Update Dockerfile to make sense

Dockerfile

@@ -1,7 +1,39 @@
-# Spreed WebRTC server.
+# Spreed WebRTC server in Docker
 #
-# To execute it install docker and then run 'sudo docker build .'
+# This Dockerfile creates a container which runs Spreed WebRTC as found in the
+# current folder. It is intended for development.
 #
+# Install docker and then run `docker build -t spreed-webrtc .` to build the
+# image. Afterwards run the container like this:
+#
+#   ```
+#   docker run --rm --name my-spreed-webrtc -p 8080:8080 -p 8443:8443 \
+#       -v `pwd`:/srv/extra -i -t spreed-webrtc
+#   ```
+#
+# Now you can either use a frontend proxy like Nginx to provide TLS to Spreed
+# WebRTC and even run it in production like that from the Docker container, or
+# for easy development testing, the container also provides a TLS listener with
+# a self-signed certificate on port 8443.
+#
+# To use custom configuration, use the `server.conf.in` file as template and
+# remove the listeners from [http] and [https] sections. Then provide that file
+# when running the docker container as with `-c` parameter like this:
+#
+#   ```
+#   docker run --rm --name my-spreed-webrtc -p 8080:8080 \
+#       -v `pwd`:/srv/extra -i -t spreed-webrtc` \
+#       -c /srv/extra/server.conf
+#   ```
+#
+# And last, this container checks environment variables NEWCERT and NEWSECRETS,
+# on startup. Set those to `1` to regenerate the corresponding values on start.
+# The current certificate and secrets are printed before startup so you can use
+# them easily for other services. Of course, if you want to have persistent cert
+# and secrets, the container needs to be persistent in the first place, so no
+# `--rm` parameter in the example from above in that case.
+#
+
 FROM ubuntu:xenial
 MAINTAINER Simon Eisenmann <simon@struktur.de>
 
@@ -11,29 +43,69 @@ ENV LC_ALL en_US.UTF-8
 
 ENV DEBIAN_FRONTEND noninteractive
 
-# Base system
-RUN apt-get update -q
-
 # Base build dependencies.
-RUN apt-get install -qy golang nodejs build-essential git mercurial automake autoconf
+RUN apt-get update && apt-get install -qy \
+	golang nodejs build-essential git automake autoconf
 
 # Add and build Spreed WebRTC server.
 ADD . /srv/spreed-webrtc
 WORKDIR /srv/spreed-webrtc
-RUN ./autogen.sh
-RUN ./configure
-RUN make pristine && make get && make
+RUN ./autogen.sh && ./configure && make pristine && make get && make
+
+# Create entrypoint script.
+RUN echo '\n\
+set -e\n\
+if [ "$NEWCERT" = "1" -o ! -e /srv/cert.pem ]; then\n\
+	echo "Creating new self signed TLS certificate ..."\n\
+	rm -f /srv/privkey.pem\n\
+	rm -f /srv/cert.pem\n\
+	openssl ecparam -genkey -name secp384r1 -out /srv/privkey.pem\n\
+	openssl req -new -x509 -key /srv/privkey.pem \\\n\
+				-out /srv/cert.pem -days 3650 \\\n\
+				-subj /CN=spreed-webrtc \\\n\
+				-config /etc/ssl/openssl.cnf \\\n\
+				-sha256 -extensions v3_req\n\
+
+fi\n\
+echo "TLS certificate:"\n\
+openssl x509 -in /srv/cert.pem -text\n\
+if [ "$NEWSECRETS" = "1" -o ! -e /srv/secrets.conf ]; then\n\
+	echo "Creating new server secrets ..."\n\
+	rm -f /srv/secrets.conf.tmp\n\
+	echo "SESSION_SECRET=$(openssl rand -hex 32)" >>/srv/secrets.conf.tmp\n\
+	echo "ENCRYPTION_SECRET=$(openssl rand -hex 32)" >>/srv/secrets.conf.tmp\n\
+	echo "SERVER_TOKEN=$(openssl rand -hex 32)" >>/srv/secrets.conf.tmp\n\
+	echo "SHARED_SECRET=$(openssl rand -hex 32)" >>/srv/secrets.conf.tmp\n\
+	. /srv/secrets.conf.tmp\n\
+	sed -i -e "s/sessionSecret =.*/sessionSecret = $SESSION_SECRET/" /srv/spreed-webrtc/default.conf\n\
+	sed -i -e "s/encryptionSecret =.*/encryptionSecret = $ENCRYPTION_SECRET/" /srv/spreed-webrtc/default.conf\n\
+	sed -i -e "s/serverToken =.*/serverToken = $SERVER_TOKEN/" /srv/spreed-webrtc/default.conf\n\
+	sed -i -e "s/;sharedsecret_secret =.*/sharedsecret_secret = $SHARED_SECRET/" /srv/spreed-webrtc/default.conf\n\
+	mv /srv/secrets.conf.tmp /srv/secrets.conf\n\
+fi\n\
+echo "Server secrets:"\n\
+cat /srv/secrets.conf\n\
+echo "Staring Spreed WebRTC server ..."\n\
+exec /srv/spreed-webrtc/spreed-webrtc-server "$@"\n'\
+>> /srv/entrypoint.sh
 
 # Create default config file.
-RUN cp -v /srv/spreed-webrtc/server.conf.in /srv/spreed-webrtc/server.conf && \
-	sed -i 's|listen = 127.0.0.1:8080|listen = 0.0.0.0:8080|' /srv/spreed-webrtc/server.conf && \
-	sed -i 's|;root = .*|root = /srv/spreed-webrtc|' /srv/spreed-webrtc/server.conf
+RUN cp -v /srv/spreed-webrtc/server.conf.in /srv/spreed-webrtc/default.conf && \
+	sed -i 's|listen = 127.0.0.1:8080|listen = 0.0.0.0:8080|' /srv/spreed-webrtc/default.conf && \
+	sed -i 's|;root = .*|root = /srv/spreed-webrtc|' /srv/spreed-webrtc/default.conf && \
+	sed -i 's|;listen = 127.0.0.1:8443|listen = 0.0.0.0:8443|' /srv/spreed-webrtc/default.conf && \
+	sed -i 's|;certificate = .*|certificate = /srv/cert.pem|' /srv/spreed-webrtc/default.conf && \
+	sed -i 's|;key = .*|key = /srv/privkey.pem|' /srv/spreed-webrtc/default.conf
+RUN touch /srv/spreed-webrtc/server.conf
 
-# Allow to mount.
-VOLUME /srv/spreed-webrtc
+# Add mount point for extra things.
+RUN mkdir /srv/extra
+VOLUME /srv/extra
 
 # Tell about our service.
 EXPOSE 8080
+EXPOSE 8443
 
-# Define entry point.
-ENTRYPOINT ["/srv/spreed-webrtc/spreed-webrtc-server", "-c /srv/spreed-webrtc/server.conf"]
+# Define entry point with default command.
+ENTRYPOINT ["/bin/sh", "/srv/entrypoint.sh", "-dc", "/srv/spreed-webrtc/default.conf"]
+CMD ["-c", "/srv/spreed-webrtc/server.conf"]