Merge "Improve README to provide example of Resource usage"

README.rst

@@ -1,3 +1,4 @@
+============
 openstacksdk
 ============
 
@@ -10,48 +11,73 @@ It also contains an abstraction interface layer. Clouds can do many things, but
 there are probably only about 10 of them that most people care about with any
 regularity. If you want to do complicated things, the per-service oriented
 portions of the SDK are for you. However, if what you want is to be able to
-write an application that talks to clouds no matter what crazy choices the
+write an application that talks to any OpenStack cloud regardless of
-deployer has made in an attempt to be more hipster than their self-entitled
+configuration, then the Cloud Abstraction layer is for you.
-narcissist peers, then the Cloud Abstraction layer is for you.
 
-More information about its history can be found at
+More information about the history of openstacksdk can be found at
 https://docs.openstack.org/openstacksdk/latest/contributor/history.html
 
-openstack
+Getting started
-=========
+---------------
 
-List servers using objects configured with the ``clouds.yaml`` file:
+openstacksdk aims to talk to any OpenStack cloud. To do this, it requires a
+configuration file. openstacksdk favours ``clouds.yaml`` files, but can also
+use environment variables. The ``clouds.yaml`` file should be provided by your
+cloud provider or deployment tooling. An example:
 
-.. code-block:: python
+.. code-block:: yaml
 
-    import openstack
+    clouds:
+      mordred:
+        region_name: Dallas
+        auth:
+          username: 'mordred'
+          password: XXXXXXX
+          project_name: 'demo'
+          auth_url: 'https://identity.example.com'
 
-    # Initialize and turn on debug logging
+openstacksdk will look for ``clouds.yaml`` files in the following locations:
-    openstack.enable_logging(debug=True)
 
-    # Initialize cloud
+* ``.`` (the current directory)
-    conn = openstack.connect(cloud='mordred')
+* ``$HOME/.config/openstack``
+* ``/etc/openstack``
 
-    for server in conn.compute.servers():
+openstacksdk consists of three layers. Most users will make use of the *proxy*
-        print(server.to_dict())
+layer. Using the above ``clouds.yaml``, consider listing servers:
-
+
-Cloud Layer
+.. code-block:: python
-===========
+
-
+    import openstack
-``openstacksdk`` contains a higher-level layer based on logical operations.
+
-
+    # Initialize and turn on debug logging
-.. code-block:: python
+    openstack.enable_logging(debug=True)
-
+
-    import openstack
+    # Initialize connection
-
+    conn = openstack.connect(cloud='mordred')
-    # Initialize and turn on debug logging
+
-    openstack.enable_logging(debug=True)
+    # List the servers
-
+    for server in conn.compute.servers():
-    for server in conn.list_servers():
+        print(server.to_dict())
-        print(server.to_dict())
+
-
+openstacksdk also contains a higher-level *cloud* layer based on logical
-The benefit is mostly seen in more complicated operations that take multiple
+operations:
-steps and where the steps vary across providers:
+
+.. code-block:: python
+
+    import openstack
+
+    # Initialize and turn on debug logging
+    openstack.enable_logging(debug=True)
+
+    # Initialize connection
+    conn = openstack.connect(cloud='mordred')
+
+    # List the servers
+    for server in conn.list_servers():
+        print(server.to_dict())
+
+The benefit of this layer is mostly seen in more complicated operations that
+take multiple steps and where the steps vary across providers. For example:
 
 .. code-block:: python
 
@@ -61,7 +87,6 @@ steps and where the steps vary across providers:
     openstack.enable_logging(debug=True)
 
     # Initialize connection
-    # Cloud configs are read with openstack.config
     conn = openstack.connect(cloud='mordred')
 
     # Upload an image to the cloud
@@ -72,14 +97,37 @@ steps and where the steps vary across providers:
     flavor = conn.get_flavor_by_ram(512)
 
     # Boot a server, wait for it to boot, and then do whatever is needed
-    # to get a public ip for it.
+    # to get a public IP address for it.
     conn.create_server(
         'my-server', image=image, flavor=flavor, wait=True, auto_ip=True)
 
-openstack.config
+Finally, there is the low-level *resource* layer. This provides support for the
-================
+basic CRUD operations supported by REST APIs and is the base building block for
+the other layers. You typically will not need to use this directly:
 
-``openstack.config`` will find cloud configuration for as few as 1 clouds and
+.. code-block:: python
+
+    import openstack
+    import openstack.config.loader
+    import openstack.compute.v2.server
+
+    # Initialize and turn on debug logging
+    openstack.enable_logging(debug=True)
+
+    # Initialize connection
+    conn = openstack.connect(cloud='mordred')
+
+    # List the servers
+    for server in openstack.compute.v2.server.Server.list(session=conn.compute):
+        print(server.to_dict())
+
+.. _openstack.config:
+
+Configuration
+-------------
+
+openstacksdk uses the ``openstack.config`` module to parse configuration.
+``openstack.config`` will find cloud configuration for as few as one cloud and
 as many as you want to put in a config file. It will read environment variables
 and config files, and it also contains some vendor specific default values so
 that you don't have to know extra info to use OpenStack
@@ -88,32 +136,17 @@ that you don't have to know extra info to use OpenStack
 * If you have environment variables, you will get a cloud named `envvars`
 * If you have neither, you will get a cloud named `defaults` with base defaults
 
-Sometimes an example is nice.
+You can view the configuration identified by openstacksdk in your current
+environment by running ``openstack.config.loader``. For example:
 
-Create a ``clouds.yaml`` file:
+.. code-block:: bash
 
-.. code-block:: yaml
+   $ python -m openstack.config.loader
-
-     clouds:
-      mordred:
-        region_name: Dallas
-        auth:
-          username: 'mordred'
-          password: XXXXXXX
-          project_name: 'shade'
-          auth_url: 'https://identity.example.com'
-
-Please note: ``openstack.config`` will look for a file called ``clouds.yaml``
-in the following locations:
-
-* Current Directory
-* ``~/.config/openstack``
-* ``/etc/openstack``
 
 More information at https://docs.openstack.org/openstacksdk/latest/user/config/configuration.html
 
 Links
-=====
+-----
 
 * `Issue Tracker <https://storyboard.openstack.org/#!/project/openstack/openstacksdk>`_
 * `Code Review <https://review.opendev.org/#/q/status:open+project:openstack/openstacksdk,n,z>`_