Docker build error while containerizing a microservice build using flask and flask-restful

Question

Can't containerize a flask microservice. I have been through GitHub pages describing ways to solve the error but nothing seems to work.I have tried different python3.X-alpine runtimes but still the same thing. I can't really understand why the logs tell me error: command 'gcc' failed with exit status 1 when I have added the needed GCC dependicies.

Dockerfile

FROM python:3.7.4-alpine
RUN apk add --no-cache --virtual .build-deps gcc musl-dev \
 && pip install cython \
 && apk del .build-deps
RUN mkdir /app
WORKDIR /app
COPY . /app
RUN pip install -r requirements.txt --default-timeout=100 future
EXPOSE 5000
CMD ["python3", "app.py"]

Error

   command: /usr/local/bin/python -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-ohfwxr4o/typed-ast/setup.py'"'"'; __file__='"'"'/tmp/pip-install-ohfwxr4o/typed-ast/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' bdist_wheel -d /tmp/pip-wheel-6vb5bz2_ --python-tag cp37
       cwd: /tmp/pip-install-ohfwxr4o/typed-ast/
  Complete output (23 lines):
  running bdist_wheel
  running build
  running build_py
  creating build
  creating build/lib.linux-x86_64-3.7
  creating build/lib.linux-x86_64-3.7/typed_ast
  copying typed_ast/ast3.py -> build/lib.linux-x86_64-3.7/typed_ast
  copying typed_ast/conversions.py -> build/lib.linux-x86_64-3.7/typed_ast
  copying typed_ast/ast27.py -> build/lib.linux-x86_64-3.7/typed_ast
  copying typed_ast/__init__.py -> build/lib.linux-x86_64-3.7/typed_ast
  package init file 'ast3/tests/__init__.py' not found (or not a regular file)
  creating build/lib.linux-x86_64-3.7/typed_ast/tests
  copying ast3/tests/test_basics.py -> build/lib.linux-x86_64-3.7/typed_ast/tests
  running build_ext
  building '_ast27' extension
  creating build/temp.linux-x86_64-3.7
  creating build/temp.linux-x86_64-3.7/ast27
  creating build/temp.linux-x86_64-3.7/ast27/Parser
  creating build/temp.linux-x86_64-3.7/ast27/Python
  creating build/temp.linux-x86_64-3.7/ast27/Custom
  gcc -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -DTHREAD_STACK_SIZE=0x100000 -fPIC -Iast27/Include -I/usr/local/include/python3.7m -c ast27/Parser/acceler.c -o build/temp.linux-x86_64-3.7/ast27/Parser/acceler.o
  unable to execute 'gcc': No such file or directory
  error: command 'gcc' failed with exit status 1
  ----------------------------------------
  ERROR: Failed building wheel for typed-ast
  Running setup.py clean for typed-ast
  Building wheel for wrapt (setup.py): started
  Building wheel for wrapt (setup.py): finished with status 'done'
  Created wheel for wrapt: filename=wrapt-1.11.2-cp37-none-any.whl size=19592 sha256=82243e530eafb10da7c6b0645a61b8808dcb9136c0e5787bc6c161172f7ca90d
  Stored in directory: /root/.cache/pip/wheels/d7/de/2e/efa132238792efb6459a96e85916ef8597fcb3d2ae51590dfd
Successfully built future MarkupSafe wrapt
Failed to build typed-ast
Installing collected packages: future, aniso8601, wrapt, lazy-object-proxy, six, typed-ast, astroid, Click, MarkupSafe, Jinja2, itsdangerous, Werkzeug, Flask, pytz, Flask-RESTful, isort, mccabe, pylint
  Running setup.py install for typed-ast: started
    Running setup.py install for typed-ast: finished with status 'error'
    ERROR: Command errored out with exit status 1:
     command: /usr/local/bin/python -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-ohfwxr4o/typed-ast/setup.py'"'"'; __file__='"'"'/tmp/pip-install-ohfwxr4o/typed-ast/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-glxx7aqy/install-record.txt --single-version-externally-managed --compile
         cwd: /tmp/pip-install-ohfwxr4o/typed-ast/
    Complete output (23 lines):
    running install
    running build
    running build_py
    creating build
    creating build/lib.linux-x86_64-3.7
    creating build/lib.linux-x86_64-3.7/typed_ast
    copying typed_ast/ast3.py -> build/lib.linux-x86_64-3.7/typed_ast
    copying typed_ast/conversions.py -> build/lib.linux-x86_64-3.7/typed_ast
    copying typed_ast/ast27.py -> build/lib.linux-x86_64-3.7/typed_ast
    copying typed_ast/__init__.py -> build/lib.linux-x86_64-3.7/typed_ast
    package init file 'ast3/tests/__init__.py' not found (or not a regular file)
    creating build/lib.linux-x86_64-3.7/typed_ast/tests
    copying ast3/tests/test_basics.py -> build/lib.linux-x86_64-3.7/typed_ast/tests
    running build_ext
    building '_ast27' extension
    creating build/temp.linux-x86_64-3.7
    creating build/temp.linux-x86_64-3.7/ast27
    creating build/temp.linux-x86_64-3.7/ast27/Parser
    creating build/temp.linux-x86_64-3.7/ast27/Python
    creating build/temp.linux-x86_64-3.7/ast27/Custom
    gcc -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -DTHREAD_STACK_SIZE=0x100000 -fPIC -Iast27/Include -I/usr/local/include/python3.7m -c ast27/Parser/acceler.c -o build/temp.linux-x86_64-3.7/ast27/Parser/acceler.o
    unable to execute 'gcc': No such file or directory
    error: command 'gcc' failed with exit status 1
    ----------------------------------------
ERROR: Command errored out with exit status 1: /usr/local/bin/python -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-ohfwxr4o/typed-ast/setup.py'"'"'; __file__='"'"'/tmp/pip-install-ohfwxr4o/typed-ast/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-glxx7aqy/install-record.txt --single-version-externally-managed --compile Check the logs for full command output.
The command '/bin/sh -c pip install -r requirements.txt --default-timeout=100 future' returned a non-zero code: 1```

Answer 1

In the start of your Dockerfile, you uninstall gcc. When you later go to install your application's dependencies, if one of those has native extensions, you'll get the error you see.

RUN ... apk del .build-deps
# Now gcc is gone
RUN pip install -r requirements.txt

To make this work, you need to move the pip install line into the block between the apk add and apk del. To make that work, the requirements.txt file needs to be in the image already. However, you don't need the entire application source. If you COPY in only the requirements.txt file then repeating a docker build will re-install packages if that file has changed, but otherwise Docker's layer caching will reuse what was already there.

This should bring you to:

FROM python:3.7.4-alpine
WORKDIR /app # Docker creates this for you
COPY requirements.txt .
RUN apk add --no-cache --virtual .build-deps gcc musl-dev \
 && pip install cython \
 && pip install -r requirements.txt --default-timeout=100 future \
 && apk del .build-deps
COPY . .
EXPOSE 5000
CMD ["python3", "app.py"]