ResourceWarning: unclosed socket reported whenever I use `docker-compose stop`

[arbaes]

Description of the issue

Whenever I use the command stop from docker-compose I have multiple warning telling the docker socket wasn't closed properly:

sys:1: ResourceWarning: unclosed <socket.socket fd=14, family=AddressFamily.AF_UNIX, type=SocketKind.SOCK_STREAM, proto=0> ResourceWarning: Enable tracemalloc to get the object allocation traceback 

I noticed i get it too if I run docker-compose config.

Context information (for bug reports)

Output of docker-compose version

docker-compose version 1.28.0, build unknown
docker-py version: 4.4.1
CPython version: 3.9.1
OpenSSL version: OpenSSL 1.1.1i  8 Dec 2020

Output of docker version

Client:
 Version:           20.10.2
 API version:       1.41
 Go version:        go1.15.6
 Git commit:        2291f610ae
 Built:             Tue Jan 19 17:19:21 2021
 OS/Arch:           linux/amd64
 Context:           default
 Experimental:      true

Server:
 Engine:
  Version:          20.10.2
  API version:      1.41 (minimum version 1.12)
  Go version:       go1.15.6
  Git commit:       8891c58a43
  Built:            Tue Jan 19 17:18:55 2021
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          v1.4.3
  GitCommit:        269548fa27e0089a8b8278fc4fc781d7f65a939b.m
 runc:
  Version:          1.0.0-rc92
  GitCommit:        ff819c7e9184c13b7c2607fe6c30ae19403a7aff
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

Output of docker-compose config
(Make sure to add the relevant -f and other flags)

docker-compose config
services:
  redis:
    image: redis:alpine
  web:
    build:
      context: /home/arbaes/dkrcmp
    ports:
    - published: 5000
      target: 5000
version: '3.9'

sys:1: ResourceWarning: unclosed <socket.socket fd=6, family=AddressFamily.AF_UNIX, type=SocketKind.SOCK_STREAM, proto=0>
ResourceWarning: Enable tracemalloc to get the object allocation traceback

Steps to reproduce the issue

FYI, i can reproduce with any project, including this one.
So i use it here for simplicty's sake

1. Up the containers with docker-compose up
2. Stop them with docker-compose stop

Observed result

No errors but multiple ResourceWarnings for unclosed sockets

Expected result

No ResourceWarning and sockets properly closed

Stacktrace / full error message

❯ docker-compose up    
Building with native build. Learn about native build in Compose here: https://docs.docker.com/go/compose-native-build/
Starting dkrcmp_redis_1 ... done
Starting dkrcmp_web_1   ... done
Attaching to dkrcmp_redis_1, dkrcmp_web_1
redis_1  | 1:C 29 Jan 2021 16:22:52.286 # oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo
redis_1  | 1:C 29 Jan 2021 16:22:52.286 # Redis version=6.0.10, bits=64, commit=00000000, modified=0, pid=1, just started
redis_1  | 1:C 29 Jan 2021 16:22:52.286 # Warning: no config file specified, using the default config. In order to specify a config file use redis-server /path/to/redis.conf
redis_1  | 1:M 29 Jan 2021 16:22:52.287 * Running mode=standalone, port=6379.
redis_1  | 1:M 29 Jan 2021 16:22:52.287 # Server initialized
redis_1  | 1:M 29 Jan 2021 16:22:52.287 # WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add 'vm.overcommit_memory = 1' to /etc/sysctl.conf and then reboot or run the command 'sysctl vm.overcommit_memory=1' for this to take effect.
redis_1  | 1:M 29 Jan 2021 16:22:52.287 * Loading RDB produced by version 6.0.10
redis_1  | 1:M 29 Jan 2021 16:22:52.287 * RDB age 247 seconds
redis_1  | 1:M 29 Jan 2021 16:22:52.287 * RDB memory usage when created 0.77 Mb
redis_1  | 1:M 29 Jan 2021 16:22:52.287 * DB loaded from disk: 0.000 seconds
redis_1  | 1:M 29 Jan 2021 16:22:52.287 * Ready to accept connections
web_1    |  * Serving Flask app "app.py"
web_1    |  * Environment: production
web_1    |    WARNING: This is a development server. Do not use it in a production deployment.
web_1    |    Use a production WSGI server instead.
web_1    |  * Debug mode: off
web_1    |  * Running on http://0.0.0.0:5000/ (Press CTRL+C to quit)
^CGracefully stopping... (press Ctrl+C again to force)
Stopping dkrcmp_web_1   ... done
Stopping dkrcmp_redis_1 ... done
sys:1: ResourceWarning: unclosed <socket.socket fd=37, family=AddressFamily.AF_UNIX, type=SocketKind.SOCK_STREAM, proto=0>
ResourceWarning: Enable tracemalloc to get the object allocation traceback
sys:1: ResourceWarning: unclosed <socket.socket fd=24, family=AddressFamily.AF_UNIX, type=SocketKind.SOCK_STREAM, proto=0, raddr=/run/docker.sock>
ResourceWarning: Enable tracemalloc to get the object allocation traceback
sys:1: ResourceWarning: unclosed <socket.socket fd=26, family=AddressFamily.AF_UNIX, type=SocketKind.SOCK_STREAM, proto=0, raddr=/run/docker.sock>
ResourceWarning: Enable tracemalloc to get the object allocation traceback

Additional information

OS: Manjaro Linux
Kernel: 5.10.10-1-MANJARO

docker and docker-compose installed trough pacman, from community repos

[arbaes]

If I can provide any help in case you can't reproduce let me know, I just don't know how to properly debug that

[aiordache]

Hi @arbaes! I can't reproduce this on Arch Linux with docker-compose v1.28.2 installed with pacman, pip and the binary.
Do you mind trying the binary from the release page to see if you still get the issue? Thanks!
https://github.com/docker/compose/releases/tag/1.28.2

[arbaes]

Can confirm I don't have the issue with the binary 1.28.2, but I do have it with the pip version. Pretty weird.

I use python 3.9 by default, something wrong with one of the librairies maybe ?

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

This issue has been automatically closed because it had not recent activity during the stale period.

[mikenerone]

I recently began experiencing the same issue on Arch Linux (docker 1:20.10.8
and docker-compose 1.29.2), but it's no only on stop - it seems to be on just about any docker-compose command. E.g.

❯ docker-compose -f dev.yml ps
Name   Command   State   Ports
------------------------------
sys:1: ResourceWarning: unclosed <socket.socket fd=4, family=AddressFamily.AF_UNIX, type=SocketKind.SOCK_STREAM, proto=0, raddr=/run/docker.sock>
ResourceWarning: Enable tracemalloc to get the object allocation traceback
sys:1: ResourceWarning: unclosed <socket.socket fd=5, family=AddressFamily.AF_UNIX, type=SocketKind.SOCK_STREAM, proto=0, raddr=/run/docker.sock>
ResourceWarning: Enable tracemalloc to get the object allocation traceback
sys:1: ResourceWarning: unclosed <socket.socket fd=6, family=AddressFamily.AF_UNIX, type=SocketKind.SOCK_STREAM, proto=0, raddr=/run/docker.sock>
ResourceWarning: Enable tracemalloc to get the object allocation traceback
sys:1: ResourceWarning: unclosed <socket.socket fd=7, family=AddressFamily.AF_UNIX, type=SocketKind.SOCK_STREAM, proto=0>
ResourceWarning: Enable tracemalloc to get the object allocation traceback
sys:1: ResourceWarning: unclosed <socket.socket fd=3, family=AddressFamily.AF_UNIX, type=SocketKind.SOCK_STREAM, proto=0, raddr=/run/docker.sock>
ResourceWarning: Enable tracemalloc to get the object allocation traceback

Fortunately, commands do seem to succeed. The warnings appear to be delivered at or near command exit.

[mikenerone]

I later realized that the cause was that I had set the PYTHONWARNINGS environment variable as part of my dev work. I'm sure these warnings are issued all the time, but the default warning filters active when executing docker-compose hides them.