Tern crashes when running in a container

[nishakm]

Describe the bug
When running tern in a container with docker socket mounted, the debug message says "unable to load image metadata".

To Reproduce
Steps to reproduce the behavior:
Dockerfile:

FROM photon:3.0

RUN tdnf install -y python3 python3-pip python3-setuptools

# copy tern repo into root
COPY . .

RUN pip3 install -r requirements.txt

ENTRYPOINT ["./tern"]

run:

$ docker build -t tern:0.2.0 .
$ docker run -v /var/run/docker.sock:/var/run/docker.sock tern:0.2.0 report -i docker.io/vmware/photon:3.0

Error in terminal

2019-01-25 16:18:45,932 - DEBUG - tern - Starting...
2019-01-25 16:18:45,933 - DEBUG - report - Setting up...
2019-01-25 16:18:47,520 - DEBUG - container - Checking if image docker.io/photon:3.0 is available on disk...                                                                                      
2019-01-25 16:18:47,540 - DEBUG - container - Image docker.io/photon:3.0 found
2019-01-25 16:18:49,214 - WARNING - report - Cannot retrieve full image metadata
2019-01-25 16:18:49,229 - DEBUG - report - Teardown...
2019-01-25 16:18:50,399 - DEBUG - rootfs - Running command: rm -rf temp/mergedir
2019-01-25 16:18:50,406 - DEBUG - rootfs - Running command: rm -rf temp/workdir
2019-01-25 16:18:50,447 - DEBUG - tern - Report completed.
2019-01-25 16:18:50,448 - DEBUG - tern - Finished

Expected behavior
Should complete successfully

Environment you are running Tern on
photonOS container with host docker socket mounted

Please attach files if they exist

[nishakm]

Running in a photonOS container with python and requirements installed. I found this:

>>> from classes.docker_image import DockerImage
>>> d = DockerImage('docker.io/photon:3.0')
>>> d.load_image()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/classes/docker_image.py", line 164, in load_image
    layer.gen_fs_hash()
  File "/classes/image_layer.py", line 143, in gen_fs_hash
    self.__fs_hash = rootfs.calc_fs_hash(fs_dir)
  File "/utils/rootfs.py", line 176, in calc_fs_hash
    ['sudo', './tools/fs_hash.sh', os.path.abspath(fs_path)])
  File "/usr/lib/python3.7/subprocess.py", line 376, in check_output
    **kwargs).stdout
  File "/usr/lib/python3.7/subprocess.py", line 453, in run
    with Popen(*popenargs, **kwargs) as process:
  File "/usr/lib/python3.7/subprocess.py", line 756, in __init__
    restore_signals, start_new_session)
  File "/usr/lib/python3.7/subprocess.py", line 1499, in _execute_child
    raise child_exception_type(errno_num, err_msg, err_filename)
FileNotFoundError: [Errno 2] No such file or directory: 'sudo': 'sudo'

The fs_hash script needs to be run as regular user but 'sudo' is used as a default.

[nishakm]

Also, in the Dockerfile, some extra stuff needs to happen before the photonOS container can run tern:

RUN tdnf remove -y toybox && install -y findutils attr python3 python3-pip python3-setuptools