refactor alembic implementation

refactor alembic implementation to facilitate database upgrades when
using scaffolds

MANIFEST.in

@@ -1,3 +1,4 @@
 include *.txt *.ini *.cfg *.rst
 recursive-include atramhasis *.ico *.png *.css *.gif *.jpg *.pt *.txt *.jinja2 *.js *.html *.xml
 graft atramhasis/scaffolds
+graft atramhasis/alembic

alembic.ini

@@ -2,7 +2,7 @@
 
 [alembic]
 # path to migration scripts
-script_location = alembic
+script_location = atramhasis:alembic
 
 # template used to generate migration files
 # file_template = %%(rev)s_%%(slug)s
@@ -20,8 +20,9 @@ script_location = alembic
 # versions/ directory
 # sourceless = false
 
-sqlalchemy.url = sqlite:///%(here)s/atramhasis.sqlite
+# sqlalchemy.url = sqlite:///%(here)s/atramhasis.sqlite
 
+ini_location = %(here)s/development.ini
 
 # Logging configuration
 [loggers]

alembic/env.py → atramhasis/alembic/env.py

@@ -1,10 +1,12 @@
 from __future__ import with_statement
+from configparser import ConfigParser
 from alembic import context
 from sqlalchemy import engine_from_config, pool
 from logging.config import fileConfig
 from atramhasis.models import Base
 from skosprovider_sqlalchemy.models import Base as SkosBase
 from sqlalchemy.schema import MetaData
+from os import path
 
 # this is the Alembic Config object, which provides
 # access to the values within the .ini file in use.
@@ -25,6 +27,19 @@
 # my_important_option = config.get_main_option("my_important_option")
 # ... etc.
 
+def load_app_ini(ini_file):
+    """Load the settings for the application.ini file."""
+    ini = ConfigParser()
+    ini.read_file(open(ini_file))
+    here = path.abspath(path.dirname(ini_file))
+    ini.set('app:main', 'here', here)
+    return ini
+
+app_ini = config.get_main_option('ini_location')
+app_config = load_app_ini(app_ini)
+sa_url = app_config.get('app:main', 'sqlalchemy.url')
+config.set_main_option('sqlalchemy.url', sa_url)
+
 def run_migrations_offline():
     """Run migrations in 'offline' mode.
 

atramhasis/scaffolds/atramhasis_demo/alembic.ini

@@ -0,0 +1,60 @@
+# A generic, single database configuration.
+
+[alembic]
+# path to migration scripts
+script_location = atramhasis:alembic
+
+# template used to generate migration files
+# file_template = %%(rev)s_%%(slug)s
+
+# max length of characters to apply to the
+# "slug" field
+#truncate_slug_length = 40
+
+# set to 'true' to run the environment during
+# the 'revision' command, regardless of autogenerate
+# revision_environment = false
+
+# set to 'true' to allow .pyc and .pyo files without
+# a source .py file to be detected as revisions in the
+# versions/ directory
+# sourceless = false
+
+# sqlalchemy.url = sqlite:///%(here)s/atramhasis.sqlite
+
+ini_location = %(here)s/development.ini
+
+# Logging configuration
+[loggers]
+keys = root,sqlalchemy,alembic
+
+[handlers]
+keys = console
+
+[formatters]
+keys = generic
+
+[logger_root]
+level = WARN
+handlers = console
+qualname =
+
+[logger_sqlalchemy]
+level = WARN
+handlers =
+qualname = sqlalchemy.engine
+
+[logger_alembic]
+level = INFO
+handlers =
+qualname = alembic
+
+[handler_console]
+class = StreamHandler
+args = (sys.stderr,)
+level = NOTSET
+formatter = generic
+
+[formatter_generic]
+format = %(levelname)-5.5s [%(name)s] %(message)s
+datefmt = %H:%M:%S

atramhasis/scaffolds/atramhasis_demo/development.ini_tmpl

@@ -15,7 +15,7 @@ pyramid.includes =
     pyramid_debugtoolbar
     pyramid_tm
 
-sqlalchemy.url = sqlite:///%(here)s/atramhasis.sqlite
+sqlalchemy.url = sqlite:///%(here)s/{{package}}.sqlite
 
 # By default, the toolbar only appears for clients from IP addresses
 # '127.0.0.1' and '::1'.

atramhasis/scaffolds/atramhasis_scaffold/alembic.ini

@@ -0,0 +1,60 @@
+# A generic, single database configuration.
+
+[alembic]
+# path to migration scripts
+script_location = atramhasis:alembic
+
+# template used to generate migration files
+# file_template = %%(rev)s_%%(slug)s
+
+# max length of characters to apply to the
+# "slug" field
+#truncate_slug_length = 40
+
+# set to 'true' to run the environment during
+# the 'revision' command, regardless of autogenerate
+# revision_environment = false
+
+# set to 'true' to allow .pyc and .pyo files without
+# a source .py file to be detected as revisions in the
+# versions/ directory
+# sourceless = false
+
+# sqlalchemy.url = sqlite:///%(here)s/atramhasis.sqlite
+
+ini_location = %(here)s/development.ini
+
+# Logging configuration
+[loggers]
+keys = root,sqlalchemy,alembic
+
+[handlers]
+keys = console
+
+[formatters]
+keys = generic
+
+[logger_root]
+level = WARN
+handlers = console
+qualname =
+
+[logger_sqlalchemy]
+level = WARN
+handlers =
+qualname = sqlalchemy.engine
+
+[logger_alembic]
+level = INFO
+handlers =
+qualname = alembic
+
+[handler_console]
+class = StreamHandler
+args = (sys.stderr,)
+level = NOTSET
+formatter = generic
+
+[formatter_generic]
+format = %(levelname)-5.5s [%(name)s] %(message)s
+datefmt = %H:%M:%S

atramhasis/scaffolds/atramhasis_scaffold/development.ini_tmpl

@@ -15,7 +15,7 @@ pyramid.includes =
     pyramid_debugtoolbar
     pyramid_tm
 
-sqlalchemy.url = sqlite:///%(here)s/atramhasis.sqlite
+sqlalchemy.url = sqlite:///%(here)s/{{package}}.sqlite
 
 # By default, the toolbar only appears for clients from IP addresses
 # '127.0.0.1' and '::1'.