AttributeError: 'generator' object has no attribute 'read' with new python docker client version 3.0

Hello

We use docker-squash on a daily basis to squash our base-images. Today we can’t squash the images anymore. We get:

$ docker-squash -t registry.example.com/alpine  registry.exmaple.com/alpine
2018-02-01 06:24:59,601 root         INFO     docker-squash version 1.0.6, Docker c97c6d6, API 1.35...
2018-02-01 06:24:59,602 root         INFO     Using v2 image format
2018-02-01 06:24:59,614 root         INFO     Old image has 4 layers
2018-02-01 06:24:59,615 root         INFO     Checking if squashing is necessary...
2018-02-01 06:24:59,615 root         INFO     Attempting to squash last 4 layers...
2018-02-01 06:24:59,615 root         INFO     Saving image sha256:370c6891b7c58c64a715aaf93f17e1e10c8a4e4e3533e04a0959f1f205756cbe to /tmp/docker-squash-ujuyJb/old directory...
2018-02-01 06:25:00,849 root         ERROR    'generator' object has no attribute 'read'
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/docker_squash/image.py", line 321, in _save_image
    with tarfile.open(fileobj=image, mode='r|') as tar:
  File "/usr/lib/python2.7/tarfile.py", line 1705, in open
    t = cls(name, filemode, stream, **kwargs)
  File "/usr/lib/python2.7/tarfile.py", line 1587, in __init__
    self.firstmember = self.next()
  File "/usr/lib/python2.7/tarfile.py", line 2358, in next
    tarinfo = self.tarinfo.fromtarfile(self)
  File "/usr/lib/python2.7/tarfile.py", line 1251, in fromtarfile
    buf = tarfile.fileobj.read(BLOCKSIZE)
  File "/usr/lib/python2.7/tarfile.py", line 579, in read
    buf = self._read(size)
  File "/usr/lib/python2.7/tarfile.py", line 587, in _read
    return self.__read(size)
  File "/usr/lib/python2.7/tarfile.py", line 612, in __read
    buf = self.fileobj.read(self.bufsize)
AttributeError: 'generator' object has no attribute 'read'

Docker-squash was installed on our builder Image (docker:latest) by pip:

$ pip install docker-squash
Collecting docker-squash
  Downloading docker-squash-1.0.6.tar.gz
Collecting docker (from docker-squash)
  Downloading docker-3.0.0-py2.py3-none-any.whl (120kB)
Collecting six (from docker-squash)
  Downloading six-1.11.0-py2.py3-none-any.whl
Collecting backports.ssl-match-hostname>=3.5; python_version < "3.5" (from docker->docker-squash)
  Downloading backports.ssl_match_hostname-3.5.0.1.tar.gz
Collecting ipaddress>=1.0.16; python_version < "3.3" (from docker->docker-squash)
  Downloading ipaddress-1.0.19.tar.gz
Collecting docker-pycreds>=0.2.1 (from docker->docker-squash)
  Downloading docker_pycreds-0.2.1-py2.py3-none-any.whl
Collecting requests!=2.18.0,>=2.14.2 (from docker->docker-squash)
  Downloading requests-2.18.4-py2.py3-none-any.whl (88kB)
Collecting websocket-client>=0.32.0 (from docker->docker-squash)
  Downloading websocket_client-0.46.0-py2.py3-none-any.whl (200kB)
Collecting chardet<3.1.0,>=3.0.2 (from requests!=2.18.0,>=2.14.2->docker->docker-squash)
  Downloading chardet-3.0.4-py2.py3-none-any.whl (133kB)
Collecting certifi>=2017.4.17 (from requests!=2.18.0,>=2.14.2->docker->docker-squash)
  Downloading certifi-2018.1.18-py2.py3-none-any.whl (151kB)
Collecting urllib3<1.23,>=1.21.1 (from requests!=2.18.0,>=2.14.2->docker->docker-squash)
  Downloading urllib3-1.22-py2.py3-none-any.whl (132kB)
Collecting idna<2.7,>=2.5 (from requests!=2.18.0,>=2.14.2->docker->docker-squash)
  Downloading idna-2.6-py2.py3-none-any.whl (56kB)
Installing collected packages: backports.ssl-match-hostname, ipaddress, six, docker-pycreds, chardet, certifi, urllib3, idna, requests, websocket-client, docker, docker-squash
  Running setup.py install for backports.ssl-match-hostname: started
    Running setup.py install for backports.ssl-match-hostname: finished with status 'done'
  Running setup.py install for ipaddress: started
    Running setup.py install for ipaddress: finished with status 'done'
  Running setup.py install for docker-squash: started
    Running setup.py install for docker-squash: finished with status 'done'
Successfully installed backports.ssl-match-hostname-3.5.0.1 certifi-2018.1.18 chardet-3.0.4 docker-3.0.0 docker-pycreds-0.2.1 docker-squash-1.0.6 idna-2.6 ipaddress-1.0.19 requests-2.18.4 six-1.11.0 urllib3-1.22 websocket-client-0.46.0

The only thing that changed from yesterday is the docker python client we are using:

Collecting docker (from docker-squash)
  Downloading docker-3.0.0-py2.py3-none-any.whl (120kB)

Yesterday it worked, but we were using docker-2.7.0.

Can you look into this?

Thanks

[goldmann]

Oh crap, I totally forgot 😦 I’ll work on this this week!

[goldmann]

1.0.7 released, sorry for the delay! https://github.com/goldmann/docker-squash/releases/tag/1.0.7