Add support to persist SDR cache to file

This allows a project to persist the frequently expensive SDR
cache run to run.

Change-Id: I8208edec3178fb229db0572b17f4b161ca6d8d1d

pyghmi/ipmi/command.py

@@ -138,6 +138,7 @@ class Command(object):
         # operations without pushing the async complexities up the stack
         self.onlogon = onlogon
         self.bmc = bmc
+        self._sdrcachedir = None
         self._sdr = None
         self._oem = None
         self._oemknown = False
@@ -165,6 +166,17 @@ class Command(object):
                                                 kg=kg,
                                                 privlevel=privlevel)
 
+    def set_sdr_cachedir(self, path):
+        """Register use of a directory for SDR cache.
+
+        Takes the given directory and uses it to persist SDR cache run to run.
+        This can greatly improve performance across runs.
+
+        :param path:
+        :return:
+        """
+        self._sdrcachedir = path
+
     def register_key_handler(self, callback, type='tls'):
         """Assign a verification handler for a public key
 
@@ -541,7 +553,7 @@ class Command(object):
         # sdr timestamp, our data version revision, aux firmware revision,
         # and oem defined field
         if self._sdr is None:
-            self._sdr = sdr.SDR(self)
+            self._sdr = sdr.SDR(self, self._sdrcachedir)
         return self._sdr
 
     def get_event_log(self, clear=False):
@@ -588,8 +600,7 @@ class Command(object):
         returns an iterable of string descriptions
         """
         yield "System"
-        if self._sdr is None:
-            self._sdr = sdr.SDR(self)
+        self.init_sdr()
         for fruid in sorted(self._sdr.fru):
             yield self._sdr.fru[fruid].fru_name
         self.oem_init()
@@ -605,8 +616,7 @@ class Command(object):
         self.oem_init()
         if component == 'System':
             return self._get_zero_fru()
-        if self._sdr is None:
-            self._sdr = sdr.SDR(self)
+        self.init_sdr()
         for fruid in self._sdr.fru:
             if self._sdr.fru[fruid].fru_name == component:
                 return self._oem.process_fru(fru.FRU(
@@ -649,8 +659,7 @@ class Command(object):
         """
         self.oem_init()
         yield ("System", self._get_zero_fru())
-        if self._sdr is None:
-            self._sdr = sdr.SDR(self)
+        self.init_sdr()
         for fruid in sorted(self._sdr.fru):
             fruinf = fru.FRU(
                 ipmicmd=self, fruid=fruid, sdr=self._sdr.fru[fruid]).info
@@ -712,8 +721,7 @@ class Command(object):
         :param sensorname:  Name of the desired sensor
         :returns: sdr.SensorReading object
         """
-        if self._sdr is None:
-            self._sdr = sdr.SDR(self)
+        self.init_sdr()
         for sensor in self._sdr.get_sensor_numbers():
             if self._sdr.sensors[sensor].name == sensorname:
                 rsp = self.raw_command(command=0x2d, netfn=4, data=(sensor,))
@@ -910,8 +918,7 @@ class Command(object):
 
         :returns: Iterator of sdr.SensorReading objects
         """
-        if self._sdr is None:
-            self._sdr = sdr.SDR(self)
+        self.init_sdr()
         for sensor in self._sdr.get_sensor_numbers():
             rsp = self.raw_command(command=0x2d, netfn=4, data=(sensor,))
             if 'error' in rsp:
@@ -930,8 +937,7 @@ class Command(object):
 
         :returns: Iterator of dicts describing each sensor
         """
-        if self._sdr is None:
-            self._sdr = sdr.SDR(self)
+        self.init_sdr()
         for sensor in self._sdr.get_sensor_numbers():
             yield {'name': self._sdr.sensors[sensor].name,
                    'type': self._sdr.sensors[sensor].sensor_type}

pyghmi/ipmi/sdr.py

@@ -30,11 +30,18 @@
 # skipped for now
 
 import math
+import os
 import pyghmi.constants as const
 import pyghmi.exceptions as exc
 import pyghmi.ipmi.private.constants as ipmiconst
+import random
+import string
 import struct
 import weakref
+try:
+    import cPickle as pickle
+except ImportError:
+    import pickle
 
 TYPE_UNKNOWN = 0
 TYPE_SENSOR = 1
@@ -604,10 +611,11 @@ class SDR(object):
 
     :param ipmicmd: A Command class object
     """
-    def __init__(self, ipmicmd):
+    def __init__(self, ipmicmd, cachedir=None):
         self.ipmicmd = weakref.proxy(ipmicmd)
         self.sensors = {}
         self.fru = {}
+        self.cachedir = cachedir
         self.read_info()
 
     def read_info(self):
@@ -679,7 +687,31 @@ class SDR(object):
             return
         except KeyError:
             pass
+        cachefilename = None
         self.broken_sensor_ids = {}
+        if self.cachedir:
+            cachefilename = 'sdrcache.{0}.{1}.{2}.{3}.{4}.{5}'.format(
+                self.mfg_id, self.prod_id, self.device_id, self.fw_major,
+                self.fw_minor, modtime)
+            cachefilename = os.path.join(self.cachedir, cachefilename)
+        if cachefilename and os.path.isfile(cachefilename):
+            with open(cachefilename, 'r') as cfile:
+                csdrs = pickle.load(cfile)
+                for sdrdata in csdrs:
+                    self.add_sdr(sdrdata)
+                for sid in self.broken_sensor_ids:
+                    try:
+                        del self.sensors[sid]
+                    except KeyError:
+                        pass
+                shared_sdrs[
+                    (self.fw_major, self.fw_minor, self.mfg_id, self.prod_id,
+                     self.device_id, modtime)] = {
+                    'sensors': self.sensors,
+                    'fru': self.fru,
+                }
+                return
+        sdrraw = [] if cachefilename else None
         while recid != 0xffff:  # per 33.12 Get SDR command, 0xffff marks end
             newrecid = 0
             currlen = 0
@@ -724,6 +756,8 @@ class SDR(object):
                 if (offset + size) > currlen:
                     size = currlen - offset
             self.add_sdr(sdrdata)
+            if sdrraw is not None:
+                sdrraw.append(sdrdata)
             offset = 0
             if size != 0xff:
                 size = 5
@@ -740,6 +774,12 @@ class SDR(object):
             'sensors': self.sensors,
             'fru': self.fru,
         }
+        if cachefilename:
+            suffix = ''.join(
+                random.choice(string.ascii_lowercase) for _ in range(12))
+            with open(cachefilename + '.' + suffix, 'w') as cfile:
+                pickle.dump(sdrraw, cfile)
+            os.rename(cachefilename + '.' + suffix, cachefilename)
 
     def get_sensor_numbers(self):
         for number in self.sensors: