haunt98 / golo

Prevent an application from running twice. This is a Golang version of rolo/solo

Description

golo prevents an application from running twice. This is useful when you launch your task thanks to cron.

The basic ideas come from the original Perl application solo and its Ruby version rolo.

Example usage

Try to create ssh port forwarding from local host to remote server. As we don't want to run this command multiple twice, golo helps

$ go run golo.go -timeout 10  -port 4040 --no-bind -- /usr/bin/ssh MyServer -o "LocalForward localhost:4040 localhost:8888" -fN
:: Port is available. App is not running
:: Now staring application '/usr/bin/ssh' from .

$ go run golo.go -timeout 10  -port 4040 --no-bind -- /usr/bin/ssh MyServer -o "LocalForward localhost:4040 localhost:8888" -fN
:: Port is not available. App is running?

Below the crontab settings to create some ssh tunnels. If any tunnel is broken due to network issue, cron will try to restart them in within 1 minute. If the tunnel is still work, cron will simply exit.

$ crontab -l

*/1 * * * * golo -port 6432 --address 127.0.0.1 --no-bind /usr/bin/ssh zproxydev -fN
*/1 * * * * golo -port 6442 --address 127.0.0.1 --no-bind /usr/bin/ssh zproxystaging -fN
*/1 * * * * golo -port 6452 --address 127.0.0.1 --no-bind /usr/bin/ssh zproxyproduction -fN