+ installing signal dependencies

+ option to link to a device when running the docker image (alpine only 
for now)

Dockerfile-alpine

@@ -1,9 +1,12 @@
 # This image is based on Alpine linux to get a minimum memory footprint
 # Some say that alpine should not be used for Python (https://pythonspeed.com/articles/alpine-docker-python/),
 # however given some additional work, overall it may be better in the end (https://nickjanetakis.com/blog/the-3-biggest-wins-when-using-alpine-as-a-base-docker-image)
-# Currently this Dockerfile is not thoroughfully tested...
-# Finally, a better option may probably be to just run the python scripts without any setup/install
-# Also : Python version > 3.4.2
+
+
+#################
+# STAGE 1
+#################
+
 FROM python:3-alpine AS builder
 
 # python:3-alpine misses gcc, ffi.h, ...
@@ -22,31 +25,52 @@ RUN apk add --no-cache build-base gcc abuild binutils cmake \
 
 COPY requirements-runtime.txt .
 RUN pip install --no-cache-dir --user -r requirements-runtime.txt
+# The 'qr' command is used in the process to link the machine with a Signal account
+RUN pip install --no-cache-dir --user qrcode
 # It could be packaged (RUN python setup.py sdist bdist_wheel) to possibly
 # improve size and speed ; probably as a multistage build
 # And update the version from git using setuptools-scm
 # But it requires a bit of work
 #RUN python setup.py sdist bdist_wheel
 
+# Signal installation
+ENV SIGNAL_VERSION=0.6.7
+RUN wget "https://github.com/AsamK/signal-cli/releases/download/v${SIGNAL_VERSION}/signal-cli-${SIGNAL_VERSION}.tar.gz"
+RUN tar xf "signal-cli-${SIGNAL_VERSION}.tar.gz" -C /opt
+RUN mv "/opt/signal-cli-${SIGNAL_VERSION}" /opt/signal-cli
 
 
+
+#################
+# STAGE 2
+#################
+
 FROM python:3-alpine
 
 WORKDIR /usr/src/app
 
 # Required at runtime
 # libressl-dev : seems required for python to locate modules, or for omemo ?
+# openjdk : requirement for signal-cli
+# A Java 8+ runtime seems to be required for 0.6, 0.7 requires JRE 11 (which is 50MB bigger...)
+# For an even smaller JRE image, see maybe https://github.com/rhuss/docker-java-jolokia/blob/master/base/alpine/jre/8/Dockerfile
+# or https://hub.docker.com/r/azul/zulu-openjdk-alpine/dockerfile
+# bash is to use extended syntax in entrypoint.sh (in particular tee >(...))
 RUN apk add --no-cache libressl-dev
+RUN apk add --no-cache bash openjdk8-jre
 
+# All Python files, including nicobot's
 COPY --from=builder /root/.local /root/.local/
+# https://www.docker.com/blog/containerized-python-development-part-1/
+ENV PATH=/root/.local/bin:$PATH
 #COPY --from=builder /root/.cache /root/.cache/
 #COPY --from=builder /usr/local/lib /usr/local/lib/
-# https://www.docker.com/blog/containerized-python-development-part-1/
-# update PATH environment variable
-#ENV PATH=/root/.local/bin:$PATH
+
+# signal-cli files
+COPY --from=builder /opt/signal-cli /opt/signal-cli
+ENV PATH=/opt/signal-cli/bin:$PATH
 
 # TODO How to do it with one COPY ?
-
 # Or it could be COPY . . with a proper .dockerignore
 # Or build the context as a preliminary step
 COPY nicobot nicobot/

docker-entrypoint.sh

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 
 usage()
 {
@@ -13,16 +13,46 @@ E.g. '$0 transbot -h' to get a more specific help for 'transbot'
 EOF
 }
 
-# It's not needed to repeat the commands for each bot but it's clearer
-bot=$1
-case $bot in
-    transbot)
-        shift
-        exec python -m "nicobot.$bot" "$@"
-        ;;
-    askbot)
-        shift
-        exec python -m "nicobot.$bot" "$@"
+
+# Displays an URL and a QRCode in the console to link the current container
+# with whichever Signal client will scan it
+signal_link() {
+    device_name=$1
+    # WARNING This command works on alpine with bash installed, not tested otherwise
+    signal-cli link --name "${device_name}" | tee >(head -1 | qr)
+}
+
+# Default values
+opt_signal_register=
+opt_bot=
+
+# Parses the command line for options to execute before running the bot
+# TODO Enhance CLI handling with getopt
+#ARGS=$(getopt -l 'signal-register:' -- "$@") || usage && exit 1
+#eval "set -- $ARGS"
+while true; do
+    case $1 in
+      (--signal-register)
+            opt_signal_register=$2
+            shift 2;;
+      (askbot|transbot)
+            opt_bot=$1
+            shift;;
+      (*)
+            # End of this script's options ; next options are for the bot
+            break;;
+    esac
+done
+
+# Registers the device with signal
+if [ -n "${opt_signal_register}" ]; then
+    signal_link "${opt_signal_register}"
+fi
+
+# Runs the right bot with the remaining args
+case "${opt_bot}" in
+    askbot|transbot)
+        exec python3 -m "nicobot.${opt_bot}" "$@"
         ;;
     *)
         usage