1// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
2// Distributed under the MIT License (http://opensource.org/licenses/MIT)
3
4#pragma once
5
6// Fast asynchronous logger.
7// Uses pre allocated queue.
8// Creates a single back thread to pop messages from the queue and log them.
9//
10// Upon each log write the logger:
11// 1. Checks if its log level is enough to log the message
12// 2. Push a new copy of the message to a queue (or block the caller until
13// space is available in the queue)
14// Upon destruction, logs all remaining messages in the queue before
15// destructing..
16
17#include <spdlog/logger.h>
18
19namespace spdlog {
20
21// Async overflow policy - block by default.
22enum class async_overflow_policy {
23 block, // Block until message can be enqueued
24 overrun_oldest, // Discard oldest message in the queue if full when trying to
25 // add new item.
26 discard_new // Discard new message if the queue is full when trying to add new item.
27};
28
29namespace details {
30class thread_pool;
31}
32
33class SPDLOG_API async_logger final : public std::enable_shared_from_this<async_logger>,
34 public logger {
35 friend class details::thread_pool;
36
37public:
38 template <typename It>
39 async_logger(std::string logger_name,
40 It begin,
41 It end,
42 std::weak_ptr<details::thread_pool> tp,
43 async_overflow_policy overflow_policy = async_overflow_policy::block)
44 : logger(std::move(logger_name), begin, end),
45 thread_pool_(std::move(tp)),
46 overflow_policy_(overflow_policy) {}
47
48 async_logger(std::string logger_name,
49 sinks_init_list sinks_list,
50 std::weak_ptr<details::thread_pool> tp,
51 async_overflow_policy overflow_policy = async_overflow_policy::block);
52
53 async_logger(std::string logger_name,
54 sink_ptr single_sink,
55 std::weak_ptr<details::thread_pool> tp,
56 async_overflow_policy overflow_policy = async_overflow_policy::block);
57
58 std::shared_ptr<logger> clone(std::string new_name) override;
59
60protected:
61 void sink_it_(const details::log_msg &msg) override;
62 void flush_() override;
63 void backend_sink_it_(const details::log_msg &incoming_log_msg);
64 void backend_flush_();
65
66private:
67 std::weak_ptr<details::thread_pool> thread_pool_;
68 async_overflow_policy overflow_policy_;
69};
70} // namespace spdlog
71
72#ifdef SPDLOG_HEADER_ONLY
73 #include "async_logger-inl.h"
74#endif
75