google.appengine.datastore.datastore_rpc.TransactionalConnection

A connection specific to one transaction.

Inherits From: BaseConnection, expected_type

google.appengine.datastore.datastore_rpc.TransactionalConnection(
    adapter=None,
    config=None,
    transaction=None,
    entity_group=None,
    _api_version=_DATASTORE_V3,
    previous_transaction=None,
    mode=TransactionMode.UNKNOWN
)

It is possible to pass the transaction and entity group to the constructor, but typically the transaction is lazily created by _get_transaction() when the first operation is started.

Args
`adapter`	Optional AbstractAdapter subclass instance; default IdentityAdapter.
`config`	Optional Configuration object.
`transaction`	Optional datastore_db.Transaction object.
`entity_group`	Deprecated, do not use.
`previous_transaction`	Optional datastore_db.Transaction object representing the transaction being reset.
`mode`	Optional datastore_db.TransactionMode representing the transaction mode.

Raises
`datastore_errors.BadArgumentError`	If previous_transaction and transaction are both set.

Attributes
`adapter`	The adapter used by this connection.
`config`	The default configuration used by this connection.
`finished`
`transaction`	The current transaction. None when state == FINISHED.

Methods

`async_begin_transaction`

View source

async_begin_transaction(
    config, app, previous_transaction=None, mode=TransactionMode.UNKNOWN
)

Asynchronous BeginTransaction operation.

Args
`config`	A configuration object or None. Defaults are taken from the connection's default configuration.
`app`	Application ID.
`previous_transaction`	The transaction to reset.
`mode`	The transaction mode.

Returns
A MultiRpc object.

`async_commit`

View source

async_commit(
    config
)

Asynchronous Commit operation.

Args
`config`	A Configuration object or None. Defaults are taken from the connection's default configuration.

Returns
A MultiRpc object.

`async_delete`

View source

async_delete(
    config, keys, extra_hook=None
)

Transactional asynchronous Delete operation.

Args
`config`	A Configuration object or None. Defaults are taken from the connection's default configuration.
`keys`	An iterable of user-level key objects.
`extra_hook`	Optional function to be called once the RPC has completed.

Returns
A MultiRpc object.

`async_get`

View source

async_get(
    config, keys, extra_hook=None
)

Asynchronous Get operation.

Args
`config`	A Configuration object or None. Defaults are taken from the connection's default configuration.
`keys`	An iterable of user-level key objects.
`extra_hook`	Optional function to be called on the result once the RPC has completed.

Returns
A MultiRpc object.

`async_get_indexes`

View source

async_get_indexes(
    config, extra_hook=None, _app=None
)

Asynchronous get indexes operation.

Args
`config`	A Configuration object or None. Defaults are taken from the connection's default configuration.
`extra_hook`	Optional function to be called once the RPC has completed.

Returns
A MultiRpc object.

`async_put`

View source

async_put(
    config, entities, extra_hook=None
)

Transactional asynchronous Put operation.

Args
config: A Configuration object or None. Defaults are taken from the connection's default configuration. entities: An iterable of user-level entity objects. extra_hook: Optional function to be called on the result once the RPC has completed.
`Returns`	A MultiRpc object.

NOTE: If any of the entities has an incomplete key, this will not patch up those entities with the complete key.

`async_rollback`

View source

async_rollback(
    config
)

Asynchronous Rollback operation.

Args
config: A Configuration object or None. Defaults are taken from the connection's default configuration.
`Returns`	A MultiRpc object.

`begin_transaction`

View source

begin_transaction(
    app, previous_transaction=None, mode=TransactionMode.UNKNOWN
)

Synchronous BeginTransaction operation.

NOTE: In most cases the new_transaction() method is preferred, since that returns a TransactionalConnection object which will begin the transaction lazily.

Args
`app`	Application ID.
`previous_transaction`	The transaction to reset.
`mode`	The transaction mode.

Returns
An object representing a transaction or None.

`check_rpc_success`

View source

check_rpc_success(
    rpc
)

Check for RPC success and translate exceptions.

This wraps rpc.check_success() and should be called instead of that.

This also removes the RPC from the list of pending RPCs, once it has completed.

Args
`rpc`	A UserRPC or MultiRpc object.

Raises
Nothing if the call succeeded; various datastore_errors.Error subclasses if ApplicationError was raised by rpc.check_success().

`commit`

View source

commit()

Synchronous Commit operation.

Returns
True if the transaction was successfully committed. False if the backend reported a concurrent transaction error.

`create_rpc`

View source

create_rpc(
    config=None, service_name=None
)

Create an RPC object using the configuration parameters.

Internal only.

Args
`config`	Optional Configuration object.
`service_name`	Optional datastore service name.

Returns
A new UserRPC object with the designated settings.

NOTES:

(1) The RPC object returned can only be used to make a single call (for details see apiproxy_stub_map.UserRPC).

(2) To make a call, use one of the specific methods on the Connection object, such as conn.put(entities). This sends the call to the server but does not wait. To wait for the call to finish and get the result, call rpc.get_result().

`delete`

View source

delete(
    keys
)

Synchronous Delete operation.

Args
`keys`	An iterable of user-level key objects.

Returns
None.

`get`

View source

get(
    keys
)

Synchronous Get operation.

Args
`keys`	An iterable of user-level key objects.

Returns
A list of user-level entity objects and None values, corresponding 1:1 to the argument keys. A None means there is no entity for the corresponding key.

`get_datastore_type`

View source

get_datastore_type(
    app=None
)

Tries to get the datastore type for the given app.

This function is only guaranteed to return something other than UNKNOWN_DATASTORE when running in production and querying the current app.

`get_indexes`

View source

get_indexes()

Synchronous get indexes operation.

Returns
user-level indexes representation

`get_pending_rpcs`

View source

get_pending_rpcs()

Return (a copy of) the list of currently pending RPCs.

`is_pending`

View source

is_pending(
    rpc
)

Check whether an RPC object is currently pending.

Note that 'pending' in this context refers to an RPC associated with this connection for which _remove_pending() hasn't been called yet; normally this is called by check_rpc_success() which itself is called by the various result hooks. A pending RPC may be in the RUNNING or FINISHING state.

If the argument is a MultiRpc object, this returns true if at least one of its wrapped RPCs is pending.

`make_rpc_call`

View source

make_rpc_call(
    config,
    method,
    request,
    response,
    get_result_hook=None,
    user_data=None,
    service_name=None
)

Make an RPC call.

Internal only.

Except for the added config argument, this is a thin wrapper around UserRPC.make_call().

Args
`config`	A Configuration object or None. Defaults are taken from the connection's default configuration.
`method`	The method name.
`request`	The request protocol buffer.
`response`	The response protocol buffer.
`get_result_hook`	Optional get-result hook function. If not None, this must be a function with exactly one argument, the RPC object (self). Its return value is returned from get_result().
`user_data`	Optional additional arbitrary data for the get-result hook function. This can be accessed as rpc.user_data. The type of this value is up to the service module.

Returns
The UserRPC object used for the call.

`put`

View source

put(
    entities
)

Synchronous Put operation.

Args
`entities`	An iterable of user-level entity objects.

Returns
A list of user-level key objects, corresponding 1:1 to the argument entities.

NOTE: If any of the entities has an incomplete key, this will not patch up those entities with the complete key.

`rollback`

View source

rollback()

Synchronous Rollback operation.

`wait_for_all_pending_rpcs`

View source

wait_for_all_pending_rpcs()

Wait for all currently pending RPCs to complete.

Class Variables
CLOSED	`3`
COMMIT_IN_FLIGHT	`1`
DEFAULT_MAX_ENTITY_GROUPS_PER_RPC	`10`
FAILED	`2`
HIGH_REPLICATION_DATASTORE	`2`
MAX_ALLOCATE_IDS_KEYS	`500`
MAX_DELETE_KEYS	`500`
MAX_GET_KEYS	`1000`
MAX_PUT_ENTITIES	`500`
MAX_RPC_BYTES	`1048576`
OPEN	`0`
UNKNOWN_DATASTORE	`0`

google.appengine.datastore.datastore_rpc.TransactionalConnection

Args

Raises

Attributes

Methods

async_begin_transaction

async_commit

async_delete

async_get

async_get_indexes

async_put

async_rollback

begin_transaction

check_rpc_success

commit

create_rpc

NOTES:

delete

get

get_datastore_type

get_indexes

get_pending_rpcs

is_pending

make_rpc_call

put

rollback

wait_for_all_pending_rpcs

Class Variables

`async_begin_transaction`

`async_commit`

`async_delete`

`async_get`

`async_get_indexes`

`async_put`

`async_rollback`

`begin_transaction`

`check_rpc_success`

`commit`

`create_rpc`

`delete`

`get`

`get_datastore_type`

`get_indexes`

`get_pending_rpcs`

`is_pending`

`make_rpc_call`

`put`

`rollback`

`wait_for_all_pending_rpcs`