How to tell docker-compose exec to read from stdin? - docker

Question

docker-compose exec is failing when reading from stdin:
$ echo "use mydb; show measurements;" | docker-compose exec influxdb influx
Connected to http://localhost:8086 version 1.2.4
InfluxDB shell version: 1.2.4
> Traceback (most recent call last):
File "/usr/local/bin/docker-compose", line 9, in <module>
load_entry_point('docker-compose==1.9.0', 'console_scripts', 'docker-compose')()
File "/usr/local/lib/python2.7/dist-packages/compose/cli/main.py", line 65, in main
command()
File "/usr/local/lib/python2.7/dist-packages/compose/cli/main.py", line 117, in perform_command
handler(command, command_options)
File "/usr/local/lib/python2.7/dist-packages/compose/cli/main.py", line 462, in exec_command
pty.start()
File "/usr/local/lib/python2.7/dist-packages/dockerpty/pty.py", line 338, in start
io.set_blocking(pump, flag)
File "/usr/local/lib/python2.7/dist-packages/dockerpty/io.py", line 32, in set_blocking
old_flag = fcntl.fcntl(fd, fcntl.F_GETFL)
ValueError: file descriptor cannot be a negative integer (-1)
Using the -T flag gets rid of the problem, but it seems to suppress reading from stdin:
$ echo "use mydb; show measurements;" | docker-compose exec -T influxdb influx
(I need to kill that command, since it shows nothing and is not able to read from stdin)
This seems like a docker-compose bug, maybe I should file this?
$ docker-compose --version
docker-compose version 1.9.0, build 2585387
EDIT
Related:
https://github.com/docker/compose/issues/3352
https://github.com/docker/compose/issues/4290

Answer 1

In https://github.com/docker/compose/issues/3352 endzyme suggests using the docker command for doing this. I created a tiny bash function I have in my bash profile based on his suggestion:
# Like `docker-compose exec` but forwarding stdin to the container
# See https://github.com/docker/compose/issues/3352
function docin() {
local service="$1"; shift
docker exec -i "$(docker-compose ps -q $service)" "$#"
}
In your case you would use it like:
echo "use mydb; show measurements;" | docin influxdb influx
It's a good enough work-around until they fix this in docker-compose.