openstack/nova
Code Issues Proposed changes

Make metadata cache time configurable

Browse Source 
The metadata cache expiration is now a config option.

New Option:
metadata_cache_expiration - Default 15
    Time in seconds to cache metadata objects.

This also adds basic unit tests for the MetadataRequestHandler, which
might be nice to have.

Co-Authored-By: Chet Burgess <cheburge@cisco.com>
Co-Authored-By: Nicolas Simonds <nisimond@cisco.com>
DocImpact
Closes-Bug: 1366139
Change-Id: I4e829ec52cf1445339f325b5895987c82dc7a8f4
This commit is contained in:
Chris St. Pierre
2015-02-25 15:52:34 -06:00
parent 283563ca3d
commit 5a93bfd484
2 changed files with 96 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

22
nova/api/metadata/handler.py
View File

@@ -35,8 +35,6 @@ from nova.openstack.common import memorycache
from nova import utils
from nova import wsgi
CACHE_EXPIRATION = 15 # in seconds
CONF = cfg.CONF
CONF.import_opt('use_forwarded_for', 'nova.api.auth')
@@ -52,7 +50,19 @@ metadata_proxy_opts = [
help='Shared secret to validate proxies Neutron metadata requests'),
]
metadata_opts = [
cfg.IntOpt('metadata_cache_expiration',
default=15,
help='Time in seconds to cache metadata; 0 to disable '
'metadata caching entirely (not recommended). Increasing'
'this should improve response times of the metadata API '
'when under heavy load. Higher values may increase memory'
'usage and result in longer times for host metadata '
'changes to take effect.')
]
CONF.register_opts(metadata_proxy_opts, 'neutron')
CONF.register_opts(metadata_opts)
LOG = logging.getLogger(__name__)
@@ -71,6 +81,7 @@ class MetadataRequestHandler(wsgi.Application):
cache_key = 'metadata-%s' % address
data = self._cache.get(cache_key)
if data:
LOG.debug("Using cached metadata for %s", address)
return data
try:
@@ -78,7 +89,8 @@ class MetadataRequestHandler(wsgi.Application):
except exception.NotFound:
return None
self._cache.set(cache_key, data, CACHE_EXPIRATION)
if CONF.metadata_cache_expiration > 0:
self._cache.set(cache_key, data, CONF.metadata_cache_expiration)
return data
@@ -86,6 +98,7 @@ class MetadataRequestHandler(wsgi.Application):
cache_key = 'metadata-%s' % instance_id
data = self._cache.get(cache_key)
if data:
LOG.debug("Using cached metadata for instance %s", instance_id)
return data
try:
@@ -94,7 +107,8 @@ class MetadataRequestHandler(wsgi.Application):
except exception.NotFound:
return None
self._cache.set(cache_key, data, CACHE_EXPIRATION)
if CONF.metadata_cache_expiration > 0:
self._cache.set(cache_key, data, CONF.metadata_cache_expiration)
return data

80
nova/tests/unit/test_metadata.py
View File

@@ -111,12 +111,13 @@ def fake_InstanceMetadata(stubs, inst_data, address=None,
def fake_request(stubs, mdinst, relpath, address="127.0.0.1",
fake_get_metadata=None, headers=None,
fake_get_metadata_by_instance_id=None):
fake_get_metadata_by_instance_id=None, app=None):
def get_metadata_by_remote_address(address):
return mdinst
app = handler.MetadataRequestHandler()
if app is None:
app = handler.MetadataRequestHandler()
if fake_get_metadata is None:
fake_get_metadata = get_metadata_by_remote_address
@@ -800,6 +801,81 @@ class MetadataHandlerTestCase(test.TestCase):
_test_metadata_path('/2009-04-04/meta-data')
def _metadata_handler_with_instance_id(self, hnd):
expected_instance_id = 'a-b-c-d'
signed = hmac.new(
CONF.neutron.metadata_proxy_shared_secret,
expected_instance_id,
hashlib.sha256).hexdigest()
self.flags(service_metadata_proxy=True, group='neutron')
response = fake_request(
None, self.mdinst,
relpath="/2009-04-04/user-data",
address="192.192.192.2",
fake_get_metadata=False,
app=hnd,
headers={'X-Forwarded-For': '192.192.192.2',
'X-Instance-ID': 'a-b-c-d',
'X-Tenant-ID': 'test',
'X-Instance-ID-Signature': signed})
self.assertEqual(200, response.status_int)
self.assertEqual(base64.b64decode(self.instance['user_data']),
response.body)
@mock.patch.object(base, 'get_metadata_by_instance_id')
def test_metadata_handler_with_instance_id(self, get_by_uuid):
# test twice to ensure that the cache works
get_by_uuid.return_value = self.mdinst
self.flags(metadata_cache_expiration=15)
hnd = handler.MetadataRequestHandler()
self._metadata_handler_with_instance_id(hnd)
self._metadata_handler_with_instance_id(hnd)
self.assertEqual(1, get_by_uuid.call_count)
@mock.patch.object(base, 'get_metadata_by_instance_id')
def test_metadata_handler_with_instance_id_no_cache(self, get_by_uuid):
# test twice to ensure that disabling the cache works
get_by_uuid.return_value = self.mdinst
self.flags(metadata_cache_expiration=0)
hnd = handler.MetadataRequestHandler()
self._metadata_handler_with_instance_id(hnd)
self._metadata_handler_with_instance_id(hnd)
self.assertEqual(2, get_by_uuid.call_count)
def _metadata_handler_with_remote_address(self, hnd):
response = fake_request(
None, self.mdinst,
fake_get_metadata=False,
app=hnd,
relpath="/2009-04-04/user-data",
address="192.192.192.2")
self.assertEqual(200, response.status_int)
self.assertEqual(base64.b64decode(self.instance.user_data),
response.body)
@mock.patch.object(base, 'get_metadata_by_address')
def test_metadata_handler_with_remote_address(self, get_by_uuid):
# test twice to ensure that the cache works
get_by_uuid.return_value = self.mdinst
self.flags(metadata_cache_expiration=15)
hnd = handler.MetadataRequestHandler()
self._metadata_handler_with_remote_address(hnd)
self._metadata_handler_with_remote_address(hnd)
self.assertEqual(1, get_by_uuid.call_count)
@mock.patch.object(base, 'get_metadata_by_address')
def test_metadata_handler_with_remote_address_no_cache(self, get_by_uuid):
# test twice to ensure that disabling the cache works
get_by_uuid.return_value = self.mdinst
self.flags(metadata_cache_expiration=0)
hnd = handler.MetadataRequestHandler()
self._metadata_handler_with_remote_address(hnd)
self._metadata_handler_with_remote_address(hnd)
self.assertEqual(2, get_by_uuid.call_count)
class MetadataPasswordTestCase(test.TestCase):
def setUp(self):