Made services installation optional during build

You can user `ENV` directive in Dockerfile to disable the installation
for some services or change `image/buildconfig`.

The flags are :

DISABLE_SSHD
DISABLE_CRON
DISABLE_SYSLOG

image/buildconfig

@@ -1,3 +1,9 @@
 export LC_ALL=C
 export DEBIAN_FRONTEND=noninteractive
 minimal_apt_get_install='apt-get install -y --no-install-recommends'
+
+# Default services
+# Set 1 to the service you want to disable
+export DISABLE_SYSLOG=${DISABLE_SYSLOG:-0}
+export DISABLE_SSH=${DISABLE_SSH:-0}
+export DISABLE_CRON=${DISABLE_CRON:-0}

image/services/cron/cron.sh

@@ -0,0 +1,17 @@
+#!/bin/bash
+set -e
+source /bd_build/buildconfig
+set -x
+
+$minimal_apt_get_install cron
+mkdir /etc/service/cron
+chmod 600 /etc/crontab
+cp /bd_build/services/cron/cron.runit /etc/service/cron/run
+
+## Remove useless cron entries.
+# Checks for lost+found and scans for mtab.
+rm -f /etc/cron.daily/standard
+rm -f /etc/cron.daily/upstart
+rm -f /etc/cron.daily/dpkg
+rm -f /etc/cron.daily/password
+rm -f /etc/cron.weekly/fstrim

image/services/sshd/sshd.sh

@@ -0,0 +1,25 @@
+#!/bin/bash
+set -e
+source /bd_build/buildconfig
+set -x
+
+SSHD_BUILD_PATH=/bd_build/services/sshd
+
+## Install the SSH server.
+$minimal_apt_get_install openssh-server
+mkdir /var/run/sshd
+mkdir /etc/service/sshd
+touch /etc/service/sshd/down
+cp $SSHD_BUILD_PATH/sshd.runit /etc/service/sshd/run
+cp $SSHD_BUILD_PATH/sshd_config /etc/ssh/sshd_config
+cp $SSHD_BUILD_PATH/00_regen_ssh_host_keys.sh /etc/my_init.d/
+
+## Install default SSH key for root and app.
+mkdir -p /root/.ssh
+chmod 700 /root/.ssh
+chown root:root /root/.ssh
+cp $SSHD_BUILD_PATH/keys/insecure_key.pub /etc/insecure_key.pub
+cp $SSHD_BUILD_PATH/keys/insecure_key /etc/insecure_key
+chmod 644 /etc/insecure_key*
+chown root:root /etc/insecure_key*
+cp $SSHD_BUILD_PATH/enable_insecure_key /usr/sbin/

image/services/syslog-ng/syslog-ng.sh

@@ -0,0 +1,24 @@
+#!/bin/bash
+set -e
+source /bd_build/buildconfig
+set -x
+
+SYSLOG_NG_BUILD_PATH=/bd_build/services/syslog-ng
+
+## Install a syslog daemon.
+$minimal_apt_get_install syslog-ng-core
+mkdir /etc/service/syslog-ng
+cp $SYSLOG_NG_BUILD_PATH/syslog-ng.runit /etc/service/syslog-ng/run
+mkdir -p /var/lib/syslog-ng
+cp $SYSLOG_NG_BUILD_PATH/syslog_ng_default /etc/default/syslog-ng
+touch /var/log/syslog
+chmod u=rw,g=r,o= /var/log/syslog
+cp $SYSLOG_NG_BUILD_PATH/syslog-ng.conf /etc/syslog-ng/syslog-ng.conf
+
+## Install syslog to "docker logs" forwarder.
+mkdir /etc/service/syslog-forwarder
+cp $SYSLOG_NG_BUILD_PATH/syslog-forwarder.runit /etc/service/syslog-forwarder/run
+
+## Install logrotate.
+$minimal_apt_get_install logrotate
+cp $SYSLOG_NG_BUILD_PATH/logrotate_syslogng /etc/logrotate.d/syslog-ng

image/system_services.sh

@@ -19,54 +19,11 @@ ln -s /etc/container_environment.sh /etc/profile.d/
 ## Install runit.
 $minimal_apt_get_install runit
 
-## Install a syslog daemon.
-$minimal_apt_get_install syslog-ng-core
-mkdir /etc/service/syslog-ng
-cp /bd_build/runit/syslog-ng /etc/service/syslog-ng/run
-mkdir -p /var/lib/syslog-ng
-cp /bd_build/config/syslog_ng_default /etc/default/syslog-ng
-touch /var/log/syslog
-chmod u=rw,g=r,o= /var/log/syslog
-cp /bd_build/config/syslog-ng.conf /etc/syslog-ng/syslog-ng.conf
-
-## Install syslog to "docker logs" forwarder.
-mkdir /etc/service/syslog-forwarder
-cp /bd_build/runit/syslog-forwarder /etc/service/syslog-forwarder/run
-
-## Install logrotate.
-$minimal_apt_get_install logrotate
-cp /bd_build/config/logrotate_syslogng /etc/logrotate.d/syslog-ng
+## Install a syslog daemon and logrotate.
+[ "$DISABLE_SYSLOG" -eq 0 ] && /bd_build/services/syslog-ng/syslog-ng.sh
 
 ## Install the SSH server.
-$minimal_apt_get_install openssh-server
-mkdir /var/run/sshd
-mkdir /etc/service/sshd
-touch /etc/service/sshd/down
-cp /bd_build/runit/sshd /etc/service/sshd/run
-cp /bd_build/config/sshd_config /etc/ssh/sshd_config
-cp /bd_build/00_regen_ssh_host_keys.sh /etc/my_init.d/
-
-## Install default SSH key for root and app.
-mkdir -p /root/.ssh
-chmod 700 /root/.ssh
-chown root:root /root/.ssh
-cp /bd_build/insecure_key.pub /etc/insecure_key.pub
-cp /bd_build/insecure_key /etc/insecure_key
-chmod 644 /etc/insecure_key*
-chown root:root /etc/insecure_key*
-cp /bd_build/bin/enable_insecure_key /usr/sbin/
+[ "$DISABLE_SSH" -eq 0 ] && /bd_build/services/sshd/sshd.sh
 
 ## Install cron daemon.
-$minimal_apt_get_install cron
-mkdir /etc/service/cron
-chmod 600 /etc/crontab
-cp /bd_build/runit/cron /etc/service/cron/run
-
-## Remove useless cron entries.
-# Checks for lost+found and scans for mtab.
-rm -f /etc/cron.daily/standard
-rm -f /etc/cron.daily/upstart
-rm -f /etc/cron.daily/dpkg
-rm -f /etc/cron.daily/password
-rm -f /etc/cron.weekly/fstrim
-
+[ "$DISABLE_CRON" -eq 0 ] && /bd_build/services/cron/cron.sh