/usr/lib/python2.7/dist-packages/ovs/db/schema.py is in python-openvswitch 2.5.5-0ubuntu0.16.04.2.
This file is owned by root:root, with mode 0o644.
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#
# 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 re
import sys
from ovs.db import error
import ovs.db.parser
from ovs.db import types
def _check_id(name, json):
if name.startswith('_'):
raise error.Error('names beginning with "_" are reserved', json)
elif not ovs.db.parser.is_identifier(name):
raise error.Error("name must be a valid id", json)
class DbSchema(object):
"""Schema for an OVSDB database."""
def __init__(self, name, version, tables):
self.name = name
self.version = version
self.tables = tables
# "isRoot" was not part of the original schema definition. Before it
# was added, there was no support for garbage collection. So, for
# backward compatibility, if the root set is empty then assume that
# every table is in the root set.
if self.__root_set_size() == 0:
for table in self.tables.itervalues():
table.is_root = True
# Find the "ref_table"s referenced by "ref_table_name"s.
#
# Also force certain columns to be persistent, as explained in
# __check_ref_table(). This requires 'is_root' to be known, so this
# must follow the loop updating 'is_root' above.
for table in self.tables.itervalues():
for column in table.columns.itervalues():
self.__follow_ref_table(column, column.type.key, "key")
self.__follow_ref_table(column, column.type.value, "value")
def __root_set_size(self):
"""Returns the number of tables in the schema's root set."""
n_root = 0
for table in self.tables.itervalues():
if table.is_root:
n_root += 1
return n_root
@staticmethod
def from_json(json):
parser = ovs.db.parser.Parser(json, "database schema")
name = parser.get("name", ['id'])
version = parser.get_optional("version", [str, unicode])
parser.get_optional("cksum", [str, unicode])
tablesJson = parser.get("tables", [dict])
parser.finish()
if (version is not None and
not re.match('[0-9]+\.[0-9]+\.[0-9]+$', version)):
raise error.Error('schema version "%s" not in format x.y.z'
% version)
tables = {}
for tableName, tableJson in tablesJson.iteritems():
_check_id(tableName, json)
tables[tableName] = TableSchema.from_json(tableJson, tableName)
return DbSchema(name, version, tables)
def to_json(self):
# "isRoot" was not part of the original schema definition. Before it
# was added, there was no support for garbage collection. So, for
# backward compatibility, if every table is in the root set then do not
# output "isRoot" in table schemas.
default_is_root = self.__root_set_size() == len(self.tables)
tables = {}
for table in self.tables.itervalues():
tables[table.name] = table.to_json(default_is_root)
json = {"name": self.name, "tables": tables}
if self.version:
json["version"] = self.version
return json
def copy(self):
return DbSchema.from_json(self.to_json())
def __follow_ref_table(self, column, base, base_name):
if not base or base.type != types.UuidType or not base.ref_table_name:
return
base.ref_table = self.tables.get(base.ref_table_name)
if not base.ref_table:
raise error.Error("column %s %s refers to undefined table %s"
% (column.name, base_name, base.ref_table_name),
tag="syntax error")
if base.is_strong_ref() and not base.ref_table.is_root:
# We cannot allow a strong reference to a non-root table to be
# ephemeral: if it is the only reference to a row, then replaying
# the database log from disk will cause the referenced row to be
# deleted, even though it did exist in memory. If there are
# references to that row later in the log (to modify it, to delete
# it, or just to point to it), then this will yield a transaction
# error.
column.persistent = True
class IdlSchema(DbSchema):
def __init__(self, name, version, tables, idlPrefix, idlHeader):
DbSchema.__init__(self, name, version, tables)
self.idlPrefix = idlPrefix
self.idlHeader = idlHeader
@staticmethod
def from_json(json):
parser = ovs.db.parser.Parser(json, "IDL schema")
idlPrefix = parser.get("idlPrefix", [str, unicode])
idlHeader = parser.get("idlHeader", [str, unicode])
subjson = dict(json)
del subjson["idlPrefix"]
del subjson["idlHeader"]
schema = DbSchema.from_json(subjson)
return IdlSchema(schema.name, schema.version, schema.tables,
idlPrefix, idlHeader)
def column_set_from_json(json, columns):
if json is None:
return tuple(columns)
elif type(json) != list:
raise error.Error("array of distinct column names expected", json)
else:
for column_name in json:
if type(column_name) not in [str, unicode]:
raise error.Error("array of distinct column names expected",
json)
elif column_name not in columns:
raise error.Error("%s is not a valid column name"
% column_name, json)
if len(set(json)) != len(json):
# Duplicate.
raise error.Error("array of distinct column names expected", json)
return tuple([columns[column_name] for column_name in json])
class TableSchema(object):
def __init__(self, name, columns, mutable=True, max_rows=sys.maxint,
is_root=True, indexes=[]):
self.name = name
self.columns = columns
self.mutable = mutable
self.max_rows = max_rows
self.is_root = is_root
self.indexes = indexes
@staticmethod
def from_json(json, name):
parser = ovs.db.parser.Parser(json, "table schema for table %s" % name)
columns_json = parser.get("columns", [dict])
mutable = parser.get_optional("mutable", [bool], True)
max_rows = parser.get_optional("maxRows", [int])
is_root = parser.get_optional("isRoot", [bool], False)
indexes_json = parser.get_optional("indexes", [list], [])
parser.finish()
if max_rows == None:
max_rows = sys.maxint
elif max_rows <= 0:
raise error.Error("maxRows must be at least 1", json)
if not columns_json:
raise error.Error("table must have at least one column", json)
columns = {}
for column_name, column_json in columns_json.iteritems():
_check_id(column_name, json)
columns[column_name] = ColumnSchema.from_json(column_json,
column_name)
indexes = []
for index_json in indexes_json:
index = column_set_from_json(index_json, columns)
if not index:
raise error.Error("index must have at least one column", json)
elif len(index) == 1:
index[0].unique = True
for column in index:
if not column.persistent:
raise error.Error("ephemeral columns (such as %s) may "
"not be indexed" % column.name, json)
indexes.append(index)
return TableSchema(name, columns, mutable, max_rows, is_root, indexes)
def to_json(self, default_is_root=False):
"""Returns this table schema serialized into JSON.
The "isRoot" member is included in the JSON only if its value would
differ from 'default_is_root'. Ordinarily 'default_is_root' should be
false, because ordinarily a table would be not be part of the root set
if its "isRoot" member is omitted. However, garbage collection was not
originally included in OVSDB, so in older schemas that do not include
any "isRoot" members, every table is implicitly part of the root set.
To serialize such a schema in a way that can be read by older OVSDB
tools, specify 'default_is_root' as True.
"""
json = {}
if not self.mutable:
json["mutable"] = False
if default_is_root != self.is_root:
json["isRoot"] = self.is_root
json["columns"] = columns = {}
for column in self.columns.itervalues():
if not column.name.startswith("_"):
columns[column.name] = column.to_json()
if self.max_rows != sys.maxint:
json["maxRows"] = self.max_rows
if self.indexes:
json["indexes"] = []
for index in self.indexes:
json["indexes"].append([column.name for column in index])
return json
class ColumnSchema(object):
def __init__(self, name, mutable, persistent, type_):
self.name = name
self.mutable = mutable
self.persistent = persistent
self.type = type_
self.unique = False
@staticmethod
def from_json(json, name):
parser = ovs.db.parser.Parser(json, "schema for column %s" % name)
mutable = parser.get_optional("mutable", [bool], True)
ephemeral = parser.get_optional("ephemeral", [bool], False)
type_ = types.Type.from_json(parser.get("type", [dict, str, unicode]))
parser.finish()
return ColumnSchema(name, mutable, not ephemeral, type_)
def to_json(self):
json = {"type": self.type.to_json()}
if not self.mutable:
json["mutable"] = False
if not self.persistent:
json["ephemeral"] = True
return json
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