Dockerfile

ARG BASE=ghcr.io/cloudnative-pg/postgresql:18-minimal-trixie
FROM $BASE AS builder

ARG PG_MAJOR
ARG EXT_VERSION
ARG POSTGIS_MAJOR

USER 0

RUN set -eux && \
	# Initial system libraries
	ldconfig -p | awk '{print $NF}' | grep '^/' | sort | uniq > /tmp/base-image-libs.out && \
	# Install PostGIS
	apt-get update && \
	apt-get install -y --no-install-recommends \
		"postgresql-${PG_MAJOR}-postgis-${POSTGIS_MAJOR}=${EXT_VERSION}" \
		"postgresql-${PG_MAJOR}-postgis-${POSTGIS_MAJOR}-scripts=${EXT_VERSION}"

# Gather PostGIS system libraries and their licenses
RUN mkdir -p /system /licenses && \
	# Get libraries
	ldd /usr/lib/postgresql/${PG_MAJOR}/lib/address_standardizer*.so \
		/usr/lib/postgresql/${PG_MAJOR}/lib/postgis*.so \
		| awk '{print $3}' | grep '^/' | sort | uniq > /tmp/all-deps.out && \
	# Extract all the libs that aren't already part of the base image
	comm -13 /tmp/base-image-libs.out /tmp/all-deps.out > /tmp/libraries.out && \
	while read -r lib; do \
		resolved=$(readlink -f "$lib"); \
		dir=$(dirname "$lib"); \
		base=$(basename "$lib"); \
		# Copy the real file
		cp -a "$resolved" /system/; \
		# Reconstruct all its symlinks
		for file in "$dir"/"${base%.so*}.so"*; do \
			[ -e "$file" ] || continue; \
			# If it's a symlink and it resolves to the same real file, we reconstruct it
			if [ -L "$file" ] && [ "$(readlink -f "$file")" = "$resolved" ]; then \
				ln -sf "$(basename "$resolved")" "/system/$(basename "$file")"; \
			fi; \
		done; \
	done < /tmp/libraries.out && \
	# Get licenses
	for lib in $(find /system -maxdepth 1 -type f -name '*.so*'); do \
		# Get the name of the pkg that installed the library
		pkg=$(dpkg -S "$(basename "$lib")" | grep -v "diversion by" | awk -F: '/:/{print $1; exit}'); \
		[ -z "$pkg" ] && continue; \
		mkdir -p "/licenses/$pkg" && cp -a "/usr/share/doc/$pkg/copyright" "/licenses/$pkg/copyright"; \
	done


FROM scratch
ARG PG_MAJOR
ARG POSTGIS_MAJOR

# Licenses
COPY --from=builder /licenses /licenses/
COPY --from=builder /usr/share/doc/postgresql-${PG_MAJOR}-postgis-${POSTGIS_MAJOR}/copyright /licenses/postgresql-${PG_MAJOR}-postgis-${POSTGIS_MAJOR}/

# Libraries
COPY --from=builder \
	/usr/lib/postgresql/${PG_MAJOR}/lib/address_standardizer* \
	/usr/lib/postgresql/${PG_MAJOR}/lib/postgis* \
	/lib/

COPY --from=builder /usr/lib/postgresql/${PG_MAJOR}/lib/bitcode/ /lib/bitcode/

# Share
COPY --from=builder \
	/usr/share/postgresql/${PG_MAJOR}/extension/address_standardizer* \
	/usr/share/postgresql/${PG_MAJOR}/extension/postgis* \
	/share/extension/

COPY --from=builder /usr/share/postgresql/${PG_MAJOR}/contrib/postgis* /share/contrib/
COPY --from=builder /usr/share/gdal/ /share/gdal/
COPY --from=builder /usr/share/proj/ /share/proj/

# System libs
COPY --from=builder /system /system/

USER 65532:65532