Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Fetching contributors…

Cannot retrieve contributors at this time

349 lines (281 sloc) 11.233 kb
"""
kombu.transport.SQS
===================
Amazon SQS transport.
:copyright: (c) 2010 - 2012 by Ask Solem
:license: BSD, see LICENSE for more details.
"""
from __future__ import absolute_import
import socket
import string
from Queue import Empty
from anyjson import loads, dumps
from boto import exception
from boto import sdb as _sdb
from boto import sqs as _sqs
from boto.sdb.domain import Domain
from boto.sdb.connection import SDBConnection
from boto.sqs.connection import SQSConnection
from boto.sqs.message import Message
from kombu.exceptions import StdChannelError
from kombu.utils import cached_property, uuid
from kombu.utils.encoding import safe_str
from . import virtual
# dots are replaced by dash, all other punctuation
# replaced by underscore.
CHARS_REPLACE_TABLE = dict((ord(c), 0x5f)
for c in string.punctuation if c not in '-_.')
CHARS_REPLACE_TABLE[0x2e] = 0x2d # '.' -> '-'
class Table(Domain):
"""Amazon SimpleDB domain describing the message routing table."""
# caches queues already bound, so we don't have to declare them again.
_already_bound = set()
def routes_for(self, exchange):
"""Iterator giving all routes for an exchange."""
return self.select("""WHERE exchange = '%s'""" % exchange)
def get_queue(self, queue):
"""Get binding for queue."""
qid = self._get_queue_id(queue)
if qid:
return self.get_item(qid)
def create_binding(self, queue):
"""Get binding item for queue.
Creates the item if it doesn't exist.
"""
item = self.get_queue(queue)
if item:
return item, item["id"]
id = uuid()
return self.new_item(id), id
def queue_bind(self, exchange, routing_key, pattern, queue):
if queue not in self._already_bound:
binding, id = self.create_binding(queue)
binding.update(exchange=exchange,
routing_key=routing_key or "",
pattern=pattern or "",
queue=queue or "",
id=id)
binding.save()
self._already_bound.add(queue)
def queue_delete(self, queue):
"""delete queue by name."""
self._already_bound.discard(queue)
item = self._get_queue_item(queue)
if item:
self.delete_item(item)
def exchange_delete(self, exchange):
"""Delete all routes for `exchange`."""
for item in self.routes_for(exchange):
self.delete_item(item["id"])
def get_item(self, item_name):
"""Uses `consistent_read` by default."""
# Domain is an old-style class, can't use super().
for consistent_read in (False, True):
item = Domain.get_item(self, item_name, consistent_read)
if item:
return item
def select(self, query='', next_token=None, consistent_read=True,
max_items=None):
"""Uses `consistent_read` by default."""
query = """SELECT * FROM `%s` %s""" % (self.name, query)
return Domain.select(self, query, next_token,
consistent_read, max_items)
def _try_first(self, query='', **kwargs):
for c in (False, True):
for item in self.select(query, consistent_read=c, **kwargs):
return item
def get_exchanges(self):
return list(set(i["exchange"] for i in self.select()))
def _get_queue_item(self, queue):
return self._try_first("""WHERE queue = '%s' limit 1""" % queue)
def _get_queue_id(self, queue):
item = self._get_queue_item(queue)
if item:
return item["id"]
class Channel(virtual.Channel):
Table = Table
default_region = "us-east-1"
domain_format = "kombu%(vhost)s"
_sdb = None
_sqs = None
_queue_cache = {}
_noack_queues = set()
def __init__(self, *args, **kwargs):
super(Channel, self).__init__(*args, **kwargs)
# SQS blows up when you try to create a new queue if one already
# exists with a different visibility_timeout, so this prepopulates
# the queue_cache to protect us from recreating
# queues that are known to already exist.
queues = self.sqs.get_all_queues()
for queue in queues:
self._queue_cache[queue.name] = queue
def basic_consume(self, queue, no_ack, *args, **kwargs):
if no_ack:
self._noack_queues.add(queue)
return super(Channel, self).basic_consume(queue, no_ack,
*args, **kwargs)
def basic_cancel(self, consumer_tag):
if consumer_tag in self._consumers:
queue = self._tag_to_queue[consumer_tag]
self._noack_queues.discard(queue)
return super(Channel, self).basic_cancel(consumer_tag)
def entity_name(self, name, table=CHARS_REPLACE_TABLE):
"""Format AMQP queue name into a legal SQS queue name."""
return unicode(safe_str(name)).translate(table)
def _new_queue(self, queue, **kwargs):
"""Ensures a queue exists in SQS."""
queue = self.queue_name_prefix + queue
try:
return self._queue_cache[queue]
except KeyError:
q = self._queue_cache[queue] = self.sqs.create_queue(
self.entity_name(queue),
self.visibility_timeout)
return q
def _queue_bind(self, *args):
"""Bind ``queue`` to ``exchange`` with routing key.
Route will be stored in SDB if so enabled.
"""
if self.supports_fanout:
self.table.queue_bind(*args)
def get_table(self, exchange):
"""Get routing table.
Retrieved from SDB if :attr:`supports_fanout`.
"""
if self.supports_fanout:
return [(r["routing_key"], r["pattern"], r["queue"])
for r in self.table.routes_for(exchange)]
return super(Channel, self).get_table(exchange)
def get_exchanges(self):
if self.supports_fanout:
return self.table.get_exchanges()
return super(Channel, self).get_exchanges()
def _delete(self, queue, *args):
"""delete queue by name."""
self._queue_cache.pop(queue, None)
if self.supports_fanout:
self.table.queue_delete(queue)
super(Channel, self)._delete(queue)
def exchange_delete(self, exchange, **kwargs):
"""Delete exchange by name."""
if self.supports_fanout:
self.table.exchange_delete(exchange)
super(Channel, self).exchange_delete(exchange, **kwargs)
def _has_queue(self, queue, **kwargs):
"""Returns True if ``queue`` has been previously declared."""
if self.supports_fanout:
return bool(self.table.get_queue(queue))
return super(Channel, self)._has_queue(queue)
def _put(self, queue, message, **kwargs):
"""Put message onto queue."""
q = self._new_queue(queue)
m = Message()
m.set_body(dumps(message))
q.write(m)
def _put_fanout(self, exchange, message, **kwargs):
"""Deliver fanout message to all queues in ``exchange``."""
for route in self.table.routes_for(exchange):
self._put(route["queue"], message, **kwargs)
def _get(self, queue):
"""Try to retrieve a single message off ``queue``."""
q = self._new_queue(queue)
rs = q.get_messages(1)
if rs:
m = rs[0]
payload = loads(rs[0].get_body())
if queue in self._noack_queues:
q.delete_message(m)
else:
payload["properties"]["delivery_info"].update({
"sqs_message": m, "sqs_queue": q, })
return payload
raise Empty()
def basic_ack(self, delivery_tag):
delivery_info = self.qos.get(delivery_tag).delivery_info
try:
queue = delivery_info["sqs_queue"]
except KeyError:
pass
else:
queue.delete_message(delivery_info["sqs_message"])
super(Channel, self).basic_ack(delivery_tag)
def _size(self, queue):
"""Returns the number of messages in a queue."""
return self._new_queue(queue).count()
def _purge(self, queue):
"""Deletes all current messages in a queue."""
q = self._new_queue(queue)
# SQS is slow at registering messages, so run for a few
# iterations to ensure messages are deleted.
size = 0
for i in xrange(10):
size += q.count()
if not size:
break
q.clear()
return size
def close(self):
super(Channel, self).close()
for conn in (self._sqs, self._sdb):
if conn:
try:
conn.close()
except AttributeError, exc: # FIXME ???
if "can't set attribute" not in str(exc):
raise
def _get_regioninfo(self, regions):
if self.region:
for _r in regions:
if _r.name == self.region:
return _r
def _aws_connect_to(self, fun, regions):
conninfo = self.conninfo
region = self._get_regioninfo(regions)
return fun(region=region,
aws_access_key_id=conninfo.userid,
aws_secret_access_key=conninfo.password,
port=conninfo.port)
def _next_delivery_tag(self):
return uuid() # See #73
@property
def sqs(self):
if self._sqs is None:
self._sqs = self._aws_connect_to(SQSConnection, _sqs.regions())
return self._sqs
@property
def sdb(self):
if self._sdb is None:
self._sdb = self._aws_connect_to(SDBConnection, _sdb.regions())
return self._sdb
@property
def table(self):
name = self.entity_name(self.domain_format % {
"vhost": self.conninfo.virtual_host})
d = self.sdb.get_object("CreateDomain", {"DomainName": name},
self.Table)
d.name = name
return d
@property
def conninfo(self):
return self.connection.client
@property
def transport_options(self):
return self.connection.client.transport_options
@cached_property
def visibility_timeout(self):
return self.transport_options.get("visibility_timeout")
@cached_property
def queue_name_prefix(self):
return self.transport_options.get("queue_name_prefix", '')
@cached_property
def supports_fanout(self):
return self.transport_options.get("sdb_persistence", False)
@cached_property
def region(self):
return self.transport_options.get("region") or self.default_region
class Transport(virtual.Transport):
Channel = Channel
polling_interval = 1
default_port = None
connection_errors = (exception.SQSError, socket.error)
channel_errors = (exception.SQSDecodeError, StdChannelError)
Jump to Line
Something went wrong with that request. Please try again.