Drop the base image's unused parts (~800 MB smaller)

Dockerfile

@@ -1,6 +1,45 @@
 # syntax=docker/dockerfile:1
 # ubuntunoble stopped receiving builds in June 2026; its older Selkies rejects h264enc
-FROM ghcr.io/linuxserver/baseimage-selkies:ubunturesolute
+FROM ghcr.io/linuxserver/baseimage-selkies:ubunturesolute AS base
+
+# Strip what ConnectHub never uses from the base: Docker-in-Docker, compilers, all but one
+# locale, CJK serif fonts (~800 MB). Deleting files in a later layer can't shrink an
+# image, so this stage's filesystem is copied into a fresh one below. CI's layer cache
+# keeps this stage, and so that copied layer, unchanged until the base image changes,
+# so updates still only download ConnectHub's own layers.
+FROM base AS slim
+COPY scripts/slim_base.sh /tmp/slim_base.sh
+RUN sh /tmp/slim_base.sh && env | sort > /connecthub-base.env
+
+FROM scratch
+COPY --from=slim / /
+
+# The base image's configuration, which copying its files doesn't carry over.
+# check_base_env.sh below fails the build if this drifts from the base image.
+ENV HOME=/config \
+    LANGUAGE=en_US.UTF-8 \
+    LANG=en_US.UTF-8 \
+    TERM=xterm \
+    SHELL=/bin/bash \
+    S6_CMD_WAIT_FOR_SERVICES_MAXTIME=0 \
+    S6_VERBOSITY=1 \
+    S6_STAGE2_HOOK=/docker-mods \
+    DISPLAY=:1 \
+    PERL5LIB=/usr/local/bin \
+    PULSE_RUNTIME_PATH=/defaults \
+    SELKIES_INTERPOSER=/usr/lib/selkies_input_interposer.so \
+    SELKIES_WEBCAM_INTERPOSER=/usr/lib/selkies_v4l2_interposer.so \
+    NVIDIA_DRIVER_CAPABILITIES=all \
+    DISABLE_DRI3=false \
+    SELKIES_ENCODER=h264enc,h265enc,vp8enc,vp9enc,av1enc,jpeg \
+    SELKIES_ENABLE_BASIC_AUTH=false \
+    SELKIES_VIDEO_STREAMING_MODE=false \
+    SELKIES_ALLOWED_ORIGINS=* \
+    SELKIES_RATE_CONTROL_MODE=crf,cbr \
+    __GL_SYNC_TO_VBLANK=0 \
+    TITLE=Selkies
+# Docker was removed above; the base's svc-docker only sleeps with this false
+ENV START_DOCKER=false
 
 LABEL maintainer="kodi"
 LABEL description="ConnectHub - WebRTC remote desktop gateway for RDP, VNC and SSH, multi-GPU encoding (NVIDIA/AMD/Intel/CPU), Authentik SSO & Basic Auth, and WebUI File Sharing."
@@ -9,7 +48,11 @@
     PIP_DISABLE_PIP_VERSION_CHECK=1 \
     PYTHONUNBUFFERED=1 \
     VIRTUAL_ENV=/app/venv \
-    PATH="/app/venv/bin:$PATH"
+    PATH="/app/venv/bin:/lsiopy/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
+
+COPY scripts/check_base_env.sh /tmp/check_base_env.sh
+RUN sh /tmp/check_base_env.sh /connecthub-base.env \
+    && rm -f /tmp/check_base_env.sh /connecthub-base.env
 
 # Install FreeRDP 3, GPU drivers for VA-API, Python 3, and utilities
 RUN apt-get update && apt-get install -y --no-install-recommends \
@@ -19,7 +62,6 @@
     libva-drm2 \
     vainfo \
     python3 \
-    python3-pip \
     python3-venv \
     procps \
     curl \
@@ -83,6 +125,13 @@
         /etc/s6-overlay/s6-rc.d \
     && rm -rf /tmp/s6-rc-check
 
+# What the session needs still runs after the slimming above
+RUN /lsiopy/bin/python3 -c "import selkies, pixelflux, pcmflux" \
+    && for bin in Xvfb nginx pulseaudio openbox xdotool xclip xterm xfreerdp3 xtigervncviewer sshpass s6-rc; do \
+           command -v "$bin" > /dev/null || { echo "missing after slimming: $bin" >&2; exit 1; }; \
+       done \
+    && locale -a | grep -qix 'en_US.utf8'
+
 # Release version, set by CI. Declared last so a new version doesn't invalidate
 # the cached package and pip layers above.
 ARG APP_VERSION=0.0.0-dev
@@ -93,3 +142,5 @@
 
 # Port 3000 (HTTP) and 3001 (HTTPS, self-signed) serve the WebUI, API, and Selkies stream
 EXPOSE 3000 3001
+
+ENTRYPOINT ["/init"]

README.md

@@ -309,6 +309,12 @@ ConnectHub/
 
 ---
 
+## Image Size
+
+The image is built on LinuxServer's Selkies base, minus the parts ConnectHub never uses: Docker-in-Docker, the C/C++ compilers and build tools, every locale except `en_US.UTF-8` (and `C.UTF-8`), and the CJK serif fonts (the sans fonts remain, so SSH terminals still show CJK text). That saves about 800 MB. Setting another `LANG` or `LC_*` locale in the container therefore has no effect; it doesn't change anything on the remote machine either way.
+
+---
+
 ## Troubleshooting
 
 The **Connection Logs & Diagnostics** panel on the dashboard has three tabs, each keeping its last 1,000 lines:

scripts/check_base_env.sh

@@ -0,0 +1,40 @@
+#!/bin/sh
+# Fails the build when the environment re-declared in the Dockerfile has drifted from
+# the base image's. The image is rebuilt FROM scratch (see slim_base.sh), so it doesn't
+# inherit the base's ENV, and a variable the base adds or changes later would otherwise
+# go missing without anyone noticing.
+#
+# $1: `env` as seen in a build stage of the base image, one VAR=value per line.
+set -eu
+
+base_env=$1
+# Set per process or per build step (BuildKit's tracing context differs on every RUN),
+# or overridden on purpose in the Dockerfile
+skip='^(HOSTNAME|PWD|OLDPWD|SHLVL|_|TRACEPARENT|TRACESTATE|PATH|VIRTUAL_ENV|START_DOCKER|DEBIAN_FRONTEND)='
+
+status=0
+# Every mismatch is reported, so one failed build shows all that needs updating
+mismatches=$(grep -Ev "$skip" "$base_env" | while IFS= read -r line; do
+    name=${line%%=*}
+    expected=${line#*=}
+    actual=$(printenv "$name" || true)
+    if [ "$actual" != "$expected" ]; then
+        echo "check_base_env: $name is '$actual' here but '$expected' in the base image"
+    fi
+done)
+if [ -n "$mismatches" ]; then
+    printf '%s\n' "$mismatches" >&2
+    status=1
+fi
+
+# PATH may only add to the front of the base image's
+base_path=$(grep '^PATH=' "$base_env" | cut -d= -f2-)
+case "$PATH" in
+    *":$base_path"|"$base_path") ;;
+    *) echo "check_base_env: PATH '$PATH' does not end with the base image's '$base_path'" >&2; status=1 ;;
+esac
+
+if [ "$status" -ne 0 ]; then
+    echo "check_base_env: update the ENV block in the Dockerfile to match the base image" >&2
+fi
+exit "$status"

scripts/slim_base.sh

@@ -0,0 +1,48 @@
+#!/bin/sh
+# Removes the parts of baseimage-selkies that ConnectHub never uses. Runs in a build
+# stage whose filesystem is then copied into a fresh image (see the Dockerfile):
+# deleting files in a later layer of the same image would not make it any smaller.
+set -eu
+
+# Docker-in-Docker (installed on amd64 only), the C/C++ toolchain and build tools,
+# and every locale. Only the ones actually installed are named, so arm64 builds,
+# which have no Docker, don't fail on unknown packages.
+PURGE=""
+for pkg in docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin \
+           gcc g++ cmake make git locales-all; do
+    if dpkg-query -W -f='${db:Status-Status}' "$pkg" 2>/dev/null | grep -qx installed; then
+        PURGE="$PURGE $pkg"
+    fi
+done
+
+if [ -n "$PURGE" ]; then
+    # apt also removes whatever depends on these. Refuse if that would take any package
+    # the base image installed on purpose, rather than silently losing it.
+    tmp=$(mktemp -d)
+    apt-get -s purge --auto-remove $PURGE | awk '/^Purg /{print $2}' | sed 's/:.*//' | sort -u > "$tmp/removed"
+    apt-mark showmanual | sed 's/:.*//' | sort -u > "$tmp/manual"
+    printf '%s\n' $PURGE | sort -u > "$tmp/purge"
+    # removed AND installed on purpose AND not one we asked for
+    unexpected=$(comm -12 "$tmp/removed" "$tmp/manual" | comm -23 - "$tmp/purge")
+    if [ -n "$unexpected" ]; then
+        echo "slim_base: purging$PURGE would also remove packages the base installs on purpose:" >&2
+        printf '  %s\n' $unexpected >&2
+        exit 1
+    fi
+    echo "slim_base: removing$PURGE ($(wc -l < "$tmp/removed") packages in total)"
+    rm -rf "$tmp"
+    apt-get purge -y --auto-remove $PURGE
+fi
+
+rm -f /etc/apt/sources.list.d/docker.list /usr/share/keyrings/docker.asc /usr/local/bin/dind
+
+# The base compiles hundreds of locales into one 180 MB archive; the image runs in en_US.UTF-8
+rm -f /usr/lib/locale/locale-archive
+localedef -i en_US -f UTF-8 en_US.UTF-8
+
+# CJK serif faces (54 MB). The sans faces stay, so SSH terminals still show CJK text.
+rm -f /usr/share/fonts/opentype/noto/NotoSerifCJK-*.ttc
+fc-cache -f >/dev/null
+
+apt-get clean
+rm -rf /var/lib/apt/lists/* /var/cache/apt/* /var/log/apt /var/log/dpkg.log /tmp/* /var/tmp/*