bbernhard · poggenpower · Feb 27, 2026 · Mar 4, 2026
diff --git a/Dockerfile b/Dockerfile
@@ -6,6 +6,8 @@ ARG SWAG_VERSION=1.16.4
 ARG GRAALVM_VERSION=21.0.0
 #ARG GRAALVM_VERSION=25.0.2
 
+ARG S6_OVERLAY_VERSION=v3.2.2.0
+
 ARG BUILD_VERSION_ARG=unset
 
 FROM golang:1.24-bookworm AS buildcontainer
@@ -42,7 +44,7 @@ RUN sed -i -e 's/# en_US.UTF-8 UTF-8/en_US.UTF-8 UTF-8/' /etc/locale.gen && \
 
 ENV JAVA_OPTS="-Djdk.lang.Process.launchMechanism=vfork"
 
-ENV LANG en_US.UTF-8
+ENV LANG=en_US.UTF-8
 
 #RUN cd /tmp/ \
 #	&& git clone https://github.com/swaggo/swag.git swag-${SWAG_VERSION} \
@@ -154,42 +156,61 @@ RUN cd /tmp/signal-cli-rest-api-src/scripts && go build -o jsonrpc2-helper
 RUN cd /tmp/signal-cli-rest-api-src && go build -buildmode=plugin -o signal-cli-rest-api_plugin_loader.so plugin_loader.go
 
 # Start a fresh container for release container
+FROM debian:trixie-slim
 
-# eclipse-temurin doesn't provide a OpenJDK 21 image for armv7 (see https://github.com/adoptium/containers/issues/502). Until this
-# is fixed we use the standard ubuntu image
-#FROM eclipse-temurin:21-jre-jammy
-
-FROM ubuntu:jammy
-
+ARG TARGETARCH # set by buildx
+ARG SIGNAL_CLI_VERSION
+ARG BUILD_VERSION_ARG
 ENV GIN_MODE=release
 
-ENV PORT=8080
+# Set environment variables to keep the image clean
+ENV DEBIAN_FRONTEND=noninteractive
 
-ARG SIGNAL_CLI_VERSION
-ARG BUILD_VERSION_ARG
+ENV PORT=8080
 
 ENV BUILD_VERSION=$BUILD_VERSION_ARG
 ENV SIGNAL_CLI_REST_API_PLUGIN_SHARED_OBJ_DIR=/usr/bin/
 
-RUN dpkg-reconfigure debconf --frontend=noninteractive \
-	&& apt-get update \
-	&& apt-get install -y --no-install-recommends util-linux supervisor netcat openjdk-21-jre curl locales \
+RUN apt-get update \
+	&& apt-get install -y --no-install-recommends netcat-traditional openjdk-21-jre curl locales xz-utils\
+	&& apt-get clean \
 	&& rm -rf /var/lib/apt/lists/* 
 
+RUN if [ -z "$TARGETARCH" ]; then \
+      # Fallback for older Docker versions not using BuildKit
+      TARGETARCH=$(uname -m | sed 's/x86_64/amd64/;s/aarch64/arm64/'); \
+	else \
+	  echo "Building for architecture: $TARGETARCH"; \
+    fi;
+
+# install s6-overlay as service control system
+RUN curl -fL -o /tmp/s6-overlay-noarch.tar.xz \
+    "https://github.com/just-containers/s6-overlay/releases/download/${S6_OVERLAY_VERSION}/s6-overlay-noarch.tar.xz" && \
+    tar -C / -Jxpf /tmp/s6-overlay-noarch.tar.xz && \
+    if [ "$TARGETARCH" = "amd64" ]; then S6_ARCH="x86_64"; \
+    elif [ "$TARGETARCH" = "arm64" ]; then S6_ARCH="aarch64"; \
+    elif [ "$TARGETARCH" = "arm" ]; then S6_ARCH="arm"; \
+    else S6_ARCH=$(uname -m | sed 's/x86_64/amd64/;s/aarch64/arm64/'); fi;\
+    curl -fL -o /tmp/s6-overlay-bin.tar.xz \
+    "https://github.com/just-containers/s6-overlay/releases/download/${S6_OVERLAY_VERSION}/s6-overlay-${S6_ARCH}.tar.xz" && \
+    tar -C / -Jxpf /tmp/s6-overlay-bin.tar.xz && \
+    rm /tmp/s6-overlay-*.tar.xz
+
 COPY --from=buildcontainer /tmp/signal-cli-rest-api-src/signal-cli-rest-api /usr/bin/signal-cli-rest-api
 COPY --from=buildcontainer /opt/signal-cli-${SIGNAL_CLI_VERSION} /opt/signal-cli-${SIGNAL_CLI_VERSION}
 COPY --from=buildcontainer /tmp/signal-cli-${SIGNAL_CLI_VERSION}-source/build/native/nativeCompile/signal-cli /opt/signal-cli-${SIGNAL_CLI_VERSION}/bin/signal-cli-native
 COPY --from=buildcontainer /tmp/signal-cli-rest-api-src/scripts/jsonrpc2-helper /usr/bin/jsonrpc2-helper
 COPY --from=buildcontainer /tmp/signal-cli-rest-api-src/signal-cli-rest-api_plugin_loader.so /usr/bin/signal-cli-rest-api_plugin_loader.so
-COPY entrypoint.sh /entrypoint.sh
 
 
 RUN groupadd -g 1000 signal-api \
 	&& useradd --no-log-init -M -d /home -s /bin/bash -u 1000 -g 1000 signal-api \
 	&& ln -s /opt/signal-cli-${SIGNAL_CLI_VERSION}/bin/signal-cli /usr/bin/signal-cli \
 	&& ln -s /opt/signal-cli-${SIGNAL_CLI_VERSION}/bin/signal-cli-native /usr/bin/signal-cli-native \
-	&& mkdir -p /signal-cli-config/ \
-	&& mkdir -p /home/.local/share/signal-cli
+	&& mkdir -p /home/.local/share/signal-cli \
+	&& chown -R signal-api:signal-api /home
+
+COPY --chmod=755 ./s6-services/ /etc/s6-overlay/s6-rc.d/
 
 # remove the temporary created signal-cli-native on armv7, as GRAALVM doesn't support 32bit
 RUN arch="$(uname -m)"; \
@@ -201,16 +222,24 @@ RUN sed -i -e 's/# en_US.UTF-8 UTF-8/en_US.UTF-8 UTF-8/' /etc/locale.gen && \
     dpkg-reconfigure --frontend=noninteractive locales && \
     update-locale LANG=en_US.UTF-8
 
-ENV LANG en_US.UTF-8
+ENV LANG=en_US.UTF-8
 
 EXPOSE ${PORT}
 
 ENV SIGNAL_CLI_CONFIG_DIR=/home/.local/share/signal-cli
-ENV SIGNAL_CLI_UID=1000
-ENV SIGNAL_CLI_GID=1000
-ENV SIGNAL_CLI_CHOWN_ON_STARTUP=true
 
-ENTRYPOINT ["/entrypoint.sh"]
+RUN mkdir -p /tmp/s6-runtime && chown -R signal-api:signal-api /tmp/s6-runtime /etc/s6-overlay
+
+USER signal-api
+
+# Mandatory ENV for non-root s6
+ENV S6_RUNTIME_PATH=/tmp/s6-runtime
+ENV S6_READ_ONLY_ROOT=1
+ENV S6_VERBOSITY=2
+
+WORKDIR /home
+
+ENTRYPOINT ["/init"]
 
 HEALTHCHECK --interval=20s --timeout=10s --retries=3 \
     CMD curl -f http://localhost:${PORT}/v1/health || exit 1
diff --git a/entrypoint.old.sh b/entrypoint.old.sh
@@ -0,0 +1,43 @@
+#!/bin/sh
+
+set -x
+set -e
+
+[ -z "${SIGNAL_CLI_CONFIG_DIR}" ] && echo "SIGNAL_CLI_CONFIG_DIR environmental variable needs to be set! Aborting!" && exit 1;
+
+usermod -u ${SIGNAL_CLI_UID} signal-api
+groupmod -o -g ${SIGNAL_CLI_GID} signal-api
+
+# Fix permissions to ensure backward compatibility if SIGNAL_CLI_CHOWN_ON_STARTUP is not set to "false"
+if [ "$SIGNAL_CLI_CHOWN_ON_STARTUP" != "false" ]; then
+  echo "Changing ownership of ${SIGNAL_CLI_CONFIG_DIR} to ${SIGNAL_CLI_UID}:${SIGNAL_CLI_GID}"
+  chown ${SIGNAL_CLI_UID}:${SIGNAL_CLI_GID} -R ${SIGNAL_CLI_CONFIG_DIR}
+else
+  echo "Skipping chown on startup since SIGNAL_CLI_CHOWN_ON_STARTUP is set to 'false'"
+fi
+
+# Show warning on docker exec
+cat <<EOF >> /root/.bashrc
+echo "WARNING: signal-cli-rest-api runs as signal-api (not as root!)" 
+echo "Run 'su signal-api' before using signal-cli!"
+echo "If you want to use signal-cli directly, don't forget to specify the config directory. e.g: \"signal-cli --config ${SIGNAL_CLI_CONFIG_DIR}\""
+EOF
+
+cap_prefix="-cap_"
+caps="$cap_prefix$(seq -s ",$cap_prefix" 0 $(cat /proc/sys/kernel/cap_last_cap))"
+
+# TODO: check mode
+if [ "$MODE" = "json-rpc" ]
+then
+/usr/bin/jsonrpc2-helper
+if [ -n "$JAVA_OPTS" ] ; then
+    echo "export JAVA_OPTS='$JAVA_OPTS'" >> /etc/default/supervisor
+fi
+service supervisor start
+supervisorctl start all
+fi
+
+export HOST_IP=$(hostname -I | awk '{print $1}')
+
+# Start API as signal-api user
+exec setpriv --reuid=${SIGNAL_CLI_UID} --regid=${SIGNAL_CLI_GID} --init-groups --inh-caps=$caps signal-cli-rest-api -signal-cli-config=${SIGNAL_CLI_CONFIG_DIR}
diff --git a/s6-services/signal-api/run b/s6-services/signal-api/run
@@ -0,0 +1,3 @@
+#!/command/with-contenv sh
+# Use with-contenv to import environment variables like SIGNAL_CLI_CONFIG_DIR
+exec signal-cli-rest-api -signal-cli-config="${SIGNAL_CLI_CONFIG_DIR}"
diff --git a/s6-services/signal-api/type b/s6-services/signal-api/type
@@ -0,0 +1 @@
+longrun
diff --git a/s6-services/signal-json-rpc/run b/s6-services/signal-json-rpc/run
@@ -0,0 +1,67 @@
+#!/command/with-contenv sh
+# File: /etc/s6-overlay/s6-rc.d/signal-json-rpc/run
+
+PIPE=/tmp/sigsocket1
+PORT=6001
+
+if [ "$MODE" != "json-rpc" ]; then
+    echo "Running as mode: $MODE - skipping json-rpc setup"
+    sleep infinity # do nothing, but keep service running
+    exit 0 
+fi
+
+## general parameters for signal-cli
+# set SIGNAL_CLI_CONFIG_DIR if not set
+if [ -z "$SIGNAL_CLI_CONFIG_DIR" ]; then
+    SIGNAL_CLI_CONFIG_DIR="/home/.local/share/signal-cli/"
+fi
+
+jsonRpcConfig="${SIGNAL_CLI_CONFIG_DIR%/}/jsonrpc2.yml"
+
+# here file to write config
+cat > "$jsonRpcConfig" <<EOL
+config:
+  <multi-account>:
+    tcp_port: $PORT
+    fifo_pathname: $PIPE
+EOL
+
+#  Trust Identities
+trustNewIdentitiesEnv="${JSON_RPC_TRUST_NEW_IDENTITIES:-}"
+trustNewIdentities=""
+
+if [ "$trustNewIdentitiesEnv" = "on-first-use" ]; then
+    trustNewIdentities=" --trust-new-identities on-first-use"
+elif [ "$trustNewIdentitiesEnv" = "always" ]; then
+    trustNewIdentities=" --trust-new-identities always"
+elif [ "$trustNewIdentitiesEnv" = "never" ]; then
+    trustNewIdentities=" --trust-new-identities never"
+elif [ -n "$trustNewIdentitiesEnv" ]; then
+    # This mirrors your log.Fatal check
+    echo "Invalid JSON_RPC_TRUST_NEW_IDENTITIES environment variable set!" >&2
+    exit 1
+fi
+
+## parameters for jsonrpc mode
+# Attachments
+ignoreAttachments="${JSON_RPC_IGNORE_ATTACHMENTS:-}"
+signalCliIgnoreAttachments=""
+if [ "$ignoreAttachments" = "true" ]; then
+    signalCliIgnoreAttachments=" --ignore-attachments"
+fi
+
+# Stories
+ignoreStories="${JSON_RPC_IGNORE_STORIES:-}"
+signalCliIgnoreStories=""
+if [ "$ignoreStories" = "true" ]; then
+    signalCliIgnoreStories=" --ignore-stories"
+fi
+
+# Load the pipe
+[ -p "$PIPE" ] || mkfifo "$PIPE"
+
+# Ensure permissions are correct for non-root
+chmod 600 "$PIPE"
+
+# Launch the circular communication
+exec sh -c "nc -l -p "${PORT}" < $PIPE | signal-cli --output=json --config "${SIGNAL_CLI_CONFIG_DIR}" "${trustNewIdentities}" jsonRpc ${signalCliIgnoreAttachments} ${signalCliIgnoreStories} > $PIPE"
diff --git a/s6-services/signal-json-rpc/type b/s6-services/signal-json-rpc/type
@@ -0,0 +1 @@
+longrun
diff --git a/s6-services/user/contents.d/signal-api b/s6-services/user/contents.d/signal-api
diff --git a/s6-services/user/contents.d/signal-json-rpc b/s6-services/user/contents.d/signal-json-rpc
diff --git a/s6-services/user/type b/s6-services/user/type
@@ -0,0 +1 @@
+bundle