Add PATH_PREFIX environment variable.

Dockerfile

@@ -17,6 +17,7 @@ ENV HANDLERS=diamond.handler.stats_d.StatsdHandler \
     STATSD_HOST=127.0.0.1 \
     STATSD_PORT=8125 \
     INTERVAL=10 \
+    PATH_PREFIX=''\
     DIAMOND_CONF=/etc/diamond/diamond.conf \
     COLLECTORS_CONF_DIR=/etc/diamond/collectors/ \
     COLLECTORS_DIR=/usr/local/share/diamond/collectors/ \

README.md

@@ -17,7 +17,8 @@ GRAPHITE_HOST          address of your graphite instance, defaults to 127.0.0.1.
 GRAPHITE_PORT          port on which your graphite listens on, default to 2003.
 STATSD_HOST            address of your StatsD daemon, defaults to 127.0.0.1.
 STATSD_PORT            port on which StatsD listens on, default to 8125.
-INTERVAL               the interval at which you wish to send metrics, default 10.
+INTERVAL               the interval at which you wish to send metrics, defaults to 10.
+PATH_PREFIX            prefix to all metrics processed by Diamond, defaults to ''
 DIAMOND_CONF           path to diamond config, defaults to /etc/diamond/diamond.conf.
 COLLECTORS_CONF_DIR    path to diamond collectors config dir, defaults to /etc/diamond/collectors.
 COLLECTORS_DIR         path to additional diamond collectors, defaults to /use/local/share/diamond/collectors.

diamond.conf

@@ -107,7 +107,7 @@ hostname          = {HOSTNAME}
 # Path Prefix and Suffix
 # you can use one or both to craft the path where you want to put metrics
 # such as: %(path_prefix)s.$(hostname)s.$(path_suffix)s.$(metric)s
-# path_prefix = servers
+path_prefix = {PATH_PREFIX}
 # path_suffix =
 
 # Path Prefix for Virtual Machines