Make check_disk_space() use bytes (given new size type options with are converted to bytes, 1k=>1024).

lib/bash/safeguards.sh

@@ -1,4 +1,4 @@
-# This program is copyright 2011 Percona Inc.
+# This program is copyright 2011-2012 Percona Inc.
 # Feedback and improvements are welcome.
 #
 # THIS PROGRAM IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED
@@ -33,46 +33,53 @@ disk_space() {
 # Sub: check_disk_space
 #   Check if there is or will be enough disk space.  Input is a file
 #   with output from <disk_space()>, i.e. `df -P -k`.  The df output
-#   must use 1k blocks, but the mb arg from the user is in MB.
+#   must use 1k blocks, which should be POSIX standard.
 #
 # Arguments:
-#   file      - File with output from <disk_space()>.
-#   mb        - Minimum MB free.
-#   pc        - Minimum percent free.
-#   mb_margin - Add this many MB to the real MB used.
+#   file           - File with output from <disk_space()>.
+#   min_free_bytes - Minimum free bytes.
+#   min_free_pct   - Minimum free percentage.
+#   bytes_margin   - Add this many bytes to the real bytes used.
 #
 # Returns:
 #   0 if there is/will be enough disk space, else 1.
 check_disk_space() {
    local file="$1"
-   local mb="${2:-0}"
-   local pc="${3:-0}"
-   local mb_margin="${4:-0}"
+   local min_free_bytes="${2:-0}"
+   local min_free_pct="${3:-0}"
+   local bytes_margin="${4:-0}"
 
-   # Convert MB to KB because the df output should be in 1k blocks.
-   local kb=$(($mb * 1024))
-   local kb_margin=$(($mb_margin * 1024))
+   # Real/actual bytes used and bytes free.
+   local used_bytes=$(cat "$file" | awk '/^\//{print $3 * 1024}');
+   local free_bytes=$(cat "$file" | awk '/^\//{print $4 * 1024}');
+   local pct_used=$(cat "$file" | awk '/^\//{print $5}' | sed -e 's/%//g');
+   local pct_free=$((100 - $pct_used))
 
-   local kb_used=$(cat "$file" | awk '/^\//{print $3}');
-   local kb_free=$(cat "$file" | awk '/^\//{print $4}');
-   local pc_used=$(cat "$file" | awk '/^\//{print $5}' | sed -e 's/%//g');
+   # Report the real values to the user.
+   local real_free_bytes=$free_bytes
+   local real_pct_free=$pct_free
 
-   if [ "$kb_margin" -gt "0" ]; then
-      local kb_total=$(($kb_used + $kb_free))
+   # If there's a margin, we need to adjust the real values.
+   if [ $bytes_margin -gt 0 ]; then
+      used_bytes=$(($used_bytes + $bytes_margin))
+      free_bytes=$(($free_bytes - $bytes_margin))
+      pct_used=$(awk "BEGIN { printf(\"%d\", ($used_bytes/($used_bytes + $free_bytes)) * 100) }")
 
-      kb_used=$(($kb_used + $kb_margin))
-      kb_free=$(($kb_free - $kb_margin))
-      pc_used=$(awk "BEGIN { printf(\"%d\", $kb_used/$kb_total * 100) }")
+      pct_free=$((100 - $pct_used))
    fi
 
-   local pc_free=$((100 - $pc_used))
+   if [ $free_bytes -lt $min_free_bytes -o $pct_free -lt $min_free_pct ]; then
+      warn "Not enough free disk space:
+    Limit: ${min_free_pct}% free, ${min_free_bytes} bytes free
+   Actual: ${real_pct_free}% free, ${real_free_bytes} bytes free (- $bytes_margin bytes margin)
+"
+      # Print the df that we used.
+      cat "$file" >&2
 
-   if [ "$kb_free" -le "$kb" -o "$pc_free" -le "$pc" ]; then
-      warn "Not enough free disk space: ${pc_free}% free, ${kb_free} KB free; wanted more than ${pc}% free or ${kb} KB free"
-      return 1
+      return 1  # not enough disk space
    fi
 
-   return 0
+   return 0  # disk space is OK
 }
 
 # ###########################################################################

t/lib/bash/safeguards.sh

@@ -18,36 +18,51 @@ is \
    "2" \
    "2-line df output"
 
-check_disk_space "$SAMPLE/diskspace001.txt" 22000 18 >$TMPDIR/out 2>&1
+# Filesystem   1024-blocks     Used Available Capacity  Mounted on
+# /dev/disk0s2   118153176 94409664  23487512    81%    /
+#
+# Those values are in Kb, so:
+#   used     = 94409664 (94.4G) = 96_675_495_936 bytes
+#   free     = 23487512 (23.4G) = 24_051_212_288 bytes
+#   pct free = 100 - 81         = 19 %
+
+# want free - 100, 18 < 19, so this should be ok.
+check_disk_space "$SAMPLE/diskspace001.txt" 24051212188 18 >$TMPDIR/out 2>&1
 is "$?" "0" "Enough disk space"
 is \
    "`cat $TMPDIR/out`" \
    "" \
    "No output if enough disk space"
 
-check_disk_space "$SAMPLE/diskspace001.txt" 24000 18 >$TMPDIR/out 2>&1
+#  want free - 100 is ok, but 20 < 19 is not.
+check_disk_space "$SAMPLE/diskspace001.txt" 24051212188 20 >$TMPDIR/out 2>&1
+is "$?" "1" "Not enough % free"
+
+# want free + 100, so this should fail
+# (real free is 100 bytes under what we want)
+check_disk_space "$SAMPLE/diskspace001.txt" 24051212388 18 >$TMPDIR/out 2>&1
 is "$?" "1" "Not enough MB free"
 cmd_ok \
-   "grep -q '19% free, 23487512 KB free; wanted more than 18% free or 24576000 KB free' $TMPDIR/out" \
+   "grep -q 'Actual: 19% free, 24051212288 bytes free (- 0 bytes margin)' $TMPDIR/out" \
    "Warning if not enough disk space"
 
-check_disk_space "$SAMPLE/diskspace001.txt" 22000 19 >$TMPDIR/out 2>&1
-is "$?" "1" "Not enough % free"
-
 # ###########################################################################
 # Check with a margin (amount we plan to use in the future).
 # ###########################################################################
 
-check_disk_space "$SAMPLE/diskspace001.txt" 22000 18 100
+# want free - 100 + 50 margin, so effectively want free - 50 is ok.
+check_disk_space "$SAMPLE/diskspace001.txt" 24051212188 18 50
 is "$?" "0" "Enough disk space with margin"
 
-check_disk_space "$SAMPLE/diskspace001.txt" 23000 18 100 >$TMPDIR/out 2>&1
+# want free - 100 + 101 margin, so real free is 1 byte under what we want.
+check_disk_space "$SAMPLE/diskspace001.txt" 24051212188 18 101 >$TMPDIR/out 2>&1
 is "$?" "1" "Not enough MB free with margin"
 
-check_disk_space "$SAMPLE/diskspace001.txt" 100 5 20000 >$TMPDIR/out 2>&1
+# want free - 100 + 50 margin ok but %free will be 19 which is < 25.
+check_disk_space "$SAMPLE/diskspace001.txt" 24051212188 25 50 >$TMPDIR/out 2>&1
 is "$?" "1" "Not enough % free with margin"
 cmd_ok \
-   "grep -q '3% free,' $TMPDIR/out" \
+   "grep -q 'Actual:[ ]*19% free,' $TMPDIR/out" \
    "Calculates % free with margin"
 
 # ###########################################################################