Add config auto generator

Add possibility to generate a config file with default values.
Run `tox -e genconfig` and etc/refstack.conf.sample appears.

Change-Id: Ie7c7d90ec056ad254f4247d4b0adc06bdd096ee6

doc/refstack.md

@@ -54,7 +54,8 @@ Refstack Quickstart
 
 ####Configuration file preparation
 
-- Make a copy of the sample config and update it with the correct information of your environment. Example of config file available in etc directory.
+- Make a copy of the sample config and update it with the correct information of your environment. Example of config file with default values available in etc directory.
+Note value of `connection` in `database` section should be corrected.
 
 ####Database sync
 

etc/refstack.conf.sample

@@ -1,2 +1,113 @@
 [DEFAULT]
-sql_connection = mysql://refstack:<your password>@127.0.0.1/refstack
+
+#
+# From refstack
+#
+
+# The backend to use for database. (string value)
+#db_backend = sqlalchemy
+
+
+[database]
+
+#
+# From oslo.db
+#
+
+# The file name to use with SQLite. (string value)
+# Deprecated group/name - [DEFAULT]/sqlite_db
+#sqlite_db = oslo.sqlite
+
+# If True, SQLite uses synchronous mode. (boolean value)
+# Deprecated group/name - [DEFAULT]/sqlite_synchronous
+#sqlite_synchronous = true
+
+# The back end to use for the database. (string value)
+# Deprecated group/name - [DEFAULT]/db_backend
+#backend = sqlalchemy
+
+# The SQLAlchemy connection string to use to connect to the database.
+# (string value)
+# Deprecated group/name - [DEFAULT]/sql_connection
+# Deprecated group/name - [DATABASE]/sql_connection
+# Deprecated group/name - [sql]/connection
+#connection = <None>
+
+# The SQLAlchemy connection string to use to connect to the slave
+# database. (string value)
+#slave_connection = <None>
+
+# The SQL mode to be used for MySQL sessions. This option, including
+# the default, overrides any server-set SQL mode. To use whatever SQL
+# mode is set by the server configuration, set this to no value.
+# Example: mysql_sql_mode= (string value)
+#mysql_sql_mode = TRADITIONAL
+
+# Timeout before idle SQL connections are reaped. (integer value)
+# Deprecated group/name - [DEFAULT]/sql_idle_timeout
+# Deprecated group/name - [DATABASE]/sql_idle_timeout
+# Deprecated group/name - [sql]/idle_timeout
+#idle_timeout = 3600
+
+# Minimum number of SQL connections to keep open in a pool. (integer
+# value)
+# Deprecated group/name - [DEFAULT]/sql_min_pool_size
+# Deprecated group/name - [DATABASE]/sql_min_pool_size
+#min_pool_size = 1
+
+# Maximum number of SQL connections to keep open in a pool. (integer
+# value)
+# Deprecated group/name - [DEFAULT]/sql_max_pool_size
+# Deprecated group/name - [DATABASE]/sql_max_pool_size
+#max_pool_size = <None>
+
+# Maximum number of database connection retries during startup. Set to
+# -1 to specify an infinite retry count. (integer value)
+# Deprecated group/name - [DEFAULT]/sql_max_retries
+# Deprecated group/name - [DATABASE]/sql_max_retries
+#max_retries = 10
+
+# Interval between retries of opening a SQL connection. (integer
+# value)
+# Deprecated group/name - [DEFAULT]/sql_retry_interval
+# Deprecated group/name - [DATABASE]/reconnect_interval
+#retry_interval = 10
+
+# If set, use this value for max_overflow with SQLAlchemy. (integer
+# value)
+# Deprecated group/name - [DEFAULT]/sql_max_overflow
+# Deprecated group/name - [DATABASE]/sqlalchemy_max_overflow
+#max_overflow = <None>
+
+# Verbosity of SQL debugging information: 0=None, 100=Everything.
+# (integer value)
+# Deprecated group/name - [DEFAULT]/sql_connection_debug
+#connection_debug = 0
+
+# Add Python stack traces to SQL as comment strings. (boolean value)
+# Deprecated group/name - [DEFAULT]/sql_connection_trace
+#connection_trace = false
+
+# If set, use this value for pool_timeout with SQLAlchemy. (integer
+# value)
+# Deprecated group/name - [DATABASE]/sqlalchemy_pool_timeout
+#pool_timeout = <None>
+
+# Enable the experimental use of database reconnect on connection
+# lost. (boolean value)
+#use_db_reconnect = false
+
+# Seconds between database connection retries. (integer value)
+#db_retry_interval = 1
+
+# If True, increases the interval between database connection retries
+# up to db_max_retry_interval. (boolean value)
+#db_inc_retry_interval = true
+
+# If db_inc_retry_interval is set, the maximum seconds between
+# database connection retries. (integer value)
+#db_max_retry_interval = 10
+
+# Maximum database connection retries before error is raised. Set to
+# -1 to specify an infinite retry count. (integer value)
+#db_max_retries = 20

refstack/opts.py

@@ -0,0 +1,41 @@
+# Copyright (c) 2015 Mirantis, Inc.
+# 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.
+"""
+    Function list_opts intended for oslo-config-generator. It tool used for
+    generate config file with help info and default values for options defined
+    anywhere in application.
+    All new options must be imported here and must be returned from
+    list_opts function as list that contain tuple.
+    Use itertools.chain if config section contain more than one imported module
+    with options. For example:
+
+    ...
+    def list_opts():
+        return [
+            ('DEFAULT', refstack.db.api.db_opts),
+            ('api',
+             itertools.chain(refstack.api.first.module.opts,
+                             refstack.api.second.modulei.opts,)),
+        ]
+    ...
+"""
+import refstack.db.api
+
+
+def list_opts():
+    return [
+        # Keep a list in alphabetical order
+        ('DEFAULT', refstack.db.api.db_opts),
+    ]

setup.cfg

@@ -29,3 +29,7 @@ scripts =
 [global]
 setup-hooks =
     pbr.hooks.setup_hook
+
+[entry_points]
+oslo.config.opts =
+    refstack = refstack.opts:list_opts

tox.ini

@@ -36,6 +36,12 @@ commands =
   flake8 --filename=refstack* bin
 distribute = false
 
+[testenv:genconfig]
+commands =
+    oslo-config-generator --output-file etc/refstack.conf.sample \
+    --namespace refstack \
+    --namespace oslo.db
+
 [testenv:venv]
 commands = {posargs}