Standarize image by using shared / similair layers

core/nginx/Dockerfile

@@ -1,9 +1,13 @@
 FROM alpine:3.8
-
+# python3 shared with most images
+RUN apk add --no-cache \
+    python3 py3-pip \
+  && pip3 install --upgrade pip
+# Shared layer between rspamd, postfix, dovecot, unbound and nginx
+RUN pip3 install jinja2
+# Image specific layers under this line
 RUN apk add --no-cache certbot nginx nginx-mod-mail openssl curl \
- python py-jinja2 py-requests-toolbelt py-pip \
- && pip install --upgrade pip \
- && pip install idna
+ && pip3 install idna requests
 
 COPY conf /conf
 COPY *.py /

core/nginx/config.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python3
 
 import jinja2
 import os

core/nginx/letsencrypt.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python3
 
 import os
 import time

core/nginx/start.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python3
 
 import os
 import subprocess