[Kimchi-devel] [PATCH v4 1/5] storagepool: refactor _get_pool_xml()

Zhou Zheng Sheng zhshzhou at linux.vnet.ibm.com
Thu Jan 2 09:59:11 UTC 2014


Thanks Sheldon. I applied all your suggestions and submitted v5 patch
series.

on 2013/12/31 19:35, Sheldon wrote:
> Reviewed-by: ShaoHe Feng <shaohef at linux.vnet.ibm.com>
> 
> On 12/31/2013 02:39 PM, Zhou Zheng Sheng wrote:
>> In src/kimchi/model.py, _get_pool_xml() is to generate libvirt storage
>> pool XML definition from arguments provided by the POST data (a JSON
>> dict). It has to support various types of pool such as dir, netfs and
>> logical. Now it uses "if ... elif ... elif" to check the requested type
>> of pool and go in to the respective branch and generates the correct
>> XML. It also performs some preparations such as create target directory.
>> This is OK for now but in future we'll have more types of pool, and add
>> more validation and preparation code. So it needs a little refactor
>>
>> In this patch we define StoragePoolDef object along with a factory
>> methoed named "create". The factory method instantiates DirPoolDef,
>> NetfsPoolDef or LogicalPoolDef according to the requested pool type.
>> Then we can call defObj.prepare() to check NFS mount and iSCSI
>> login/password. We can inspect defObj.xml to get the generated XML for
>> the respective poolType.
>>
>> v2 -> v3
>>    Call pool.build() for netfs, dir and logical pool. So do not need to
>>    create dirs any longer. Since NFS and iSCSI pool need validation,
>>    extract a StoragePoolDef object with "prepare" and "get_xml" methods.
>>
>> v3 -> v4
>>    Turn 'defObj.get_xml()' into a lazily calculated property
>> 'defObj.xml'.
>>
>> Signed-off-by: Zhou Zheng Sheng <zhshzhou at linux.vnet.ibm.com>
>> ---
>>   src/kimchi/model.py | 124
>> +++++++++++++++++++++++++++++++++++++++-------------
>>   1 file changed, 94 insertions(+), 30 deletions(-)
>>
>> diff --git a/src/kimchi/model.py b/src/kimchi/model.py
>> index a6790b8..107aa6c 100644
>> --- a/src/kimchi/model.py
>> +++ b/src/kimchi/model.py
>> @@ -994,7 +994,9 @@ class Model(object):
>>
>>               if params['type'] == 'kimchi-iso':
>>                   task_id = self._do_deep_scan(params)
>> -            xml = _get_pool_xml(**params)
>> +            poolDef = StoragePoolDef.create(params)
>> +            poolDef.prepare()
>> +            xml = poolDef.xml
>>           except KeyError, key:
>>               raise MissingParameter(key)
>>
>> @@ -1009,7 +1011,7 @@ class Model(object):
>>                   return name
>>
>>               pool = conn.storagePoolDefineXML(xml, 0)
>> -            if params['type'] in ['logical', 'dir']:
>> +            if params['type'] in ['logical', 'dir', 'netfs']:
>>                   pool.build(libvirt.VIR_STORAGE_POOL_BUILD_NEW)
>>                   # autostart dir and logical storage pool created
>> from kimchi
>>                   pool.setAutostart(1)
>> @@ -1430,28 +1432,77 @@ class LibvirtVMScreenshot(VMScreenshot):
>>           finally:
>>               os.close(fd)
>>
>> -def _get_pool_xml(**kwargs):
>> -    # Required parameters
>> -    # name:
>> -    # type:
>> -    # path:
>> -    # nfspath:
>> -    if kwargs['type'] == 'dir':
>> +
>> +class StoragePoolDef(object):
>> +    @classmethod
>> +    def create(cls, poolArgs):
>> +        for klass in cls.__subclasses__():
>> +            if poolArgs['type'] == klass.poolType:
>> +                return klass(poolArgs)
>> +        raise OperationFailed('Unsupported pool type: %s' %
>> poolArgs['type'])
>> +
>> +    def __init__(self, poolArgs):
>> +        self.poolArgs = poolArgs
>> +        self._xml = None
>> +
>> +    def prepare(self):
>> +        ''' Validate pool arguments and perform preparations.
>> Operation which
>> +        would cause side effect should be put here. Subclasses can
>> optionally
>> +        override this method, or it always succeeds by default. '''
>> +        pass
>> +
>> +    @property
>> +    def xml(self):
>> +        if self._xml is None:
>> +            self._xml = self._get_xml()
>> +        return self._xml
>> +
>> +    def _get_xml(self):
>> +        ''' Subclasses have to override this method to actually
>> generate the
>> +        storage pool XML definition. '''
>> +        raise OperationFailed('_get_xml is not implemented: %s' % self)
>> +
>> +
>> +class DirPoolDef(StoragePoolDef):
>> +    poolType = 'dir'
>> +
>> +    def _get_xml(self):
>> +        # Required parameters
>> +        # name:
>> +        # type:
>> +        # path:
>>           xml = """
>> -        <pool type='%(type)s'>
>> +        <pool type='dir'>
>>             <name>%(name)s</name>
>>             <target>
>>               <path>%(path)s</path>
>>             </target>
>>           </pool>
>> -       """
>> -    elif kwargs['type'] == 'netfs':
>> -        path = '/var/lib/kimchi/nfs_mount/' + kwargs['name'];
>> -        if not os.path.exists(path):
>> -           os.makedirs(path)
>> -        kwargs.update({'path': path})
>> +        """ % self.poolArgs
>> +        return xml
>> +
>> +
>> +class NetfsPoolDef(StoragePoolDef):
>> +    poolType = 'netfs'
>> +
>> +    def __init__(self, poolArgs):
>> +        super(NetfsPoolDef, self).__init__(poolArgs)
>> +        self.path = '/var/lib/kimchi/nfs_mount/' + self.poolArgs['name']
>> +
>> +    def prepare(self):
>> +        # TODO Verify the NFS export can be actually mounted.
>> +        pass
>> +
>> +    def _get_xml(self):
>> +        # Required parameters
>> +        # name:
>> +        # type:
>> +        # nfsserver:
>> +        # nfspath:
>> +        poolArgs = copy.deepcopy(self.poolArgs)
>> +        poolArgs['path'] = self.path
>>           xml = """
>> -        <pool type='%(type)s'>
>> +        <pool type='netfs'>
>>             <name>%(name)s</name>
>>             <source>
>>               <host name='%(nfsserver)s'/>
>> @@ -1461,13 +1512,31 @@ def _get_pool_xml(**kwargs):
>>               <path>%(path)s</path>
>>             </target>
>>           </pool>
>> -        """
>> -    elif kwargs['type'] == 'logical':
>> -        path = '/var/lib/kimchi/logical_mount/' + kwargs['name'];
>> -        if not os.path.exists(path):
>> -           os.makedirs(path)
>> +        """ % poolArgs
>> +        return xml
>> +
>> +
>> +class LogicalPoolDef(StoragePoolDef):
>> +    poolType = 'logical'
>> +
>> +    def __init__(self, poolArgs):
>> +        super(LogicalPoolDef, self).__init__(poolArgs)
>> +        self.path = '/var/lib/kimchi/logical_mount/' +
>> self.poolArgs['name']
>> +
>> +    def _get_xml(self):
>> +        # Required parameters
>> +        # name:
>> +        # type:
>> +        # devices:
>> +        poolArgs = copy.deepcopy(self.poolArgs)
>> +        devices = []
>> +        for device_path in poolArgs['devices']:
>> +            devices.append('<device path="%s" />' % device_path)
>> +
>> +        poolArgs.update({'devices': ''.join(devices),
>> +                         'path': self.path})
>>           xml = """
>> -        <pool type='%(type)s'>
>> +        <pool type='logical'>
>>           <name>%(name)s</name>
>>               <source>
>>               %(devices)s
>> @@ -1476,14 +1545,9 @@ def _get_pool_xml(**kwargs):
>>               <path>%(path)s</path>
>>           </target>
>>           </pool>
>> -        """
>> -        devices = ''
>> -        for device_path in kwargs['devices']:
>> -            devices += "<device path=\""+device_path+"\" />"
>> +        """ % poolArgs
>> +        return xml
>>
>> -        kwargs.update({'devices': devices})
>> -        kwargs.update({'path': path})
>> -    return xml % kwargs
>>
>>   def _get_volume_xml(**kwargs):
>>       # Required parameters
> 
> 


-- 
Thanks and best regards!

Zhou Zheng Sheng / 周征晟
E-mail: zhshzhou at linux.vnet.ibm.com
Telephone: 86-10-82454397




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