Switch to -slim from -alpine

Python's built distribution format (wheel) is incompatible with
alpine-based images, causing dependencies to be compiled from scratch.

This also removes a number of unnecessary system-level dependencies.

src/emailservice/Dockerfile

@@ -1,21 +1,7 @@
-FROM python:3-alpine as base
+FROM python:3-slim as base
 
 FROM base as builder
 
-# gRPC and app deps
-RUN apk add --update --no-cache \
-    gcc \
-    linux-headers \
-    make \
-    musl-dev \
-    python-dev \
-    g++ \
-    # App Deps
-    cairo-dev \
-    cairo \
-    openssl-dev \
-    gobject-introspection-dev
-
 # get packages
 COPY requirements.txt .
 RUN pip install -r requirements.txt
@@ -25,6 +11,10 @@ FROM base as final
 # Enable unbuffered logging
 ENV PYTHONUNBUFFERED=1
 
+RUN apt-get -qq update \
+    && apt-get install -y --no-install-recommends \
+        wget
+
 # Download the grpc health probe
 RUN GRPC_HEALTH_PROBE_VERSION=v0.2.0 && \
     wget -qO/bin/grpc_health_probe https://github.com/grpc-ecosystem/grpc-health-probe/releases/download/${GRPC_HEALTH_PROBE_VERSION}/grpc_health_probe-linux-amd64 && \
@@ -35,9 +25,6 @@ WORKDIR /email_server
 # Grab packages from builder
 COPY --from=builder /usr/local/lib/python3.7/ /usr/local/lib/python3.7/
 
-# Need libstdc++ for grpc
-RUN apk add --no-cache libstdc++
-
 # Add the application
 COPY . .
 

src/loadgenerator/Dockerfile

@@ -1,14 +1,10 @@
-FROM python:3-alpine as base
+FROM python:3-slim as base
 
 FROM base as builder
 
-RUN apk add --update --no-cache \
-    gcc \
-    linux-headers \
-    make \
-    musl-dev \
-    python-dev \
-    g++
+RUN apt-get -qq update \
+    && apt-get install -y --no-install-recommends \
+        g++
 
 COPY requirements.txt .