s0ph0s-2 / waitsilence Goto Github PK

Delay until stdin has recieved no input for a specified time, and then exit.

-timeout : length of time to wait, e.g. 10s
-command : instead of reading from `stdin`, execute the specified command
           inside a shell. The command is killed if `stdin` is silent for
           the specified duration.

Let's say you have process which you can signal to save everything in memory to disk in lots of little files. You don't know in advance how long this will take, but you want to wait as long as it's still writing. On Linux you can use inotifywait which will spit out text as long as files are still being modified on disk. You want to wait until the output falls silent for a short while, and then you can be sure that writing has finished. Then you can do this:

inotifywait -m -r . | waitsilence -timeout 5s

Unfortunately, this will wait longer than necessary because inotifywait will not be writing to its stdout when it has finished. This means that it won't receive the SIGPIPE until it next writes, which could be some time. In that case, you can run the command as a child inside waitsilence, where it will be killed.

If you say save-all to a minecraft server, it won't actually finish writing for some time.

This is what I use to do a backup on my minecraft server:

if ! screen -r -S minecraft -X stuff $'\nsave-all\nsave-off\n';
then
    echo "Screen is attached. Not taking world backup!"
    exit 1
fi

CMD='inotifywait -m -r server/world --exclude "^./dynmap.*" | grep -v ACCESS'

# Ensure minecraft has finished writing its files out:
waitsilence -timeout 5s -command "$CMD"

# < do whatever you want to backup your files >

screen -S minecraft -X stuff $'save-on\nsay World backup completed.\n'

I can recommend bup for taking minecraft backups. Hourly backups for 2 months currently occupy ~20GB, whereas vanilla copies would now occupy more than 1.5TB.

Use the go get tool, which will install it to your $GOPATH.

go get github.com/pwaller/waitsilence