I am trying to use a pupsub emulator. It starts but when I try to use my python script I get the following error
ModuleNotFoundError: No module named \'google\'
I'm not sure why you're trying to install python3 & pip3, they both exist in the base image. In any case, this Dockerfile will give you the python google-cloud-pubsub libraries in a nice clean image
FROM google/cloud-sdk:alpine
RUN apk add --no-cache --virtual .build-deps \
linux-headers build-base g++ python3-dev \
&& pip3 install --no-cache-dir google-cloud-pubsub \
&& apk del .build-deps
# add your stuff here