How can I install lxml in docker

Question

I want to deploy my python project in docker, I wrote lxml>=3.5.0 in the requirments.txt as the project needs lxml. Here is my dockfile:

FROM gliderlabs/alpine:3.3
RUN set -x \
    && buildDeps='\
        python-dev \
        py-pip \
        build-base \
    ' \
    && apk --update add python py-lxml $buildDeps \
    && rm -rf /var/cache/apk/* \
    && mkdir -p /app
ENV INSTALL_PATH /app
WORKDIR $INSTALL_PATH
COPY requirements-docker.txt ./
RUN pip install -r requirements.txt
COPY . .
RUN apk del --purge $buildDeps
ENTRYPOINT ["celery", "-A", "tasks", "worker", "-l", "info", "-B"]

I got this when I deploy it to docker:

*********************************************************************************
Could not find function xmlCheckVersion in library libxml2. Is libxml2 installed?
*********************************************************************************
error: command 'gcc' failed with exit status 1
----------------------------------------
Rolling back uninstall of lxml

I though it was because 'python-dev' and 'python-lxml', then I edited the dockfile like this:

WORKDIR $INSTALL_PATH
COPY requirements-docker.txt ./
RUN apt-get build-dev python-lxml
RUN pip install -r requirements.txt

It did not work, and I got another error:

---> Running in 73201a0dcd59
/bin/sh: apt-get: not found

How can I install lxml correctly in docker?

Answer 1

I added RUN apk add --update --no-cache g++ gcc libxslt-dev before RUN pip install -r requirements.txt and it worked.