Re-Adding support for sqlalchemy as it is needed by Apache project Ai…

…rflow (#687)

* Re-Adding support for sqlalchemy as it is needed by Apache project Airflow

* Re-Adding support for sqlalchemy as it is needed by Apache project Airflow

.gitignore

@@ -31,3 +31,5 @@ htmlcov/
 test.db
 coverage.xml
 venv/
+env
+.eggs

.landscape.yml

@@ -0,0 +1,3 @@
+pylint:
+  disable:
+    - cyclic-import

docs/reference/index.rst

@@ -48,6 +48,8 @@
     kombu.transport.etcd
     kombu.transport.zookeeper
     kombu.transport.filesystem
+    kombu.transport.sqlalchemy
+    kombu.transport.sqlalchemy.models
     kombu.transport.SQS
     kombu.transport.SLMQ
     kombu.transport.pyro

docs/reference/kombu.transport.SLMQ.rst

@@ -2,6 +2,7 @@
  SLMQ Transport - ``kombu.transport.SLMQ``
 =============================================
 
+
 .. currentmodule:: kombu.transport.SLMQ
 
 .. automodule:: kombu.transport.SLMQ

docs/reference/kombu.transport.sqlalchemy.models.rst

@@ -0,0 +1,32 @@
+=====================================================================
+ SQLAlchemy Transport Model - ``kombu.transport.sqlalchemy.models``
+=====================================================================
+
+
+.. currentmodule:: kombu.transport.sqlalchemy.models
+
+.. automodule:: kombu.transport.sqlalchemy.models
+
+    .. contents::
+        :local:
+
+    Models
+    ------
+
+    .. autoclass:: Queue
+
+        .. autoattribute:: Queue.id
+
+        .. autoattribute:: Queue.name
+
+    .. autoclass:: Message
+
+        .. autoattribute:: Message.id
+
+        .. autoattribute:: Message.visible
+
+        .. autoattribute:: Message.sent_at
+
+        .. autoattribute:: Message.payload
+
+        .. autoattribute:: Message.version

docs/reference/kombu.transport.sqlalchemy.rst

@@ -0,0 +1,25 @@
+===========================================================
+ SQLAlchemy Transport Model - kombu.transport.sqlalchemy
+===========================================================
+
+
+.. currentmodule:: kombu.transport.sqlalchemy
+
+.. automodule:: kombu.transport.sqlalchemy
+
+    .. contents::
+        :local:
+
+    Transport
+    ---------
+
+    .. autoclass:: Transport
+        :members:
+        :undoc-members:
+
+    Channel
+    -------
+
+    .. autoclass:: Channel
+        :members:
+        :undoc-members:

kombu/transport/__init__.py

@@ -28,6 +28,8 @@ def supports_librabbitmq():
     'sqs': 'kombu.transport.SQS:Transport',
     'mongodb': 'kombu.transport.mongodb:Transport',
     'zookeeper': 'kombu.transport.zookeeper:Transport',
+    'sqlalchemy': 'kombu.transport.sqlalchemy:Transport',
+    'sqla': 'kombu.transport.sqlalchemy:Transport',
     'SLMQ': 'kombu.transport.SLMQ.Transport',
     'slmq': 'kombu.transport.SLMQ.Transport',
     'filesystem': 'kombu.transport.filesystem:Transport',

kombu/transport/etcd.py

@@ -259,7 +259,6 @@ def driver_version(self):
         """Return the version of the etcd library.
 
         .. note::
-
            python-etcd has no __version__. This is a workaround.
         """
         try:

kombu/transport/sqlalchemy/__init__.py

@@ -0,0 +1,164 @@
+"""Kombu transport using SQLAlchemy as the message store."""
+# SQLAlchemy overrides != False to have special meaning and pep8 complains
+# flake8: noqa
+
+from __future__ import absolute_import, unicode_literals
+
+from json import loads, dumps
+
+from sqlalchemy import create_engine
+from sqlalchemy.exc import OperationalError
+from sqlalchemy.orm import sessionmaker
+
+from kombu.five import Empty
+from kombu.transport import virtual
+from kombu.utils import cached_property
+from kombu.utils.encoding import bytes_to_str
+from .models import (ModelBase, Queue as QueueBase, Message as MessageBase,
+                     class_registry, metadata)
+
+
+VERSION = (1, 1, 0)
+__version__ = '.'.join(map(str, VERSION))
+
+
+class Channel(virtual.Channel):
+    """The channel class."""
+
+    _session = None
+    _engines = {}   # engine cache
+
+    def __init__(self, connection, **kwargs):
+        self._configure_entity_tablenames(connection.client.transport_options)
+        super(Channel, self).__init__(connection, **kwargs)
+
+    def _configure_entity_tablenames(self, opts):
+        self.queue_tablename = opts.get('queue_tablename', 'kombu_queue')
+        self.message_tablename = opts.get('message_tablename', 'kombu_message')
+
+        #
+        # Define the model definitions.  This registers the declarative
+        # classes with the active SQLAlchemy metadata object.  This *must* be
+        # done prior to the ``create_engine`` call.
+        #
+        self.queue_cls and self.message_cls
+
+    def _engine_from_config(self):
+        conninfo = self.connection.client
+        transport_options = conninfo.transport_options.copy()
+        transport_options.pop('queue_tablename', None)
+        transport_options.pop('message_tablename', None)
+        return create_engine(conninfo.hostname, **transport_options)
+
+    def _open(self):
+        conninfo = self.connection.client
+        if conninfo.hostname not in self._engines:
+            engine = self._engine_from_config()
+            Session = sessionmaker(bind=engine)
+            metadata.create_all(engine)
+            self._engines[conninfo.hostname] = engine, Session
+        return self._engines[conninfo.hostname]
+
+    @property
+    def session(self):
+        if self._session is None:
+            _, Session = self._open()
+            self._session = Session()
+        return self._session
+
+    def _get_or_create(self, queue):
+        obj = self.session.query(self.queue_cls) \
+            .filter(self.queue_cls.name == queue).first()
+        if not obj:
+            obj = self.queue_cls(queue)
+            self.session.add(obj)
+            try:
+                self.session.commit()
+            except OperationalError:
+                self.session.rollback()
+        return obj
+
+    def _new_queue(self, queue, **kwargs):
+        self._get_or_create(queue)
+
+    def _put(self, queue, payload, **kwargs):
+        obj = self._get_or_create(queue)
+        message = self.message_cls(dumps(payload), obj)
+        self.session.add(message)
+        try:
+            self.session.commit()
+        except OperationalError:
+            self.session.rollback()
+
+    def _get(self, queue):
+        obj = self._get_or_create(queue)
+        if self.session.bind.name == 'sqlite':
+            self.session.execute('BEGIN IMMEDIATE TRANSACTION')
+        try:
+            msg = self.session.query(self.message_cls) \
+                .with_lockmode('update') \
+                .filter(self.message_cls.queue_id == obj.id) \
+                .filter(self.message_cls.visible != False) \
+                .order_by(self.message_cls.sent_at) \
+                .order_by(self.message_cls.id) \
+                .limit(1) \
+                .first()
+            if msg:
+                msg.visible = False
+                return loads(bytes_to_str(msg.payload))
+            raise Empty()
+        finally:
+            self.session.commit()
+
+    def _query_all(self, queue):
+        obj = self._get_or_create(queue)
+        return self.session.query(self.message_cls) \
+            .filter(self.message_cls.queue_id == obj.id)
+
+    def _purge(self, queue):
+        count = self._query_all(queue).delete(synchronize_session=False)
+        try:
+            self.session.commit()
+        except OperationalError:
+            self.session.rollback()
+        return count
+
+    def _size(self, queue):
+        return self._query_all(queue).count()
+
+    def _declarative_cls(self, name, base, ns):
+        if name in class_registry:
+            return class_registry[name]
+        return type(str(name), (base, ModelBase), ns)
+
+    @cached_property
+    def queue_cls(self):
+        return self._declarative_cls(
+            'Queue',
+            QueueBase,
+            {'__tablename__': self.queue_tablename}
+        )
+
+    @cached_property
+    def message_cls(self):
+        return self._declarative_cls(
+            'Message',
+            MessageBase,
+            {'__tablename__': self.message_tablename}
+        )
+
+
+class Transport(virtual.Transport):
+    """The transport class."""
+
+    Channel = Channel
+
+    can_parse_url = True
+    default_port = 0
+    driver_type = 'sql'
+    driver_name = 'sqlalchemy'
+    connection_errors = (OperationalError, )
+
+    def driver_version(self):
+        import sqlalchemy
+        return sqlalchemy.__version__

kombu/transport/sqlalchemy/models.py

@@ -0,0 +1,67 @@
+"""Kombu transport using SQLAlchemy as the message store."""
+from __future__ import absolute_import, unicode_literals
+
+import datetime
+
+from sqlalchemy import (Column, Integer, String, Text, DateTime,
+                        Sequence, Boolean, ForeignKey, SmallInteger)
+from sqlalchemy.ext.declarative import declarative_base, declared_attr
+from sqlalchemy.orm import relation
+from sqlalchemy.schema import MetaData
+
+class_registry = {}
+metadata = MetaData()
+ModelBase = declarative_base(metadata=metadata, class_registry=class_registry)
+
+
+class Queue(object):
+    """The queue class."""
+
+    __table_args__ = {'sqlite_autoincrement': True, 'mysql_engine': 'InnoDB'}
+
+    id = Column(Integer, Sequence('queue_id_sequence'), primary_key=True,
+                autoincrement=True)
+    name = Column(String(200), unique=True)
+
+    def __init__(self, name):
+        self.name = name
+
+    def __str__(self):
+        return '<Queue({self.name})>'.format(self=self)
+
+    @declared_attr
+    def messages(cls):
+        return relation('Message', backref='queue', lazy='noload')
+
+
+class Message(object):
+    """The message class."""
+
+    __table_args__ = {'sqlite_autoincrement': True, 'mysql_engine': 'InnoDB'}
+
+    id = Column(Integer, Sequence('message_id_sequence'),
+                primary_key=True, autoincrement=True)
+    visible = Column(Boolean, default=True, index=True)
+    sent_at = Column('timestamp', DateTime, nullable=True, index=True,
+                     onupdate=datetime.datetime.now)
+    payload = Column(Text, nullable=False)
+    version = Column(SmallInteger, nullable=False, default=1)
+
+    __mapper_args__ = {'version_id_col': version}
+
+    def __init__(self, payload, queue):
+        self.payload = payload
+        self.queue = queue
+
+    def __str__(self):
+        return '<Message: {0.sent_at} {0.payload} {0.queue_id}>'.format(self)
+
+    @declared_attr
+    def queue_id(self):
+        return Column(
+            Integer,
+            ForeignKey(
+                '%s.id' % class_registry['Queue'].__tablename__,
+                name='FK_kombu_message_queue'
+            )
+        )

requirements/extras/sqlalchemy.txt

@@ -0,0 +1 @@
+sqlalchemy

requirements/test-ci.txt

@@ -4,3 +4,4 @@ redis
 PyYAML
 msgpack-python>0.2.0
 -r extras/sqs.txt
+sqlalchemy

setup.py

@@ -141,6 +141,7 @@ def run_tests(self):
         'mongodb': extras('mongodb.txt'),
         'sqs': extras('sqs.txt'),
         'zookeeper': extras('zookeeper.txt'),
+        'sqlalchemy': extras('sqlalchemy.txt'),
         'librabbitmq': extras('librabbitmq.txt'),
         'pyro': extras('pyro.txt'),
         'slmq': extras('slmq.txt'),

t/integration/tests/test_sqla.py

@@ -0,0 +1,13 @@
+from __future__ import absolute_import, unicode_literals
+
+from funtests import transport
+
+from kombu.tests.case import skip
+
+
+@skip.unless_module('sqlalchemy')
+class test_sqla(transport.TransportCase):
+    transport = 'sqlalchemy'
+    prefix = 'sqlalchemy'
+    event_loop_max = 10
+    connection_options = {'hostname': 'sqla+sqlite://'}