Compose: "docker-compose images" produces a line break while piping

[andreyMid]

Description of the issue

I'm failed to get the relation between container name and image id by using command:

docker-compose -f ./docker-compose.yml -p InitializingVariables_supportInitializingAssign images | tail -n +3 | xargs -n 6 | cut -d " " -f1,4

since 1.25.0-rc3.

Context information (for bug reports)

Output of docker-compose version

docker-compose version
docker-compose version 1.25.0-rc3, build c7e82489
docker-py version: 4.1.0
CPython version: 3.7.4
OpenSSL version: OpenSSL 1.1.0l  10 Sep 2019

Output of docker version

Client: Docker Engine - Community
 Version:           19.03.5
 API version:       1.40
 Go version:        go1.12.12
 Git commit:        633a0ea
 Built:             Wed Nov 13 07:25:41 2019
 OS/Arch:           linux/amd64
 Experimental:      false

Server: Docker Engine - Community
 Engine:
  Version:          19.03.5
  API version:      1.40 (minimum version 1.12)
  Go version:       go1.12.12
  Git commit:       633a0ea
  Built:            Wed Nov 13 07:24:18 2019
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          1.2.10
  GitCommit:        b34a5c8af56e510852c35414db4c1f4fa6172339
 runc:
  Version:          1.0.0-rc8+dev
  GitCommit:        3e425f80a8c931f88e6d94a8c831b9d5aa481657
 docker-init:
  Version:          0.18.0
  GitCommit:        fec3683

Output of docker-compose.yml

version: "3"
services:
    client1:
        image: "httpd"
        networks:
            httpd_network:
                aliases:
                    - apache1
        ports:
            - "8331:8080"

    client2:
        image: "httpd"
        networks:
            httpd_network:
                aliases:
                    - apache2
        ports:
            - "8333:8080"

networks:
    httpd_network:

Steps to reproduce the issue

1. yes | docker-compose -f ./docker-compose.yml -p InitializingVariables_supportInitializingAssign up --no-start
2. docker-compose -f ./docker-compose.yml -p InitializingVariables_supportInitializingAssign images | tail -n 2

Observed result

initializingvariables_supportini httpd latest c2aa7e16edd8 165.3 MB
tializingassign_client1_1
initializingvariables_supportini httpd latest c2aa7e16edd8 165.3 MB
tializingassign_client2_1

Expected result

initializingvariables_supportinitializingassign_client1_1 httpd latest c2aa7e16edd8 157.6 MB
initializingvariables_supportinitializingassign_client2_1 httpd latest c2aa7e16edd8 157.6 MB
(output from 1.25.0-rc2)

Additional information

Red Hat Enterprise Linux Server release 7.5 (Maipo)

Installation method:
curl -L https://github.com/docker/compose/releases/download/1.25.0-rc3/docker-compose-uname -s-uname -m -o /usr/local/bin/docker-compose
chmod +x /usr/local/bin/docker-compose

[ndeloof]

As table formatter do adapt to TTY width, this might be a side effect of https://github.com/docker/compose/commit/452880af7cd3c59f3bbe9a7714a0176f52f2d12d

[ndeloof]

made a quick test (docker-compose 1.25.0 / ubuntu) and docker-compose image do not split image/container names until terminal side becomes too short for them.

[andreyMid]

Thank you, your comment is very useful for me
Made a test with 1.25.0:
$ stty size
53 192

In this case docker-compose truly does not split a container name:
docker-compose -f ./docker-compose.yml -p InitializingVariables_supportInitializingAssign images

initializingvariables_supportinitializingassign_client1_1 httpd latest c2aa7e16edd8 165.3 MB
initializingvariables_supportinitializingassign_client2_1 httpd latest c2aa7e16edd8 165.3 MB
(105 < 192)

But when i using a pipe:
docker-compose -f ./docker-compose.yml -p InitializingVariables_supportInitializingAssign images | tail

docker-compose gets the tty width 80 and splits the string according this value:

initializingvariables_supportini httpd latest c2aa7e16edd8 165.3 MB
tializingassign_client1_1
initializingvariables_supportini httpd latest c2aa7e16edd8 165.3 MB
tializingassign_client2_1
(105 > 80)

But why does a docker-compose gets a wrong tty width in this case?

When i using a piping with echo, there is no splitting:
echo "initializingvariables_supportinitializingassign_client1_1 httpd latest c2aa7e16edd8 165.3 MB" | tail

initializingvariables_supportinitializingassign_client1_1 httpd latest c2aa7e16edd8 165.3 MB

[ndeloof]

same issue here. Weird. Thanks for helping in diagnostic

[ndeloof]

souds like a weird python/shutil bug.
using

#test.py
import shutil
from shutil import get_terminal_size

x,y = get_terminal_size()
print(x)
print(y)

➜  python3 test.py 
156
24
➜  python3 test.py | tail
80
24

[ndeloof]

Interesting related discussion on https://groups.google.com/forum/#!topic/comp.lang.python/v9VszdDzpdE