rally/doc/specs/in-progress/refactor_scenario_utils.rst
Yair Fried 836808cb5e [spec] Refactoring scenario utils
Change-Id: I3bae09bc6528d5a019e0c42ebf946aafb31abf07
2016-02-22 19:44:38 +02:00

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This work is licensed under a Creative Commons Attribution 3.0 Unported
License.
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=========================================================
Refactor scenarios' utils into central os-services tree
=========================================================
It's hard to reuse code from different scenario utils in areas like context.
Problem description
===================
* Code that wraps openstack services from different scenario utils is
difficult to reuse in context plugins (or, sometimes in different scenarios
plugins), which causes code duplications.
* Wrappers don't fully integrate with the current structure (example: network
operations need to alternate between calls to utils and calls to network
wrappers).
* It is impossible to do versioning of current utils which makes them
hard to reuse as a base for out of tree plugins.
* Is is not possible to have separated common functionality (e.g. network) and
specific implementation features (nova network and neutron)
Proposed change
===============
Group all service related utils under a single tree accessible from all areas
of the project.
Also, inheritance structure in scenarios is problematic. This would be a great
opportunity to move to composition.
Alternatives
------------
None comes to mind.
Implementation
==============
Current source tree
-------------------
.. code-block::
rally/
|
+-- plugins/
+-- openstack/
| +-- scenarios/
| | |
| | +-- nova/
| | | |
| | | +-- servers.py
| | | |
| | | +-- utils.py
| | |
| | +-- ...
| +-- wrappers/
| |
| +-- keystone.py
| |
| +-- network.py
keystone scenarios use plugins/openstack/scenarios/keystone/utils.py
.. code-block:: python
@atomic.action_timer("keystone.create_tenant")
def _tenant_create(self, name_length=10, **kwargs):
"""Creates keystone tenant with random name.
:param name_length: length of generated (random) part of name
:param kwargs: Other optional parameters
:returns: keystone tenant instance
"""
name = self._generate_random_name(length=name_length)
return self.admin_clients("keystone").tenants.create(name, **kwargs)
.. code-block:: python
class KeystoneBasic(kutils.KeystoneScenario):
"""Basic benchmark scenarios for Keystone."""
@validation.number("name_length", minval=10)
@validation.required_openstack(admin=True)
@scenario.configure(context={"admin_cleanup": ["keystone"]})
def create_tenant(self, name_length=10, **kwargs):
"""Create a keystone tenant with random name.
:param name_length: length of the random part of tenant name
:param kwargs: Other optional parameters
"""
self._tenant_create(name_length=name_length, **kwargs)
while keystone contexts use
plugins/openstack/wrappers/keystone.py
.. code-block:: python
@six.add_metaclass(abc.ABCMeta)
class KeystoneWrapper(object):
def __init__(self, client):
self.client = client
def __getattr__(self, attr_name):
return getattr(self.client, attr_name)
@abc.abstractmethod
def create_project(self, project_name, domain_name="Default"):
"""Creates new project/tenant and return project object.
:param project_name: Name of project to be created.
:param domain_name: Name or id of domain where to create project,
for implementations that don't support
domains this
argument must be None or 'Default'.
"""
@abc.abstractmethod
def delete_project(self, project_id):
"""Deletes project."""
class KeystoneV2Wrapper(KeystoneWrapper):
def create_project(self, project_name, domain_name="Default"):
self._check_domain(domain_name)
tenant = self.client.tenants.create(project_name)
return KeystoneV2Wrapper._wrap_v2_tenant(tenant)
def delete_project(self, project_id):
self.client.tenants.delete(project_id)
class KeystoneV3Wrapper(KeystoneWrapper):
def create_project(self, project_name, domain_name="Default"):
domain_id = self._get_domain_id(domain_name)
project = self.client.projects.create(
name=project_name, domain=domain_id)
return KeystoneV3Wrapper._wrap_v3_project(project)
def delete_project(self, project_id):
self.client.projects.delete(project_id)
Users context:
.. code-block:: python
@context.configure(name="users", order=100)
class UserGenerator(UserContextMixin, context.Context):
"""Context class for generating temporary
users/tenants for benchmarks."""
def _create_tenants(self):
cache["client"] = keystone.wrap(clients.keystone())
tenant = cache["client"].create_project(
self.PATTERN_TENANT % {"task_id": task_id, "iter": i}, domain)
Suggested change
----------------
.. code-block::
plugins/
|
+-- openstack/
|
|
+-- scenarios/
| |
| |
| +-- neutron/
| +-- authenticate/
|
+-- services/
| # Here we will store base code for openstack services.
| # like wait_for, and wait_for_delete
+-- base.py
|
+-- compute/
| |
| +-- compute.py
|
+-- identity/
| | # Here is common service when we care to do things
| | # and regardless of which API/service is used for
| | # that. So we will implement here parts that can be
| | # done in both.
| +-- identity.py
| | # Here is api for working with specific API
| | # version/service Like keystone_v2/keystone_v3 or
| | # nova_network/neutron. This will be used in
| | # main.py for implementation.
| +-- kestone_v2.py
| |
| +-- kestone_v3.py
|
+-- network/
| | # Here is common service when we care to do things
| | # and regardless of which API/service is used for
| | # that. So we will implement here parts that can be
| | # done in both.
| +-- network.py
| | # Here is api for working with specific API
| | # version/service Like nova_network/neutron.
| | # This will be used in main.py for implementation.
| +-- nova_network.py
| |
| +-- neutron.py
|
+-- ...
Base class that allow us to use atomic actions in services is inside the
rally/plugins/openstack/services/base.py:
.. code-block:: python
class Service(object):
def __init__(self, clients, atomic_inst=None):
self.clients = clients
if atomic_inst:
if not isinstance(atomic_inst, ActionTimerMixin):
raise TypeError()
# NOTE(boris-42): This allows us to use atomic actions
# decorators but they will add values
# to the scenario or context instance
self._atomic_actions = atomic_inst._atomic_actions
else:
# NOTE(boris-42): If one is using this not for scenarios and
# context, Service instance will store atomic
# actions data.
self._atomic_actions = costilus.OrderedDict()
Implementation of IdentityService in services/identity/identity.py:
.. code-block:: python
class IdentityService(Service):
"""Contains only common methods for Keystone V2 and V3."""
def __init__(self, clients, atomic_inst=None, version=None):
super(self).__init__(clients, atomic_inst=atomic_inst)
if version:
if version == "2":
self.impl = KeystoneV2Service()
else:
self.impl = KeysotneServiceV3()
else:
self.impl = auto_discover_version()
def project_create(self, name, **kwargs):
result = self.impl.project_create(name)
# handle the difference between implementations
return magic(result)
# ...
Inside services/identity/keystone_v2.py:
.. code-block:: python
class KeystoneV2Service(KeystoneService):
# NOTE(boris-42): we can use specific atomic action names
# for specific implementation of service
@atomic.action_timer("keystone_v2.tenant_create")
def project_create(self, project_name):
"""Implementation."""
Inside services/identity/keystone_v3.py:
.. code-block:: python
class KeystoneV3Service(KeystoneService):
@atomic.action_timer("keystone_v3.project_create")
def project_create(self, project_name):
"""Implementation."""
def domain_create(self, *args, **kwargs):
"""Specific method for KesytoneV3."""
Both context.keystone and scenario.keystone can use now services/identity.py
usage is the same in context and scenario, so it's enough to show in case
of scenario.
.. code-block:: python
from rally.plugins.openstack.services.identity import identity
from rally.plugins.openstack.services.identity import keystone_v3
class KeystoneBasic(scenario.OpenStackScenario): # no more utils.py
"""Basic benchmark scenarios for Keystone."""
@validation.number("name_length", minval=10)
@validation.required_openstack(admin=True)
@scenario.configure(context={"admin_cleanup": ["keystone"]})
def create_tenant(self, name_length=10, **kwargs):
"""Create a keystone tenant with random name.
:param name_length: length of the random part of tenant name
:param kwargs: Other optional parameters
"""
name = self._generate_random_name(length=name_length)
# NOTE(boris-42): Code above works in keystone V2 and V3
# as well it will add atomic action, and name
# will be "keystone_v3.project_create" or
# "keystone_v2.tenant_create" depending on used
# version
common.Identity(self.clients, self).create_project(name,
**kwargs)
# NOTE(boris-42): If you need specific operation for keystone v3
keystone_v3.KeystoneV3Service(self.clients, self).domain_create()
# NOTE(boris-42): One of the nice thing is that we can move
# initialization of services to __init__ method
# of sceanrio.
Assignee(s)
-----------
- boris-42
Work Items
----------
#. Create a base.Service class
#. Create for each project services
#. Use in all scenarios and context services instead of utils
#. Deprecate utils
#. Remove utils
Dependencies
============
none