+
+
+class SchemaHelper(object):
+ """IDL Schema helper.
+
+ This class encapsulates the logic required to generate schemas suitable
+ for creating 'ovs.db.idl.Idl' objects. Clients should register columns
+ they are interested in using register_columns(). When finished, the
+ get_idl_schema() function may be called.
+
+ The location on disk of the schema used may be found in the
+ 'schema_location' variable."""
+
+ def __init__(self, location=None):
+ """Creates a new Schema object."""
+
+ if location is None:
+ location = "%s/vswitch.ovsschema" % ovs.dirs.PKGDATADIR
+
+ self.schema_location = location
+ self._tables = {}
+ self._all = False
+
+ def register_columns(self, table, columns):
+ """Registers interest in the given 'columns' of 'table'. Future calls
+ to get_idl_schema() will include 'table':column for each column in
+ 'columns'. This function automatically avoids adding duplicate entries
+ to the schema.
+
+ 'table' must be a string.
+ 'columns' must be a list of strings.
+ """
+
+ assert type(table) is str
+ assert type(columns) is list
+
+ columns = set(columns) | self._tables.get(table, set())
+ self._tables[table] = columns
+
+ def register_all(self):
+ """Registers interest in every column of every table."""
+ self._all = True
+
+ def get_idl_schema(self):
+ """Gets a schema appropriate for the creation of an 'ovs.db.id.IDL'
+ object based on columns registered using the register_columns()
+ function."""
+
+ schema = ovs.db.schema.DbSchema.from_json(
+ ovs.json.from_file(self.schema_location))
+
+ if not self._all:
+ schema_tables = {}
+ for table, columns in self._tables.iteritems():
+ schema_tables[table] = (
+ self._keep_table_columns(schema, table, columns))
+
+ schema.tables = schema_tables
+ return schema
+
+ def _keep_table_columns(self, schema, table_name, columns):
+ assert table_name in schema.tables
+ table = schema.tables[table_name]
+
+ new_columns = {}
+ for column_name in columns:
+ assert type(column_name) is str
+ assert column_name in table.columns
+
+ new_columns[column_name] = table.columns[column_name]
+
+ table.columns = new_columns
+ return table
git://git.onelab.eu / sliver-openvswitch.git / blobdiff