ImportError: No module named backports.ssl_match_hostname

[Hadmut Danisch]

The error ImportError: No module named backports.ssl_match_hostname is back again. When running docker-compose, it terminates with the error message

% docker-compose
Traceback (most recent call last):
  File "/usr/bin/docker-compose", line 11, in <module>
    load_entry_point('docker-compose==1.17.1', 'console_scripts', 'docker-compose')()
  File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 480, in load_entry_point
    return get_distribution(dist).load_entry_point(group, name)
  File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 2693, in load_entry_point
    return ep.load()
  File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 2324, in load
    return self.resolve()
  File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 2330, in resolve
    module = __import__(self.module_name, fromlist=['__name__'], level=0)
  File "/usr/lib/python2.7/dist-packages/compose/cli/main.py", line 17, in <module>
    from . import errors
  File "/usr/lib/python2.7/dist-packages/compose/cli/errors.py", line 11, in <module>
    from docker.errors import APIError
  File "/usr/lib/python2.7/dist-packages/docker/__init__.py", line 2, in <module>
    from .api import APIClient
  File "/usr/lib/python2.7/dist-packages/docker/api/__init__.py", line 2, in <module>
    from .client import APIClient
  File "/usr/lib/python2.7/dist-packages/docker/api/client.py", line 11, in <module>
    from .build import BuildApiMixin
  File "/usr/lib/python2.7/dist-packages/docker/api/build.py", line 9, in <module>
    from .. import utils
  File "/usr/lib/python2.7/dist-packages/docker/utils/__init__.py", line 2, in <module>
    from .build import tar, exclude_paths
  File "/usr/lib/python2.7/dist-packages/docker/utils/build.py", line 5, in <module>
    from .utils import create_archive
  File "/usr/lib/python2.7/dist-packages/docker/utils/utils.py", line 18, in <module>
    from .. import tls
  File "/usr/lib/python2.7/dist-packages/docker/tls.py", line 5, in <module>
    from .transport import SSLAdapter
  File "/usr/lib/python2.7/dist-packages/docker/transport/__init__.py", line 3, in <module>
    from .ssladapter import SSLAdapter
  File "/usr/lib/python2.7/dist-packages/docker/transport/ssladapter.py", line 21, in <module>
    from backports.ssl_match_hostname import match_hostname
ImportError: No module named backports.ssl_match_hostname

Probable reason: On my system (ubuntu 18.04) docker.io is

Package: docker.io
Version: 18.09.7-0ubuntu1~18.04.4

but docker-compose is

Package: docker-compose
Version: 1.17.1-2

Loading a newer docker-compose binary from the git repo (e.g. 1.24.0) solves the problem, but it's still a flaw if the ubuntu packages need to be fixed by replacing binaries with external files.

E.g. download with

sudo curl -L "https://github.com/docker/compose/releases/download/1.24.0/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: docker-compose 1.17.1-2
ProcVersionSignature: Ubuntu 4.15.0-60.67-generic 4.15.18
Uname: Linux 4.15.0-60-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.9-0ubuntu7.7
Architecture: amd64
CurrentDesktop: XFCE
Date: Fri Oct 4 12:36:47 2019
InstallationDate: Installed on 2018-06-09 (481 days ago)
InstallationMedia: Lubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
PackageArchitecture: all
SourcePackage: docker-compose
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Digulla-hepe (digulla-hepe)]

Test cases:

    python2 -c "import backports.ssl_match_hostname"
    docker-compose --version

Fix / workaround (as root):

    echo "# package" > /usr/lib/python2.7/dist-packages/backports/__init__.py

Note: I'm not sure whether sudo will work with output redirection.