Docker Exec does not resize terminal on container

[mabombo]

• This is a bug report
• This is a feature request
• I searched existing issues before opening this one

Expected behavior

Host with docker installed (stty -a)

[~]# stty -a
speed 38400 baud; rows 42; columns 210; line = 0;
..........................
..........................

Shell inside a container (docker exec -it 9804cf214e7e21a3b63a7a227512d93ba5b4ac4df0c7ef7d01a1b7a2b5e106e6 /bin/bash)

[~]# stty -a
speed 38400 baud; rows 42; columns 210; line = 0;
...........................
...........................

Actual behavior

Host with docker installed (stty -a)

[~]# stty -a
speed 38400 baud; rows 42; columns 210; line = 0;
..........................
..........................

Shell inside a container (docker exec -it 9804cf214e7e21a3b63a7a227512d93ba5b4ac4df0c7ef7d01a1b7a2b5e106e6 /bin/bash)

[~]# stty -a
speed 38400 baud; rows 0; columns 0; line = 0;
...........................
...........................

Steps to reproduce the behavior

[ ~]# docker pull ubuntu
[ ~]# docker run -d -it ubuntu /bin/bash
16dffb0af8ab1fd0bc755ecb8be39b739d6408f2009bf028483723db5d6ff6a9
[~]# docker exec -it 16dffb0af8ab1fd0bc755ecb8be39b739d6408f2009bf028483723db5d6ff6a9 /bin/bash
root@16dffb0af8ab:/# 
root@16dffb0af8ab:/# stty -a
speed 38400 baud; rows 0; columns 0; line = 0;

Sometime on first exec the rows and columns are set correctly, try more time to exec inside a container
The problem is for all images. With previous Docker CE version the problem disappear .

Output of docker version:

Docker version 18.03.1-ce, build 9ee9f40

Output of docker info:

Containers: 15
 Running: 15
 Paused: 0
 Stopped: 0
Images: 11
Server Version: 18.03.1-ce
Storage Driver: overlay2
 Backing Filesystem: xfs
 Supports d_type: true
 Native Overlay Diff: true
Logging Driver: json-file
Cgroup Driver: cgroupfs
Plugins:
 Volume: local
 Network: bridge host macvlan null overlay
 Log: awslogs fluentd gcplogs gelf journald json-file logentries splunk syslog
Swarm: inactive
Runtimes: runc
Default Runtime: runc
Init Binary: docker-init
containerd version: 773c489c9c1b21a6d78b5c538cd395416ec50f88
runc version: 4fc53a81fb7c994640722ac585fa9ca548971871
init version: 949e6fa
Security Options:
 seccomp
  Profile: default
Kernel Version: 3.10.0-862.el7.x86_64
Operating System: Red Hat Enterprise Linux Server 7.5 (Maipo)
OSType: linux
Architecture: x86_64
CPUs: 16
Total Memory: 31.25GiB
Name: epress02docker
ID: VX3P:3XSO:6BQJ:V6AS:HZYH:CCEZ:7X3G:XSBX:ARWN:KCR4:JNPD:IMOA
Docker Root Dir: /dockerStorage
Debug Mode (client): false
Debug Mode (server): false
Registry: https://index.docker.io/v1/
Labels:
Experimental: false
Insecure Registries:
 127.0.0.0/8
Live Restore Enabled: false

Additional environment details (AWS, VirtualBox, physical, etc.)

OS Host with docker installed
[~]# cat /etc/redhat-release
Red Hat Enterprise Linux Server release 7.5 (Maipo)

Tested Image Ubuntu

[thaJeztah]

This looks like the same issue as reported in moby/moby#35407

The cause is a race-condition in the resize-event being sent to the container.
There's no fix available yet, but as a workaround; if you resize your terminal-window, the container should pick up the correct size.

[danielpops]

Here is another workaround:

sudo docker exec -it -e COLUMNS="$(tput cols)" -e LINES="$(tput lines)" container_name bash

[mabombo]

Thank you best regards MAURO Inviato da iPhone

…

Il giorno 25 mag 2018, alle ore 19:57, Daniel Popescu ***@***.***> ha scritto: Here is another workaround: sudo docker exec -it -e COLUMNS="tput cols" -e LINES="tput lines" container_name bash — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub, or mute the thread.

[thaJeztah]

Fixed on master through moby/moby#37172

[mishas]

Can we reopen this, as this doesn't seem to be fixed:

Using docker 18.09.0-ce on both Linux (Debian 9.6) and Mac:

root@server:~# docker exec -ti test stty size
0 0

When I added a lot of sleep, I got:

root@server:~# docker exec -ti test /bin/bash -c "sleep 1; stty size"
54 235

When I added a little bit of sleep, I got:

root@server:~# docker exec -ti test /bin/bash -c "sleep 0.05; stty size"
54 235
root@server:~# docker exec -ti test /bin/bash -c "sleep 0.05; stty size"
0 0
root@server:~# docker exec -ti test /bin/bash -c "sleep 0.05; stty size"
54 235
root@server:~# docker exec -ti test /bin/bash -c "sleep 0.05; stty size"
0 0

So - the race condition seems to still be present :(.

[haridsv]

Workaround by @danielpops doesn't seem to help. It does set ROWS and COLUMNS, but stty -a still shows 0 rows and columns and this is problematic for JRuby and JRuby based interactive programs as discussed here: https://stackoverflow.com/questions/49649449/hbase-shell-crash-after-backspace

$ echo $LINES $COLUMNS
107 364
$ stty -a
speed 38400 baud; rows 0; columns 0; line = 0;
intr = ^C; quit = ^\; erase = ^?; kill = ^U; eof = ^D; eol = <undef>; eol2 = <undef>; swtch = <undef>; start = ^Q; stop = ^S; susp = ^Z; rprnt = ^R; werase = ^W; lnext = ^V; flush = ^O; min = 1; time = 0;
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opost -olcuc -ocrnl onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0
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[thaJeztah]

There was a follow-up pull request that's been merged in the cli, and should fix the remaining issues with resizing; docker/cli#1529 (it's not in a release yet though)