Add hardware memory buffer and cache metrics

This patch aims to add two metrics to gather memory buffer and
memory cache information of a physical machine through SNMP
inspector.

Change-Id: Id9b953820a1e38c0f832405359a25015b6f20017
Implements: blueprint hardware-memory-buffer-and-cache-metrics

ceilometer/hardware/inspector/snmp.py

@@ -68,6 +68,8 @@ class SNMPInspector(base.Inspector):
     _memory_avail_real_oid = "1.3.6.1.4.1.2021.4.6.0"
     _memory_total_swap_oid = "1.3.6.1.4.1.2021.4.3.0"
     _memory_avail_swap_oid = "1.3.6.1.4.1.2021.4.4.0"
+    _memory_buffer_oid = "1.3.6.1.4.1.2021.4.14.0"
+    _memory_cached_oid = "1.3.6.1.4.1.2021.4.15.0"
     # Disk OIDs
     _disk_index_oid = "1.3.6.1.4.1.2021.9.1.1"
     _disk_path_oid = "1.3.6.1.4.1.2021.9.1.2"
@@ -207,6 +209,18 @@ class SNMPInspector(base.Inspector):
             'metadata': {},
             'post_op': None,
         },
+        'memory.buffer': {
+            'matching_type': EXACT,
+            'metric_oid': (_memory_buffer_oid, int),
+            'metadata': {},
+            'post_op': None,
+        },
+        'memory.cached': {
+            'matching_type': EXACT,
+            'metric_oid': (_memory_cached_oid, int),
+            'metadata': {},
+            'post_op': None,
+        },
         'disk.size.total': {
             'matching_type': PREFIX,
             'metric_oid': (_disk_size_oid, int),

ceilometer/hardware/pollsters/memory.py

@@ -52,3 +52,11 @@ class MemorySwapTotalPollster(_Base):
 
 class MemorySwapAvailPollster(_Base):
     IDENTIFIER = 'memory.swap.avail'
+
+
+class MemoryBufferPollster(_Base):
+    IDENTIFIER = 'memory.buffer'
+
+
+class MemoryCachedPollster(_Base):
+    IDENTIFIER = 'memory.cached'

ceilometer/tests/hardware/pollsters/base.py

@@ -35,6 +35,8 @@ class FakeInspector(inspector_base.Inspector):
         'cpu.load.15min': (0.55, {}, {}),
         'memory.total': (1000, {}, {}),
         'memory.used': (90, {}, {}),
+        'memory.buffer': (500, {}, {}),
+        'memory.cached': (200, {}, {}),
         'network.incoming.bytes': (90, net_metadata, {}),
         'network.outgoing.bytes': (80, net_metadata, {}),
         'network.outgoing.errors': (1, net_metadata, {}),

ceilometer/tests/hardware/pollsters/test_memory.py

@@ -30,3 +30,13 @@ class TestMemoryPollsters(base.TestPollsterBase):
         self._check_get_samples(memory.MemoryUsedPollster,
                                 'hardware.memory.used',
                                 90, sample.TYPE_GAUGE)
+
+    def test_memory_size_buffer(self):
+        self._check_get_samples(memory.MemoryBufferPollster,
+                                'hardware.memory.buffer',
+                                500, sample.TYPE_GAUGE)
+
+    def test_memory_size_cached(self):
+        self._check_get_samples(memory.MemoryCachedPollster,
+                                'hardware.memory.cached',
+                                200, sample.TYPE_GAUGE)

setup.cfg

@@ -214,6 +214,8 @@ ceilometer.poll.central =
     hardware.network.outgoing.errors = ceilometer.hardware.pollsters.net:OutgoingErrorsPollster
     hardware.memory.total = ceilometer.hardware.pollsters.memory:MemoryTotalPollster
     hardware.memory.used = ceilometer.hardware.pollsters.memory:MemoryUsedPollster
+    hardware.memory.buffer = ceilometer.hardware.pollsters.memory:MemoryBufferPollster
+    hardware.memory.cached = ceilometer.hardware.pollsters.memory:MemoryCachedPollster
     hardware.memory.swap.total = ceilometer.hardware.pollsters.memory:MemorySwapTotalPollster
     hardware.memory.swap.avail = ceilometer.hardware.pollsters.memory:MemorySwapAvailPollster
     hardware.system_stats.cpu.idle = ceilometer.hardware.pollsters.system:SystemCpuIdlePollster