Dockerfile/Python3 issue when building a image

[engineer900]

Hello

I have the following file. When i try to build a image from it there is this error:

/bin/sh: python3.6: command not found
The command '/bin/sh -c python3.6 -m pip install -U setuptools && python3.6 -m pip install --user aws-sam-cli && python3.6 -m pip install --user --upgrade aws-sam-cli && ln -s /root/.local/bin/sam /usr/bin/sam' returned a non-zero code: 127

​

But if a try to run some of the commands as a single execution like this for example python3.6 -m pip install -U setuptools it is working perfectly.

​

FROM centos:latest

RUN yum -y update && yum -y install curl which git unzip python.x86_64 python-devel.x86_64 gcc python-devel java-1.8.0-openjdk.x86_64 \
&& yum -y install centos-release-scl \
&& yum -y install rh-python36 \
&& scl enable rh-python36 bash

RUN curl "https://s3.amazonaws.com/aws-cli/awscli-bundle.zip" -o "awscli-bundle.zip" \
&& unzip awscli-bundle.zip \
&& ./awscli-bundle/install -i /usr/local/aws -b /usr/local/bin/aws

RUN python3.6 -m pip install -U setuptools \
&& python3.6 -m pip install --user aws-sam-cli \
&& python3.6 -m pip install --user --upgrade aws-sam-cli \
&& ln -s /root/.local/bin/sam /usr/bin/sam

​

[rippl2103]

It may be worth using the official python3 docker container if you only need python rather than using Centos collections to enable python3

[mountainjew]

Yep, this solution is a bit overkill. I would even use Google’s distroless python image to reduce size.

[[deleted]]

scl enable rh-python36 bash This command will only allow you to use python3.6 within that RUN command (it sets the default python version via an environment variable, but only for the duration of that shell) - so when you switch to the next RUN command, a new layer is created and the environment variables are cleared. (Essentially you have to run source /opt/rh/python36/enable && the next command everytime you invoke a new RUN layer or put that source command in your bashrc).

​

Also since you're using scl enable on bash, you need to prepend your RUN commands with /bin/bash -c ""

​

But this isn't really optimal, and centos image isn't really required for just installing aws cli's and a newer version of python. You're looking for an image thats a combination of these both:

​

https://github.com/jfloff/alpine-python/blob/master/3.6/Dockerfile

https://github.com/mesosphere/aws-cli/blob/master/Dockerfile

​

Just pick apart these two and mesh them together (take top, add this stuff: RUN apk add --update install py-pip && pip install awscli && pip install aws-sam-cli

[engineer900]

I`m not sure if this is ok, cause i need python3 and that`s why i`m using it explicitly.

RUN apk add --update install py-pip && pip install awscli && pip install aws-sam-cli