First version available on the (simple) mem plugin

2 files changed, 116 insertions, 63 deletions

diff --git a/glances/plugins/mem/model.py b/glances/plugins/mem/model.py
index 52ceed0c..c3d6b5c5 100644
--- a/glances/plugins/mem/model.py
+++ b/glances/plugins/mem/model.py
@@ -12,12 +12,16 @@
 from glances.globals import iterkeys
 from glances.plugins.plugin.model import GlancesPluginModel
 
-import psutil
-
 # Fields description
 fields_description = {
-    'total': {'description': 'Total physical memory available.', 'unit': 'bytes', 'min_symbol': 'K'},
+    'total': {
+        'getter': 'psutil.virtual_memory',
+        'description': 'Total physical memory available.',
+        'unit': 'bytes',
+        'min_symbol': 'K'
+    },
     'available': {
+        'getter': 'psutil.virtual_memory',
         'description': 'The actual amount of available memory that can be given instantly \
 to processes that request more memory in bytes; this is calculated by summing \
 different memory values depending on the platform (e.g. free + buffers + cached on Linux) \
@@ -26,49 +30,62 @@ and it is supposed to be used to monitor actual memory usage in a cross platform
         'min_symbol': 'K',
     },
     'percent': {
+        'getter': 'psutil.virtual_memory',
         'description': 'The percentage usage calculated as (total - available) / total * 100.',
         'unit': 'percent',
     },
-    'used': {
-        'description': 'Memory used, calculated differently depending on the platform and \
-designed for informational purposes only.',
-        'unit': 'bytes',
-        'min_symbol': 'K',
-    },
-    'free': {
-        'description': 'Memory not being used at all (zeroed) that is readily available; \
-note that this doesn\'t reflect the actual memory available (use \'available\' instead).',
-        'unit': 'bytes',
-        'min_symbol': 'K',
-    },
     'active': {
+        'getter': 'psutil.virtual_memory',
         'description': '*(UNIX)*: memory currently in use or very recently used, and so it is in RAM.',
         'unit': 'bytes',
         'min_symbol': 'K',
     },
     'inactive': {
+        'getter': 'psutil.virtual_memory',
         'description': '*(UNIX)*: memory that is marked as not used.',
         'unit': 'bytes',
         'min_symbol': 'K',
         'short_name': 'inacti',
     },
     'buffers': {
+        'getter': 'psutil.virtual_memory',
         'description': '*(Linux, BSD)*: cache for things like file system metadata.',
         'unit': 'bytes',
         'min_symbol': 'K',
         'short_name': 'buffer',
     },
-    'cached': {'description': '*(Linux, BSD)*: cache for various things.', 'unit': 'bytes', 'min_symbol': 'K'},
+    'cached': {
+        'getter': 'psutil.virtual_memory',
+        'description': '*(Linux, BSD)*: cache for various things.',
+        'unit': 'bytes',
+        'min_symbol': 'K'
+    },
     'wired': {
+        'getter': 'psutil.virtual_memory',
         'description': '*(BSD, macOS)*: memory that is marked to always stay in RAM. It is never moved to disk.',
         'unit': 'bytes',
         'min_symbol': 'K',
     },
     'shared': {
+        'getter': 'psutil.virtual_memory',
         'description': '*(BSD)*: memory that may be simultaneously accessed by multiple processes.',
         'unit': 'bytes',
         'min_symbol': 'K',
     },
+    'free': {
+        'getter': 'compute',
+        'description': 'Memory not being used at all (zeroed) that is readily available; \
+note that this doesn\'t reflect the actual memory available (use \'available\' instead).',
+        'unit': 'bytes',
+        'min_symbol': 'K',
+    },
+    'used': {
+        'getter': 'compute',
+        'description': 'Memory used, calculated differently depending on the platform and \
+designed for informational purposes only.',
+        'unit': 'bytes',
+        'min_symbol': 'K',
+    },
 }
 
 # SNMP OID
@@ -115,25 +132,42 @@ class PluginModel(GlancesPluginModel):
     def __init__(self, args=None, config=None):
         """Init the plugin."""
         super(PluginModel, self).__init__(
-            args=args, config=config, items_history_list=items_history_list, fields_description=fields_description
+            args=args,
+            config=config,
+            items_history_list=items_history_list,
+            fields_description=fields_description
         )
 
         # We want to display the stat in the curse interface
         self.display_curse = True
 
+    def free(self, stats):
+        """Return the free memory compute parameter"""
+        # Use the 'free'/htop calculation
+        # free=available+buffer+cached
+        ret = stats['available']
+        if hasattr(stats, 'buffers'):
+            ret += stats['buffers']
+        if hasattr(stats, 'cached'):
+            ret += stats['cached']
+        return ret
+
+    def used(self, stats):
+        """Return the used memory compute parameter"""
+        return stats['total'] - stats['free']
+
     @GlancesPluginModel._check_decorator
     @GlancesPluginModel._log_result_decorator
     def update(self):
         """Update RAM memory stats using the input method."""
+
         # Init new stats
         stats = self.get_init_value()
 
         if self.input_method == 'local':
-            # Update stats using the standard system lib
-            # Grab MEM using the psutil virtual_memory method
-            vm_stats = psutil.virtual_memory()
-
-            # Get all the memory stats (copy/paste of the psutil documentation)
+            #
+            # Under the wood, Glances use psutil.virtual_memory() to get the memory stats
+            #
             # total: total physical memory available.
             # available: the actual amount of available memory that can be given instantly
             # to processes that request more memory in bytes; this is calculated by summing
@@ -151,32 +185,8 @@ class PluginModel(GlancesPluginModel):
             # cached: (Linux, BSD): cache for various things.
             # wired: (BSD, macOS): memory that is marked to always stay in RAM. It is never moved to disk.
             # shared: (BSD): memory that may be simultaneously accessed by multiple processes.
-            self.reset()
-            for mem in [
-                'total',
-                'available',
-                'percent',
-                'used',
-                'free',
-                'active',
-                'inactive',
-                'buffers',
-                'cached',
-                'wired',
-                'shared',
-            ]:
-                if hasattr(vm_stats, mem):
-                    stats[mem] = getattr(vm_stats, mem)
-
-            # Use the 'free'/htop calculation
-            # free=available+buffer+cached
-            stats['free'] = stats['available']
-            if hasattr(stats, 'buffers'):
-                stats['free'] += stats['buffers']
-            if hasattr(stats, 'cached'):
-                stats['free'] += stats['cached']
-            # used=total-free
-            stats['used'] = stats['total'] - stats['free']
+            stats = self.update_local(stats)
+
         elif self.input_method == 'snmp':
             # Update stats using SNMP
             if self.short_system_name in ('windows', 'esxi'):
diff --git a/glances/plugins/plugin/model.py b/glances/plugins/plugin/model.py
index 3c2eb4b4..af6993b5 100644
--- a/glances/plugins/plugin/model.py
+++ b/glances/plugins/plugin/model.py
@@ -16,6 +16,9 @@ I am your father...
 import re
 import copy
 
+# PsUtil is call "dynamically", so the import should not be removed
+import psutil
+
 from glances.globals import iterkeys, itervalues, listkeys, mean, nativestr, json_dumps, json_dumps_dictlist
 from glances.actions import GlancesActions
 from glances.history import GlancesHistory
@@ -111,6 +114,21 @@ class GlancesPluginModel(object):
 
         # Init stats description
         self.fields_description = fields_description
+        if fields_description:
+            # Return a list of getter (external functions to run to get the stats)
+            self.getters = list(set([fields_description[i]['getter'] for i in fields_description
+                                if (i in fields_description and
+                                    'getter' in fields_description[i] and
+                                    fields_description[i]['getter'] not in ('compute'))]))
+            # Return a list of internal functions to run to compute the stats
+            # Computation is done after the getters
+            self.computes = [i for i in fields_description
+                             if (i in fields_description and
+                                 'getter' in fields_description[i] and
+                                 fields_description[i]['getter'] in ('compute'))]
+        else:
+            self.getters = []
+            self.computes = []
 
         # Init the stats
         self.stats_init_value = stats_init_value
@@ -175,6 +193,31 @@ class GlancesPluginModel(object):
             logger.debug("Reset history for plugin {} (items: {})".format(self.plugin_name, reset_list))
             self.stats_history.reset()
 
+    def update_getters(self, stats):
+        """Return the stats updated from the getters functions."""
+        for g in self.getters:
+            # For each "getter", the Python function is called
+            g_call = getattr(globals()[g.split('.')[0]], g.split('.')[1])()
+            # The result is stored in the stats dict
+            # (only if the field is in the self.fields_description)
+            for name in [f for f in g_call._fields if f in self.fields_description]:
+                stats[name] = getattr(g_call, name)
+        return stats
+
+    def update_computes(self, stats):
+        """Return the stats updated from the computes functions."""
+        for c in self.computes:
+            stats[c] = getattr(self, c)(stats)
+        return stats
+
+    def update_local(self, stats):
+        """Return the stats updated by getters and computes."""
+        # Update the stats from the getters
+        stats = self.update_getters(stats)
+        # Update the stats from the computes
+        stats = self.update_computes(stats)
+        return stats
+
     def update_stats_history(self):
         """Update stats history."""
         # Build the history
@@ -483,9 +526,9 @@ class GlancesPluginModel(object):
                         'splittable': False,
                         'hidden': False,
                         '_zero': self.views[i[self.get_key()]][key]['_zero']
-                        if i[self.get_key()] in self.views
-                        and key in self.views[i[self.get_key()]]
-                        and 'zero' in self.views[i[self.get_key()]][key]
+                        if i[self.get_key()] in self.views and
+                        key in self.views[i[self.get_key()]] and
+                        'zero' in self.views[i[self.get_key()]][key]
                         else True,
                     }
                     ret[i[self.get_key()]][key] = value
@@ -962,9 +1005,9 @@ class GlancesPluginModel(object):
 
         # Check if unit is defined and get the short unit char in the unit_sort dict
         if (
-            key in self.fields_description
-            and 'unit' in self.fields_description[key]
-            and self.fields_description[key]['unit'] in fields_unit_short
+            key in self.fields_description and
+            'unit' in self.fields_description[key] and
+            self.fields_description[key]['unit'] in fields_unit_short
         ):
             # Get the shortname
             unit_short = fields_unit_short[self.fields_description[key]['unit']]
@@ -973,9 +1016,9 @@ class GlancesPluginModel(object):
 
         # Check if unit is defined and get the unit type unit_type dict
         if (
-            key in self.fields_description
-            and 'unit' in self.fields_description[key]
-            and self.fields_description[key]['unit'] in fields_unit_type
+            key in self.fields_description and
+            'unit' in self.fields_description[key] and
+            self.fields_description[key]['unit'] in fields_unit_type
         ):
             # Get the shortname
             unit_type = fields_unit_type[self.fields_description[key]['unit']]
@@ -984,9 +1027,9 @@ class GlancesPluginModel(object):
 
         # Is it a rate ? Yes, compute it thanks to the time_since_update key
         if (
-            key in self.fields_description
-            and 'rate' in self.fields_description[key]
-            and self.fields_description[key]['rate'] is True
+            key in self.fields_description and
+            'rate' in self.fields_description[key] and
+            self.fields_description[key]['rate'] is True
         ):
             value = self.stats[key] // self.stats['time_since_update']
         else:
@@ -1010,8 +1053,8 @@ class GlancesPluginModel(object):
             msg_value = (
                 msg_template.format(
                     self.auto_unit(int(value), min_symbol=self.fields_description[key]['min_symbol']), unit_short
-                )
-                + trailer
+                ) +
+                trailer
             )
         else:
             msg_value = msg_template.format(int(value), unit_short) + trailer
@@ -1055,7 +1098,7 @@ class GlancesPluginModel(object):
         """
         symbols = ('K', 'M', 'G', 'T', 'P', 'E', 'Z', 'Y')
         if min_symbol in symbols:
-            symbols = symbols[symbols.index(min_symbol) :]
+            symbols = symbols[symbols.index(min_symbol):]
         prefix = {
             'Y': 1208925819614629174706176,
             'Z': 1180591620717411303424,