--- a/doc/book/en/devrepo/migration.rst Mon Jul 06 17:39:35 2015 +0200
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,250 +0,0 @@
-.. -*- coding: utf-8 -*-
-
-.. _migration:
-
-Migration
-=========
-
-One of the main design goals of *CubicWeb* was to support iterative and agile
-development. For this purpose, multiple actions are provided to facilitate the
-improvement of an instance, and in particular to handle the changes to be
-applied to the data model, without loosing existing data.
-
-The current version of a cube (and of cubicweb itself) is provided in the file
-`__pkginfo__.py` as a tuple of 3 integers.
-
-Migration scripts management
-----------------------------
-
-Migration scripts has to be located in the directory `migration` of your
-cube and named accordingly:
-
-::
-
- <version n° X.Y.Z>[_<description>]_<mode>.py
-
-in which :
-
-* X.Y.Z is the model version number to which the script enables to migrate.
-
-* *mode* (between the last "_" and the extension ".py") is used for
- distributed installation. It indicates to which part
- of the application (RQL server, web server) the script applies.
- Its value could be :
-
- * `common`, applies to the RQL server as well as the web server and updates
- files on the hard drive (configuration files migration for example).
-
- * `web`, applies only to the web server and updates files on the hard drive.
-
- * `repository`, applies only to the RQL server and updates files on the
- hard drive.
-
- * `Any`, applies only to the RQL server and updates data in the database
- (schema and data migration for example).
-
-Again in the directory `migration`, the file `depends.map` allows to indicate
-that for the migration to a particular model version, you always have to first
-migrate to a particular *CubicWeb* version. This file can contain comments (lines
-starting with `#`) and a dependency is listed as follows: ::
-
- <model version n° X.Y.Z> : <cubicweb version n° X.Y.Z>
-
-For example: ::
-
- 0.12.0: 2.26.0
- 0.13.0: 2.27.0
- # 0.14 works with 2.27 <= cubicweb <= 2.28 at least
- 0.15.0: 2.28.0
-
-Base context
-------------
-
-The following identifiers are pre-defined in migration scripts:
-
-* `config`, instance configuration
-
-* `interactive_mode`, boolean indicating that the script is executed in
- an interactive mode or not
-
-* `versions_map`, dictionary of migrated versions (key are cubes
- names, including 'cubicweb', values are (from version, to version)
-
-* `confirm(question)`, function asking the user and returning true
- if the user answers yes, false otherwise (always returns true in
- non-interactive mode)
-
-* `_()` is equivalent to `unicode` allowing to flag the strings to
- internationalize in the migration scripts.
-
-In the `repository` scripts, the following identifiers are also defined:
-
-* `commit(ask_confirm=True)`, request confirming and executing a "commit"
-
-* `schema`, instance schema (readen from the database)
-
-* `fsschema`, installed schema on the file system (e.g. schema of
- the updated model and cubicweb)
-
-* `repo`, repository object
-
-* `session`, repository session object
-
-
-New cube dependencies
----------------------
-
-If your code depends on some new cubes, you have to add them in a migration
-script by using:
-
-* `add_cube(cube, update_database=True)`, add a cube.
-* `add_cubes(cubes, update_database=True)`, add a list of cubes.
-
-The `update_database` parameter is telling if the database schema
-should be updated or if only the relevant persistent property should be
-inserted (for the case where a new cube has been extracted from an
-existing one, so the new cube schema is actually already in there).
-
-If some of the added cubes are already used by an instance, they'll simply be
-silently skipped.
-
-
-Schema migration
-----------------
-The following functions for schema migration are available in `repository`
-scripts:
-
-* `add_attribute(etype, attrname, attrtype=None, commit=True)`, adds a new
- attribute to an existing entity type. If the attribute type is not specified,
- then it is extracted from the updated schema.
-
-* `drop_attribute(etype, attrname, commit=True)`, removes an attribute from an
- existing entity type.
-
-* `rename_attribute(etype, oldname, newname, commit=True)`, renames an attribute
-
-* `add_entity_type(etype, auto=True, commit=True)`, adds a new entity type.
- If `auto` is True, all the relations using this entity type and having a known
- entity type on the other hand will automatically be added.
-
-* `drop_entity_type(etype, commit=True)`, removes an entity type and all the
- relations using it.
-
-* `rename_entity_type(oldname, newname, commit=True)`, renames an entity type
-
-* `add_relation_type(rtype, addrdef=True, commit=True)`, adds a new relation
- type. If `addrdef` is True, all the relations definitions of this type will
- be added.
-
-* `drop_relation_type(rtype, commit=True)`, removes a relation type and all the
- definitions of this type.
-
-* `rename_relation_type(oldname, newname, commit=True)`, renames a relation type.
-
-* `add_relation_definition(subjtype, rtype, objtype, commit=True)`, adds a new
- relation definition.
-
-* `drop_relation_definition(subjtype, rtype, objtype, commit=True)`, removes
- a relation definition.
-
-* `sync_schema_props_perms(ertype=None, syncperms=True, syncprops=True, syncrdefs=True, commit=True)`,
- synchronizes properties and/or permissions on:
- - the whole schema if ertype is None
- - an entity or relation type schema if ertype is a string
- - a relation definition if ertype is a 3-uple (subject, relation, object)
-
-* `change_relation_props(subjtype, rtype, objtype, commit=True, **kwargs)`, changes
- properties of a relation definition by using the named parameters of the properties
- to change.
-
-* `set_widget(etype, rtype, widget, commit=True)`, changes the widget used for the
- relation <rtype> of entity type <etype>.
-
-* `set_size_constraint(etype, rtype, size, commit=True)`, changes the size constraints
- for the relation <rtype> of entity type <etype>.
-
-Data migration
---------------
-The following functions for data migration are available in `repository` scripts:
-
-* `rql(rql, kwargs=None, cachekey=None, ask_confirm=True)`, executes an arbitrary RQL
- query, either to interrogate or update. A result set object is returned.
-
-* `add_entity(etype, *args, **kwargs)`, adds a new entity of the given type.
- The attribute and relation values are specified as named positional
- arguments.
-
-Workflow creation
------------------
-
-The following functions for workflow creation are available in `repository`
-scripts:
-
-* `add_workflow(label, workflowof, initial=False, commit=False, **kwargs)`, adds a new workflow
- for a given type(s)
-
-You can find more details about workflows in the chapter :ref:`Workflow` .
-
-Configuration migration
------------------------
-
-The following functions for configuration migration are available in all
-scripts:
-
-* `option_renamed(oldname, newname)`, indicates that an option has been renamed
-
-* `option_group_change(option, oldgroup, newgroup)`, indicates that an option does not
- belong anymore to the same group.
-
-* `option_added(oldname, newname)`, indicates that an option has been added.
-
-* `option_removed(oldname, newname)`, indicates that an option has been deleted.
-
-The `config` variable is an object which can be used to access the
-configuration values, for reading and updating, with a dictionary-like
-syntax.
-
-Example 1: migration script changing the variable 'sender-addr' in
-all-in-one.conf. The script also checks that in that the instance is
-configured with a known value for that variable, and only updates the
-value in that case.
-
-.. sourcecode:: python
-
- wrong_addr = 'cubicweb@loiglab.fr' # known wrong address
- fixed_addr = 'cubicweb@logilab.fr'
- configured_addr = config.get('sender-addr')
- # check that the address has not been hand fixed by a sysadmin
- if configured_addr == wrong_addr:
- config['sender-addr'] = fixed-addr
- config.save()
-
-Example 2: checking the value of the database backend driver, which
-can be useful in case you need to issue backend-dependent raw SQL
-queries in a migration script.
-
-.. sourcecode:: python
-
- dbdriver = config.sources()['system']['db-driver']
- if dbdriver == "sqlserver2005":
- # this is now correctly handled by CW :-)
- sql('ALTER TABLE cw_Xxxx ALTER COLUMN cw_name varchar(64) NOT NULL;')
- commit()
- else: # postgresql
- sync_schema_props_perms(ertype=('Xxxx', 'name', 'String'),
- syncperms=False)
-
-
-Others migration functions
---------------------------
-Those functions are only used for low level operations that could not be
-accomplished otherwise or to repair damaged databases during interactive
-session. They are available in `repository` scripts:
-
-* `sql(sql, args=None, ask_confirm=True)`, executes an arbitrary SQL query on the system source
-* `add_entity_type_table(etype, commit=True)`
-* `add_relation_type_table(rtype, commit=True)`
-* `uninline_relation(rtype, commit=True)`
-
-
-[FIXME] Add explanation on how to use cubicweb-ctl shell