add generic UDP reporter

reporters/udp.sh

@@ -0,0 +1,38 @@
+#!/bin/sh
+
+defaults () {
+  if [ -z $UDP_HOST ]; then
+    UDP_HOST="127.0.0.1"
+  fi
+  if [ -z $UDP_DELIMITER ]; then
+    UDP_DELIMITER="="
+  fi
+}
+
+start () {
+  if [ -z $UDP_PORT ]; then
+    echo "Error: udp requires \$UDP_PORT to be specified"
+    return 1
+  fi
+
+  if [ -n "$UDP_PREFIX" ]; then
+    prefix="$UDP_PREFIX."
+  fi
+  if [ -n "$UDP_DELIMITER" ]; then
+    delimiter="$UDP_DELIMITER"
+  fi
+}
+
+report () {
+  local metric=$1
+  local value=$2
+  echo "$prefix$metric$delimiter$value" | nc -u -w0 $UDP_HOST $UDP_PORT
+}
+
+docs () {
+  echo "Send data to any service using UDP."
+  echo "UDP_HOST=$UDP_HOST"
+  echo "UDP_PORT=$UDP_PORT"
+  echo "UDP_PREFIX=$UDP_PREFIX"
+  echo "UDP_DELIMITER=\"$UDP_DELIMITER\""
+}