Add script to autogenerate doc/source/plugin-registry.rst

This generates the plugin-registry document from a static header,
a scan of openstack/ git repositories, and a static footer.  It
is intended to be run by a periodic job proposal bot to keep the
list of plugins current.

Change-Id: Ia04ab72900c8efd5d5289fbd7632201dcaa3e5d9

data/devstack-plugins-registry.footer

@@ -0,0 +1,28 @@
+
+Drivers
+=======
+
++--------------------+-------------------------------------------------+------------------+
+|Plugin Name         |URL                                              |Comments          |
++--------------------+-------------------------------------------------+------------------+
+|dragonflow          |git://git.openstack.org/openstack/dragonflow     |[d1]_             |
++--------------------+-------------------------------------------------+------------------+
+|odl                 |git://git.openstack.org/openstack/networking-odl |[d2]_             |
++--------------------+-------------------------------------------------+------------------+
+
+.. [d1] demonstrates example of installing 3rd party SDN controller
+.. [d2] demonstrates a pretty advanced set of modes that that allow
+        one to run OpenDayLight either from a pre-existing install, or
+        also from source
+
+Alternate Configs
+=================
+
++-------------+------------------------------------------------------------+------------+
+| Plugin Name | URL                                                        | Comments   |
+|             |                                                            |            |
++-------------+------------------------------------------------------------+------------+
+|glusterfs    |git://git.openstack.org/openstack/devstack-plugin-glusterfs |            |
++-------------+------------------------------------------------------------+------------+
+|             |                                                            |            |
++-------------+------------------------------------------------------------+------------+

data/devstack-plugins-registry.header

@@ -0,0 +1,19 @@
+==========================
+ DevStack Plugin Registry
+==========================
+
+Since we've created the external plugin mechanism, it's gotten used by
+a lot of projects. The following is a list of plugins that currently
+exist. Any project that wishes to list their plugin here is welcomed
+to.
+
+Detected Plugins
+================
+
+The following are plugins that a script has found in the openstack/
+namespace, which includes but is not limited to official OpenStack
+projects.
+
++------------------+------------------------------------------------------------+------------+
+|Plugin Name       |URL                                                         |Date        |
++------------------+------------------------------------------------------------+------------+

tools/generate-devstack-plugins-list.sh

@@ -0,0 +1,59 @@
+#!/bin/bash -ex
+
+# Copyright 2016 Hewlett Packard Enterprise Development Company, L.P.
+#
+# 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.
+
+# This script is intended to be run as a periodic proposal bot job
+# in OpenStack infrastructure, though you can run it as a one-off.
+#
+# In order to function correctly, the environment in which the
+# script runs must have
+#   * git
+#   * all git repos meant to be searched for plugins cloned and
+#     at the desired level of up-to-datedness
+#   * a writable doc/source directory relative to the current
+#     working directory
+#
+# If a file named data/devstack-plugins-registry.header or
+# data/devstack-plugins-registry.footer is found relative to the
+# current working directory, it will be prepended or appended to
+# the generated reStructuredText plugins table respectively.
+
+(
+declare -A plugins
+
+test -r data/devstack-plugins-registry.header && cat data/devstack-plugins-registry.header
+
+pushd ${git_dir:-/opt/openstack} >/dev/null
+for i in *; do
+    pushd ${i} >/dev/null
+    if output="$(git log --diff-filter=A --format='%cd' --date=short -1 -- devstack/plugin.sh)"; then
+        test -n "$output" && plugins[$i]=${output}
+    fi
+    popd >/dev/null
+done
+popd >/dev/null
+
+sorted_plugins=( $(for k in "${!plugins[@]}"; do echo "$k"; done | sort))
+
+for k in "${sorted_plugins[@]}"; do
+    project=${k:0:18}
+    giturl="git://git.openstack.org/openstack/${k:0:26}"
+    pdate="${plugins[$k]}"
+    printf "|%-18s|%-60s|%-12s|\n" "${project}" "${giturl}" "${pdate}"
+    printf "+------------------+------------------------------------------------------------+------------+\n"
+done
+
+test -r data/devstack-plugins-registry.footer && cat data/devstack-plugins-registry.footer
+) > doc/source/plugin-registry.rst