Varnish sample vcl for rtmp / m3u8 stream

vcl 4.0;
import std;
backend default {
.host = "127.0.0.1";
.port = "8090";
}
acl purge {
"127.0.0.1";
}
sub vcl_recv {
if(req.method == "PURGE"){
if (!client.ip ~ purge) {
return(synth(405,"Not allowed."));
}
return (purge);
}
return (hash);
}

sub vcl_backend_response {

if (bereq.url ~ "m3u8") {
# assuming chunks are 2 seconds long
set beresp.ttl = 1s;
set beresp.grace = 0s;
} else {
set beresp.ttl = 10m;
set beresp.grace = 5m;
}
}