move to scratch dockerfile (saves 100M)

Dockerfile

@@ -1,9 +1,76 @@
-FROM python:3.8.7-alpine3.12
+FROM python:3.9-slim-buster AS builder
+# staticx has two issues:
+# 1. It does not seem to play well with alpine (at least for Python+pie).
+#    In that configuration, it seems to think it's a glibc executable
+# 2. It does not play well with PIE executables, see
+#       https://github.com/JonathonReinhart/staticx/issues/71
 
-WORKDIR /app
-ENTRYPOINT ["etags.py"]
+RUN true \
+    && apt-get update                             \
+    && apt-get install --no-install-recommends -y \
+         build-essential=12.6                     \
+         patchelf=0.9*                            \
+    && pip3 install pyinstaller==4.1              \
+                    scons==4.0.1                  \
+                    patchelf-wrapper==1.2.0       \
+                    staticx==0.12.0               \
+    && rm -rf /var/lib/apt/lists/*
 
-COPY requirements.txt /app/
-COPY etags.py /app/
+ARG PYINSTALLER_TAG=v4.1
 
-RUN pip3 install -r requirements.txt && rm /app/requirements.txt
+# HACK to get around https://github.com/JonathonReinhart/staticx/issues/71
+RUN true \
+    && apt-get update                                                     \
+    && apt-get install --no-install-recommends -y                         \
+          git=1:2.20*                                                     \
+          zlib1g-dev=1:1.2.11*                                            \
+    && git clone --depth 1 --single-branch --branch ${PYINSTALLER_TAG}    \
+          https://github.com/pyinstaller/pyinstaller.git /tmp/pyinstaller \
+    && cd /tmp/pyinstaller/bootloader                                     \
+    && CC="gcc -no-pie" python ./waf configure --no-lsb all               \
+    && cp -R /tmp/pyinstaller/PyInstaller/bootloader/*                    \
+             /usr/local/lib/python*/site-packages/PyInstaller/bootloader/ \
+    && rm -rf /var/lib/apt/lists/*
+
+# # ENTRYPOINT ["etags.py"]
+#
+COPY requirements.txt /src/
+COPY etags.py /src/
+
+WORKDIR /src
+
+RUN true                                        \
+    && pip3 install -r requirements.txt         \
+    && pyinstaller -F etags.py                  \
+    && staticx                                  \
+         --strip                                \
+         --no-compress                          \
+         -l /lib/x86_64-linux-gnu/libgcc_s.so.1 \
+         dist/etags dist/app                    \
+    && chmod 755 dist/app
+
+FROM scratch
+
+# Allow ssl comms
+COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
+
+# So we can set the user
+COPY --from=builder /etc/passwd /etc/passwd
+COPY --from=builder /etc/group /etc/group
+
+# This should need no privileges
+USER nobody:nogroup
+
+# Environment variables that should be set
+ENV AWS_DEFAULT_REGION=us-west-2
+ENV AWS_ACCESS_KEY_ID=AKIAEXAMPLE
+ENV AWS_SECRET_ACCESS_KEY=dummy
+# Set if you're not talking to real DDB
+# ENV DDB_ENDPOINT
+ENV ETAGS_TABLE=etags
+# Setting this variable to nothing will turn off bus notification
+ENV ETAGS_BUS_NAME=
+
+ENTRYPOINT ["/app"]
+
+COPY --from=builder /src/dist/app /app