code cleaup. add disk_usage reporter. add handling for docs(). various tweaks and fixes

lib/utils/functions.sh

@@ -1,19 +1,11 @@
 #!/bin/sh
 
-# http://stackoverflow.com/a/1369211/183097
-copy_function () {
-  declare -F $1 > /dev/null || return 1
-  eval "$(echo "${2}()"; declare -f ${1} | tail -n +2)"
-}
-
 is_function () {
   [ "`type -t $1`" == 'function' ]
 }
 
-OS_TYPE=$(case "$OSTYPE" in
-  (solaris*) echo solaris;;
-  (darwin*)  echo osx;;
-  (linux*)   echo linux;;
-  (bsd*)     echo bsd;;
-  (*)        echo unknown;;
-esac)
+# http://stackoverflow.com/a/1369211/183097
+copy_function () {
+  declare -F $1 > /dev/null || return 1
+  eval "$(echo "${2}()"; declare -f ${1} | tail -n +2)"
+}

lib/utils/os.sh

@@ -0,0 +1,15 @@
+#!/bin/sh
+
+declare -r OS_TYPE=$(case "$OSTYPE" in
+  (solaris*) echo solaris;;
+  (darwin*)  echo osx;;
+  (linux*)   echo linux;;
+  (bsd*)     echo bsd;;
+  (*)        echo unknown;;
+esac)
+
+is_solaris () { [ $OS_TYPE == 'solaris' ]; }
+is_osx ()     { [ $OS_TYPE == 'osx' ]; }
+is_linux ()   { [ $OS_TYPE == 'solaris' ]; }
+is_bsd ()     { [ $OS_TYPE == 'bsd']; }
+is_unknown () { [ $OS_TYPE == 'unknown' ]; }

metrics/cpu.sh

@@ -1,5 +1,9 @@
 #!/bin/sh
 
 collect () {
-  echo $(ps aux | awk {'sum+=$3;print sum'} | tail -n 1)
+  echo $(ps aux | awk '{sum+=$3} END {printf "%.1f\n", sum}' | tail -n 1)
+}
+
+docs () {
+  echo "CPU load percentage."
 }

metrics/disk_usage.sh

@@ -0,0 +1,19 @@
+#!/bin/sh
+
+if [ -z $DISK_USAGE_MOUNTPOINT ]; then
+  if is_osx; then
+    DISK_USAGE_MOUNTPOINT="/dev/disk1"
+  else
+    DISK_USAGE_MOUNTPOINT="/dev/vda"
+  fi
+fi
+
+collect () {
+  echo $(df | awk -v disk_regexp="^$DISK_USAGE_MOUNTPOINT" \
+              '$0 ~ disk_regexp {printf "%.1f", $5}')
+}
+
+docs () {
+  echo "Disk usage percentage for a file system at a given mount point."
+  echo "\$DISK_USAGE_MOUNTPOINT=$DISK_USAGE_MOUNTPOINT"
+}

metrics/memory.sh

@@ -1,21 +1,24 @@
 #!/bin/sh
 
-if [ $OS_TYPE == "osx" ]; then
+if is_osx; then
 
-  # FIXME: total_memory leaks out
-  total_memory=$(sysctl -n hw.memsize)
+  declare -r __memory_os_memsize=$(sysctl -n hw.memsize)
 
   collect () {
-    echo $(vm_stat | awk -v total_memory=$total_memory \
-              'BEGIN {FS="   *"; pages=0}
-               /Pages (free|inactive|speculative)/ {pages+=$2}
-               END {printf "%.2f", 100 - (pages * 4096) / total_memory * 100.0}')
+    echo $(vm_stat | awk -v total_memory=$__memory_os_memsize \
+            'BEGIN {FS="   *"; pages=0}
+             /Pages (free|inactive|speculative)/ {pages+=$2}
+             END {printf "%.1f", 100 - (pages * 4096) / total_memory * 100.0}')
   }
 
 else
 
   collect () {
-    echo $(free | awk '/buffers\/cache/{printf "%.2f", $4 / ($3 + $4) * 100.0}')
+    echo $(free | awk '/buffers\/cache/{printf "%.1f", 100 - $4 / ($3 + $4) * 100.0}')
   }
 
-fi
+fi
+
+docs () {
+  echo "Percentage of used memory."
+}

metrics/swap.sh

@@ -1,15 +1,19 @@
 #!/bin/sh
 
-if [ $OS_TYPE == "osx" ]; then
+if is_osx; then
 
   collect () {
-    echo $(sysctl -n vm.swapusage | awk '{printf "%.2f", $6 / $3 * 100.0}')
+    echo $(sysctl -n vm.swapusage | awk '{printf "%.1f", $6 / $3 * 100.0}')
   }
 
 else
 
   collect () {
-    echo $(free | awk '/Swap/{printf "%.2f", $3/$2 * 100.0;}')
+    echo $(free | awk '/Swap/{printf "%.1f", $3/$2 * 100.0}')
   }
 
-fi
+fi
+
+docs () {
+  echo "Percentage of used swap space."
+}

reporters/stathat.sh

@@ -4,4 +4,9 @@ report () {
   METRIC=$1
   VALUE=$2
   curl -d "stat=$METRIC&ezkey=$API_KEY&value=$VALUE" http://api.stathat.com/ez
+}
+
+docs () {
+  echo "Send data to StatHat (https://www.stathat.com)."
+  echo "\$API_KEY=<ez_key>"
 }

reporters/stdout.sh

@@ -4,4 +4,8 @@ report () {
   METRIC=$1
   VALUE=$2
   echo $METRIC: $VALUE
+}
+
+docs () {
+  echo "Print to standard output (e.g. the TTY you're running the script in)"
 }

sysmetricsd.sh

@@ -4,43 +4,67 @@
 INTERVAL=2
 REPORTER=stdout
 
-# init
-source ./lib/utils.sh
-_METRICS=()
+#init
+__METRICS=()
+
+# load utils
+for util in ./lib/utils/*.sh; do source $util; done
 
 # load reporter
 source ./reporters/${REPORTER}.sh
-copy_function report _r_${REPORTER}_report
-unset -f init report terminate
+copy_function init      __r_${REPORTER}_init
+copy_function report    __r_${REPORTER}_report
+copy_function terminate __r_${REPORTER}_terminate
+copy_function docs      __r_${REPORTER}_docs
+unset -f init report terminate docs
 
 # load metrics
-for file in $(find ./metrics -type f -name '*.sh'); do
-  source $file
+for file in ./metrics/*.sh; do
   filename=$(basename $file)
   metric=${filename%.*}
-  copy_function collect _m_${metric}_collect
-  _METRICS+=($metric)
-  unset -f init collect terminate
+
+  # soruce file and copy functions
+  source $file
+  copy_function init      __m_${metric}_init
+  copy_function collect   __m_${metric}_collect
+  copy_function terminate __m_${metric}_terminate
+  copy_function docs      __m_${metric}_docs
+  unset -f init collect terminate docs
+
+  # register metric
+  __METRICS+=($metric)
 done
 
 # init metrics
-for metric in ${_METRICS[@]}; do
-  if ! is_function _m_${metric}_init; then
+for metric in ${__METRICS[@]}; do
+  if ! is_function __m_${metric}_init; then
     continue
   fi
 
-  _m_${metric}_init
+  __m_${metric}_init
+done
+
+# print docs for metrics
+echo "Available metrics:"
+for metric in ${__METRICS[@]}; do
+  if ! is_function __m_${metric}_docs; then
+    continue
+  fi
+
+  echo "[$metric]"
+  __m_${metric}_docs
+  echo
 done
 
 # collect metrics
 while true; do
-  for metric in ${_METRICS[@]}; do
-    if ! is_function _m_${metric}_collect; then
+  for metric in ${__METRICS[@]}; do
+    if ! is_function __m_${metric}_collect; then
       continue
     fi
 
-    result=$(_m_${metric}_collect)
-    _r_${REPORTER}_report $metric $result
+    result=$(__m_${metric}_collect)
+    __r_${REPORTER}_report $metric $result
   done
 
   sleep $INTERVAL