Simplify build

Dockerfile

 FROM debian:stable-slim
 
-COPY build.sh /tmp/build.sh
-
-RUN /tmp/build.sh && rm /tmp/build.sh
+RUN apt-get -q update && \
+    env DEBIAN_FRONTEND=noninteractive apt-get -y install prometheus && \
+    apt-get clean && \
+    rm -fr /var/lib/apt/lists/*
 
 ENTRYPOINT ["/usr/bin/prometheus"]
 

build.sh

-#!/bin/sh
-#
-# Install script for chaperone inside a Docker container.
-#
-
-# Packages required to serve the website and run the services.
-PACKAGES="prometheus"
-
-# The default bitnami/minideb image defines an 'install_packages'
-# command which is just a convenient helper. Define our own in
-# case we are using some other Debian image.
-if [ "x$(which install_packages)" = "x" ]; then
-    install_packages() {
-        env DEBIAN_FRONTEND=noninteractive apt-get install -qy -o Dpkg::Options::="--force-confdef" -o Dpkg::Options::="--force-confold" --no-install-recommends "$@"
-    }
-fi
-
-die() {
-    echo "ERROR: $*" >&2
-    exit 1
-}
-
-set -x
-
-apt-get -q update
-
-# Install required packages
-install_packages ${PACKAGES} \
-    || die "could not install packages"
-
-# Remove packages used for installation.
-#apt-get remove -y --purge ${BUILD_PACKAGES}
-apt-get autoremove -y
-apt-get clean
-rm -fr /var/lib/apt/lists/*