goagain
Zero-downtime restarts in Go
The goagain
package provides primitives for bringing zero-downtime restarts to Go applications that accept connections from a net.TCPListener
or net.UnixListener
.
Have a look at the examples because it isn't just a matter of importing the library and everything working. Your main
function will have to accomodate the goagain
protocols and your process will have to have some definition (however contrived you like) of a graceful shutdown process.
Installation
go get github.com/rcrowley/goagain
Usage
Send SIGUSR2
to a process using goagain
and it will restart without downtime.
example/single/main.go
: The Single
strategy (named because it calls execve
(2) once) operates similarly to Nginx and Unicorn. The parent forks a child, the child execs, and then the child kills the parent. This is easy to understand but doesn't play nicely with Upstart and similar direct-supervision init
(8) daemons. It should play nicely with systemd
.
example/double/main.go
: The Double
strategy (named because it calls execve
(2) twice) is experimental so proceed with caution. The parent forks a child, the child execs, the child signals the parent, the parent execs, and finally the parent kills the child. This is regrettably much more complicated but plays nicely with Upstart and similar direct-supervision init
(8) daemons.