Updated kiwix-serve dockerfile from upstream

Reusing upstream's arch logic (even though we don't need it all)
Kept our flexible VERSION handling for dev/release/nightly
Solely extracting kiwix-serve from archive

kiwix-serve/Dockerfile

@@ -1,51 +1,48 @@
-# dumb-init to use as entrypoint so it can forward signals to our CMD
-FROM debian:bullseye-slim as builder
-RUN apt-get update -y \
-    && apt-get install -y --no-install-recommends \
-    build-essential ca-certificates musl-tools wget unzip make \
-    && apt-get clean \
-    && rm -rf /var/lib/apt/lists/* \
-    # compile dumb-init ; \
-    && wget -nv https://github.com/Yelp/dumb-init/archive/refs/tags/v1.2.5.zip \
-    && unzip v1.2.5.zip && cd dumb-init-1.2.5 && CC=musl-gcc make
-
-# declare build option ARCH if not using buildx
-ARG ARCH=
-# declare version to build image for
-ARG VERSION=
-
-# alpine is a multi-arch image
 FROM alpine:3
 LABEL org.opencontainers.image.source https://github.com/offspot/container-images
 
-# TARGETARCH is injected by buildx
-ARG TARGETARCH
+# TARGETPLATFORM is injected by docker build
+ARG TARGETPLATFORM
 ARG VERSION
-ARG ARCH
-
-# copy built dumb-init
-COPY --from=builder /dumb-init-1.2.5/dumb-init /usr/bin/dumb-init
 
-# find and store arch in image, using (in this order):
-# $TARGETARCH || --build-arg ARCH (not using buildx) || amd64
-RUN echo "amd64" > /etc/docker_arch && \
-    if [ ! -z "$ARCH" ] ; then echo "$ARCH" > /etc/docker_arch ; fi && \
-    if [ ! -z "$TARGETARCH" ] ; then echo "$TARGETARCH" > /etc/docker_arch ; fi \
-    # decide which kiwix arch to download later (`armhf` for all arm* and x86_64 otherwise); \
-    && if [ $(cat /etc/docker_arch) = "arm64" ] ; then echo "aarch64" > /etc/kiwix_arch ; elif [ $(cut -c 1-3 /etc/docker_arch) = "arm" ] ; then echo "armhf" > /etc/kiwix_arch ; else echo "x86_64" > /etc/kiwix_arch ; fi \
-    # dev version means latest
-    && if [ "$VERSION" = "dev" ] ; then export VERSION="" ; fi \
+RUN set -e && \
+    # default (no VERSION set) means latest release
+    # `dev` version means today's nightly
+    if [ "$VERSION" = "dev" ] ; then export VERSION="$(date +"%Y-%m-%d")" ; fi && \
+    apk --no-cache add dumb-init curl && \
+    echo "TARGETPLATFORM: $TARGETPLATFORM" && \
+    if [ "$TARGETPLATFORM" = "linux/386" ]; then ARCH="i586"; \
+    # linux/arm64/v8 points to linux/arm64
+    elif [ "$TARGETPLATFORM" = "linux/arm64/v8" \
+        -o "$TARGETPLATFORM" = "linux/arm64" ]; then ARCH="aarch64"; \
+    # linux/arm translates to linux/arm/v7
+    elif [ "$TARGETPLATFORM" = "linux/arm/v7" ]; then ARCH="armv8"; \
+    elif [ "$TARGETPLATFORM" = "linux/arm/v6" ]; then ARCH="armv6"; \
+    elif [ "$TARGETPLATFORM" = "linux/amd64/v3" \
+        -o "$TARGETPLATFORM" = "linux/amd64/v2" \
+        -o "$TARGETPLATFORM" = "linux/amd64" ]; then ARCH="x86_64"; \
+    # we dont suppot any other arch so let it fail
+    else ARCH="unknown"; fi && \
+    # default download source is releases
+    export DLFROM="https://download.kiwix.org/release/kiwix-tools" && \
     # change download source for nightlies (VERSION is a date)
-    && export DLFROM="https://download.kiwix.org/release/kiwix-tools/" \
-    && if [[ "$VERSION" =~ ^[0-9]{4}-[0-9]{2}-[0-9]{2}$ ]] ; then export DLFROM="https://download.kiwix.org/nightly/${VERSION}" ; fi \
-    # fallback version if not suppplied; \
-    && if [ ! -z "$VERSION" ] ; then export VERSION="-$VERSION" ; fi \
-    # Install kiwix-tools
-    && url="$DLFROM/kiwix-tools_linux-$(cat /etc/kiwix_arch)$VERSION.tar.gz" \
-    && echo "URL: $url" \
-    && wget -q -O - $url | tar -xz \
-    && mv kiwix-tools*/kiwix-serve /usr/local/bin/ \
-    && rm -r kiwix-tools*
+    if [[ "$VERSION" =~ ^[0-9]{4}-[0-9]{2}-[0-9]{2}$ ]] ; then \
+    export DLFROM="https://download.kiwix.org/nightly/${VERSION}" ; fi && \
+    # only non-specified (latest) release doesnt include VERSION in filename (sep by dash)
+    if [ ! -z "$VERSION" ] ; then export VERSION="-$VERSION" ; fi && \
+    export filename="kiwix-tools_linux-$ARCH$VERSION.tar.gz" && \
+    # download requested kiwix-tools version
+    url="$DLFROM/$filename" && \
+    echo "URL: $url" && \
+    if [ -z "$VERSION" ] ; then \
+    # fetch actual filename (latest release is a redirect)
+    export foldername="$(curl --head --insecure --location --silent --no-buffer $url |grep -m 1 'location:' | cut -d '/' -f 6 | sed 's/.tar.gz//' | sed 's/\r//')"; \
+    else export foldername=$(echo -n $filename|sed 's/.tar.gz//'); fi && \
+    echo "foldername: $foldername" && \
+    # download and extract just kiwix-serve
+    curl --insecure --location $url | tar -xzo -f - -C /usr/local/bin/ --strip-components 1 -- "$foldername/kiwix-serve" && \
+    # only needed in dockerfile
+    apk del curl
 
 # expose kiwix-serve default port
 EXPOSE 80