Adds architecture docs and enables Graphviz sphinx extension. Also cleans up source code formatting in docs.

This commit is contained in:
jaypipes@gmail.com 2011-01-26 16:01:48 +00:00 committed by Tarmac
commit a8d791c2d7
4 changed files with 92 additions and 5 deletions

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..
Copyright 2010 OpenStack, LLC
All Rights Reserved.
Licensed 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.
Glance Architecture
===================
Glance is designed to be as adaptable as possible for various back-end storage
and registry database solutions. There is a main Glance API server
(the ``glance-api`` program) that serves as the communications hub between
various client programs, the registry of image metadata, and the storage
systems that actually contain the virtual machine image data.
From a birdseye perspective, one can visualize the Glance architectural model
like so:
.. graphviz::
digraph birdseye {
node [fontsize=10 fontname="Monospace"]
a [label="Client A"]
b [label="Client B"]
c [label="Client C"]
d [label="Glance API Server"]
e [label="Registry Server"]
f [label="Store Adapter"]
g [label="S3 Store"]
h [label="Swift Store"]
i [label="Filesystem Store"]
j [label="HTTP Store"]
a -> d [dir=both]
b -> d [dir=both]
c -> d [dir=both]
d -> e [dir=both]
d -> f [dir=both]
f -> g [dir=both]
f -> h [dir=both]
f -> i [dir=both]
f -> j [dir=both]
}
What is a Registry Server?
==========================
A registry server is any service that publishes image metadata that conforms
to the Glance Registry REST-ful API. Glance comes with a reference
implementation of a registry server called ``glance-registry``, but this is
only a reference implementation that uses a SQL database for its metdata
storage.
What is a Store?
================
A store is a Python class that inherits from ``glance.store.Backend`` and
conforms to that class' API for reading, writing, and deleting virtual
machine image data.
Glance currently ships with stores for S3, Swift, a simple filesystem store,
and a read-only HTTP(S) store.
Implementors are encouraged to create stores for other backends, including
other distributed storage systems like Sheepdog or Ceph.

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@ -36,7 +36,9 @@ Requesting a List of Public VM Images
We want to see a list of available virtual machine images that the Glance
server knows about.
Using Glance's Client, we can do this using the following code::
Using Glance's Client, we can do this using the following code
.. code-block:: python
from glance.client import Client
@ -51,7 +53,9 @@ Requesting Detailed Metadata on Public VM Images
We want to see more detailed information on available virtual machine images
that the Glance server knows about.
Using Glance's Client, we can do this using the following code::
Using Glance's Client, we can do this using the following code
.. code-block:: python
from glance.client import Client
@ -72,7 +76,9 @@ data returned includes the `uri` field for each available image. This
for a specific image.
Continuing the example from above, in order to get metadata about the
first public image returned, we can use the following code::
first public image returned, we can use the following code
.. code-block:: python
from glance.client import Client
@ -93,7 +99,9 @@ data returned includes the `uri` field for each available image. This
for a specific image.
Continuing the example from above, in order to get both the metadata about the
first public image returned and its image data, we can use the following code::
first public image returned and its image data, we can use the following code
.. code-block:: python
from glance.client import Client
@ -222,7 +230,9 @@ The list of metadata that `image_meta` can contain are listed below.
set to the value `queued`.
As a complete example, the following code would add a new machine image to
Glance::
Glance
.. code-block:: python
from glance.client import Client

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@ -47,6 +47,7 @@ extensions = ['sphinx.ext.autodoc',
'sphinx.ext.ifconfig',
'sphinx.ext.intersphinx',
'sphinx.ext.pngmath',
'sphinx.ext.graphviz',
'sphinx.ext.todo']
todo_include_todos = True

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@ -67,6 +67,7 @@ Developer Docs
.. toctree::
:maxdepth: 1
architecture
community
Outstanding Documentation Tasks