====Using the Cloud SDK====
This document gives a quick introduction to using the Openstack Python client to discover and consume compute resources.

Before beginning, get an account as described in the [[ cloud:intro | Introduction ]]. This is the right place to read about writing python scripts. A companion document shows how to use the [[ cloud:cli | Command Line ]].

======Installation======

From a suitable host (this was done on linux.cs.uchicago.edu), create your environment.

<code>
$ python3 -m venv cloudsdk
$ source cloudsdk/bin/activate
$ pip3 install openstacksdk
$ python -m openstack version
</code>

=====Configuration=====

Obtain your configuration from the [[ https://overcloud.cs.uchicago.edu/project/api_access/clouds.yaml/ | Web Interface ]]. The preceding link is for authenticated and authorized users only. Please read [[ cloud:intro | Intro ]] for access. After logging in to the web interface at [[ https://overcloud.cs.uchicago.edu ]], click the menu on the left side, Project->API Access. On the right side of the top of the page, click "Download Openstack RC File"->"Openstack clouds.yaml file".

Save the clouds.yaml file to the current working directory, or see the [[ https://docs.openstack.org/openstacksdk/latest/user/config/configuration.html#config-files | Upstream Docs ]] about config file search order:

<code>
USER_CONFIG_DIR
    Linux: ~/.config/openstack
    OSX: ~/Library/Application Support/openstack
    Windows: C:\Users\USERNAME\AppData\Local\OpenStack\openstack
SITE_CONFIG_DIR
    Linux: /etc/openstack
    OSX: /Library/Application Support/openstack
    Windows: C:\ProgramData\OpenStack\openstack
</code>

====Sample Configuration File====
<code>
clouds:
  openstack:
    auth:
      auth_url: https://overcloud.cs.uchicago.edu:5000
      username: "CNetID"
      password: "sekret"
      project_id: YOUR PROJECT UUID
      project_name: "CNetID"
      user_domain_name: "CS_LDAP"
    region_name: "RegionOne"
    interface: "public"
    identity_api_version: 3
</code>

The main flaw here is that you are taking risks by storing your University credentials in a file. Instead, you can use the API or web interface to create an Application Credential. For example,

<code>
openstack application credential create --secret sekret --role member --expiration 2020-10-10:10:10:10 --restricted myapp
</code>
=====Testing and Usage=====
Ensure you can load the python module
<code>
python -m openstack version
</code>

Check your configuration
<code>
python -m openstack.config.loader
</code>
Check the exact error if one is displayed. For example, if you see
<code>
keystoneauth1.exceptions.auth_plugins.MissingRequiredOptions: Auth plugin requires parameters which were not given: auth_url
</code>
You have failed to provide a configuration file. This is different from a syntax error, but not so different from a permission problem, for example.

======Demo Code======

The following Python code shows how to create and destroy a server, and obtain information about Networks, Images, and Flavors. Consult the [[ https://docs.openstack.org/openstacksdk/latest/user/index.html#api-documentation | API Resource Documentation ]] to see what else is possible.

For your learning, contrast this with the equivalent actions that are taken in the [[ cloud:cli | Command Line Usage Guide ]].

<code Python>

import openstack
from openstack.config import loader
# to enable debug logging
# openstack.enable_logging(True)
config = loader.OpenStackConfig()
cloud = openstack.connect(cloud='openstack')
flavor = cloud.get_flavor_by_ram(2048)
# print(flavor.name)
image = cloud.get_image('20.04')
# pretty print
# cloud.pprint(image)
network = cloud.get_network('campus37')
try:
    server = cloud.create_server('myserver', image=image, flavor=flavor, network=network, wait=True, auto_ip=True)
finally:
    cloud.delete_server('myserver', wait=True, delete_ips=True)
</code>