Question

I want to convert the output of ifstat command into JSON and serve it over http on the fly to be used for a javascript graph app. Are there any lightweight — sed or awk — command-line solutions which I can use? I do not want to store JSON output on the disk and it would be good if the web-server was a small lightweight command line tool into which I can pipe JSON output.

EDIT 1:

This is the live streaming chart library which will use the data. I’m not keen on a specific web server; any webserver that does the job would be fine.

Answer 1

This is what I have tried.

Terminal #1

ifstat -n | awk 'NR>2{print systime(),$0; fflush()}' | tee ifstat.log

Terminal #2

while :
do
{ 
    echo -e "HTTP/1.1 200 OK"
    echo -e "Content-Type: application/json\n"
    tail -n1 ifstat.log | awk '{ printf("{\"time\":%s, \"in\":%s, \"out\":%s}\n", $1, $2, $3) }'
} | nc -l 8000
done

firefox

open: http://localhost:8000

{"time":1332052321, "in":1.24, "out":2.62}

I know little about JSON. Maybe the output is invalid. You should rewrite the awk command.