电报-python-bot ImportError No module named 'cryptography' Alpine Docker

Question

I am trying to run script which sends message to telegram using python-telegram-bot module. The script runs in docker on alpine.

The script cannot import Telegram, I get an error ModuleNotFoundError: No module named 'cryptography'

My docker file

FROM nickgryg/alpine-pandas:3.7.7 as base
FROM base as builder

RUN pip install --upgrade pip

RUN mkdir /install
RUN apk update && apk add postgresql-dev gcc musl-dev python3-dev libffi-dev openssl-dev 
WORKDIR /install
COPY requirements.txt /requirements.txt
RUN pip install --install-option="--prefix=/install" -r /requirements.txt
FROM base
COPY --from=builder /install /usr/local
COPY src /app
RUN apk --no-cache add libpq 
WORKDIR /app

requirements.txt is below

certifi==2020.4.5.1
chardet==3.0.4
Django==3.0.3
future==0.18.2
idna==2.9
pandas==1.0.3
pycountry==19.8.18
python-dateutil==2.8.1
pytz==2019.3
requests==2.23.0
six==1.14.0
sqlparse==0.3.1
urllib3==1.25.8
vertica-python==0.10.3
currencyconverter==0.14.1
python-telegram-bot==12.6.1
psycopg2==2.8.5

I also tried to add line add apk py3-cryptography to dockerfile but that didn't help.

I found many questions related to issues with cryptography but no solutions helped.

Answer 1

Managed to resolve it myself. As the image is built in two stages I don't install cryptography during the first stage now, it is packaged into a wheel file. Which will then be copied and installed in the new image.

FROM nickgryg/alpine-pandas as base
FROM base as builder

RUN pip install --upgrade pip

RUN mkdir /install
RUN apk update && apk add gcc musl-dev python3-dev libffi-dev openssl-dev libc-dev postgresql-dev 
WORKDIR /install
COPY requirements.txt /requirements.txt
RUN pip install --install-option="--prefix=/install" -r /requirements.txt

RUN mkdir /wheels
WORKDIR /wheels
RUN pip wheel cryptography

FROM base
RUN apk add libressl
COPY --from=builder /install /usr/local
COPY --from=builder /wheels /wheels
RUN pip install /wheels/*.whl
COPY src /app
RUN apk --no-cache add libpq 
WORKDIR /app

Answer 2

The image you're using is alpine. If you're having a dependency on cryptography module, then follow the below steps to get it fixed.

Building cryptography on Linux

Cryptography ships manylinux wheels (as of 2.0) so all dependencies are included. For users on pip 8.1 or above running on a manylinux1 or manylinux2010 compatible distribution (almost everything except Alpine ) all you should need to do is:

$ pip install cryptography

If you are on Alpine or just want to compile it yourself then cryptography requires a compiler, headers for Python (if you're not using pypy ), and headers for the OpenSSL and libffi libraries available on your system.

Alpine

Replace python3-dev with python-dev if you're using Python 2.

$ sudo apk add gcc musl-dev python3-dev libffi-dev openssl-dev

If you get an error with openssl-dev you may have to use libressl-dev.

So making the changes on the above apk given packages in your Dockerfile should work.

Just in case, if you want more details for other OS distributions, it can be found in section Building cryptography on Linux on the Cryptography Official Site and Cryptography GitHub .