python api: fixes and improvements to MMV wrappers

src/python/mmv.c

@@ -86,6 +86,8 @@ MOD_INIT(cmmv)
     dict_add(dict, "MMV_SEM_INSTANT", MMV_SEM_INSTANT);
     dict_add(dict, "MMV_SEM_DISCRETE", MMV_SEM_DISCRETE);
 
+    dict_add(dict, "MMV_INDOM_NULL", MMV_INDOM_NULL);
+
     dict_add(dict, "MMV_FLAG_NOPREFIX", MMV_FLAG_NOPREFIX);
     dict_add(dict, "MMV_FLAG_PROCESS", MMV_FLAG_PROCESS);
     dict_add(dict, "MMV_FLAG_SENTINEL", MMV_FLAG_SENTINEL);

src/python/pcp/mmv.py

@@ -71,7 +71,7 @@
 """
 
 from pcp.pmapi import pmUnits, pmAtomValue
-from cmmv import MMV_NAMEMAX
+from cmmv import MMV_NAMEMAX, MMV_INDOM_NULL
 
 import ctypes
 from ctypes import Structure, POINTER
@@ -121,7 +121,7 @@ def __init__(self, serial, shorttext='', helptext=''):
         if shorttext is not None and not isinstance(shorttext, bytes):
             shorttext = shorttext.encode('utf-8')
         self.shorttext = shorttext
-        self.helptext = shorttext
+        self.helptext = helptext
         self.serial = serial
 
     def set_instances(self, instances):
@@ -146,20 +146,21 @@ class mmv_metric(Structure):
                 ("shorttext", c_char_p),
                 ("helptext", c_char_p)]
 
-    def __init__(self, name, item, typeof, semantics, dimension, indom=0, shorttext='', helptext=''): # pylint: disable=R0913
+    def __init__(self, name, item, typeof, semantics, dimension, indom=MMV_INDOM_NULL, shorttext='', helptext=''): # pylint: disable=R0913
         Structure.__init__(self)
         if not isinstance(name, bytes):
             name = name.encode('utf-8')
+        self.name = name
         if helptext is not None and not isinstance(helptext, bytes):
             helptext = helptext.encode('utf-8')
+        self.helptext = helptext
         if shorttext is not None and not isinstance(shorttext, bytes):
             shorttext = shorttext.encode('utf-8')
         self.shorttext = shorttext
-        self.helptext = shorttext
+        self.semantics = semantics
         self.typeof = typeof
         self.indom = indom
         self.item = item
-        self.name = name
 
 ##
 # PCP Memory Mapped Value Services
@@ -248,11 +249,11 @@ def start(self):
             On completion of this call, we're all visible to pmdammv.
         """
         count_metrics = len(self._metrics)
-        metrics = (mmv_metric * count_metrics)()
+        metrics = (mmv_metric * count_metrics)() if count_metrics > 0 else None
         for i in range(count_metrics):
             metrics[i] = self._metrics[i]
         count_indoms = len(self._indoms)
-        indoms = (mmv_indom * count_indoms)()
+        indoms = (mmv_indom * count_indoms)() if count_indoms > 0 else None
         for i in range(count_indoms):
             indoms[i] = self._indoms[i]
         self._handle = LIBPCP_MMV.mmv_stats_init(self._name, self._cluster,

src/python/pcp/pmi.py

@@ -18,7 +18,6 @@
 
 # Example use of this module for creating a PCP archive:
 
-        import math
         import time
         import pmapi
         from pcp import pmi
@@ -43,21 +42,21 @@
         log.pmiPutValue("kernel.all.load", "1 minute", "%f" % 0.01)
         log.pmiPutValue("kernel.all.load", "5 minute", "%f" % 0.05)
         log.pmiPutValue("kernel.all.load", "15 minute", "%f" % 0.15)
-        timetuple = math.modf(time.time())
-        useconds = int(timetuple[0] * 1000000)
-        seconds = int(timetuple[1])
-        log.pmiWrite(seconds, useconds)
+        log.pmiWrite(time.time())  # float seconds since epoch, or
+        #log.pmiWrite(seconds, useconds)
+
         del log
 """
 
 from pcp.pmapi import pmID, pmInDom, pmUnits, pmHighResResult, pmResult
 from cpmi import pmiErrSymDict, PMI_MAXERRMSGLEN
-
-import ctypes
-from ctypes import cast, c_int, c_uint, c_longlong, c_char_p, POINTER
+from ctypes import c_int, c_uint, c_longlong, c_char_p
+from ctypes import cast, create_string_buffer, POINTER, CDLL
+from ctypes.util import find_library
+from math import modf
 
 # Performance Co-Pilot PMI library (C)
-LIBPCP_IMPORT = ctypes.CDLL(ctypes.util.find_library("pcp_import"))
+LIBPCP_IMPORT = CDLL(find_library("pcp_import"))
 
 ##
 # PMI Log Import Services
@@ -156,7 +155,7 @@ def __init__(self, *args):
     def __str__(self):
         try:
             error_symbol = pmiErrSymDict[self.code]
-            error_string = ctypes.create_string_buffer(PMI_MAXERRMSGLEN)
+            error_string = create_string_buffer(PMI_MAXERRMSGLEN)
             error_string = LIBPCP_IMPORT.pmiErrStr_r(self.code, error_string,
                                                      PMI_MAXERRMSGLEN)
         except KeyError:
@@ -360,11 +359,15 @@ def pmiHighResWrite(self, sec, nsec):
             raise pmiErr(status)
         return status
 
-    def pmiWrite(self, sec, usec):
+    def pmiWrite(self, sec, usec=None):
         """PMI - flush data to a Log Import archive """
         status = LIBPCP_IMPORT.pmiUseContext(self._ctx)
         if status < 0:
             raise pmiErr(status)
+        if sec and not usec and isinstance(sec, float):
+            ts = modf(sec)
+            sec = ts[1]
+            usec = ts[0] * 1000000
         status = LIBPCP_IMPORT.pmiWrite2(sec, usec)
         if status < 0:
             raise pmiErr(status)