[PATCH] Added new cpu.py module to exposes cpu information. It has two methods: - usage - gets the average cpu usage, returns per cpu percentage for user, nice, system, idle, iowait, etc. - jiffies - fetches cpu statistics from /proc/stat and returns them

[Greg Swift]

Adjusted to original submission:
- support additional CPU values if a system has them
- reduce some of the processing time by using a generator
- attempted to minimize repeated string and list operations

Signed-off-by: Greg Swift <gregswift-***@public.gmane.org>
---
func/minion/modules/cpu.py | 118 ++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 118 insertions(+), 0 deletions(-)
create mode 100644 func/minion/modules/cpu.py

diff --git a/func/minion/modules/cpu.py b/func/minion/modules/cpu.py
new file mode 100644
index 0000000..56b8431
--- /dev/null
+++ b/func/minion/modules/cpu.py
@@ -0,0 +1,118 @@
+
+#
+# Copyright 2011
+# Tomas Edwardsson <tommi-***@public.gmane.org>
+#
+# This software may be freely redistributed under the terms of the GNU
+# general public license.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+import func_module
+from timemodule import sleep
+from func.minion.codes import FuncException
+
+SAMPLE_TIMER = 5
+MAX_SAMPLE_TIMER = 18
+
+class CpuModule(func_module.FuncModule):
+ version = "0.0.1"
+ api_version = "0.0.1"
+ description = "Gathering CPU related information"
+
+ def jiffies(self):
+
+ # Which fields we are parsing from /proc stat
+ fields = ['user', 'nice', 'system', 'idle', 'iowait', 'irq', 'softirq', 'steal', 'guest']
+
+ # Returning struct
+ res = {}
+
+ # Open the /proc/stat
+ try:
+ stat_fd = open("/proc/stat", "r")
+ except Exception, e:
+ raise FuncException("Unable to open /proc/stat: %s" % (e))
+
+ # Run through the contents of /proc/stat
+ for statline in stat_fd.readlines():
+ # We don't care about non CPU stuff
+ if statline[0:3] != 'cpu':
+ break
+ statline = (statline.split())
+
+ # split cpu name and its stats
+ cpu, stat = statline[0], statline[1:]
+
+ # Total jiffies for this cpu
+ total = 0
+
+ # Create the dictionary
+ res[cpu] = {}
+
+ # Run through stats, matching with named fields
+ for i in xrange(1, (len(stat))):
+ try:
+ res[cpu][fields[i]] = int(stat[i])
+ except IndexError:
+ break
+ total += int(stat[i])
+
+ # Record total jiffies
+ res[cpu]['total'] = total
+
+ return res
+
+ def usage(self, sampletime=SAMPLE_TIMER):
+ """
+ Returns percentage CPU utilization in an given
+ timeperiod.
+ """
+ if int(sampletime) > MAX_SAMPLE_TIMER:
+ raise FuncException("sampletime maximum is %s" % MAX_SAMPLE_TIMER)
+
+ # Get CPU statistics
+ prestat = self.jiffies()
+
+ # Wait for some activity
+ sleep(int(sampletime))
+
+ # Re fetch CPU statistics
+ poststat = self.jiffies()
+
+ # Dict to store results
+ results = {}
+
+ # Run through each CPU entry
+ for cpu in prestat.keys():
+ total = poststat[cpu]['total'] - prestat[cpu]['total']
+ results[cpu] = {}
+ for k in prestat[cpu].keys():
+ if k == 'total': continue
+ # Calculate the percentage
+ results[cpu][k] = float(poststat[cpu][k] - prestat[cpu][k]) / float(total) * 100
+ return results
+
+ def register_method_args(self):
+ """
+ Register the CPU method arguments
+ """
+ return{
+ 'usage':{
+ 'args':{
+ 'sampletime':{
+ 'type': 'int',
+ 'default': SAMPLE_TIMER,
+ 'optional':True,
+ 'description':'How long to sample CPU usage',
+ },
+ },
+ 'description':'Gather CPU data over period and return percent averages',
+ },
+ 'jiffies':{
+ 'args':{},
+ 'description':'Fetch the CPU jiffies from /proc/stat',
+ },
+ }