Testing connection by sending two spaces breaks some Carbon implementations

[tkirill]

Hi!

I'm using carbon-clickhouse implementation of Carbon. I discovered that it doesn't accept first datapoint from a collection which I pass to graphiteClient.SendAsync.

After some research I found out that the reason is two spaces before first datapoint. They come from testing connection procedure. I reproduced the problem with netcat:

# this datapoint will be ignored because of leading spaces
echo "  test.some.metric 275 `date +%s`" | nc localhost 2003 -vN

What do you think about changing space to LF (0x0A) for testing connection purposes? Since plaintext protocol is line-based it looks safer. I tried it with both original Carbon and clickhouse-carbon and it works wihtout any errors in logs or datapoint loss:

# this datapoint will be successfully accepeted
echo -e "\n\ntest.some.metric 275 `date +%s`" | nc localhost 2003 -vN