tstream/tstream

#!/bin/sh
# Kimapr's streaming setup
# how to use:
# install ncat, lua (tested with 5.4.3), and script
# mkdir ~/stream
# make a text file ~/stream/welcome, it will be displayed on stream startup.
# make a text file ~/stream/the_end, it will be displayed on stream end.
# start the stream by running this script (see usage in the echo command below)
# after it starts you can connect via the port provided from any interface
# end the stream by exitting from the shell in the stream window
# you can also replay past streams using `scriptreplay -O live -T live-timing` in ~/stream/hist/*/

echo "usage: tstream <port> <width> <height> [max bandwidth in KiB/s (per-client)]"
port=$1
width=$2
height=$3
bandwidth=$4
if [ "x$bandwidth" = "x" ]; then
	bandwidth=32
fi
randid=`head -c 16 /dev/urandom | xxd -p`
name=`date -u +%Y-%m-%d_%H-%M-%S_UTC`
tmux new-session -d -s wstream_$randid "clear;cat ~/stream/welcome;$SHELL"
tmux resize-window -t wstream_$randid -x $width -y $(($height - 1))
tmux set-option -t wstream_$randid status-right "? viewers"
cat >/tmp/tstream-helper_$randid <<EOF
#!/bin/sh
clear
TMUX= tmux attach -t wstream_$randid
clear
cat ~/stream/the_end
for i in \$(seq 7); do
	echo -n .
	sleep 0.1
done
echo DISCONNECT
EOF
chmod +x /tmp/tstream-helper_$randid
mkdir -p ~/stream/hist/$name
tmux new-session -d -s stream_$randid "SHELL='/tmp/tstream-helper_$randid' script -f ~/stream/hist/$name/live -T ~/stream/hist/$name/live-timing;sleep 2"
tmux resize-window -t stream_$randid -x $width -y $height
cat >/tmp/tstream-refresh_$randid <<EOF
#!/usr/bin/env lua
local file=io.popen("tmux list-clients")
local lines={}
local line=file:read()
while line do
	lines[#lines+1]=line
	line=file:read()
end
local clients={}
for k,v in ipairs(lines) do
	local cl,sess=string.match(v,"(.-)%: (.-) ")
	if sess=="wstream_$randid" then
		os.execute("tmux refresh-client -t "..cl)
	end
end
EOF
echo 0 > /tmp/tstream-count_$randid
vcrefresh="tmux set-option -t wstream_$randid status-right \"\$(cat /tmp/tstream-count_$randid) viewers\""
sh -c "$vcrefresh"
cat >/tmp/tstream-smarttail_$randid <<EOF
#!/usr/bin/env lua
local unpack=unpack or table.unpack
local file=io.open("$HOME/stream/hist/$name/live")
file:seek("end")
local bandwidth=$bandwidth * 1024
local checkpoints={}
local coro=coroutine.create(function()
	local file=io.open("/tmp/tstream-seektimes_$randid")
	while true do
		local curseek=file:seek()
		local endseek=file:seek("end")
		local avail=endseek-curseek
		file:seek("set",curseek)
		if avail>0 then
			local str=file:read()
			local seek,t=str:match("(.-) (.+)")
			seek,t=tonumber(seek),tonumber(t)
			if seek and t then
				table.insert(checkpoints,{seek,t})
			end
		else
			coroutine.yield()
		end
	end
end)
local ct=os.time()
local count=0
local counts={}
while true do
	local curseek=file:seek()
	local endseek=file:seek("end")
	local avail=endseek-curseek
	file:seek("set",curseek)
	assert(coroutine.resume(coro))
	if avail>0 then
		local str=file:read(math.min(avail,512))
		assert(str)
		io.write(str)
		io.flush()
		count=count+#str
		local cpc=#checkpoints
		local avg=0
		for k,v in pairs(counts) do
			avg=avg+v
		end
		avg=avg/#counts
		if avg>bandwidth then
			os.execute("clear")
			print("overload! "..(avg/1024).." KiB/s > "..(bandwidth/1024).." KiB/s")
			while true do
				os.execute("sleep 0.1")
				assert(coroutine.resume(coro))
				if #checkpoints>cpc then
					cpc=#checkpoints
					break
				end
			end
			local seek=checkpoints[cpc][1]
			print("seeking to "..seek.."/"..file:seek("end"))
			os.execute("sleep 1")
			counts={}
			count=0
			file:seek("set",checkpoints[cpc][1]) --congestion
		end
	else
		os.execute("sleep 0.01")
	end
	local tf=io.open("/tmp/tstream-death_$randid")
	if tf then
		tf:close()
		io.stdin:close()
		io.stdout:close()
		return
	end
	local ct2=os.time()
	if ct2~=ct then
		ct=ct2
		table.insert(counts,count)
		count=0
		while #counts>5 do
			table.remove(counts,1)
		end
	end
end
EOF
chmod +x /tmp/tstream-smarttail_$randid
cat >/tmp/tstream-cat_$randid <<EOF
#!/bin/sh
vcrefresh='$vcrefresh'
echo "\$vcrefresh"
{ sleep 5;/tmp/tstream-refresh_$randid; } &
echo "Welcome to Kimapr's stream. Please wait..."
echo \$((\$(cat /tmp/tstream-count_$randid) + 1)) > /tmp/tstream-count_$randid
sh -c "\$vcrefresh"
/tmp/tstream-smarttail_$randid
echo \$((\$(cat /tmp/tstream-count_$randid) - 1)) > /tmp/tstream-count_$randid
sh -c "\$vcrefresh"
EOF
chmod +x /tmp/tstream-cat_$randid
chmod +x /tmp/tstream-refresh_$randid
touch /tmp/tstream-seektimes_$randid
{
	while true; do
		sleep 5
		echo "$(lua -e "local file=io.open(\"$HOME/stream/hist/$name/live\")print(file:seek(\"end\")..\" \"..os.time())file:close()")" >>/tmp/tstream-seektimes_$randid
		/tmp/tstream-refresh_$randid
	done
} &
ncat -l -k -c "/tmp/tstream-cat_$randid" $port &
sleep 1
tmux attach -t stream_$randid
tmux kill-session -t wstream_$randid
tmux kill-session -t stream_$randid
touch /tmp/tstream-death_$randid
echo PLEASE WAIT...
sleep 2;
rm /tmp/tstream-death_$randid
rm /tmp/tstream-helper_$randid
rm /tmp/tstream-refresh_$randid
rm /tmp/tstream-cat_$randid
rm /tmp/tstream-count_$randid
rm /tmp/tstream-smarttail_$randid
rm /tmp/tstream-seektimes_$randid
kill %1
kill %2
echo exit complete