From c32056287704e4ce6e616bbbc37b7be98c44b218 Mon Sep 17 00:00:00 2001
From: Ryan Wilson <wryan@vmware.com>
Date: Tue, 15 Oct 2013 06:09:43 -0700
Subject: [PATCH] Adds locking to completion caches
Previously, completion caches were not thread-safe and multiple
threads could not make calls to python-novaclient simultaneously.
With locking, the completion caches are now thread-safe.
Closes-Bug: #1213958
Change-Id: I201c2ed0f1eb09b1c2a74de96119cbae9ed6f4b0
---
novaclient/base.py | 72 +++++++++++++++++++++++++---------------------
1 file changed, 39 insertions(+), 33 deletions(-)
diff --git a/novaclient/base.py b/novaclient/base.py
index b506286a9..45bea18d8 100644
--- a/novaclient/base.py
+++ b/novaclient/base.py
@@ -25,6 +25,7 @@ import contextlib
import hashlib
import inspect
import os
+import threading
import six
@@ -50,6 +51,7 @@ class Manager(utils.HookableMixin):
etc.) and provide CRUD operations for them.
"""
resource_class = None
+ cache_lock = threading.RLock()
def __init__(self, api):
self.api = api
@@ -90,46 +92,50 @@ class Manager(utils.HookableMixin):
Delete is not handled because listings are assumed to be performed
often enough to keep the cache reasonably up-to-date.
"""
- base_dir = utils.env('NOVACLIENT_UUID_CACHE_DIR',
- default="~/.novaclient")
+ # NOTE(wryan): This lock protects read and write access to the
+ # completion caches
+ with self.cache_lock:
+ base_dir = utils.env('NOVACLIENT_UUID_CACHE_DIR',
+ default="~/.novaclient")
- # NOTE(sirp): Keep separate UUID caches for each username + endpoint
- # pair
- username = utils.env('OS_USERNAME', 'NOVA_USERNAME')
- url = utils.env('OS_URL', 'NOVA_URL')
- uniqifier = hashlib.md5(username.encode('utf-8') +
- url.encode('utf-8')).hexdigest()
+ # NOTE(sirp): Keep separate UUID caches for each username +
+ # endpoint pair
+ username = utils.env('OS_USERNAME', 'NOVA_USERNAME')
+ url = utils.env('OS_URL', 'NOVA_URL')
+ uniqifier = hashlib.md5(username.encode('utf-8') +
+ url.encode('utf-8')).hexdigest()
- cache_dir = os.path.expanduser(os.path.join(base_dir, uniqifier))
+ cache_dir = os.path.expanduser(os.path.join(base_dir, uniqifier))
- try:
- os.makedirs(cache_dir, 0o755)
- except OSError:
- # NOTE(kiall): This is typicaly either permission denied while
- # attempting to create the directory, or the directory
- # already exists. Either way, don't fail.
- pass
+ try:
+ os.makedirs(cache_dir, 0o755)
+ except OSError:
+ # NOTE(kiall): This is typicaly either permission denied while
+ # attempting to create the directory, or the
+ # directory already exists. Either way, don't
+ # fail.
+ pass
- resource = obj_class.__name__.lower()
- filename = "%s-%s-cache" % (resource, cache_type.replace('_', '-'))
- path = os.path.join(cache_dir, filename)
+ resource = obj_class.__name__.lower()
+ filename = "%s-%s-cache" % (resource, cache_type.replace('_', '-'))
+ path = os.path.join(cache_dir, filename)
- cache_attr = "_%s_cache" % cache_type
+ cache_attr = "_%s_cache" % cache_type
- try:
- setattr(self, cache_attr, open(path, mode))
- except IOError:
- # NOTE(kiall): This is typicaly a permission denied while
- # attempting to write the cache file.
- pass
+ try:
+ setattr(self, cache_attr, open(path, mode))
+ except IOError:
+ # NOTE(kiall): This is typicaly a permission denied while
+ # attempting to write the cache file.
+ pass
- try:
- yield
- finally:
- cache = getattr(self, cache_attr, None)
- if cache:
- cache.close()
- delattr(self, cache_attr)
+ try:
+ yield
+ finally:
+ cache = getattr(self, cache_attr, None)
+ if cache:
+ cache.close()
+ delattr(self, cache_attr)
def write_to_completion_cache(self, cache_type, val):
cache = getattr(self, "_%s_cache" % cache_type, None)