Switch to ubuntu base image

Change to use ubuntu base image instead of python. Also refactor Dockerfile
to remove unnecessary build dependencies to reduce size.

BREAKING CHANGE: The `make images` PYTHON_BASE_IMAGE arg is now renamed to BASE_IMAGE.

Change-Id: I63556290d8e007bfac4315529261d75e362806d6

Dockerfile

@@ -1,4 +1,4 @@
-ARG FROM=python:3.6
+ARG FROM=ubuntu:18.04
 FROM ${FROM}
 
 LABEL org.opencontainers.image.authors='airship-discuss@lists.airshipit.org, irc://#airshipit@freenode'
@@ -14,31 +14,67 @@ ENV LC_ALL=C.UTF-8
 
 EXPOSE 8000
 
-ENTRYPOINT ["./entrypoint.sh"]
-CMD ["server"]
-
-RUN mkdir -p /armada && \
-    apt-get update && \
-    apt-get install -y --no-install-recommends \
-        netbase \
-        curl \
-        git && \
-    useradd -u 1000 -g users -d /armada armada && \
-    rm -rf \
-        /root/.cache \
-        /var/lib/apt/lists/*
+RUN set -ex && \
+    apt-get -qq update && \
+    apt-get -y install \
+    ca-certificates \
+    curl \
+    netbase \
+    python3-dev \
+    python3-setuptools \
+    --no-install-recommends \
+    && apt-get autoremove -yqq --purge \
+    && apt-get clean \
+    && rm -rf \
+        /var/lib/apt/lists/* \
+        /tmp/* \
+        /var/tmp/* \
+        /usr/share/man \
+        /usr/share/doc \
+        /usr/share/doc-base
 
 WORKDIR /armada
 
-COPY requirements.txt /tmp/
-RUN pip3 install -r /tmp/requirements.txt
+# Add armada user
+RUN useradd -u 1000 -g users -d $(pwd) armada
 
-COPY . /armada
+ENTRYPOINT ["./entrypoint.sh"]
+CMD ["server"]
+
+COPY requirements.txt ./
+
+# Build
+RUN set -ex \
+    && buildDeps=' \
+      gcc \
+      libssl-dev \
+      make \
+      python3-pip \
+    ' \
+    && apt-get -qq update \
+    # Keep git separate so it's not removed below
+    && apt-get install -y $buildDeps git --no-install-recommends \
+    && python3 -m pip install -U pip \
+    && pip3 install -r requirements.txt --no-cache-dir \
+    && apt-get purge -y --auto-remove $buildDeps \
+    && apt-get autoremove -yqq --purge \
+    && apt-get clean \
+    && rm -rf \
+        /var/lib/apt/lists/* \
+        /tmp/* \
+        /var/tmp/* \
+        /usr/share/man \
+        /usr/share/doc \
+        /usr/share/doc-base
+
+COPY . ./
+
+# Setting the version explicitly for PBR
+ENV PBR_VERSION 0.8.0
 
 RUN \
-    mv /armada/etc/armada /etc/ && \
-    cd /armada && \
-    chown -R armada:users /armada && \
+    mv etc/armada /etc/ && \
+    chown -R armada:users . && \
     python3 setup.py install
 
 USER armada

Makefile

@@ -29,7 +29,7 @@ COMMIT            ?= $(shell git rev-parse HEAD)
 PYTHON            = python3
 CHARTS            := $(patsubst charts/%/.,%,$(wildcard charts/*/.))
 IMAGE             := ${DOCKER_REGISTRY}/${IMAGE_PREFIX}/${IMAGE_NAME}:${IMAGE_TAG}
-PYTHON_BASE_IMAGE ?= python:3.6
+BASE_IMAGE        ?=
 
 # VERSION INFO
 GIT_COMMIT = $(shell git rev-parse HEAD)
@@ -99,6 +99,8 @@ run_images: run_armada
 run_armada: build_armada
 	./tools/armada_image_run.sh $(IMAGE)
 
+_BASE_IMAGE_ARG := $(if $(BASE_IMAGE),--build-arg FROM="${BASE_IMAGE}" ,)
+
 .PHONY: build_armada
 build_armada:
 ifeq ($(USE_PROXY), true)
@@ -107,7 +109,7 @@ ifeq ($(USE_PROXY), true)
 		--label "org.opencontainers.image.created=$(shell date --rfc-3339=seconds --utc)" \
 		--label "org.opencontainers.image.title=$(IMAGE_NAME)" \
 		-f ./Dockerfile \
-		--build-arg FROM=$(PYTHON_BASE_IMAGE) \
+		$(_BASE_IMAGE_ARG) \
 		--build-arg http_proxy=$(PROXY) \
 		--build-arg https_proxy=$(PROXY) \
 		--build-arg HTTP_PROXY=$(PROXY) \
@@ -120,7 +122,7 @@ else
 		--label "org.opencontainers.image.created=$(shell date --rfc-3339=seconds --utc)" \
 		--label "org.opencontainers.image.title=$(IMAGE_NAME)" \
 		-f ./Dockerfile \
-		--build-arg FROM=$(PYTHON_BASE_IMAGE) .
+		$(_BASE_IMAGE_ARG) .
 endif
 ifeq ($(PUSH_IMAGE), true)
 	docker push $(IMAGE)