Yunying(云影) is a simple HTTP server that supports static file serving, reverse proxy and in-memory cache. It is written in C++ and uses epoll to handle network events.
Yunying can now serve static files and reverse proxy for other HTTP or HTTPS servers. It cannot serve HTTPS yet.
You need a Linux machine and CMake to build and run Yunying.
After cloning this repository, you should first initialize the submodules:
git submodule update --init --recursiveThen you can build Yunying with CMake:
cmake -B build
cmake --build buildAfter build, you will get yunying executable file. You can refer to the config document to edit the config file. After editing the config file, you can run it directly:
build/yunying [config_file] # config_file can be omitted, default to ./config.luaReference: Configuration Document
Yunying is a single-process, multi-threaded web server.
Yunying utilizes four types of threads in its architecture:
- Main thread: The entrance and control thread for the server.
- Listener thread: Listens for connections from clients and allocate them to worker threads via epoll instances.
- Worker threads: Could have multiple worker threads. They interact with clients via connections, parse and craft HTTP requests and responses; using cache to get contents from either upstream server or the disk.
- Cache cleaning thread: Free up expired cache items from memory periodically.
Below diagram shows the thread model of Yunying, note that Cache is not belong to any thread, it's a piece of memory that all worker threads and cache cleaning thread can access.
Singleton Pattern: The Conf instance and the Metrics instance are implemented as singletons. This design enables effortless access to configurations or the ability to record metrics from anywhere in the program by obtaining the instances easily.
Abstract Class: The Origin class serves as an abstract class representing the content origin. It can be specialized into either UpstreamOrigin or StaticFileOrigin. The abstract class defines two pure virtual methods:
virtual std::string getKey(HttpRequest request) = 0;
virtual HttpResponse* get(HttpRequest request, int* max_age) = 0;These methods are utilized by the cache module to retrieve keys for indexing cache items and obtaining contents along with their expiration age in the cache. Both UpstreamOrigin and StaticFileOrigin inherit from the Origin class and provide corresponding implementations of these two methods to cater to different types of content origins.
Run benchmarks with wrk in a cloud server with 2 CPU cores and 2 GB memory.
Run wrk for two URLs, one is a 301 page which is short and the other is the main page of en.wikipedia.org which is relatively long. The results are as follows:
$ wrk -t4 -c1000 -d60s http://localhost:8080/ # 301 page
Running 1m test @ http://localhost:8080/
4 threads and 1000 connections
Thread Stats Avg Stdev Max +/- Stdev
Latency 20.09ms 26.16ms 1.70s 99.57%
Req/Sec 11.06k 2.14k 21.18k 71.05%
2638746 requests in 1.00m, 2.52GB read
Socket errors: connect 0, read 0, write 0, timeout 74
Requests/sec: 43919.38
Transfer/sec: 42.93MB
$ wrk -t4 -c1000 -d60s http://localhost:8080/wiki/Main_Page # Wikipedia main page
Running 1m test @ http://localhost:8080/wiki/Main_Page
4 threads and 1000 connections
Thread Stats Avg Stdev Max +/- Stdev
Latency 90.47ms 15.09ms 200.38ms 77.62%
Req/Sec 2.77k 238.44 3.52k 71.24%
661140 requests in 1.00m, 63.89GB read
Requests/sec: 11004.69
Transfer/sec: 1.06GB- Lua - A lightweight scripting language, used as the configuration language of Yunying.
- sol2 - A C++ wrapper for Lua.
- libcurl - A C library for transferring data with URL syntax, used for upstream requests.
- Google Test - A C++ testing framework.