問題： 使用“cinder show”查詢一個(gè)不存在的volumeid吸祟，使用時(shí)間很長(zhǎng)瑟慈。
[root@node1 ~]# time cinder show aksjdfkajsdkfjsakdf
ERROR: No volume with a name or ID of 'aksjdfkajsdkfjsakdf' exists.
real 0m35.374s
user 0m0.855s
sys 0m0.107s
分析：
1. cinderclient.v2.shell.do_show說(shuō)明
指令“cinder show”的入口函數(shù)是cinderclient.v2.shell.do_show：
@utils.arg('volume',
metavar='<volume>',
help='Name or ID of volume.')
def do_show(cs, args):
"""Shows volume details."""
info = dict()
volume = utils.find_volume(cs, args.volume)
info.update(volume._info)
if 'readonly' in info['metadata']:
info['readonly'] = info['metadata']['readonly']
info.pop('links', None)
# 打印字典
utils.print_dict(info,
formatters=['metadata', 'volume_image_metadata',
'attachments'])
@utils.arg 是用于定義參數(shù)的標(biāo)簽桃移。
指令參數(shù)根據(jù)必填、選填分為兩種：
- 1)
@utils.arg('volume', metavar='<volume>', help='Name or ID of volume.')
必填參數(shù)葛碧，使用時(shí)不用帶參數(shù)名借杰。例如”cinder show 123123”，這里的123123就是<volume>进泼。 - 2)
@utils.arg('--tenant', type=str, dest='tenant', nargs='?', metavar='<tenant>', help='Display information from single tenant (Admin only).')
選填參數(shù)蔗衡，名字多了個(gè)破折號(hào) --，指令使用時(shí)必須帶參數(shù)名乳绕。例如”cinder list --tenant 123123”绞惦。
根據(jù)參數(shù)值分類：
- 1)@utils.arg('volume', metavar='<volume>', nargs='+', help='Name or ID of volume or volumes to delete.')
如果設(shè)置nargs='+'，代表值為數(shù)組型洋措，以空格分隔济蝉，輸入1個(gè)以上。如”cinder delete 111 2222 3333”呻纹，刪除volume_id=111堆生、volume_id=222、volume_id=333 的volume雷酪。
此外還有nargs='*' 表示參數(shù)可設(shè)置零個(gè)或多個(gè)淑仆；nargs=' '+' 表示參數(shù)可設(shè)置一個(gè)或多個(gè)；nargs='?' 表示參數(shù)可設(shè)置零個(gè)或一個(gè)哥力。 - 2)@utils.arg('--metadata', type=str, nargs='*', metavar='<key=value>', default=None, help='Snapshot metadata key and value pairs. Default=None.')
設(shè)置metavar='<key=value>'蔗怠，值為鍵值對(duì)形式。比如”cinder storage-create --metadata storage_protocol='fc' storage_ip='172.24.1.21' ”
@utils.arg定義的參數(shù)會(huì)傳入def do_show(cs, args)的args吩跋，通過(guò)args.xxxx來(lái)調(diào)用寞射。
2.utils.find_volume(cs, args.volume) 說(shuō)明
cinderclient.utils.find_volume：
def find_volume(cs, volume):
"""Get a volume by name or ID."""
return find_resource(cs.volumes, volume)
def find_resource(manager, name_or_id):
"""Helper for the _find_* methods."""
# first try to get entity as integer id
try:
if isinstance(name_or_id, int) or name_or_id.isdigit():
return manager.get(int(name_or_id))
except exceptions.NotFound:
pass
else:
# now try to get entity as uuid
try:
uuid.UUID(name_or_id)
return manager.get(name_or_id)
except (ValueError, exceptions.NotFound):
pass
if sys.version_info <= (3, 0):
name_or_id = encodeutils.safe_decode(name_or_id)
try:
try:
resource = getattr(manager, 'resource_class', None)
name_attr = resource.NAME_ATTR if resource else 'name'
return manager.find(**{name_attr: name_or_id})
except exceptions.NotFound:
pass
# finally try to find entity by human_id
try:
return manager.find(human_id=name_or_id)
except exceptions.NotFound:
msg = "No %s with a name or ID of '%s' exists." % \
(manager.resource_class.__name__.lower(), name_or_id)
raise exceptions.CommandError(msg)
except exceptions.NoUniqueMatch:
msg = ("Multiple %s matches found for '%s', use an ID to be more"
" specific." % (manager.resource_class.__name__.lower(),
name_or_id))
raise exceptions.CommandError(msg)
調(diào)用了cinderclient.utils.find_resource(manager, name_or_id)方法，find_resource的邏輯是：
① 如果id是int型锌钮，直接調(diào)用VolumeManager.get桥温。如果沒查到，走下一步梁丘。
② id轉(zhuǎn)換成uuid侵浸，直接調(diào)用VolumeManager.get。如果沒查到氛谜，走下一步掏觉。
③ 如果volumes類定義了NAME_ATTR屬性，用{name_attr: name_or_id}作為條件調(diào)用VolumeManager.find查詢值漫。如果沒查到澳腹，走下一步。
④ 用{human_id：name_or_id}作為條件調(diào)用VolumeManager.find查詢。
3.VolumeManager.get說(shuō)明
cinderclient.v2.volumes.VolumeManager#get
def get(self, volume_id):
"""Get a volume.
:param volume_id: The ID of the volume to get.
:rtype: :class:`Volume`
"""
return self._get("/volumes/%s" % volume_id, "volume")
self._get調(diào)用cinderclient.base.Manager#_get
def _get(self, url, response_key=None):
resp, body = self.api.client.get(url)
if response_key:
return self.resource_class(self, body[response_key], loaded=True,
resp=resp)
else:
return self.resource_class(self, body, loaded=True, resp=resp)
self.resource_class在cinderclient.v2.volumes.VolumeManager定義：resource_class = Volume酱塔。所以返回值是body[response_key]轉(zhuǎn)換出的cinderclient.v2.volumes.Volume(base.Resource)對(duì)象沥邻。
4.VolumeManager.find說(shuō)明
VolumeManager.find調(diào)用cinderclient.base.ManagerWithFind#findall(self, **kwargs)：
def find(self, **kwargs):
"""
Find a single item with attributes matching ``**kwargs``.
This isn't very efficient for search options which require the
Python side filtering(e.g. 'human_id')
"""
matches = self.findall(**kwargs)
num_matches = len(matches)
if num_matches == 0:
msg = "No %s matching %s." % (self.resource_class.__name__, kwargs)
raise exceptions.NotFound(404, msg)
elif num_matches > 1:
raise exceptions.NoUniqueMatch
else:
matches[0].append_request_ids(matches.request_ids)
return matches[0]
def findall(self, **kwargs):
"""
Find all items with attributes matching ``**kwargs``.
This isn't very efficient for search options which require the
Python side filtering(e.g. 'human_id')
"""
# Want to search for all tenants here so that when attempting to delete
# that a user like admin doesn't get a failure when trying to delete
# another tenant's volume by name.
search_opts = {'all_tenants': 1}
# Pass 'name' or 'display_name' search_opts to server filtering to
# increase search performance.
if 'name' in kwargs:
search_opts['name'] = kwargs['name']
elif 'display_name' in kwargs:
search_opts['display_name'] = kwargs['display_name']
found = common_base.ListWithMeta([], None)
searches = kwargs.items()
listing = self.list(search_opts=search_opts)
found.append_request_ids(listing.request_ids)
# Not all resources attributes support filters on server side
# (e.g. 'human_id' doesn't), so when doing findall some client
# side filtering is still needed.
for obj in listing:
try:
if all(getattr(obj, attr) == value
for (attr, value) in searches):
found.append(obj)
except AttributeError:
continue
return found
findall的邏輯是：
① 檢查kwargs字典key有無(wú)'name'，有則加入查詢條件search_opts羊娃。
② 檢查kwargs字典key有無(wú)'display_name'谋国，有則加入查詢條件search_opts。
③ self.list(search_opts=search_opts) 用查詢條件查詢VolumeManager.list迁沫。如果前兩步都為否芦瘾，則查詢條件為空，那么list方法將查詢所有卷信息返回集畅。cinder的db api有配置單次查詢最大條數(shù)是1000（配置項(xiàng)osapi_max_limit近弟，默認(rèn)1000），而我們的卷目前有8k多條挺智，其中2528條可用的祷愉，所以得查三次才能查出所有卷記錄。這占用時(shí)間很長(zhǎng)赦颇。
④ 對(duì)第三步查出的卷列表做遍歷二鳄，用kwargs字典的key和value檢查，符合getattr(obj, attr) == value的記錄添加進(jìn)found數(shù)組返回媒怯。
5.human_id說(shuō)明
上文介紹cinderclient.utils.find_volume方法里用{human_id：name_or_id}作為條件調(diào)用VolumeManager.find查詢订讼。human_id是什么？我們可以看到cinderclient.v3.volumes.Volume繼承自cinderclient.apiclient.base.Resource扇苞，而Resource類里定義了HUMAN_ID = False和NAME_ATTR = 'name'欺殿，Resource類里還有一個(gè)human_id(self)屬性方法。
cinderclient.apiclient.base.Resource：
class Resource(RequestIdMixin):
"""Base class for OpenStack resources (tenant, user, etc.).
This is pretty much just a bag for attributes.
"""
HUMAN_ID = False
NAME_ATTR = 'name'
@property
def human_id(self):
"""Human-readable ID which can be used for bash completion.
"""
if self.NAME_ATTR in self.__dict__ and self.HUMAN_ID:
return strutils.to_slug(getattr(self, self.NAME_ATTR))
return None
根據(jù)human_id(self)屬性方法的邏輯鳖敷，我們可以這么理解：如果在cinderclient.v3.volumes.Volume類里有定義HUMAN_ID = True脖苏，且定義了類的名字屬性NAME_ATTR ，那么volume.human_id=strutils.to_slug(getattr(self, self.NAME_ATTR))定踱。strutils.to_slug這個(gè)方法的作用是把參數(shù)轉(zhuǎn)換成小寫棍潘、移除non-word的字符（比如中文）、空格轉(zhuǎn)連字符（-）崖媚、刪除前后端空格亦歉。
那么現(xiàn)在我們基本明白human_id的作用了：
human_id是用于查詢字符格式不標(biāo)準(zhǔn)的NAME_ATTR 的記錄。db里可能存的NAME_ATTR包含了非不正常的字符至扰，比如中文啊鳍徽、多出的空格啊资锰，cinderclient指令無(wú)法傳遞正確編碼的參數(shù)到服務(wù)端查詢敢课。所以通過(guò)volume.human_id=strutils.to_slug(getattr(self, self.NAME_ATTR))方法設(shè)置human_id的值為NAME_ATTR（即name）轉(zhuǎn)換格式后的值，這樣對(duì)human_id來(lái)查詢，就能查到了直秆。比如下面的例子：
數(shù)據(jù)庫(kù)里有個(gè)volume的display_name= miaomiao喵喵貓濒募，
但是在linux顯示亂碼：
如果直接使用” cinder show miaomiao喵喵貓 ” 來(lái)查詢，會(huì)提示錯(cuò)誤 “ERROR: 'utf8' codec can't decode byte 0xdf in position 8: invalid continuation byte”圾结，無(wú)法使用name來(lái)查詢：
但只要我們?cè)赾inderclient.v3.volumes.Volume類里設(shè)置HUMAN_ID=True瑰剃，strutils.to_slug(u'miaomiao喵喵貓') == 'miaomiao'，即可使用`”cinder show miaomiao”查到結(jié)果。
但是我們看cinderclient.v3.volumes.Volume沒有復(fù)寫HUMAN_ID，根據(jù)屬性方法 human_id(self)的邏輯署拟，如果self.HUMAN_ID==False丧枪，返回None作為volume的human_id屬性值。所以够掠，如果用{human_id：name_or_id}作為條件調(diào)用VolumeManager.find查詢，getattr(obj, attr) == value是一定為False，find結(jié)果一定為空宝磨。
既然cinderclient.v3.volumes.Volume的human_id=None，為什么utils.find_resource(manager, name_or_id, **kwargs) 最后一步還要用human_id查詢呢盅安？用human_id查詢是不是有什么特別的用途唤锉？
我用HUMAN_ID搜索cinderclient整個(gè)項(xiàng)目，發(fā)現(xiàn)只有cinderclient.apiclient.base.Resource里有用到别瞭，其它Resource的子類都沒有復(fù)寫窿祥。
用human_id搜索cinderclient整個(gè)項(xiàng)目，也沒用對(duì)human_id特別賦值的地方蝙寨。
這樣看來(lái)壁肋，HUMAN_ID在cinderclient整個(gè)項(xiàng)目里的調(diào)用值都為False，human_id將始終未None籽慢，用{human_id：name_or_id}作為條件調(diào)用VolumeManager.find查詢?cè)诋?dāng)前的cinderclient里實(shí)在毫無(wú)意義浸遗。
解決方案：
可以考慮把{human_id：name_or_id}查詢屏蔽。
