cpu load plugin: fix test and minor cleanups

This test was failing randomly because it uses a timeout of 0.5 seconds, which
is sometimes not enough to run commands.

Increase the timeout to something large enough so that we don't have timeout
failures when test machine is busy.

Also simplify the whole thing by using python instead of parsing the output
of processes.

slapos/promise/plugin/check_server_cpu_load.py

@@ -4,6 +4,7 @@ from slapos.grid.promise.generic import GenericPromise
 
 import subprocess
 import os
+import psutil
 
 @implementer(interface.IPromise)
 class RunPromise(GenericPromise):
@@ -14,13 +15,9 @@ class RunPromise(GenericPromise):
     self.setPeriodicity(minute=3)
 
   def checkCPULoad(self, tolerance=2.2):
-
     # tolerance=1.5 => accept CPU load up to 1.5 =150%
-    uptime_result = subprocess.check_output('uptime', universal_newlines=True)
-    line = uptime_result.strip().split(' ')
-    load, load5, long_load = line[-3:]
-    long_load = float(long_load.replace(',', '.'))
-    core_count = int(subprocess.check_output('nproc').strip())
+    load, load5, long_load = psutil.getloadavg()
+    core_count = psutil.cpu_count()
     max_load = core_count * tolerance
     if long_load > max_load:
       # display top statistics
@@ -51,9 +48,9 @@ class RunPromise(GenericPromise):
     self.checkCPULoad(threshold or 2.2)
 
   def test(self):
-    # fail if load is high than the threshold for more than 30 minutes
+    # fail if load is higher than the threshold for more than 30 minutes
     return self._test(result_count=10, failure_amount=10)
 
   def anomaly(self):
-    # fail if load is high than the threshold for more than 30 minutes
+    # fail if load is higher than the threshold for more than 30 minutes
     return self._test(result_count=10, failure_amount=10)

slapos/test/promise/plugin/test_check_server_cpu_load.py

@@ -32,7 +32,7 @@ import os
 class TestCheckServerCPULoad(TestPromisePluginMixin):
 
   def setUp(self):
-    TestPromisePluginMixin.setUp(self)
+    super(TestCheckServerCPULoad, self).setUp()
     self.promise_name = "server-cpu-load-promise.py"
 
     content = """from slapos.promise.plugin.check_server_cpu_load import RunPromise
@@ -44,13 +44,10 @@ extra_config_dict = {
     self.writePromise(self.promise_name, content)
 
   def test_check_cpu_load_run(self):
-    self.configureLauncher()
+    self.configureLauncher(timeout=5)
     self.launcher.run()
     result = self.getPromiseResult(self.promise_name)
     if result['result']['failed']:
       self.assertTrue("CPU load is high" in result['result']['message'])
     else:
       self.assertEqual("CPU load is OK", result['result']['message'].strip())
-
-if __name__ == '__main__':
-  unittest.main()