It is often a pain to write a server program that supports graceful restarts, with no resource leaks. Server::Starter solves the problem by splitting the task into two. One is start_server, a script provided as a part of the module, which works as a superdaemon that binds to zero or more TCP ports or unix sockets, and repeatedly spawns the server program that actually handles the necessary tasks (for example, responding to incoming commenctions). The spawned server programs under Server::Starter call accept(2) and handle the requests.
To gracefully restart the server program, send SIGHUP to the superdaemon. The superdaemon spawns a new server program, and if (and only if) it starts up successfully, sends SIGTERM to the old server program.
By using Server::Starter it is much easier to write a hot-deployable server. Following are the only requirements a server program to be run under Server::Starter should conform to:
- receive file descriptors to listen to through an environment variable
- perform a graceful shutdown when receiving SIGTERM
A Net::Server personality that can be run under Server::Starter exists under the name Net::Server::SS::PreFork.