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OpenStack Study: utils.py**** CubicPower OpenStack Study ****
# Copyright 2010 United States Government as represented by the # Administrator of the National Aeronautics and Space Administration. # Copyright 2010-2011 OpenStack Foundation. # Copyright 2012 Justin Santa Barbara # 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. import logging import re from migrate.changeset import UniqueConstraint import sqlalchemy from sqlalchemy import Boolean from sqlalchemy import CheckConstraint from sqlalchemy import Column from sqlalchemy.engine import reflection from sqlalchemy.ext.compiler import compiles from sqlalchemy import func from sqlalchemy import Index from sqlalchemy import Integer from sqlalchemy import MetaData from sqlalchemy import or_ from sqlalchemy.sql.expression import literal_column from sqlalchemy.sql.expression import UpdateBase from sqlalchemy.sql import select from sqlalchemy import String from sqlalchemy import Table from sqlalchemy.types import NullType from nova.openstack.common import context as request_context from nova.openstack.common.db.sqlalchemy import models from nova.openstack.common.gettextutils import _, _LI, _LW from nova.openstack.common import timeutils LOG = logging.getLogger(__name__) _DBURL_REGEX = re.compile(r"[^:]+://([^:]+):([^@]+)@.+")
**** CubicPower OpenStack Study **** def sanitize_db_url(url): match = _DBURL_REGEX.match(url) if match: return '%s****:****%s' % (url[:match.start(1)], url[match.end(2):]) return url
**** CubicPower OpenStack Study **** class InvalidSortKey(Exception): message = _("Sort key supplied was not valid.") # copy from glance/db/sqlalchemy/api.py
**** CubicPower OpenStack Study **** def paginate_query(query, model, limit, sort_keys, marker=None, sort_dir=None, sort_dirs=None): """Returns a query with sorting / pagination criteria added. Pagination works by requiring a unique sort_key, specified by sort_keys. (If sort_keys is not unique, then we risk looping through values.) We use the last row in the previous page as the 'marker' for pagination. So we must return values that follow the passed marker in the order. With a single-valued sort_key, this would be easy: sort_key > X. With a compound-values sort_key, (k1, k2, k3) we must do this to repeat the lexicographical ordering: (k1 > X1) or (k1 == X1 && k2 > X2) or (k1 == X1 && k2 == X2 && k3 > X3) We also have to cope with different sort_directions. Typically, the id of the last row is used as the client-facing pagination marker, then the actual marker object must be fetched from the db and passed in to us as marker. :param query: the query object to which we should add paging/sorting :param model: the ORM model class :param limit: maximum number of items to return :param sort_keys: array of attributes by which results should be sorted :param marker: the last item of the previous page; we returns the next results after this value. :param sort_dir: direction in which results should be sorted (asc, desc) :param sort_dirs: per-column array of sort_dirs, corresponding to sort_keys :rtype: sqlalchemy.orm.query.Query :return: The query with sorting/pagination added. """ if 'id' not in sort_keys: # TODO(justinsb): If this ever gives a false-positive, check # the actual primary key, rather than assuming its id LOG.warning(_LW('Id not in sort_keys; is sort_keys unique?')) assert(not (sort_dir and sort_dirs)) # Default the sort direction to ascending if sort_dirs is None and sort_dir is None: sort_dir = 'asc' # Ensure a per-column sort direction if sort_dirs is None: sort_dirs = [sort_dir for _sort_key in sort_keys] assert(len(sort_dirs) == len(sort_keys)) # Add sorting for current_sort_key, current_sort_dir in zip(sort_keys, sort_dirs): try: sort_dir_func = { 'asc': sqlalchemy.asc, 'desc': sqlalchemy.desc, }[current_sort_dir] except KeyError: raise ValueError(_("Unknown sort direction, " "must be 'desc' or 'asc'")) try: sort_key_attr = getattr(model, current_sort_key) except AttributeError: raise InvalidSortKey() query = query.order_by(sort_dir_func(sort_key_attr)) # Add pagination if marker is not None: marker_values = [] for sort_key in sort_keys: v = getattr(marker, sort_key) marker_values.append(v) # Build up an array of sort criteria as in the docstring criteria_list = [] for i in range(len(sort_keys)): crit_attrs = [] for j in range(i): model_attr = getattr(model, sort_keys[j]) crit_attrs.append((model_attr == marker_values[j])) model_attr = getattr(model, sort_keys[i]) if sort_dirs[i] == 'desc': crit_attrs.append((model_attr < marker_values[i])) else: crit_attrs.append((model_attr > marker_values[i])) criteria = sqlalchemy.sql.and_(*crit_attrs) criteria_list.append(criteria) f = sqlalchemy.sql.or_(*criteria_list) query = query.filter(f) if limit is not None: query = query.limit(limit) return query
**** CubicPower OpenStack Study **** def _read_deleted_filter(query, db_model, read_deleted): if 'deleted' not in db_model.__table__.columns: raise ValueError(_("There is no `deleted` column in `%s` table. " "Project doesn't use soft-deleted feature.") % db_model.__name__) default_deleted_value = db_model.__table__.c.deleted.default.arg if read_deleted == 'no': query = query.filter(db_model.deleted == default_deleted_value) elif read_deleted == 'yes': pass # omit the filter to include deleted and active elif read_deleted == 'only': query = query.filter(db_model.deleted != default_deleted_value) else: raise ValueError(_("Unrecognized read_deleted value '%s'") % read_deleted) return query
**** CubicPower OpenStack Study **** def _project_filter(query, db_model, context, project_only): if project_only and 'project_id' not in db_model.__table__.columns: raise ValueError(_("There is no `project_id` column in `%s` table.") % db_model.__name__) if request_context.is_user_context(context) and project_only: if project_only == 'allow_none': is_none = None query = query.filter(or_(db_model.project_id == context.project_id, db_model.project_id == is_none)) else: query = query.filter(db_model.project_id == context.project_id) return query
**** CubicPower OpenStack Study **** def model_query(context, model, session, args=None, project_only=False, read_deleted=None): """Query helper that accounts for context's `read_deleted` field. :param context: context to query under :param model: Model to query. Must be a subclass of ModelBase. :type model: models.ModelBase :param session: The session to use. :type session: sqlalchemy.orm.session.Session :param args: Arguments to query. If None - model is used. :type args: tuple :param project_only: If present and context is user-type, then restrict query to match the context's project_id. If set to 'allow_none', restriction includes project_id = None. :type project_only: bool :param read_deleted: If present, overrides context's read_deleted field. :type read_deleted: bool Usage: result = (utils.model_query(context, models.Instance, session=session) .filter_by(uuid=instance_uuid) .all()) query = utils.model_query( context, Node, session=session, args=(func.count(Node.id), func.sum(Node.ram)) ).filter_by(project_id=project_id) """ if not read_deleted: if hasattr(context, 'read_deleted'): # NOTE(viktors): some projects use `read_deleted` attribute in # their contexts instead of `show_deleted`. read_deleted = context.read_deleted else: read_deleted = context.show_deleted if not issubclass(model, models.ModelBase): raise TypeError(_("model should be a subclass of ModelBase")) query = session.query(model) if not args else session.query(*args) query = _read_deleted_filter(query, model, read_deleted) query = _project_filter(query, model, context, project_only) return query
**** CubicPower OpenStack Study **** def get_table(engine, name): """Returns an sqlalchemy table dynamically from db. Needed because the models don't work for us in migrations as models will be far out of sync with the current data. """ metadata = MetaData() metadata.bind = engine return Table(name, metadata, autoload=True)
**** CubicPower OpenStack Study **** class InsertFromSelect(UpdateBase): """Form the base for `INSERT INTO table (SELECT ... )` statement."""
**** CubicPower OpenStack Study **** def __init__(self, table, select): self.table = table self.select = select @compiles(InsertFromSelect) def visit_insert_from_select(element, compiler, **kw): """Form the `INSERT INTO table (SELECT ... )` statement.""" return "INSERT INTO %s %s" % ( compiler.process(element.table, asfrom=True), compiler.process(element.select))
**** CubicPower OpenStack Study **** def visit_insert_from_select(element, compiler, **kw): """Form the `INSERT INTO table (SELECT ... )` statement.""" return "INSERT INTO %s %s" % ( compiler.process(element.table, asfrom=True), compiler.process(element.select))
**** CubicPower OpenStack Study **** class ColumnError(Exception): """Error raised when no column or an invalid column is found."""
**** CubicPower OpenStack Study **** def is_deleted_column_constraint(constraint): # NOTE(boris-42): There is no other way to check is CheckConstraint # associated with deleted column. if not isinstance(constraint, CheckConstraint): return False sqltext = str(constraint.sqltext) return (sqltext.endswith("deleted in (0, 1)") or sqltext.endswith("deleted IN (:deleted_1, :deleted_2)")) constraints = [] for constraint in table.constraints: if not is_deleted_column_constraint(constraint): constraints.append(constraint.copy()) new_table = Table(table_name + "__tmp__", meta, *(columns + constraints)) new_table.create() indexes = [] for index in insp.get_indexes(table_name): column_names = [new_table.c[c] for c in index['column_names']] indexes.append(Index(index["name"], *column_names, unique=index["unique"])) ins = InsertFromSelect(new_table, table.select()) migrate_engine.execute(ins) table.drop() [index.create(migrate_engine) for index in indexes] new_table.rename(table_name) deleted = True # workaround for pyflakes new_table.update().\ where(new_table.c.deleted == deleted).\ values(deleted=new_table.c.id).\ execute() # NOTE(boris-42): Fix value of deleted column: False -> "" or 0. deleted = False # workaround for pyflakes new_table.update().\ where(new_table.c.deleted == deleted).\ values(deleted=default_deleted_value).\ execute() def get_connect_string(backend, database, user=None, passwd=None): """Get database connection Try to get a connection with a very specific set of values, if we get these then we'll run the tests, otherwise they are skipped """ args = {'backend': backend, 'user': user, 'passwd': passwd, 'database': database} if backend == 'sqlite': template = '%(backend)s:///%(database)s' else: template = "%(backend)s://%(user)s:%(passwd)s@localhost/%(database)s" return template % args def is_backend_avail(backend, database, user=None, passwd=None): try: connect_uri = get_connect_string(backend=backend, database=database, user=user, passwd=passwd) engine = sqlalchemy.create_engine(connect_uri) connection = engine.connect() except Exception: # intentionally catch all to handle exceptions even if we don't # have any backend code loaded. return False else: connection.close() engine.dispose() return True def get_db_connection_info(conn_pieces): database = conn_pieces.path.strip('/') loc_pieces = conn_pieces.netloc.split('@') host = loc_pieces[1] auth_pieces = loc_pieces[0].split(':') user = auth_pieces[0] password = "" if len(auth_pieces) > 1: password = auth_pieces[1].strip() return (user, password, database, host)
**** CubicPower OpenStack Study **** def get_connect_string(backend, database, user=None, passwd=None): """Get database connection Try to get a connection with a very specific set of values, if we get these then we'll run the tests, otherwise they are skipped """ args = {'backend': backend, 'user': user, 'passwd': passwd, 'database': database} if backend == 'sqlite': template = '%(backend)s:///%(database)s' else: template = "%(backend)s://%(user)s:%(passwd)s@localhost/%(database)s" return template % args
**** CubicPower OpenStack Study **** def is_backend_avail(backend, database, user=None, passwd=None): try: connect_uri = get_connect_string(backend=backend, database=database, user=user, passwd=passwd) engine = sqlalchemy.create_engine(connect_uri) connection = engine.connect() except Exception: # intentionally catch all to handle exceptions even if we don't # have any backend code loaded. return False else: connection.close() engine.dispose() return True
**** CubicPower OpenStack Study **** def get_db_connection_info(conn_pieces): database = conn_pieces.path.strip('/') loc_pieces = conn_pieces.netloc.split('@') host = loc_pieces[1] auth_pieces = loc_pieces[0].split(':') user = auth_pieces[0] password = "" if len(auth_pieces) > 1: password = auth_pieces[1].strip() return (user, password, database, host)
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