124 lines
3.7 KiB
C++
124 lines
3.7 KiB
C++
#ifndef __ETCD_KEEPALIVE_HPP__
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#define __ETCD_KEEPALIVE_HPP__
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#include <atomic>
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#include <chrono>
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#include <condition_variable>
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#include <exception>
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#include <functional>
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#include <mutex>
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#include <string>
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#include <thread>
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#include "etcd/Response.hpp"
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#include "etcd/SyncClient.hpp"
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namespace etcd {
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// forward declaration to avoid header/library dependency
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class Client;
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/**
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* If ID is set to 0, the library will choose an ID, and can be accessed from
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* ".Lease()".
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*/
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class KeepAlive {
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public:
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KeepAlive(Client const& client, int ttl, int64_t lease_id = 0);
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KeepAlive(SyncClient const& client, int ttl, int64_t lease_id = 0);
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KeepAlive(std::string const& address, int ttl, int64_t lease_id = 0);
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KeepAlive(std::string const& address, std::string const& username,
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std::string const& password, int ttl, int64_t lease_id = 0,
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int const auth_token_ttl = 300);
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KeepAlive(Client const& client,
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std::function<void(std::exception_ptr)> const& handler, int ttl,
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int64_t lease_id = 0);
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KeepAlive(SyncClient const& client,
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std::function<void(std::exception_ptr)> const& handler, int ttl,
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int64_t lease_id = 0);
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KeepAlive(std::string const& address,
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std::function<void(std::exception_ptr)> const& handler, int ttl,
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int64_t lease_id = 0);
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KeepAlive(std::string const& address, std::string const& username,
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std::string const& password,
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std::function<void(std::exception_ptr)> const& handler, int ttl,
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int64_t lease_id = 0, int const auth_token_ttl = 300);
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KeepAlive(std::string const& address, std::string const& ca,
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std::string const& cert, std::string const& privkey,
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std::function<void(std::exception_ptr)> const& handler, int ttl,
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int64_t lease_id = 0, std::string const& target_name_override = "");
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KeepAlive(KeepAlive const&) = delete;
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KeepAlive(KeepAlive&&) = delete;
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int64_t Lease() const { return lease_id; }
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/**
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* Stop the keep alive action.
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*/
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void Cancel();
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/**
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* Check if the keep alive is still valid (invalid when there's an async
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* exception).
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*
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* Nothing will happen if valid and an exception will be rethrowed if invalid.
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*/
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void Check();
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/**
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* Set a timeout value for grpc operations.
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*/
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template <typename Rep = std::micro>
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void set_grpc_timeout(std::chrono::duration<Rep> const& timeout) {
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this->grpc_timeout =
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std::chrono::duration_cast<std::chrono::milliseconds>(timeout);
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}
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/**
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* Get the current timeout value for grpc operations.
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*/
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std::chrono::microseconds get_grpc_timeout() const {
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return this->grpc_timeout;
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}
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~KeepAlive();
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protected:
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// automatically refresh loop, returns the error message if failed
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std::string refresh();
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// refresh once immediately, returns the error message if failed
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std::string refresh_once();
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struct EtcdServerStubs;
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struct EtcdServerStubsDeleter {
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void operator()(EtcdServerStubs* stubs);
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};
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std::unique_ptr<EtcdServerStubs, EtcdServerStubsDeleter> stubs;
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private:
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// error handling
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std::exception_ptr eptr_;
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std::function<void(std::exception_ptr)> handler_;
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// Don't use `pplx::task` to avoid sharing thread pool with other actions on
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// the client to avoid any potential blocking, which may block the keepalive
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// loop and evict the lease.
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std::thread refresh_task_;
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int ttl;
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int64_t lease_id;
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// protect the initializing status of `timer`.
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std::mutex mutex_for_refresh_;
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std::condition_variable cv_for_refresh_;
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std::atomic_bool continue_next;
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// grpc timeout in `refresh()`
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mutable std::chrono::microseconds grpc_timeout =
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std::chrono::microseconds::zero();
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};
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} // namespace etcd
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#endif
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