Docker build error and ad-hoc workaround

[HiroIshida]

Following the manual on the README.md, I try to build the docker image. However the following error occured.

Installing collected packages: zipp, six, ipython-genutils, decorator, wcwidth, traitlets, pyrsistent, pyparsing, ptyprocess, parso, importlib-metadata, attrs, webencodings, tornado, pyzmq, python-dateutil, pygments, pycparser, prompt-toolkit, pickleshare, pexpect, packaging, MarkupSafe, jupyter-core, jsonschema, jedi, backcall, urllib3, testpath, pyasn1, pandocfilters, nbformat, mistune, jupyter-client, jinja2, ipython, idna, entrypoints, defusedxml, chardet, cffi, certifi, bleach, terminado, Send2Trash, rsa, requests, pyasn1-modules, prometheus-client, oauthlib, nbconvert, ipykernel, cachetools, argon2-cffi, requests-oauthlib, notebook, google-auth, widgetsnbextension, werkzeug, tensorboard-plugin-wit, qtpy, protobuf, numpy, markdown, grpcio, google-auth-oauthlib, absl-py, wrapt, toml, termcolor, tensorflow-estimator, tensorboard, qtconsole, pyyaml, opt-einsum, kiwisolver, keras-preprocessing, jupyter-console, ipywidgets, h5py, google-pasta, gast, future, cycler, astunparse, torch, tensorflow, matplotlib, jupytext, jupyter
    Running setup.py install for cffi: started
    Running setup.py install for cffi: finished with status 'error'
    ERROR: Command errored out with exit status 1:
     command: /venv/bin/python3 -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-mtguxpqj/cffi_d5737db583504be9a035883b828bf208/setup.py'"'"'; __file__='"'"'/tmp/pip-install-mtguxpqj/cffi_d5737db583504be9a035883b828bf208/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' install --record /tmp/pip-record-xacrcb2k/install-record.txt --single-version-externally-managed --compile --install-headers /venv/include/site/python3.5/cffi
         cwd: /tmp/pip-install-mtguxpqj/cffi_d5737db583504be9a035883b828bf208/
    Complete output (48 lines):
    unable to execute 'x86_64-linux-gnu-gcc': No such file or directory
    unable to execute 'x86_64-linux-gnu-gcc': No such file or directory

Also please see the full log log.txt.

I guess the gcc compilar is supporsed to be installed because of apt instal python3-dev in the original dockerfile. So, It's strange to me. But, as an ad-hoc workaround, I added build-essential and libffi-dev to be installed via apt, so the resulting corresponding part of the dockerfile is below, and now that docker build is successfully accomplished.

RUN             apt-get update -qq \
                && apt-get install -qq -y \
                    hdf5-tools \
                    python3-dev \
                    python3-tk \
                    wget \
                    virtualenv \
                    zlib1g-dev \
                    build-essential \
                    libffi-dev

The reason I put libffi-dev is that, without adding this, compilation of cffi failed with error saying fatal error: ffi.h: No such file or directory