Support SMTP in cloud server

docker/cloud/Dockerfile

@@ -5,7 +5,7 @@ ENV DEBIAN_FRONTEND noninteractive
 RUN \
   apt-get update && \
   add-apt-repository -y ppa:opencpu/opencpu-2.2 && \
-  apt-get install -y opencpu-server rstudio-server
+  apt-get install -y opencpu-server rstudio-server postfix libsasl2-modules
 
 RUN \
   ln -sf /proc/self/fd/1 /var/log/apache2/access.log && \
@@ -16,4 +16,6 @@ RUN \
 # Workaround for rstudio apparmor bug
 RUN echo "server-app-armor-enabled=0" >> /etc/rstudio/rserver.conf
 
-CMD service cron start && /usr/lib/rstudio-server/bin/rserver && apachectl -DFOREGROUND
+COPY startup /startup
+
+ENTRYPOINT ["/startup"]

docker/cloud/startup

@@ -0,0 +1,21 @@
+#!/bin/bash
+set -e
+
+# Setup postfix if not done yet
+if [ -f "/etc/postfix/sasl_passwd" ] && [ ! -f "/etc/postfix/sasl_passwd.db" ]; then
+  echo "Configuring postfix..."
+  postmap /etc/postfix/sasl_passwd
+  chmod 0600 /etc/postfix/sasl_passwd /etc/postfix/sasl_passwd.db
+  echo "relayhost = smtp.mailgun.org" >> /etc/postfix/main.cf
+  echo "smtp_sasl_auth_enable = yes" >> /etc/postfix/main.cf
+  echo "smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd" >> /etc/postfix/main.cf
+  echo "smtp_sasl_security_options = noanonymous" >> /etc/postfix/main.cf
+fi
+
+# Start background services
+service postfix start
+service cron start 
+/usr/lib/rstudio-server/bin/rserver
+
+# Start OpenCPU in foreground (blocking)
+apachectl -DFOREGROUND