# limitations under the License.
import logging
+import uuid
import ovs.jsonrpc
import ovs.db.parser
import ovs.db.schema
from ovs.db import error
import ovs.ovsuuid
+import ovs.poller
class Idl:
"""Open vSwitch Database Interface Definition Language (OVSDB IDL).
JSON-RPC requests and reports to the client whether the transaction
completed successfully.
- If 'schema_cb' is provided, it should be a callback function that accepts
- an ovs.db.schema.DbSchema as its argument. It should determine whether the
- schema is acceptable and raise an ovs.db.error.Error if it is not. It may
- also delete any tables or columns from the schema that the client has no
- interest in monitoring, to save time and bandwidth during monitoring. Its
- return value is ignored."""
+ The client is allowed to access the following attributes directly, in a
+ read-only fashion:
- def __init__(self, remote, db_name, schema_cb=None):
+ - 'tables': This is the 'tables' map in the ovs.db.schema.DbSchema provided
+ to the Idl constructor. Each ovs.db.schema.TableSchema in the map is
+ annotated with a new attribute 'rows', which is a dict from a uuid.UUID
+ to a Row object.
+
+ The client may directly read and write the Row objects referenced by the
+ 'rows' map values. Refer to Row for more details.
+
+ - 'change_seqno': A number that represents the IDL's state. When the IDL
+ is updated (by Idl.run()), its value changes.
+
+ - 'lock_name': The name of the lock configured with Idl.set_lock(), or None
+ if no lock is configured.
+
+ - 'has_lock': True, if the IDL is configured to obtain a lock and owns that
+ lock, and False otherwise.
+
+ Locking and unlocking happens asynchronously from the database client's
+ point of view, so the information is only useful for optimization
+ (e.g. if the client doesn't have the lock then there's no point in trying
+ to write to the database).
+
+ - 'is_lock_contended': True, if the IDL is configured to obtain a lock but
+ the database server has indicated that some other client already owns the
+ requested lock, and False otherwise.
+
+ - 'txn': The ovs.db.idl.Transaction object for the database transaction
+ currently being constructed, if there is one, or None otherwise.
+"""
+
+ def __init__(self, remote, schema):
"""Creates and returns a connection to the database named 'db_name' on
'remote', which should be in a form acceptable to
ovs.jsonrpc.session.open(). The connection will maintain an in-memory
- replica of the remote database."""
- self.remote = remote
- self.session = ovs.jsonrpc.Session.open(remote)
- self.db_name = db_name
- self.last_seqno = None
- self.schema = None
- self.state = None
+ replica of the remote database.
+
+ 'schema' should be the schema for the remote database. The caller may
+ have cut it down by removing tables or columns that are not of
+ interest. The IDL will only replicate the tables and columns that
+ remain. The caller may also add a attribute named 'alert' to selected
+ remaining columns, setting its value to False; if so, then changes to
+ those columns will not be considered changes to the database for the
+ purpose of the return value of Idl.run() and Idl.change_seqno. This is
+ useful for columns that the IDL's client will write but not read.
+
+ The IDL uses and modifies 'schema' directly."""
+
+ self.tables = schema.tables
+ self._db = schema
+ self._session = ovs.jsonrpc.Session.open(remote)
+ self._monitor_request_id = None
+ self._last_seqno = None
self.change_seqno = 0
- self.data = {}
- self.schema_cb = schema_cb
+
+ # Database locking.
+ self.lock_name = None # Name of lock we need, None if none.
+ self.has_lock = False # Has db server said we have the lock?
+ self.is_lock_contended = False # Has db server said we can't get lock?
+ self._lock_request_id = None # JSON-RPC ID of in-flight lock request.
+
+ # Transaction support.
+ self.txn = None
+ self._outstanding_txns = {}
+
+ for table in schema.tables.itervalues():
+ for column in table.columns.itervalues():
+ if not hasattr(column, 'alert'):
+ column.alert = True
+ table.need_table = False
+ table.rows = {}
+ table.idl = self
def close(self):
- self.session.close()
+ """Closes the connection to the database. The IDL will no longer
+ update."""
+ self._session.close()
def run(self):
"""Processes a batch of messages from the database server. Returns
True if the database as seen through the IDL changed, False if it did
not change. The initial fetch of the entire contents of the remote
- database is considered to be one kind of change.
+ database is considered to be one kind of change. If the IDL has been
+ configured to acquire a database lock (with Idl.set_lock()), then
+ successfully acquiring the lock is also considered to be a change.
This function can return occasional false positives, that is, report
that the database changed even though it didn't. This happens if the
not supposed to do that.)
As an alternative to checking the return value, the client may check
- for changes in the value returned by self.get_seqno()."""
+ for changes in self.change_seqno."""
+ assert not self.txn
initial_change_seqno = self.change_seqno
- self.session.run()
- if self.session.is_connected():
- seqno = self.session.get_seqno()
- if seqno != self.last_seqno:
- self.last_seqno = seqno
- self.state = (self.__send_schema_request, None)
- if self.state:
- self.state[0]()
+ self._session.run()
+ i = 0
+ while i < 50:
+ i += 1
+ if not self._session.is_connected():
+ break
+
+ seqno = self._session.get_seqno()
+ if seqno != self._last_seqno:
+ self._last_seqno = seqno
+ self.__txn_abort_all()
+ self.__send_monitor_request()
+ if self.lock_name:
+ self.__send_lock_request()
+ break
+
+ msg = self._session.recv()
+ if msg is None:
+ break
+ if (msg.type == ovs.jsonrpc.Message.T_NOTIFY
+ and msg.method == "update"
+ and len(msg.params) == 2
+ and msg.params[0] == None):
+ # Database contents changed.
+ self.__parse_update(msg.params[1])
+ elif (msg.type == ovs.jsonrpc.Message.T_REPLY
+ and self._monitor_request_id is not None
+ and self._monitor_request_id == msg.id):
+ # Reply to our "monitor" request.
+ try:
+ self.change_seqno += 1
+ self._monitor_request_id = None
+ self.__clear()
+ self.__parse_update(msg.result)
+ except error.Error, e:
+ logging.error("%s: parse error in received schema: %s"
+ % (self._session.get_name(), e))
+ self.__error()
+ elif (msg.type == ovs.jsonrpc.Message.T_REPLY
+ and self._lock_request_id is not None
+ and self._lock_request_id == msg.id):
+ # Reply to our "lock" request.
+ self.__parse_lock_reply(msg.result)
+ elif (msg.type == ovs.jsonrpc.Message.T_NOTIFY
+ and msg.method == "locked"):
+ # We got our lock.
+ self.__parse_lock_notify(msg.params, True)
+ elif (msg.type == ovs.jsonrpc.Message.T_NOTIFY
+ and msg.method == "stolen"):
+ # Someone else stole our lock.
+ self.__parse_lock_notify(msg.params, False)
+ elif msg.type == ovs.jsonrpc.Message.T_NOTIFY and msg.id == "echo":
+ # Reply to our echo request. Ignore it.
+ pass
+ elif (msg.type in (ovs.jsonrpc.Message.T_ERROR,
+ ovs.jsonrpc.Message.T_REPLY)
+ and self.__txn_process_reply(msg)):
+ # __txn_process_reply() did everything needed.
+ pass
+ else:
+ # This can happen if a transaction is destroyed before we
+ # receive the reply, so keep the log level low.
+ logging.debug("%s: received unexpected %s message"
+ % (self._session.get_name(),
+ ovs.jsonrpc.Message.type_to_string(msg.type)))
+
return initial_change_seqno != self.change_seqno
def wait(self, poller):
"""Arranges for poller.block() to wake up when self.run() has something
to do or when activity occurs on a transaction on 'self'."""
- self.session.wait(poller)
- if self.state and self.state[1]:
- self.state[1](poller)
-
- def get_seqno(self):
- """Returns a number that represents the IDL's state. When the IDL
- updated (by self.run()), the return value changes."""
- return self.change_seqno
-
- def __send_schema_request(self):
- msg = ovs.jsonrpc.Message.create_request("get_schema", [self.db_name])
- self.session.send(msg)
- self.state = (lambda: self.__recv_schema(msg.id), self.__recv_wait)
-
- def __recv_schema(self, id):
- msg = self.session.recv()
- if msg and msg.type == ovs.jsonrpc.Message.T_REPLY and msg.id == id:
- try:
- self.schema = ovs.db.schema.DbSchema.from_json(msg.result)
- except error.Error, e:
- logging.error("%s: parse error in received schema: %s"
- % (self.remote, e))
- self.__error()
- return
+ self._session.wait(poller)
+ self._session.recv_wait(poller)
- if self.schema_cb:
- try:
- self.schema_cb(self.schema)
- except error.Error, e:
- logging.error("%s: error validating schema: %s"
- % (self.remote, e))
- self.__error()
- return
+ def has_ever_connected(self):
+ """Returns True, if the IDL successfully connected to the remote
+ database and retrieved its contents (even if the connection
+ subsequently dropped and is in the process of reconnecting). If so,
+ then the IDL contains an atomic snapshot of the database's contents
+ (but it might be arbitrarily old if the connection dropped).
+
+ Returns False if the IDL has never connected or retrieved the
+ database's contents. If so, the IDL is empty."""
+ return self.change_seqno != 0
+
+ def force_reconnect(self):
+ """Forces the IDL to drop its connection to the database and reconnect.
+ In the meantime, the contents of the IDL will not change."""
+ self._session.force_reconnect()
+
+ def set_lock(self, lock_name):
+ """If 'lock_name' is not None, configures the IDL to obtain the named
+ lock from the database server and to avoid modifying the database when
+ the lock cannot be acquired (that is, when another client has the same
+ lock).
+
+ If 'lock_name' is None, drops the locking requirement and releases the
+ lock."""
+ assert not self.txn
+ assert not self._outstanding_txns
+
+ if self.lock_name and (not lock_name or lock_name != self.lock_name):
+ # Release previous lock.
+ self.__send_unlock_request()
+ self.lock_name = None
+ self.is_lock_contended = False
+
+ if lock_name and not self.lock_name:
+ # Acquire new lock.
+ self.lock_name = lock_name
+ self.__send_lock_request()
+
+ def __clear(self):
+ changed = False
+
+ for table in self.tables.itervalues():
+ if table.rows:
+ changed = True
+ table.rows = {}
- self.__send_monitor_request()
- elif msg:
- logging.error("%s: unexpected message expecting schema: %s"
- % (self.remote, msg))
- self.__error()
-
- def __recv_wait(self, poller):
- self.session.recv_wait(poller)
+ if changed:
+ self.change_seqno += 1
+
+ def __update_has_lock(self, new_has_lock):
+ if new_has_lock and not self.has_lock:
+ if self._monitor_request_id is None:
+ self.change_seqno += 1
+ else:
+ # We're waiting for a monitor reply, so don't signal that the
+ # database changed. The monitor reply will increment
+ # change_seqno anyhow.
+ pass
+ self.is_lock_contended = False
+ self.has_lock = new_has_lock
+
+ def __do_send_lock_request(self, method):
+ self.__update_has_lock(False)
+ self._lock_request_id = None
+ if self._session.is_connected():
+ msg = ovs.jsonrpc.Message.create_request(method, [self.lock_name])
+ msg_id = msg.id
+ self._session.send(msg)
+ else:
+ msg_id = None
+ return msg_id
+
+ def __send_lock_request(self):
+ self._lock_request_id = self.__do_send_lock_request("lock")
+
+ def __send_unlock_request(self):
+ self.__do_send_lock_request("unlock")
+
+ def __parse_lock_reply(self, result):
+ self._lock_request_id = None
+ got_lock = type(result) == dict and result.get("locked") is True
+ self.__update_has_lock(got_lock)
+ if not got_lock:
+ self.is_lock_contended = True
+
+ def __parse_lock_notify(self, params, new_has_lock):
+ if (self.lock_name is not None
+ and type(params) in (list, tuple)
+ and params
+ and params[0] == self.lock_name):
+ self.__update_has_lock(self, new_has_lock)
+ if not new_has_lock:
+ self.is_lock_contended = True
def __send_monitor_request(self):
monitor_requests = {}
- for table in self.schema.tables.itervalues():
+ for table in self.tables.itervalues():
monitor_requests[table.name] = {"columns": table.columns.keys()}
msg = ovs.jsonrpc.Message.create_request(
- "monitor", [self.db_name, None, monitor_requests])
- self.session.send(msg)
- self.state = (lambda: self.__recv_monitor_reply(msg.id),
- self.__recv_wait)
-
- def __recv_monitor_reply(self, id):
- msg = self.session.recv()
- if msg and msg.type == ovs.jsonrpc.Message.T_REPLY and msg.id == id:
- try:
- self.change_seqno += 1
- self.state = (self.__recv_update, self.__recv_wait)
- self.__clear()
- self.__parse_update(msg.result)
- except error.Error, e:
- logging.error("%s: parse error in received schema: %s"
- % (self.remote, e))
- self.__error()
- elif msg:
- logging.error("%s: unexpected message expecting schema: %s"
- % (self.remote, msg))
- self.__error()
-
- def __recv_update(self):
- msg = self.session.recv()
- if (msg and msg.type == ovs.jsonrpc.Message.T_NOTIFY and
- type(msg.params) == list and len(msg.params) == 2 and
- msg.params[0] is None):
- self.__parse_update(msg.params[1])
- elif msg:
- logging.error("%s: unexpected message expecting update: %s"
- % (self.remote, msg))
- self.__error()
-
- def __error(self):
- self.session.force_reconnect()
+ "monitor", [self._db.name, None, monitor_requests])
+ self._monitor_request_id = msg.id
+ self._session.send(msg)
def __parse_update(self, update):
try:
self.__do_parse_update(update)
except error.Error, e:
- logging.error("%s: error parsing update: %s" % (self.remote, e))
+ logging.error("%s: error parsing update: %s"
+ % (self._session.get_name(), e))
def __do_parse_update(self, table_updates):
if type(table_updates) != dict:
table_updates)
for table_name, table_update in table_updates.iteritems():
- table = self.schema.tables.get(table_name)
+ table = self.tables.get(table_name)
if not table:
raise error.Error('<table-updates> includes unknown '
'table "%s"' % table_name)
raise error.Error('<row-update> missing "old" and '
'"new" members', row_update)
- if self.__parse_row_update(table, uuid, old, new):
+ if self.__process_update(table, uuid, old, new):
self.change_seqno += 1
- def __parse_row_update(self, table, uuid, old, new):
+ def __process_update(self, table, uuid, old, new):
"""Returns True if a column changed, False otherwise."""
- row = self.data[table.name].get(uuid)
+ row = table.rows.get(uuid)
changed = False
if not new:
# Delete row.
if row:
- del self.data[table.name][uuid]
+ del table.rows[uuid]
changed = True
else:
# XXX rate-limit
# XXX rate-limit
logging.warning("cannot add existing row %s to table %s"
% (uuid, table.name))
- if self.__modify_row(table, row, new):
+ if self.__row_update(table, row, new):
changed = True
else:
if not row:
# XXX rate-limit
logging.warning("cannot modify missing row %s in table %s"
% (uuid, table.name))
- if self.__modify_row(table, row, new):
+ if self.__row_update(table, row, new):
changed = True
return changed
- def __modify_row(self, table, row, row_json):
+ def __row_update(self, table, row, row_json):
changed = False
for column_name, datum_json in row_json.iteritems():
column = table.columns.get(column_name)
% (column_name, table.name, e))
continue
- if datum != getattr(row, column_name):
- setattr(row, column_name, datum)
- changed = True
+ if datum != row._data[column_name]:
+ row._data[column_name] = datum
+ if column.alert:
+ changed = True
else:
# Didn't really change but the OVSDB monitor protocol always
# includes every value in a row.
pass
return changed
- def __clear(self):
- if self.data != {}:
- for table_name in self.schema.tables:
- if self.data[table_name] != {}:
- self.change_seqno += 1
- break
-
- self.data = {}
- for table_name in self.schema.tables:
- self.data[table_name] = {}
-
def __create_row(self, table, uuid):
- row = self.data[table.name][uuid] = Row()
+ data = {}
for column in table.columns.itervalues():
- setattr(row, column.name, ovs.db.data.Datum.default(column.type))
+ data[column.name] = ovs.db.data.Datum.default(column.type)
+ row = table.rows[uuid] = Row(self, table, uuid, data)
return row
- def force_reconnect(self):
- """Forces the IDL to drop its connection to the database and reconnect.
- In the meantime, the contents of the IDL will not change."""
- self.session.force_reconnect()
+ def __error(self):
+ self._session.force_reconnect()
+
+ def __txn_abort_all(self):
+ while self._outstanding_txns:
+ txn = self._outstanding_txns.popitem()[1]
+ txn._status = Transaction.TRY_AGAIN
+
+ def __txn_process_reply(self, msg):
+ txn = self._outstanding_txns.pop(msg.id, None)
+ if txn:
+ txn._process_reply(msg)
+
+def _uuid_to_row(atom, base):
+ if base.ref_table:
+ return base.ref_table.rows.get(atom)
+ else:
+ return atom
+
+def _row_to_uuid(value):
+ if type(value) == Row:
+ return value.uuid
+ else:
+ return value
class Row(object):
- """A row within an Idl. Data for each column is stored as an attribute
- with the same name as the column and using an ovs.db.data.Datum as the
- value."""
- pass
+ """A row within an IDL.
+
+ The client may access the following attributes directly:
+
+ - 'uuid': a uuid.UUID object whose value is the row's database UUID.
+
+ - An attribute for each column in the Row's table, named for the column,
+ whose values are as returned by Datum.to_python() for the column's type.
+
+ If some error occurs (e.g. the database server's idea of the column is
+ different from the IDL's idea), then the attribute values is the
+ "default" value return by Datum.default() for the column's type. (It is
+ important to know this because the default value may violate constraints
+ for the column's type, e.g. the default integer value is 0 even if column
+ contraints require the column's value to be positive.)
+
+ When a transaction is active, column attributes may also be assigned new
+ values. Committing the transaction will then cause the new value to be
+ stored into the database.
+
+ *NOTE*: In the current implementation, the value of a column is a *copy*
+ of the value in the database. This means that modifying its value
+ directly will have no useful effect. For example, the following:
+ row.mycolumn["a"] = "b" # don't do this
+ will not change anything in the database, even after commit. To modify
+ the column, instead assign the modified column value back to the column:
+ d = row.mycolumn
+ d["a"] = "b"
+ row.mycolumn = d
+"""
+ def __init__(self, idl, table, uuid, data):
+ # All of the explicit references to self.__dict__ below are required
+ # to set real attributes with invoking self.__getattr__().
+ self.__dict__["uuid"] = uuid
+
+ self.__dict__["_idl"] = idl
+ self.__dict__["_table"] = table
+
+ # _data is the committed data. It takes the following values:
+ #
+ # - A dictionary that maps every column name to a Datum, if the row
+ # exists in the committed form of the database.
+ #
+ # - None, if this row is newly inserted within the active transaction
+ # and thus has no committed form.
+ self.__dict__["_data"] = data
+
+ # _changes describes changes to this row within the active transaction.
+ # It takes the following values:
+ #
+ # - {}, the empty dictionary, if no transaction is active or if the
+ # row has yet not been changed within this transaction.
+ #
+ # - A dictionary that maps a column name to its new Datum, if an
+ # active transaction changes those columns' values.
+ #
+ # - A dictionary that maps every column name to a Datum, if the row
+ # is newly inserted within the active transaction.
+ #
+ # - None, if this transaction deletes this row.
+ self.__dict__["_changes"] = {}
+
+ # A dictionary whose keys are the names of columns that must be
+ # verified as prerequisites when the transaction commits. The values
+ # in the dictionary are all None.
+ self.__dict__["_prereqs"] = {}
+
+ def __getattr__(self, column_name):
+ assert self._changes is not None
+
+ datum = self._changes.get(column_name)
+ if datum is None:
+ datum = self._data[column_name]
+
+ return datum.to_python(_uuid_to_row)
+
+ def __setattr__(self, column_name, value):
+ assert self._changes is not None
+ assert self._idl.txn
+
+ column = self._table.columns[column_name]
+ try:
+ datum = ovs.db.data.Datum.from_python(column.type, value,
+ _row_to_uuid)
+ except error.Error, e:
+ # XXX rate-limit
+ logging.error("attempting to write bad value to column %s (%s)"
+ % (column_name, e))
+ return
+ self._idl.txn._write(self, column, datum)
+
+ def verify(self, column_name):
+ """Causes the original contents of column 'column_name' in this row to
+ be verified as a prerequisite to completing the transaction. That is,
+ if 'column_name' changed in this row (or if this row was deleted)
+ between the time that the IDL originally read its contents and the time
+ that the transaction commits, then the transaction aborts and
+ Transaction.commit() returns Transaction.TRY_AGAIN.
+
+ The intention is that, to ensure that no transaction commits based on
+ dirty reads, an application should call Row.verify() on each data item
+ read as part of a read-modify-write operation.
+
+ In some cases Row.verify() reduces to a no-op, because the current
+ value of the column is already known:
+
+ - If this row is a row created by the current transaction (returned
+ by Transaction.insert()).
+
+ - If the column has already been modified within the current
+ transaction.
+
+ Because of the latter property, always call Row.verify() *before*
+ modifying the column, for a given read-modify-write.
+
+ A transaction must be in progress."""
+ assert self._idl.txn
+ assert self._changes is not None
+ if not self._data or column_name in self._changes:
+ return
+
+ self._prereqs[column_name] = None
+
+ def delete(self):
+ """Deletes this row from its table.
+
+ A transaction must be in progress."""
+ assert self._idl.txn
+ assert self._changes is not None
+ if self._data is None:
+ del self._idl.txn._txn_rows[self.uuid]
+ self.__dict__["_changes"] = None
+ del self._table.rows[self.uuid]
+
+def _uuid_name_from_uuid(uuid):
+ return "row%s" % str(uuid).replace("-", "_")
+
+def _where_uuid_equals(uuid):
+ return [["_uuid", "==", ["uuid", str(uuid)]]]
+
+class _InsertedRow(object):
+ def __init__(self, op_index):
+ self.op_index = op_index
+ self.real = None
+
+class Transaction(object):
+ # Status values that Transaction.commit() can return.
+ UNCOMMITTED = "uncommitted" # Not yet committed or aborted.
+ UNCHANGED = "unchanged" # Transaction didn't include any changes.
+ INCOMPLETE = "incomplete" # Commit in progress, please wait.
+ ABORTED = "aborted" # ovsdb_idl_txn_abort() called.
+ SUCCESS = "success" # Commit successful.
+ TRY_AGAIN = "try again" # Commit failed because a "verify" operation
+ # reported an inconsistency, due to a network
+ # problem, or other transient failure.
+ NOT_LOCKED = "not locked" # Server hasn't given us the lock yet.
+ ERROR = "error" # Commit failed due to a hard error.
+
+ @staticmethod
+ def status_to_string(status):
+ """Converts one of the status values that Transaction.commit() can
+ return into a human-readable string.
+
+ (The status values are in fact such strings already, so
+ there's nothing to do.)"""
+ return status
+
+ def __init__(self, idl):
+ """Starts a new transaction on 'idl' (an instance of ovs.db.idl.Idl).
+ A given Idl may only have a single active transaction at a time.
+
+ A Transaction may modify the contents of a database by assigning new
+ values to columns (attributes of Row), deleting rows (with
+ Row.delete()), or inserting rows (with Transaction.insert()). It may
+ also check that columns in the database have not changed with
+ Row.verify().
+
+ When a transaction is complete (which must be before the next call to
+ Idl.run()), call Transaction.commit() or Transaction.abort()."""
+ assert idl.txn is None
+
+ idl.txn = self
+ self._request_id = None
+ self.idl = idl
+ self.dry_run = False
+ self._txn_rows = {}
+ self._status = Transaction.UNCOMMITTED
+ self._error = None
+ self._comments = []
+
+ self._inc_table = None
+ self._inc_column = None
+ self._inc_where = None
+
+ self._inserted_rows = {} # Map from UUID to _InsertedRow
+
+ def add_comment(self, comment):
+ """Appens 'comment' to the comments that will be passed to the OVSDB
+ server when this transaction is committed. (The comment will be
+ committed to the OVSDB log, which "ovsdb-tool show-log" can print in a
+ relatively human-readable form.)"""
+ self._comments.append(comment)
+
+ def increment(self, table, column, where):
+ assert not self._inc_table
+ self._inc_table = table
+ self._inc_column = column
+ self._inc_where = where
+
+ def wait(self, poller):
+ if self._status not in (Transaction.UNCOMMITTED,
+ Transaction.INCOMPLETE):
+ poller.immediate_wake()
+
+ def _substitute_uuids(self, json):
+ if type(json) in (list, tuple):
+ if (len(json) == 2
+ and json[0] == 'uuid'
+ and ovs.ovsuuid.is_valid_string(json[1])):
+ uuid = ovs.ovsuuid.from_string(json[1])
+ row = self._txn_rows.get(uuid, None)
+ if row and row._data is None:
+ return ["named-uuid", _uuid_name_from_uuid(uuid)]
+ return json
+
+ def __disassemble(self):
+ self.idl.txn = None
+
+ for row in self._txn_rows.itervalues():
+ if row._changes is None:
+ row._table.rows[row.uuid] = row
+ elif row._data is None:
+ del row._table.rows[row.uuid]
+ row.__dict__["_changes"] = {}
+ row.__dict__["_prereqs"] = {}
+ self._txn_rows = {}
+
+ def commit(self):
+ """Attempts to commit this transaction and returns the status of the
+ commit operation, one of the constants declared as class attributes.
+ If the return value is Transaction.INCOMPLETE, then the transaction is
+ not yet complete and the caller should try calling again later, after
+ calling Idl.run() to run the Idl.
+
+ Committing a transaction rolls back all of the changes that it made to
+ the Idl's copy of the database. If the transaction commits
+ successfully, then the database server will send an update and, thus,
+ the Idl will be updated with the committed changes."""
+ # The status can only change if we're the active transaction.
+ # (Otherwise, our status will change only in Idl.run().)
+ if self != self.idl.txn:
+ return self._status
+
+ # If we need a lock but don't have it, give up quickly.
+ if self.idl.lock_name and not self.idl.has_lock():
+ self._status = Transaction.NOT_LOCKED
+ self.__disassemble()
+ return self._status
+
+ operations = [self.idl._db.name]
+
+ # Assert that we have the required lock (avoiding a race).
+ if self.idl.lock_name:
+ operations.append({"op": "assert",
+ "lock": self.idl.lock_name})
+
+ # Add prerequisites and declarations of new rows.
+ for row in self._txn_rows.itervalues():
+ if row._prereqs:
+ rows = {}
+ columns = []
+ for column_name in row._prereqs:
+ columns.append(column_name)
+ rows[column_name] = row._data[column_name].to_json()
+ operations.append({"op": "wait",
+ "table": row._table.name,
+ "timeout": 0,
+ "where": _where_uuid_equals(row.uuid),
+ "until": "==",
+ "columns": columns,
+ "rows": [rows]})
+
+ # Add updates.
+ any_updates = False
+ for row in self._txn_rows.itervalues():
+ if row._changes is None:
+ if row._table.is_root:
+ operations.append({"op": "delete",
+ "table": row._table.name,
+ "where": _where_uuid_equals(row.uuid)})
+ any_updates = True
+ else:
+ # Let ovsdb-server decide whether to really delete it.
+ pass
+ elif row._changes:
+ op = {"table": row._table.name}
+ if row._data is None:
+ op["op"] = "insert"
+ op["uuid-name"] = _uuid_name_from_uuid(row.uuid)
+ any_updates = True
+
+ op_index = len(operations) - 1
+ self._inserted_rows[row.uuid] = _InsertedRow(op_index)
+ else:
+ op["op"] = "update"
+ op["where"] = _where_uuid_equals(row.uuid)
+
+ row_json = {}
+ op["row"] = row_json
+
+ for column_name, datum in row._changes.iteritems():
+ if row._data is not None or not datum.is_default():
+ row_json[column_name] = self._substitute_uuids(datum.to_json())
+
+ # If anything really changed, consider it an update.
+ # We can't suppress not-really-changed values earlier
+ # or transactions would become nonatomic (see the big
+ # comment inside Transaction._write()).
+ if (not any_updates and row._data is not None and
+ row._data[column_name] != datum):
+ any_updates = True
+
+ if row._data is None or row_json:
+ operations.append(op)
+
+ # Add increment.
+ if self._inc_table and any_updates:
+ self._inc_index = len(operations) - 1
+
+ operations.append({"op": "mutate",
+ "table": self._inc_table,
+ "where": self._substitute_uuids(self._inc_where),
+ "mutations": [[self._inc_column, "+=", 1]]})
+ operations.append({"op": "select",
+ "table": self._inc_table,
+ "where": self._substitute_uuids(self._inc_where),
+ "columns": [self._inc_column]})
+
+ # Add comment.
+ if self._comments:
+ operations.append({"op": "comment",
+ "comment": "\n".join(self._comments)})
+
+ # Dry run?
+ if self.dry_run:
+ operations.append({"op": "abort"})
+
+ if not any_updates:
+ self._status = Transaction.UNCHANGED
+ else:
+ msg = ovs.jsonrpc.Message.create_request("transact", operations)
+ self._request_id = msg.id
+ if not self.idl._session.send(msg):
+ self.idl._outstanding_txns[self._request_id] = self
+ self._status = Transaction.INCOMPLETE
+ else:
+ self._status = Transaction.TRY_AGAIN
+
+ self.__disassemble()
+ return self._status
+
+ def commit_block(self):
+ while True:
+ status = self.commit()
+ if status != Transaction.INCOMPLETE:
+ return status
+
+ self.idl.run()
+
+ poller = ovs.poller.Poller()
+ self.idl.wait(poller)
+ self.wait(poller)
+ poller.block()
+
+ def get_increment_new_value(self):
+ assert self._status == Transaction.SUCCESS
+ return self._inc_new_value
+
+ def abort(self):
+ """Aborts this transaction. If Transaction.commit() has already been
+ called then the transaction might get committed anyhow."""
+ self.__disassemble()
+ if self._status in (Transaction.UNCOMMITTED,
+ Transaction.INCOMPLETE):
+ self._status = Transaction.ABORTED
+
+ def get_error(self):
+ """Returns a string representing this transaction's current status,
+ suitable for use in log messages."""
+ if self._status != Transaction.ERROR:
+ return Transaction.status_to_string(self._status)
+ elif self._error:
+ return self._error
+ else:
+ return "no error details available"
+
+ def __set_error_json(self, json):
+ if self._error is None:
+ self._error = ovs.json.to_string(json)
+
+ def get_insert_uuid(self, uuid):
+ """Finds and returns the permanent UUID that the database assigned to a
+ newly inserted row, given the UUID that Transaction.insert() assigned
+ locally to that row.
+
+ Returns None if 'uuid' is not a UUID assigned by Transaction.insert()
+ or if it was assigned by that function and then deleted by Row.delete()
+ within the same transaction. (Rows that are inserted and then deleted
+ within a single transaction are never sent to the database server, so
+ it never assigns them a permanent UUID.)
+
+ This transaction must have completed successfully."""
+ assert self._status in (Transaction.SUCCESS,
+ Transaction.UNCHANGED)
+ inserted_row = self._inserted_rows.get(uuid)
+ if inserted_row:
+ return inserted_row.real
+ return None
+
+ def _write(self, row, column, datum):
+ assert row._changes is not None
+
+ txn = row._idl.txn
+
+ # If this is a write-only column and the datum being written is the
+ # same as the one already there, just skip the update entirely. This
+ # is worth optimizing because we have a lot of columns that get
+ # periodically refreshed into the database but don't actually change
+ # that often.
+ #
+ # We don't do this for read/write columns because that would break
+ # atomicity of transactions--some other client might have written a
+ # different value in that column since we read it. (But if a whole
+ # transaction only does writes of existing values, without making any
+ # real changes, we will drop the whole transaction later in
+ # ovsdb_idl_txn_commit().)
+ if not column.alert and row._data.get(column.name) == datum:
+ new_value = row._changes.get(column.name)
+ if new_value is None or new_value == datum:
+ return
+
+ txn._txn_rows[row.uuid] = row
+ row._changes[column.name] = datum.copy()
+
+ def insert(self, table, new_uuid=None):
+ """Inserts and returns a new row in 'table', which must be one of the
+ ovs.db.schema.TableSchema objects in the Idl's 'tables' dict.
+
+ The new row is assigned a provisional UUID. If 'uuid' is None then one
+ is randomly generated; otherwise 'uuid' should specify a randomly
+ generated uuid.UUID not otherwise in use. ovsdb-server will assign a
+ different UUID when 'txn' is committed, but the IDL will replace any
+ uses of the provisional UUID in the data to be to be committed by the
+ UUID assigned by ovsdb-server."""
+ assert self._status == Transaction.UNCOMMITTED
+ if new_uuid is None:
+ new_uuid = uuid.uuid4()
+ row = Row(self.idl, table, new_uuid, None)
+ table.rows[row.uuid] = row
+ self._txn_rows[row.uuid] = row
+ return row
+
+ def _process_reply(self, msg):
+ if msg.type == ovs.jsonrpc.Message.T_ERROR:
+ self._status = Transaction.ERROR
+ elif type(msg.result) not in (list, tuple):
+ # XXX rate-limit
+ logging.warning('reply to "transact" is not JSON array')
+ else:
+ hard_errors = False
+ soft_errors = False
+ lock_errors = False
+
+ ops = msg.result
+ for op in ops:
+ if op is None:
+ # This isn't an error in itself but indicates that some
+ # prior operation failed, so make sure that we know about
+ # it.
+ soft_errors = True
+ elif type(op) == dict:
+ error = op.get("error")
+ if error is not None:
+ if error == "timed out":
+ soft_errors = True
+ elif error == "not owner":
+ lock_errors = True
+ elif error == "aborted":
+ pass
+ else:
+ hard_errors = True
+ self.__set_error_json(op)
+ else:
+ hard_errors = True
+ self.__set_error_json(op)
+ # XXX rate-limit
+ logging.warning("operation reply is not JSON null or "
+ "object")
+
+ if not soft_errors and not hard_errors and not lock_errors:
+ if self._inc_table and not self.__process_inc_reply(ops):
+ hard_errors = True
+
+ for insert in self._inserted_rows.itervalues():
+ if not self.__process_insert_reply(insert, ops):
+ hard_errors = True
+
+ if hard_errors:
+ self._status = Transaction.ERROR
+ elif lock_errors:
+ self._status = Transaction.NOT_LOCKED
+ elif soft_errors:
+ self._status = Transaction.TRY_AGAIN
+ else:
+ self._status = Transaction.SUCCESS
+
+ @staticmethod
+ def __check_json_type(json, types, name):
+ if not json:
+ # XXX rate-limit
+ logging.warning("%s is missing" % name)
+ return False
+ elif type(json) not in types:
+ # XXX rate-limit
+ logging.warning("%s has unexpected type %s" % (name, type(json)))
+ return False
+ else:
+ return True
+
+ def __process_inc_reply(self, ops):
+ if self._inc_index + 2 > len(ops):
+ # XXX rate-limit
+ logging.warning("reply does not contain enough operations for "
+ "increment (has %d, needs %d)" %
+ (len(ops), self._inc_index + 2))
+
+ # We know that this is a JSON object because the loop in
+ # __process_reply() already checked.
+ mutate = ops[self._inc_index]
+ count = mutate.get("count")
+ if not Transaction.__check_json_type(count, (int, long),
+ '"mutate" reply "count"'):
+ return False
+ if count != 1:
+ # XXX rate-limit
+ logging.warning('"mutate" reply "count" is %d instead of 1'
+ % count)
+ return False
+
+ select = ops[self._inc_index + 1]
+ rows = select.get("rows")
+ if not Transaction.__check_json_type(rows, (list, tuple),
+ '"select" reply "rows"'):
+ return False
+ if len(rows) != 1:
+ # XXX rate-limit
+ logging.warning('"select" reply "rows" has %d elements '
+ 'instead of 1' % len(rows))
+ return False
+ row = rows[0]
+ if not Transaction.__check_json_type(row, (dict,),
+ '"select" reply row'):
+ return False
+ column = row.get(self._inc_column)
+ if not Transaction.__check_json_type(column, (int, long),
+ '"select" reply inc column'):
+ return False
+ self._inc_new_value = column
+ return True
+
+ def __process_insert_reply(self, insert, ops):
+ if insert.op_index >= len(ops):
+ # XXX rate-limit
+ logging.warning("reply does not contain enough operations "
+ "for insert (has %d, needs %d)"
+ % (len(ops), insert.op_index))
+ return False
+
+ # We know that this is a JSON object because the loop in
+ # __process_reply() already checked.
+ reply = ops[insert.op_index]
+ json_uuid = reply.get("uuid")
+ if not Transaction.__check_json_type(json_uuid, (tuple, list),
+ '"insert" reply "uuid"'):
+ return False
+
+ try:
+ uuid_ = ovs.ovsuuid.from_json(json_uuid)
+ except error.Error:
+ # XXX rate-limit
+ logging.warning('"insert" reply "uuid" is not a JSON UUID')
+ return False
+ insert.real = uuid_
+ return True
git://git.onelab.eu / sliver-openvswitch.git / blobdiff