Metadata-Version: 2.1
Name: nti.transactions
Version: 3.0.0
Summary: NTI Transactions Utility
Home-page: https://github.com/NextThought/nti.transactions
Author: Jason Madden
Author-email: jason@nextthought.com
License: Apache
Description: ==================
         nti.transactions
        ==================
        
        
        .. _transaction: https://pypi.python.org/pypi/transaction
        
        .. image:: https://coveralls.io/repos/github/NextThought/nti.transactions/badge.svg?branch=master
        	:target: https://coveralls.io/github/NextThought/nti.transactions?branch=master
        
        .. image:: https://travis-ci.org/NextThought/nti.transactions.svg?branch=master
            :target: https://travis-ci.org/NextThought/nti.transactions
        
        .. image:: https://readthedocs.org/projects/ntitransactions/badge/?version=latest
           :target: https://ntitransactions.readthedocs.io/en/latest/?badge=latest
           :alt: Documentation Status
        
        Extensions to the `transaction`_ package.
        
        Transaction Manager
        ===================
        
        ``nti.transactions.transactions.TransactionsLoop`` is a retryable
        transaction manager. It is conceptually similar to the `attempts`_
        context manager provided by the transaction package itself, but much
        more powerful and extensible via subclasses. Features include:
        
        - Configurable commit vetos.
        - Extensible tests for which exceptions should be retried.
        - The ability to abort the transaction and bypass a potentially
          expensive commit when there are expected to be no side-effects.
        - Sleeping between retries.
        - Extensive logging and timing.
        
        The TransactionLoop can be used as-is, or it can be subclassed for
        customization. For use in a Pyramid tween, for example, a minimal
        subclass might look like this::
        
          >>> class PyramidTransactionLoop(TransactionLoop):
          ...    def prep_for_retry(self, number, request):
          ...        request.make_body_seekable()
          ...    def describe_transaction(self, request):
          ...        return request.url
        
        Data Managers
        =============
        
        A few `data managers`_ are provided for convenience.
        
        The first data manager is used to put an object in a ``queue``
        (something with the ``full`` and ``put_nowait`` methods) when a
        transaction succeeds. If the queue is full, then the transaction will
        not be allowed to commit::
        
          >>> from nti.transactions.transactions import put_nowait
          >>> put_nowait(queue, object)
        
        This is a special case of the ``ObjectDataManager``, which will call
        one method with any arguments when a transaction commits. It can be
        configured to vote on whether the transaction should be allowed to commit.
        or not. This is useful for, say, putting an item in a Redis queue when
        the transaction is successful. It can be constructed directly, but the
        ``do`` function is a shorthand way of joining one to the current
        transaction::
        
          >>> from nti.transactions.transactions import do
          >>> do(print, args=("Committed"))
        
        .. caution:: See the documentation of this object for numerous
        			 warnings about side-effects and its interaction with the
        			 transaction machinery. Use it with care!
        
        .. _attempts: http://zodb.readthedocs.io/en/latest/transactions.html#retrying-transactions
        .. _data managers: http://zodb.readthedocs.io/en/latest/transactions.html#data-managers
        
        =========
         Changes
        =========
        
        3.0.0 (2019-09-06)
        ==================
        
        - Make ``TransactionLoop`` place its transaction manager in explicit
          mode. This can be faster and is easier to reason about, but forbids
          the called handler from manually calling ``begin()``, ``abort()`` or
          ``commit()``. See `issue 20
          <https://github.com/NextThought/nti.transactions/issues/20>`_.
        
        - Move ``transaction.begin()`` out of the block of code that is
          retried. Previously, an error there would probably be raised
          *anyway* and not retried, unless a subclass had made customizations.
        
        - Add ``setUp`` and ``tearDown`` methods to TransactionLoop to give
          subclasses a place to hook into the inners of the transaction loop.
          This is particularly helpful if they need to do something after the
          transaction manager has been put in explicit mode. See `issue 22
          <https://github.com/NextThought/nti.transactions/issues/22>`_.
        
        2.0.1 (2019-09-03)
        ==================
        
        - Fix compatibility with perfmetrics 3.0: drop ``from __future__
          import unicode_literals``.
        
        
        2.0.0 (2018-07-20)
        ==================
        
        - Use the new public ``isRetryableError`` in transaction 2.2. The
          interface for this package is unchanged, but a major version bump of
          a dependency necessitates a major bump here. See `issue 12
          <https://github.com/NextThought/nti.transactions/issues/12>`_.
        
        - Test support for Python 3.7; remove test support for Python 3.4.
        
        - ``TransactionLoop`` is more careful to not keep traceback objects
          around, especially on Python 2.
        
        1.1.1 (2018-07-19)
        ==================
        
        - When the ``TransactionLoop`` raises a ``CommitFailedError`` from a
          ``TypeError``, it preserves the original message.
        
        - Test support for Python 3.6.
        
        1.1.0 (2017-04-17)
        ==================
        
        - Add a new ObjectDataManager that will attempt to execute after
          other ObjectDataManagers.
        
        
        1.0.0 (2016-07-28)
        ==================
        
        - Add support for Python 3.
        - Eliminate ZODB dependency. Instead of raising a
          ``ZODB.POSException.StorageError`` for unexpected ``TypeErrors``
          during commit, the new class
          ``nti.transactions.interfaces.CommitFailedError`` is raised.
        - Introduce a new subclass of ``TransactionError``,
          ``AbortFailedError`` that is raised when an abort fails due to a
          system error.
        
Keywords: ZODB transaction
Platform: UNKNOWN
Classifier: Intended Audience :: Developers
Classifier: Natural Language :: English
Classifier: Operating System :: OS Independent
Classifier: Development Status :: 5 - Production/Stable
Classifier: Programming Language :: Python :: 2
Classifier: Programming Language :: Python :: 2.7
Classifier: Programming Language :: Python :: 3.5
Classifier: Programming Language :: Python :: 3.6
Classifier: Programming Language :: Python :: 3.7
Classifier: Programming Language :: Python :: Implementation :: CPython
Classifier: Programming Language :: Python :: Implementation :: PyPy
Classifier: Framework :: ZODB
Provides-Extra: gevent
Provides-Extra: docs
Provides-Extra: test
