openstack如何扩展API之一：新添加API
（文章来自作者维护的社区微信公众号【虚拟化云计算】)
一。创建API资源模块
为新的Restful资源写一个controller实现标准操作（如index、create、delete…），以及其它定制的动作。
定义extensions.V21APIExtensionBase 的一个子类，此子类实现get_resources和get_controller_extensions方法，建立一个新的资源或控制器扩展。添加一个文件：
nova/api/openstack/compute/extended_comcat api/openstack/compute/extended_common.py |
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"""The instance interface extension."""
import webob
from webob import exc
from nova.api.openstack.compute.schemas import extended_common
from nova.api.openstack import extensions
from nova.api.openstack import wsgi
from nova.api import validation
from nova import exception
from nova import db
from nova.i18n import _
from nova.policies import extended_common as extended_common_policies
from oslo_log import log as logging
LOG = logging.getLogger(__name__)
ALIAS = 'os-extended-common'
class ExtendedCommonController(wsgi.Controller):
def __init__(self):
super(ExtendedCommonController, self).__init__()
@extensions.expected_errors(404)
@validation.schema(extended_common.create)
def create(self, req, body):
context = req.environ['nova.context']
context.can(extended_common_policies.BASE_POLICY_NAME)
context.can(extended_common_policies.POLICY_ROOT % 'create')
LOG.info(body)
@extensions.expected_errors(())
def gettest(self, req):
context = req.environ['nova.context']
return dict(controller={'myhost': 'compute1'} )
class ExtendedCommon(extensions.V21APIExtensionBase):
"""extended common support."""
name = "ExtendedCommon"
alias = ALIAS
version = 1
def get_resources(self):
member_actions = {'action': 'POST'}
collection_actions = {'gettest': 'GET'}
resources = [
extensions.ResourceExtension(
ALIAS,
ExtendedCommonController(),
collection_actions=collection_actions,
member_actions=member_actions)]
return resources
def get_controller_extensions(self):
return []
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这里我们建立了一个新的文件：extended_common.py；在里面建立了类ExtendedCommon。其ALIAS='os-extended-common'。这些后面会使用到。
二。规定API调用到的数据结构
nova/api/openstack/compute/schemas/extended_common.py |
|
from nova.api.validation import parameter_types
create = {
'type': 'object',
'properties': {
'MyTest': {
'type': 'object',
'properties': {
'myhost': parameter_types.hostname,
},
'additionalProperties': False,
},
},
'additionalProperties': False,
}
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三。注册API
nova/policies/__init__.py |
|
from nova.policies import extended_common
......
def list_rules():
return itertools.chain(
......
extended_common.list_rules(),
......
|
nova/policies/extended_common.py |
|
from oslo_policy import policy
from nova.policies import base
BASE_POLICY_NAME = 'os_compute_api:os-extended-common'
POLICY_ROOT = 'os_compute_api:os-extended-common:%s'
extended_common_policies = [
policy.RuleDefault(
name=BASE_POLICY_NAME,
check_str=base.RULE_ADMIN_API),
policy.RuleDefault(
name=POLICY_ROOT % 'create',
check_str=base.RULE_ANY),
policy.RuleDefault(
name=POLICY_ROOT % 'discoverable',
check_str=base.RULE_ANY),
policy.RuleDefault(
name=POLICY_ROOT % 'show',
check_str=base.RULE_ANY),
]
def list_rules():
return extended_common_policies
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四。添加entry_points
nova.egg-info/entry_points.txt |
extended_common = nova.api.openstack.compute.extended_common:ExtendedCommon |
五。查看API是否被导出
# systemctl restart nova-api
# nova list-extensions
应该能看到os-extended-common。
六。测试
测试程序 |
|
import json
import urllib2
CONTROLLER_HOSTNAME='controller'
class Opthttp(object):
def __init__(self, passwd):
self.token = None
self.tenant = None
self.token, self.tenant = self.__get_token(passwd)
def __get_token(self, passwd):
url = 'http://%s:5000/v2.0/tokens' % CONTROLLER_HOSTNAME
values = {"auth": {"tenantName": "admin", "passwordCredentials": {"username": "admin", "password": passwd}}}
data = self.http_post(url, values)
token = data['access']['token']['id']
tenant = data['access']['token']['tenant']['id']
return token, tenant
def http_get(self, url):
req = urllib2.Request(url)
req.add_header('X-Auth-Token', self.token)
response = urllib2.urlopen(req)
data = response.read()
data = json.loads(data)
return data
def _do_http_post(self, method, url, body):
if body:
jdata = json.dumps(body)
req = urllib2.Request(url, jdata)
else:
req = urllib2.Request(url, None)
req.add_header('Content-Type', 'application/json')
req.add_header('Accept', 'application/json')
if self.token:
req.add_header('X-Auth-Token', self.token)
req.get_method = lambda: method
response = urllib2.urlopen(req)
data = response.read()
if data != '':
data = json.loads(data)
return data
def http_post(self, url, body):
return self._do_http_post('POST', url, body)
def http_put(self, url, body):
return self._do_http_post('PUT', url, body)
def http_delete(self, url, body):
return self._do_http_post('DELETE', url, body)
url = '%s/5ad08373b2814d16833959228c714329/os-extended-common' %('http://127.0.0.1:8774/v2.1')
body = {"MyTest": {'myhost': 'compute2'}}
ret = Opthttp('cloud').http_post(url, body)
url = '%s/5ad08373b2814d16833959228c714329/os-extended-common/gettest' %('http://127.0.0.1:8774/v2.1')
controller = Opthttp('cloud').http_get(url)
print controller
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