Pipe input to dockerized socat run on socket present on docker host

Question

My goal is to query Haproxy Runtime API using dockerized socat.

Below command returns empty result (/var/run/haproxy.stat is haproxy socket located on the docker host)

 echo "-h" | docker run  -a stdin -a stderr alpine/socat stdio /var/run/haproxy.stat

I've tried to add haproxy socket via volume, but the result is still empty.

echo "-h" | docker run  -a stdin -a stderr  -v /var/run/haproxy.stat:/var/run/haproxy.stat alpine/socat stdio /var/run/haproxy.stat

Answer 1

Command that worked is:

echo "-h" | docker run -i -a stdin -a stderr -a stdout -v /var/run/haproxy.stat:/var/run/haproxy.stat alpine/socat stdio /var/run/haproxy.stat

Needed to add -a stdout and -i to docker run

Following suggestion by BMitch" tried below command and it worked as well

echo "-h" | docker run -i -v /var/run/haproxy.stat:/var/run/haproxy.stat alpine/socat stdio /var/run/haproxy.stat