add simple python3 base image (no s6 included)

alpine-base-python3/Dockerfile.tmpl

@@ -0,0 +1,29 @@
+FROM unocha/alpine-base:%%UPSTREAM%%
+
+# Parse arguments for the build command.
+ARG VERSION
+ARG VCS_URL
+ARG VCS_REF
+ARG BUILD_DATE
+
+# A little bit of metadata management.
+# See http://label-schema.org/
+LABEL org.label-schema.schema-version="1.0" \
+      org.label-schema.build-date=$BUILD_DATE \
+      org.label-schema.vendor="UN-OCHA" \
+      org.label-schema.version=$VERSION \
+      org.label-schema.vcs-url=$VCS_URL \
+      org.label-schema.vcs-ref=$VCS_REF \
+      org.label-schema.name="python3" \
+      org.label-schema.description="This service provides a base python3 platform." \
+      org.label-schema.architecture="x86_64" \
+      org.label-schema.distribution="Alpine Linux" \
+      org.label-schema.distribution-version="3.8"
+
+RUN apk add --update-cache \
+        python3 && \
+    python3 -m ensurepip && \
+    rm -r /usr/lib/python*/ensurepip && \
+    pip3 install --upgrade pip setuptools && \
+    rm -r /root/.cache && \
+    rm -rf /var/cache/apk/*

alpine-base-python3/Makefile

@@ -0,0 +1,8 @@
+include ../Makefile.conf
+
+IMAGE=alpine-base-python3
+VERSION=$$(VERSION)
+
+all: build tag
+
+mrproper: clean_images clean