python-desktopcouch-application 1.0.8-0ubuntu3 / usr / share / pyshared / desktopcouch / application / migration / __init__.py

# Copyright 2010 Canonical Ltd.
#
# This file is part of desktopcouch.
#
# desktopcouch is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License version 3
# as published by the Free Software Foundation.
#
# desktopcouch is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with desktopcouch.  If not, see <http://www.gnu.org/licenses/>.
#
# Authors: Eric Casteleijn <eric.casteleijn@canonical.com>
#          Vincenzo Di Somma <vincenzo.di.somma@canonical.com>

"""Basic migration infrastructure"""

import logging
import os
import glob
import itertools
import xdg.BaseDirectory

from desktopcouch.records import database
from desktopcouch.application import server
from desktopcouch.application.platform import find_port
from desktopcouch.application.server import DesktopDatabase


MIGRATION_DESIGN_DOCUMENT = 'dc_migration'


def update_design_documents(ctx=None):
    """Check system design documents and update any that need updating

    A database should be created if
    $XDG_DATA_DIRs/desktop-couch/databases/dbname/database.cfg exists

    Design docs are defined by the existence of
    $XDG_DATA_DIRs/desktop-couch/databases/dbname/_design/designdocname\
        /views/viewname/map.js

    reduce.js may also exist in the same folder.
    """
    from desktopcouch.application import local_files
    if ctx is None:
        ctx = local_files.DEFAULT_CONTEXT
    ctx_data_dir = os.path.split(ctx.db_dir)[0]
    for base in itertools.chain([ctx_data_dir],
                                xdg.BaseDirectory.xdg_data_dirs):
        # FIXME base may have magic chars. assert not glob.has_magic(base)?
        db_spec = os.path.join(
            base, "desktop-couch", "databases", "*", "database.cfg")
        for database_path in glob.glob(db_spec):
            database_root = os.path.split(database_path)[0]
            database_name = os.path.split(database_root)[1]
            # Just the presence of database.cfg is enough to create
            # the database
            logging.info("Updating database %s", database_name)
            db = DesktopDatabase(database_name, create=True, ctx=ctx)
            # look for design documents
            dd_spec = os.path.join(
                database_root, "_design", "*", "views", "*", "map.js")
            # FIXME: dd_path may have magic chars.
            for dd_path in glob.glob(dd_spec):
                view_root = os.path.split(dd_path)[0]
                view_name = os.path.split(view_root)[1]
                dd_root = os.path.split(os.path.split(view_root)[0])[0]
                dd_name = os.path.split(dd_root)[1]

                def load_js_file(filename_no_extension):
                    """Load javascript view definition from a file."""
                    fn = os.path.join(
                        view_root, "%s.js" % (filename_no_extension))
                    if not os.path.isfile(fn):
                        return None
                    fp = open(fn)
                    data = fp.read()
                    fp.close()
                    return data

                mapjs = load_js_file("map")
                reducejs = load_js_file("reduce")

                # XXX check whether this already exists or not, rather
                # than inefficiently just overwriting it regardless
                if reducejs is not None:
                    db.add_view(
                        view_name, mapjs, reduce_js=reducejs,
                        design_doc=dd_name)
                else:
                    db.add_view(
                        view_name, mapjs, design_doc=dd_name)


def _all_dbs(ctx):
    """Get all the non private dbs from a server."""
    port = find_port(ctx=ctx)
    uri = "http://localhost:%s" % port
    couchdb_server = server.DesktopServer(uri, oauth_tokens=None, ctx=ctx)
    return [x for x in couchdb_server if not
            x.startswith('_') and not x == database.DCTRASH]


def register(migration_method, dbs=None):
    """Register a migration script, with the view and the dbs it is meant to
    migrate."""
    if dbs is None:
        dbs = []
    MIGRATIONS_REGISTRY.append(
        {'method': migration_method, 'dbs': dbs})


def run_needed_migrations(ctx=None):
    """Run the actual migration."""
    from desktopcouch.application import local_files
    if ctx is None:
        ctx = local_files.DEFAULT_CONTEXT
    all_dbs = _all_dbs(ctx)
    for migration in MIGRATIONS_REGISTRY:
        dbs = migration['dbs']
        if not dbs:
            dbs = all_dbs
        for db_name in dbs:
            db = server.DesktopDatabase(database=db_name, ctx=ctx)
            try:
                migration['method'](db)
                logging.info("Migrating DB: %s", db_name)
            except database.NoSuchDatabase:
                pass

DELETION_VIEW_NAME = 'migrate_deleted'

DELETION_VIEW_CODE = """
    function(doc) {
        if (doc['application_annotations']['Ubuntu One']
        ['private_application_annotations']['deleted'] && doc.record_type) {
        emit(doc.id, doc.id);
        }
    }"""


def migrate_from_deleted_to_trash(migrateable_db):
    """Migrate from deleted flag to the dc_trash database."""
    migrateable_db.add_view(
        DELETION_VIEW_NAME, map_js=DELETION_VIEW_CODE,
        design_doc=MIGRATION_DESIGN_DOCUMENT)
    view_result = migrateable_db.execute_view(
        view_name=DELETION_VIEW_NAME, design_doc=MIGRATION_DESIGN_DOCUMENT)
    for result in view_result:
        migrateable_db.delete_record(result.id)


MIGRATIONS_REGISTRY = [{'method': migrate_from_deleted_to_trash, 'dbs': []}]