Metadata-Version: 1.1
Name: nomad
Version: 1.19
Summary: simple sql migration tool to save you from becoming mad
Home-page: http://github.com/piranha/nomad/
Author: Alexander Solovyov
Author-email: alexander@solovyov.net
License: ISC
Description: .. -*- mode: rst -*-
        
        =======
         Nomad
        =======
        
        Nomad is a simple migration application, which specifically takes into account
        properties of development with DVCS and is completely agnostic from ORM or
        whatever you are using to access your database. It uses simple SQL scripts to
        migrate and can run pre- and post-processing routines written in any language
        (Python, Ruby or whatever do you use for your application).
        
        Tests status: |travis|, `changelog <https://github.com/piranha/nomad/blob/master/CHANGELOG.rst>`_
        
        .. |travis| image:: https://travis-ci.org/piranha/nomad.png
           :target: https://travis-ci.org/piranha/nomad
        
        .. begin-writeup
        
        Layout
        -------
        
        Nomad's migration store is a directory with ``nomad.ini`` and directories with
        migrations inside. Each such directory must contain ``migration.ini`` to be
        recognized as a migration and this directory name is an unique identifier of a
        migration.
        
        Your directory tree thus will look like this::
        
          migrations/
            nomad.ini
            2011-11-11-first-migration/
              migration.ini
              up.sql
            2011-11-12-second-migration/
              migration.ini
              1-pre.py
              2-up.sql
              3-post.py
            2011-11-13-third-migration/
              migration.ini
              1-pre.py
              2-up.sql
              3-post.sql.j2
        
        Nomad uses table called ``nomad`` to track what was applied already. It's just a
        list of applied migrations and dates when they were applied.
        
        Interface
        ---------
        
        To start working, create ``nomad.ini``, and initialize your database (I assume
        it already exists)::
        
          $ nomad init
        
        Then you can start creating your first migration::
        
          $ nomad create 0-initial
        
        Put your ALTERs and CREATEs in ``0-initial/up.sql`` and apply a migration::
        
          $ nomad apply -a # or nomad apply 0-initial
        
        Nomad should report which migrations it applied successfully, but you can check
        status of that with ``nomad ls -a`` (or ``nomad ls`` to see only unapplied
        migrations).
        
        I guess it's time to create new migration::
        
          $ nomad create 1-next -d 0-initial
        
        ``-d 0-initial`` means you want your ``1-next`` to depend on ``0-initial``. This
        means Nomad will never apply ``1-next`` without applying ``0-initial``
        first. You usually want to depend on migrations which created tables you're
        going to alter, or just to make it easier - on the latest available migration.
        
        Usage
        -----
        
        There are three types of migration files that ``nomad`` supports:
        
        1.  Plain SQL files with the extension ``.sql``. Just put SQL commands you need
            to execute in the migration folder and they will be executed.
        2.  Executable files. All file extensions are supported as long as the file
            is executable. These files must contain everything necessary to migrate
            your data, including setting up a database connection. ``nomad`` will pass
            all of the `Configuration`_ variables as environmental variables, prefixed
            with their section.
        3.  Template files with the extension ``.j2``. These templates will be
            passed through the Jinja2 templating library. You must install the
            ``jinja2`` library for this functionality. The entire `Configuration`_ is
            available to the template files as a single dictionary. These could be
            useful if you are distributing an application where the end user needs to
            control some aspects of the migrations (ie. additional database users and
            passwords, additonal database names, etc.).
        
            ::
        
              # nomad.ini
              [db]
              another_user = reader
              another_pass = pass
        
            ::
        
              # migrations/0001-initial/up.sql.j2
              CREATE ROLE {{ db.another_user }};
              ALTER ROLE {{ db.another_user }} WITH NOSUPERUSER LOGIN PASSWORD '{{ db.another_pass }}' VALID UNTIL 'infinity';
        
        
        Files inside of each migration folder are executed in lexographical order.
        
        
        Configuration
        -------------
        
        Nomad reads database connection information from the ``[nomad]`` section of the
        ``nomad.ini`` file.
        
        ::
        
          [nomad]
          engine = sqla
          url = pgsql://user:password@host:port/db
        
        Possible configuration options:
        
        - ``engine`` (required) - SQL engine to use, possible options:
        
          - ``sqla`` - use SQLAlchemy as an adapter, supports everything SQLAlchemy supports
          - ``dbapi`` - use regular DB API, supports ``sqlite``, ``mysql`` and ``pgsql``
        
        - ``url`` (required) - URL to database, takes multiple options, see format below
        - ``path`` - path to migrations (default: directory with ``nomad.ini``)
        
        Each migration has its own ``migration.ini`` file, which, by default, has a
        single configuration option, ``nomad.dependencies``, defining which migration
        (or migrations) this one depends.
        
        You may add your own configuration variables to either the ``nomad.ini`` or
        ``migration.ini`` files and they will be available in your jinja2 templates
        as a single dictionary and your executable files as environmental
        variables.
        
        Note that ini-files are parsed with extended interpolation (use it like
        ``${var}`` or ``${section.var}``).
        
        A few predefined variables are provided to every migration:
        
        - ``confpath`` - path to ``nomad.ini``
        - ``confdir`` - path to directory, containing ``nomad.ini``
        - ``dir`` - path to directory of migration
        
        
        Example configuration:
        
        +------------------+---------------------------+------------------------------+
        |   configration   |         executable        |          template            |
        +==================+===========================+==============================+
        | ::               | ::                        | ::                           |
        |                  |                           |                              |
        |   [nomad]        |   NOMAD_ENGINE = sqla     |   nomad.engine = sqla        |
        |   engine = sqla  |   NOMAD_URL = someurl     |   nomad.url = someurl        |
        |   url = someurl  |                           |                              |
        |                  |   FOO_BAR = zeta          |   foo.bar = zeta             |
        |   [foo]          |                           |                              |
        |   bar = zeta     |   NOMAD_CONFPATH = path   |   nomad.confpath = path      |
        |                  |   NOMAD_CONFDIR = dir1    |   nomad.confdir = dir1       |
        |                  |   NOMAD_DIR = dir2        |   nomad.dir = dir2           |
        +------------------+---------------------------+------------------------------+
        
        
        URL format
        ~~~~~~~~~~
        
        Nomad can read connection url to database in a few various ways. ``nomad.url``
        configuration option is a space separated list of descriptions of how Nomad can
        obtain database connection url.
        
        The easiest one is simply an url (like in config example). The others are:
        
        - ``file:<path-to-file>`` - a path to file containing connection url
        - ``env:<var-name>`` - an environment variable (do not prefix with `$`)
        - ``py:<python.mod>:<variable.name>`` - a Python path to a module,
          containing a variable with connection url
        - ``cmd:<cmd-to-execute>`` - command to execute to get connection url
        - ``json:<path-to-file>:key.0.key`` - path to file with JSON and then path
          to a connection url within JSON object
        - ``yaml:<path-to-file>:key.0.key`` - path to file with YAML and then path
          to a connection url within YAML object
        - ``ini:<path-to-file>:<section.key>`` - path to INI file (parsed by
          configparser with extended interpolation) and then path to a connection url
          within this file
        
        An example::
        
          [nomad]
          url =
            ini:${confdir}/../settings.ini:db.url
            json:${confdir}/../settings.json:db.url
            sqlite:///${confdir}/../local.db
        
        Notice that in all cases in the end you have to return URL to a database in
        normal format, i.e. ``dbtype://user:pass@host:port/dbname?options``.
        
        ``options`` are supported only by pgsql right now, whatever you put there, nomad
        will do ``set ...`` before every migration. Note that if you do not supply
        anything there, nomad sets ``statement_timeout`` to 1000 ms and ``lock_timeout``
        to 500 ms by default.
        
        Main ideas
        ----------
        
        - There are no downgrades - nobody ever tests them, and they are rarely
          necessary. Just write an upgrade if you need to cancel something.
        - You can write migration in whatever language you want, Nomad only helps you
          track applied migrations and dependencies.
        - ``.sql`` is treated differently and executed against database, configured in
          ``nomad.ini``.
        - Only ``.sql``, ``.j2``, and executable files (sorry, Windows! - though I am eager to
          hear ideas how to support it) are executed. You can put READMEs, pieces of
          documentation, whatever you want alongside your migrations.
        - Name matters - everything is executed in order. Order is determined by using
          human sort (so that ``x-1.sql`` is earlier than ``x-10.sql``, you can always
          check sorting with ``ls --sort=version``).
        
        .. end-writeup
        
Platform: any
Classifier: Environment :: Console
Classifier: Intended Audience :: Developers
Classifier: License :: OSI Approved :: BSD License
Classifier: Operating System :: OS Independent
Classifier: Programming Language :: Python
Classifier: Topic :: Software Development
Classifier: Topic :: Software Development :: Version Control
Classifier: Topic :: Database
