move(task));
sp_->ce.add_count();
return true;
}
void BthreadGroup::Start(int timeout_us) {
StartBthread();
is_started_ = true;
if (timeout_us > 0) {
const timespec end_time = butil::microseconds_from_now(timeout_us);
const int status = sp_->ce.timed_wait(end_time);
if (status == ETIMEDOUT) {
g_bthread_group_timeout_count << 1;
} else if (status != 0) {
LOG(ERROR) << "bthread group is stopped du to: " << berror(status);
}
} else {
const int status = sp_->ce.wait();
if (status != 0) {
LOG(ERROR) << "bthread group is stopped du to: " << berror(status);
}
}
NotifyStop();
}
void BthreadGroup::StartBthread() {
if (tasks_.empty()) {
return;
}
for (size_t i = 0; i < tasks_.size() - 1; ++i) {
CHECK_EQ(0, bthread_start_background(
&tasks_[i]->bthread_, nullptr, Task::InternalRun, tasks_[i].get()))
<< "Failed to start a bthread, error: " << berror();
}
CHECK_EQ(0, bthread_start_urgent(&tasks_.back()->bthread_,
nullptr,
Task::InternalRun,
tasks_.back().get()))
<< "Failed to start a bthread, error: " << berror();
}
void BthreadGroup::NotifyStop() {
for (const std::unique_ptr<Task>& task : tasks_) {
task->should_stop_.store(true, std::memory_order_release);
}
}
BthreadGroup::~BthreadGroup() {
// Ensure the task thread aware of the finish state.
ForeachFinishedTask([](Task* dummy){});
g_bthread_groups << -1;
}
BthreadGroup::Task::Task() {
g_bthread_group_tasks << 1;
}
BthreadGroup::Task::~Task() {
g_bthread_group_tasks << -1;
}
bool BthreadGroup::Task::ShouldStop() const {
return should_stop_.load(std::memory_order_acquire) ||
1 == bthread_stopped(bthread_self());
}
void* BthreadGroup::Task::InternalRun(void* data) {
Task* task = static_cast<Task*>(data);
task->Run();
if (task->is_finished_.exchange(true, std::memory_order_seq_cst)) {
delete task;
} else if (std::shared_ptr<SharedPart> sp = task->sp_.lock()) {
sp->ce.signal();
}
return nullptr;
}
```
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[GitHub] [incubator-brpc] feng-y closed issue #1243: brpc::Join(CallId id) 支持带超时的等待
Posted by GitBox <gi...@apache.org>.
feng-y closed issue #1243:
URL: https://github.com/apache/incubator-brpc/issues/1243
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[GitHub] [incubator-brpc] feng-y edited a comment on issue #1243: brpc::Join(CallId id) 支持带超时的等待
Posted by GitBox <gi...@apache.org>.
feng-y edited a comment on issue #1243:
URL: https://github.com/apache/incubator-brpc/issues/1243#issuecomment-693761761
> 启动一个bthread sleep超时的时间后 brpc::StartCancel就可以，并不复杂。
wait 和 sleep 不是一个语义，和复杂没有关系，哪里需要sleep 多长时间呢，假设是5ms， 可能这个请求在1ms 后就返回了，需要的是异步通知机制， 我看看用 bthread::CountdownEvent来实现看看
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[GitHub] [incubator-brpc] feng-y edited a comment on issue #1243: brpc::Join(CallId id) 支持带超时的等待
Posted by GitBox <gi...@apache.org>.
feng-y edited a comment on issue #1243:
URL: https://github.com/apache/incubator-brpc/issues/1243#issuecomment-693219844
一个不太靠谱的基于future的实现
callback 里面设置 future
```
void HandleEchoResponse(
brpc::Controller* cntl,
example::EchoResponse* response,
std::shared_ptr<std::promise<bool>> waiter) {
waiter->set_value(true);
}
```
等待的时候不join， 等future ，如果futre 不成功就 cancel 请求
```
std::shared_ptr<std::promise<bool>> waiter(std::make_shared<std::promise<bool>>());
// Because `done'(last parameter) is NULL, this function waits until
// the response comes back or error occurs(including timedout).
google::protobuf::Closure* done = brpc::NewCallback(
&HandleEchoResponse, &cntl, &response, waiter);
auto call_id = cntl.call_id();
stub.Echo(&cntl, &request, &response, done);
LOG(INFO) << "waiting Join:" << errno << ", " << EINVAL;
// brpc::Join(call_id);
if (waiter->get_future().wait_for(std::chrono::microseconds(1)) != std::future_status::ready) {
LOG(INFO) << "timeout";
brpc::StartCancel(call_id);
} else {
.......
}
```
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[GitHub] [incubator-brpc] feng-y commented on issue #1243: brpc::Join(CallId id) 支持带超时的等待
Posted by GitBox <gi...@apache.org>.
feng-y commented on issue #1243:
URL: https://github.com/apache/incubator-brpc/issues/1243#issuecomment-693197866
还是关注问题本身吧! 一个带超时的逻辑还需要启动一个定时任务去cancel，我理解一个超时等待的功能也算是一个合理的需求吧
呼唤大神来看看 @jamesge @zyearn
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[GitHub] [incubator-brpc] feng-y closed issue #1243: brpc::Join(CallId id) 支持带超时的等待
Posted by GitBox <gi...@apache.org>.
feng-y closed issue #1243:
URL: https://github.com/apache/incubator-brpc/issues/1243
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[GitHub] [incubator-brpc] feng-y commented on issue #1243: brpc::Join(CallId id) 支持带超时的等待
Posted by GitBox <gi...@apache.org>.
feng-y commented on issue #1243:
URL: https://github.com/apache/incubator-brpc/issues/1243#issuecomment-693219844
一个不太靠谱的基于future的实现
```
std::shared_ptr<std::promise<bool>> waiter(std::make_shared<std::promise<bool>>());
// Because `done'(last parameter) is NULL, this function waits until
// the response comes back or error occurs(including timedout).
google::protobuf::Closure* done = brpc::NewCallback(
&HandleEchoResponse, &cntl, &response, waiter);
auto call_id = cntl.call_id();
stub.Echo(&cntl, &request, &response, done);
LOG(INFO) << "waiting Join:" << errno << ", " << EINVAL;
// brpc::Join(call_id);
if (waiter->get_future().wait_for(std::chrono::microseconds(1)) != std::future_status::ready) {
LOG(INFO) << "timeout";
brpc::StartCancel(call_id);
} else {
.......
}
```
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[GitHub] [incubator-brpc] gydong commented on issue #1243: brpc::Join(CallId id) 支持带超时的等待
Posted by GitBox <gi...@apache.org>.
gydong commented on issue #1243:
URL: https://github.com/apache/incubator-brpc/issues/1243#issuecomment-693790906
> @zyearn 感谢提供的方案，另外再请教一个问题，cancel 和正常的请求 在 回调里面有办法区分么？
ErrorCode 会是 ECANCELED 的
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[GitHub] [incubator-brpc] feng-y commented on issue #1243: brpc::Join(CallId id) 支持带超时的等待
Posted by GitBox <gi...@apache.org>.
feng-y commented on issue #1243:
URL: https://github.com/apache/incubator-brpc/issues/1243#issuecomment-693147740
哪怎么保证是安全的呢？
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[GitHub] [incubator-brpc] cdjingit commented on issue #1243: brpc::Join(CallId id) 支持带超时的等待
Posted by GitBox <gi...@apache.org>.
cdjingit commented on issue #1243:
URL: https://github.com/apache/incubator-brpc/issues/1243#issuecomment-693343012
启动一个bthread sleep超时的时间后 brpc::StartCancel就可以，并不复杂。
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[GitHub] [incubator-brpc] feng-y commented on issue #1243: brpc::Join(CallId id) 支持带超时的等待
Posted by GitBox <gi...@apache.org>.
feng-y commented on issue #1243:
URL: https://github.com/apache/incubator-brpc/issues/1243#issuecomment-693761761
> 启动一个bthread sleep超时的时间后 brpc::StartCancel就可以，并不复杂。
wait 和 sleep 不是一个语义，和复杂没有关系，哪里需要sleep 多长时间呢，加速5ms， 可能这个请求在1ms 后就返回了，需要的是异步通知机制， 我看看用 bthread::CountdownEvent来实现看看
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[GitHub] [incubator-brpc] cdjingit commented on issue #1243: brpc::Join(CallId id) 支持带超时的等待
Posted by GitBox <gi...@apache.org>.
cdjingit commented on issue #1243:
URL: https://github.com/apache/incubator-brpc/issues/1243#issuecomment-693136308
超时后，rpc实际没有结束，需要cancel掉才可以，否则会有资源访问问题。原来的语义join后，rpc一定是结束了，后续处理是安全的。
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[GitHub] [incubator-brpc] gydong commented on issue #1243: brpc::Join(CallId id) 支持带超时的等待
Posted by GitBox <gi...@apache.org>.
gydong commented on issue #1243:
URL: https://github.com/apache/incubator-brpc/issues/1243#issuecomment-693155824
相关逻辑都在用户代码中，要做到安全比较难把控。你的场景，通过灵活调整SB的超时时间不可以吗？
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[GitHub] [incubator-brpc] cdjingit commented on issue #1243: brpc::Join(CallId id) 支持带超时的等待
Posted by GitBox <gi...@apache.org>.
cdjingit commented on issue #1243:
URL: https://github.com/apache/incubator-brpc/issues/1243#issuecomment-693175268
启动一个定时任务cancel掉这个rpc
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[GitHub] [incubator-brpc] feng-y commented on issue #1243: brpc::Join(CallId id) 支持带超时的等待
Posted by GitBox <gi...@apache.org>.
feng-y commented on issue #1243:
URL: https://github.com/apache/incubator-brpc/issues/1243#issuecomment-693767387
> > 一个不太靠谱的基于future的实现
> > callback 里面设置 future
> > ```
> > void HandleEchoResponse(
> > brpc::Controller* cntl,
> > example::EchoResponse* response,
> > std::shared_ptr<std::promise<bool>> waiter) {
> > waiter->set_value(true);
> > }
> > ```
> >
> >
> > 等待的时候不join， 等future ，如果futre 不成功就 cancel 请求
> > ```
> > std::shared_ptr<std::promise<bool>> waiter(std::make_shared<std::promise<bool>>());
> >
> > // Because `done'(last parameter) is NULL, this function waits until
> > // the response comes back or error occurs(including timedout).
> > google::protobuf::Closure* done = brpc::NewCallback(
> > &HandleEchoResponse, &cntl, &response, waiter);
> >
> > auto call_id = cntl.call_id();
> > stub.Echo(&cntl, &request, &response, done);
> > LOG(INFO) << "waiting Join:" << errno << ", " << EINVAL;
> > // brpc::Join(call_id);
> > if (waiter->get_future().wait_for(std::chrono::microseconds(1)) != std::future_status::ready) {
> > LOG(INFO) << "timeout";
> > brpc::StartCancel(call_id);
> > } else {
> > .......
> > }
> > ```
>
> 这里用future来实现不太合适，future.wait会阻塞brpc的worker线程。
>
> Join的语义暗含的意思是当Join返回的时候，被Join的对象已经处于一个结束的状态，这里加个timeout会有点破坏语义。
>
> 这个需求也可以通过bthread::CountdownEvent来实现，在原来future set_value的地方改成signal，在Join的地方改成timed_wait。
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[GitHub] [incubator-brpc] feng-y commented on issue #1243: brpc::Join(CallId id) 支持带超时的等待
Posted by GitBox <gi...@apache.org>.
feng-y commented on issue #1243:
URL: https://github.com/apache/incubator-brpc/issues/1243#issuecomment-693768005
@zyearn 感谢提供的方案，另外再请教一个问题，cancel 和正常的请求 在 回调里面有办法区分么？
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