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

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."
+}