Python type annotations / hints for the base Libcloud compute API have been added in v2.8.0.
The goal behind type annotations is to make developer lives easier by introducing optional static typing for Python programs.
This allows you to catch bugs and issues which are related to variable types
earlier and faster (aka when you run
mypy locally either manually or
integrated in your editor / IDE and also as part of you CI/CD build
An example of how to use type annotations correctly is shown below.
# Licensed to the Apache Software Foundation (ASF) under one or more # contributor license agreements. See the NOTICE file distributed with # this work for additional information regarding copyright ownership. # The ASF licenses this file to You under the Apache License, Version 2.0 # (the "License"); you may not use this file except in compliance with # the License. You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. from typing import Type, cast from libcloud.compute.types import Provider from libcloud.compute.providers import get_driver from libcloud.compute.drivers.ec2 import EC2NodeDriver from libcloud.compute.drivers.rackspace import RackspaceNodeDriver ec2_cls = get_driver(Provider.EC2) rackspace_cls = get_driver(Provider.RACKSPACE) # NOTE: If you are using driver methods which are not part of the standard API, # you need to explicitly cast the driver class reference to the correct class # for type checking to work correctly EC2 = cast(Type[EC2NodeDriver], ec2_cls) Rackspace = cast(Type[RackspaceNodeDriver], rackspace_cls) drivers = [ EC2("access key id", "secret key", region="us-east-1"), Rackspace("username", "api key", region="iad"), ] nodes =  for driver in drivers: nodes.extend(driver.list_nodes()) print(nodes) # [ <Node: provider=Amazon, status=RUNNING, name=bob, ip=220.127.116.11.5>, # <Node: provider=Rackspace, status=REBOOT, name=korine, ip=18.104.22.168.10>, ... ] # grab the node named "test" node = [n for n in nodes if n.name == "test"] # reboot "test" node.reboot()
If you reference an invalid object attribute or a method, you would see an error similar to the one beloe when running mypy:
... print(nodes.name) print(nodes.invalid) print(nodes.rebbot()) print(nodes.reboot(foo='invalid')) ...
$ mypy --no-incremental example_compute.py example_compute.py:41: error: "Node" has no attribute "invalid" example_compute.py:42: error: "Node" has no attribute "rebbot"; maybe "reboot"? example_compute.py:43: error: Unexpected keyword argument "foo" for "reboot" of "Node"
If you are using driver methods which are not part of the Libcloud standard
API, you need to use
cast() method as shown below to cast the driver class
to the correct type. If you don’t do that,
mypy will only be aware of the
methods which are part of the Libcloud base compute API (aka
This is needed because of how Libcloud utilizes meta programming for the
get_driver() and related methods (there is no other way without writing
a mypy plugin to achieve that).
All of the communication about Libcloud development happens on our mailing lists.
- firstname.lastname@example.org - Moderated and low volume mailing list which is only used for distributing important project announcements and updates. (announce-archive)
- email@example.com - Mailing list for general talk about Libcloud and other off-topic things (users-archive)
- firstname.lastname@example.org - General mailing list for developers (dev-archive)
- email@example.com - Commits messages and other automatically generated notifications go to this mailing list. Keep in mind that unlike the others, this mailing list is fairly noisy. (notifications-archive, commits-archive)
Archive of old incubator mailing lists:
For bug and issue tracking we use Github issues located at https://github.com/apache/libcloud/issues.
For information how to run the tests and how to generate the test coverage report, please see the Testing page.
For continuous integration we use Travis-CI. You can find build reports on the following links:
Travis-CI builder is also integrated with Github which means that if you open a pull request there, Travis-CI will automatically build it.
If you want to validate the build before raising the PR, Travis-CI can be enabled for personal accounts and branches separately.
Test coverage report is automatically generated after every push and can be found at https://codecov.io/github/apache/libcloud?branch=trunk.