15 files changed, 245 insertions, 187 deletions

diff --git a/src/mailman/app/subscriptions.py b/src/mailman/app/subscriptions.py
index 60f8cdebe..5852a7483 100644
--- a/src/mailman/app/subscriptions.py
+++ b/src/mailman/app/subscriptions.py
@@ -17,7 +17,7 @@
 
 """Module stuff."""
 
-from __future__ import absolute_import, unicode_literals
+from __future__ import absolute_import, print_function, unicode_literals
 
 __metaclass__ = type
 __all__ = [
@@ -36,6 +36,7 @@ from zope.interface import implements
 from mailman.app.membership import add_member, delete_member
 from mailman.config import config
 from mailman.core.constants import system_preferences
+from mailman.database.transaction import dbconnection
 from mailman.interfaces.address import IEmailValidator
 from mailman.interfaces.listmanager import (
     IListManager, ListDeletedEvent, NoSuchListError)
@@ -90,9 +91,10 @@ class SubscriptionService:
                 sorted(by_role.get('member', []), key=address_of_member))
         return all_members
 
-    def get_member(self, member_id):
+    @dbconnection
+    def get_member(self, store, member_id):
         """See `ISubscriptionService`."""
-        members = config.db.store.find(
+        members = store.find(
             Member,
             Member._member_id == member_id)
         if members.count() == 0:
@@ -101,7 +103,9 @@ class SubscriptionService:
             assert members.count() == 1, 'Too many matching members'
             return members[0]
 
-    def find_members(self, subscriber=None, fqdn_listname=None, role=None):
+    @dbconnection
+    def find_members(self, store,
+                     subscriber=None, fqdn_listname=None, role=None):
         """See `ISubscriptionService`."""
         # If `subscriber` is a user id, then we'll search for all addresses
         # which are controlled by the user, otherwise we'll just search for
@@ -137,7 +141,7 @@ class SubscriptionService:
             query.append(Member.mailing_list == fqdn_listname)
         if role is not None:
             query.append(Member.role == role)
-        results = config.db.store.find(Member, And(*query))
+        results = store.find(Member, And(*query))
         return sorted(results, key=_membership_sort_key)
 
     def __iter__(self):
diff --git a/src/mailman/model/autorespond.py b/src/mailman/model/autorespond.py
index 7b42205b4..9e0fbd042 100644
--- a/src/mailman/model/autorespond.py
+++ b/src/mailman/model/autorespond.py
@@ -17,7 +17,7 @@
 
 """Module stuff."""
 
-from __future__ import absolute_import, unicode_literals
+from __future__ import absolute_import, print_function, unicode_literals
 
 __metaclass__ = type
 __all__ = [
@@ -29,8 +29,8 @@ __all__ = [
 from storm.locals import And, Date, Desc, Int, Reference
 from zope.interface import implements
 
-from mailman.config import config
 from mailman.database.model import Model
+from mailman.database.transaction import dbconnection
 from mailman.database.types import Enum
 from mailman.interfaces.autorespond import (
     IAutoResponseRecord, IAutoResponseSet, Response)
@@ -66,27 +66,30 @@ class AutoResponseSet:
     def __init__(self, mailing_list):
         self._mailing_list = mailing_list
 
-    def todays_count(self, address, response_type):
+    @dbconnection
+    def todays_count(self, store, address, response_type):
         """See `IAutoResponseSet`."""
-        return config.db.store.find(
+        return store.find(
             AutoResponseRecord,
             And(AutoResponseRecord.address == address,
                 AutoResponseRecord.mailing_list == self._mailing_list,
                 AutoResponseRecord.response_type == response_type,
                 AutoResponseRecord.date_sent == today())).count()
 
-    def response_sent(self, address, response_type):
+    @dbconnection
+    def response_sent(self, store, address, response_type):
         """See `IAutoResponseSet`."""
         response = AutoResponseRecord(
             self._mailing_list, address, response_type)
-        config.db.store.add(response)
+        store.add(response)
 
-    def last_response(self, address, response_type):
+    @dbconnection
+    def last_response(self, store, address, response_type):
         """See `IAutoResponseSet`."""
-        results = config.db.store.find(
+        results = store.find(
             AutoResponseRecord,
             And(AutoResponseRecord.address == address,
                 AutoResponseRecord.mailing_list == self._mailing_list,
                 AutoResponseRecord.response_type == response_type)
-            ).order_by(Desc(AutoResponseRecord.date_sent)) 
+            ).order_by(Desc(AutoResponseRecord.date_sent))
         return (None if results.count() == 0 else results.first())
diff --git a/src/mailman/model/bans.py b/src/mailman/model/bans.py
index 9dc0c51ba..89addd8c7 100644
--- a/src/mailman/model/bans.py
+++ b/src/mailman/model/bans.py
@@ -17,7 +17,7 @@
 
 """Ban manager."""
 
-from __future__ import absolute_import, unicode_literals
+from __future__ import absolute_import, print_function, unicode_literals
 
 __metaclass__ = type
 __all__ = [
@@ -30,8 +30,8 @@ import re
 from storm.locals import Int, Unicode
 from zope.interface import implements
 
-from mailman.config import config
 from mailman.database.model import Model
+from mailman.database.transaction import dbconnection
 from mailman.interfaces.bans import IBan, IBanManager
 
 
@@ -53,43 +53,43 @@ class Ban(Model):
 class BanManager:
     implements(IBanManager)
 
-    def ban(self, email, mailing_list=None):
+    @dbconnection
+    def ban(self, store, email, mailing_list=None):
         """See `IBanManager`."""
-        bans = config.db.store.find(
-            Ban, email=email, mailing_list=mailing_list)
+        bans = store.find(Ban, email=email, mailing_list=mailing_list)
         if bans.count() == 0:
             ban = Ban(email, mailing_list)
-            config.db.store.add(ban)
+            store.add(ban)
 
-    def unban(self, email, mailing_list=None):
+    @dbconnection
+    def unban(self, store, email, mailing_list=None):
         """See `IBanManager`."""
-        ban = config.db.store.find(
-            Ban, email=email, mailing_list=mailing_list).one()
+        ban = store.find(Ban, email=email, mailing_list=mailing_list).one()
         if ban is not None:
-            config.db.store.remove(ban)
+            store.remove(ban)
 
-    def is_banned(self, email, mailing_list=None):
+    @dbconnection
+    def is_banned(self, store, email, mailing_list=None):
         """See `IBanManager`."""
         # A specific mailing list ban is being checked, however the email
         # address could be banned specifically, or globally.
         if mailing_list is not None:
             # Try specific bans first.
-            bans = config.db.store.find(
-                Ban, email=email, mailing_list=mailing_list)
+            bans = store.find(Ban, email=email, mailing_list=mailing_list)
             if bans.count() > 0:
                 return True
             # Try global bans next.
-            bans = config.db.store.find(Ban, email=email, mailing_list=None)
+            bans = store.find(Ban, email=email, mailing_list=None)
             if bans.count() > 0:
                 return True
             # Now try specific mailing list bans, but with a pattern.
-            bans = config.db.store.find(Ban, mailing_list=mailing_list)
+            bans = store.find(Ban, mailing_list=mailing_list)
             for ban in bans:
                 if (ban.email.startswith('^') and
                     re.match(ban.email, email, re.IGNORECASE) is not None):
                     return True
             # And now try global pattern bans.
-            bans = config.db.store.find(Ban, mailing_list=None)
+            bans = store.find(Ban, mailing_list=None)
             for ban in bans:
                 if (ban.email.startswith('^') and
                     re.match(ban.email, email, re.IGNORECASE) is not None):
@@ -97,12 +97,11 @@ class BanManager:
         else:
             # The client is asking for global bans.  Look up bans on the
             # specific email address first.
-            bans = config.db.store.find(
-                Ban, email=email, mailing_list=None)
+            bans = store.find(Ban, email=email, mailing_list=None)
             if bans.count() > 0:
                 return True
             # And now look for global pattern bans.
-            bans = config.db.store.find(Ban, mailing_list=None)
+            bans = store.find(Ban, mailing_list=None)
             for ban in bans:
                 if (ban.email.startswith('^') and
                     re.match(ban.email, email, re.IGNORECASE) is not None):
diff --git a/src/mailman/model/bounce.py b/src/mailman/model/bounce.py
index 8c55e3d16..b957a2243 100644
--- a/src/mailman/model/bounce.py
+++ b/src/mailman/model/bounce.py
@@ -17,7 +17,7 @@
 
 """Bounce support."""
 
-from __future__ import absolute_import, unicode_literals
+from __future__ import absolute_import, print_function, unicode_literals
 
 __metaclass__ = type
 __all__ = [
@@ -29,8 +29,8 @@ __all__ = [
 from storm.locals import Bool, Int, DateTime, Unicode
 from zope.interface import implements
 
-from mailman.config import config
 from mailman.database.model import Model
+from mailman.database.transaction import dbconnection
 from mailman.database.types import Enum
 from mailman.interfaces.bounce import (
     BounceContext, IBounceEvent, IBounceProcessor)
@@ -62,21 +62,23 @@ class BounceEvent(Model):
 class BounceProcessor:
     implements(IBounceProcessor)
 
-    def register(self, mlist, email, msg, where=None):
+    @dbconnection
+    def register(self, store, mlist, email, msg, where=None):
         """See `IBounceProcessor`."""
         event = BounceEvent(mlist.fqdn_listname, email, msg, where)
-        config.db.store.add(event)
+        store.add(event)
         return event
 
     @property
-    def events(self):
+    @dbconnection
+    def events(self, store):
         """See `IBounceProcessor`."""
-        for event in config.db.store.find(BounceEvent):
+        for event in store.find(BounceEvent):
             yield event
 
     @property
-    def unprocessed(self):
+    @dbconnection
+    def unprocessed(self, store):
         """See `IBounceProcessor`."""
-        for event in config.db.store.find(BounceEvent,
-                                          BounceEvent.processed == False):
+        for event in store.find(BounceEvent, BounceEvent.processed == False):
             yield event
diff --git a/src/mailman/model/domain.py b/src/mailman/model/domain.py
index 49c935740..e93335328 100644
--- a/src/mailman/model/domain.py
+++ b/src/mailman/model/domain.py
@@ -17,7 +17,7 @@
 
 """Domains."""
 
-from __future__ import unicode_literals
+from __future__ import absolute_import, print_function, unicode_literals
 
 __metaclass__ = type
 __all__ = [
@@ -31,8 +31,8 @@ from storm.locals import Int, Unicode
 from zope.event import notify
 from zope.interface import implements
 
-from mailman.config import config
 from mailman.database.model import Model
+from mailman.database.transaction import dbconnection
 from mailman.interfaces.domain import (
     BadDomainSpecificationError, DomainCreatedEvent, DomainCreatingEvent,
     DomainDeletedEvent, DomainDeletingEvent, IDomain, IDomainManager)
@@ -90,9 +90,10 @@ class Domain(Model):
         return urlparse(self.base_url).scheme
 
     @property
-    def mailing_lists(self):
+    @dbconnection
+    def mailing_lists(self, store):
         """See `IDomain`."""
-        mailing_lists = config.db.store.find(
+        mailing_lists = store.find(
             MailingList,
             MailingList.mail_host == self.mail_host)
         for mlist in mailing_lists:
@@ -119,7 +120,9 @@ class DomainManager:
 
     implements(IDomainManager)
 
-    def add(self, mail_host,
+    @dbconnection
+    def add(self, store,
+            mail_host,
             description=None,
             base_url=None,
             contact_address=None):
@@ -131,20 +134,22 @@ class DomainManager:
                 'Duplicate email host: %s' % mail_host)
         notify(DomainCreatingEvent(mail_host))
         domain = Domain(mail_host, description, base_url, contact_address)
-        config.db.store.add(domain)
+        store.add(domain)
         notify(DomainCreatedEvent(domain))
         return domain
 
-    def remove(self, mail_host):
+    @dbconnection
+    def remove(self, store, mail_host):
         domain = self[mail_host]
         notify(DomainDeletingEvent(domain))
-        config.db.store.remove(domain)
+        store.remove(domain)
         notify(DomainDeletedEvent(mail_host))
         return domain
 
-    def get(self, mail_host, default=None):
+    @dbconnection
+    def get(self, store, mail_host, default=None):
         """See `IDomainManager`."""
-        domains = config.db.store.find(Domain, mail_host=mail_host)
+        domains = store.find(Domain, mail_host=mail_host)
         if domains.count() < 1:
             return default
         assert domains.count() == 1, (
@@ -159,14 +164,17 @@ class DomainManager:
             raise KeyError(mail_host)
         return domain
 
-    def __len__(self):
-        return config.db.store.find(Domain).count()
+    @dbconnection
+    def __len__(self, store):
+        return store.find(Domain).count()
 
-    def __iter__(self):
+    @dbconnection
+    def __iter__(self, store):
         """See `IDomainManager`."""
-        for domain in config.db.store.find(Domain):
+        for domain in store.find(Domain):
             yield domain
 
-    def __contains__(self, mail_host):
+    @dbconnection
+    def __contains__(self, store, mail_host):
         """See `IDomainManager`."""
-        return config.db.store.find(Domain, mail_host=mail_host).count() > 0
+        return store.find(Domain, mail_host=mail_host).count() > 0
diff --git a/src/mailman/model/listmanager.py b/src/mailman/model/listmanager.py
index 0ea87a082..8d845b36f 100644
--- a/src/mailman/model/listmanager.py
+++ b/src/mailman/model/listmanager.py
@@ -17,7 +17,7 @@
 
 """A mailing list manager."""
 
-from __future__ import absolute_import, unicode_literals
+from __future__ import absolute_import, print_function, unicode_literals
 
 __metaclass__ = type
 __all__ = [
@@ -28,7 +28,7 @@ __all__ = [
 from zope.event import notify
 from zope.interface import implements
 
-from mailman.config import config
+from mailman.database.transaction import dbconnection
 from mailman.interfaces.address import InvalidEmailAddressError
 from mailman.interfaces.listmanager import (
     IListManager, ListAlreadyExistsError, ListCreatedEvent, ListCreatingEvent,
@@ -43,13 +43,14 @@ class ListManager:
 
     implements(IListManager)
 
-    def create(self, fqdn_listname):
+    @dbconnection
+    def create(self, store, fqdn_listname):
         """See `IListManager`."""
         listname, at, hostname = fqdn_listname.partition('@')
         if len(hostname) == 0:
             raise InvalidEmailAddressError(fqdn_listname)
         notify(ListCreatingEvent(fqdn_listname))
-        mlist = config.db.store.find(
+        mlist = store.find(
             MailingList,
             MailingList.list_name == listname,
             MailingList.mail_host == hostname).one()
@@ -57,47 +58,53 @@ class ListManager:
             raise ListAlreadyExistsError(fqdn_listname)
         mlist = MailingList(fqdn_listname)
         mlist.created_at = now()
-        config.db.store.add(mlist)
+        store.add(mlist)
         notify(ListCreatedEvent(mlist))
         return mlist
 
-    def get(self, fqdn_listname):
+    @dbconnection
+    def get(self, store, fqdn_listname):
         """See `IListManager`."""
         listname, at, hostname = fqdn_listname.partition('@')
-        return config.db.store.find(MailingList,
-                                    list_name=listname,
-                                    mail_host=hostname).one()
+        return store.find(MailingList,
+                          list_name=listname,
+                          mail_host=hostname).one()
 
-    def delete(self, mlist):
+    @dbconnection
+    def delete(self, store, mlist):
         """See `IListManager`."""
         fqdn_listname = mlist.fqdn_listname
         notify(ListDeletingEvent(mlist))
-        config.db.store.remove(mlist)
+        store.remove(mlist)
         notify(ListDeletedEvent(fqdn_listname))
 
     @property
-    def mailing_lists(self):
+    @dbconnection
+    def mailing_lists(self, store):
         """See `IListManager`."""
-        for mlist in config.db.store.find(MailingList):
+        for mlist in store.find(MailingList):
             yield mlist
 
-    def __iter__(self):
+    @dbconnection
+    def __iter__(self, store):
         """See `IListManager`."""
-        for mlist in config.db.store.find(MailingList):
+        for mlist in store.find(MailingList):
             yield mlist
 
     @property
-    def names(self):
+    @dbconnection
+    def names(self, store):
         """See `IListManager`."""
-        result_set = config.db.store.find(MailingList)
-        for mail_host, list_name in result_set.values(MailingList.mail_host, 
+        result_set = store.find(MailingList)
+        for mail_host, list_name in result_set.values(MailingList.mail_host,
                                                       MailingList.list_name):
             yield '{0}@{1}'.format(list_name, mail_host)
 
     @property
-    def name_components(self):
+    @dbconnection
+    def name_components(self, store):
         """See `IListManager`."""
-        result_set = config.db.store.find(MailingList)
-        for mail_host, list_name in result_set.values(MailingList.mail_host, 
+        result_set = store.find(MailingList)
+        for mail_host, list_name in result_set.values(MailingList.mail_host,
                                                       MailingList.list_name):
             yield list_name, mail_host
diff --git a/src/mailman/model/member.py b/src/mailman/model/member.py
index ae83fb388..5a71eb8be 100644
--- a/src/mailman/model/member.py
+++ b/src/mailman/model/member.py
@@ -17,7 +17,7 @@
 
 """Model for members."""
 
-from __future__ import absolute_import, unicode_literals
+from __future__ import absolute_import, print_function, unicode_literals
 
 __metaclass__ = type
 __all__ = [
@@ -29,9 +29,9 @@ from storm.properties import UUID
 from zope.component import getUtility
 from zope.interface import implements
 
-from mailman.config import config
 from mailman.core.constants import system_preferences
 from mailman.database.model import Model
+from mailman.database.transaction import dbconnection
 from mailman.database.types import Enum
 from mailman.interfaces.action import Action
 from mailman.interfaces.address import IAddress
@@ -176,7 +176,8 @@ class Member(Model):
         # XXX Um, this is definitely wrong
         return 'http://example.com/' + self.address.email
 
-    def unsubscribe(self):
+    @dbconnection
+    def unsubscribe(self, store):
         """See `IMember`."""
-        config.db.store.remove(self.preferences)
-        config.db.store.remove(self)
+        store.remove(self.preferences)
+        store.remove(self)
diff --git a/src/mailman/model/message.py b/src/mailman/model/message.py
index 3345c64c9..67c4caf79 100644
--- a/src/mailman/model/message.py
+++ b/src/mailman/model/message.py
@@ -17,8 +17,7 @@
 
 """Model for messages."""
 
-
-from __future__ import absolute_import, unicode_literals
+from __future__ import absolute_import, print_function, unicode_literals
 
 __metaclass__ = type
 __all__ = [
@@ -28,8 +27,8 @@ __all__ = [
 from storm.locals import AutoReload, Int, RawStr, Unicode
 from zope.interface import implements
 
-from mailman.config import config
 from mailman.database.model import Model
+from mailman.database.transaction import dbconnection
 from mailman.interfaces.messages import IMessage
 
 
@@ -45,9 +44,10 @@ class Message(Model):
     path = RawStr()
     # This is a Messge-ID field representation, not a database row id.
 
-    def __init__(self, message_id, message_id_hash, path):
+    @dbconnection
+    def __init__(self, store, message_id, message_id_hash, path):
         super(Message, self).__init__()
         self.message_id = message_id
         self.message_id_hash = message_id_hash
         self.path = path
-        config.db.store.add(self)
+        store.add(self)
diff --git a/src/mailman/model/messagestore.py b/src/mailman/model/messagestore.py
index 59490993b..df2205ff8 100644
--- a/src/mailman/model/messagestore.py
+++ b/src/mailman/model/messagestore.py
@@ -17,8 +17,7 @@
 
 """Model for message stores."""
 
-
-from __future__ import absolute_import, unicode_literals
+from __future__ import absolute_import, print_function, unicode_literals
 
 __metaclass__ = type
 __all__ = [
@@ -34,6 +33,7 @@ import cPickle as pickle
 from zope.interface import implements
 
 from mailman.config import config
+from mailman.database.transaction import dbconnection
 from mailman.interfaces.messages import IMessageStore
 from mailman.model.message import Message
 from mailman.utilities.filesystem import makedirs
@@ -49,7 +49,8 @@ EMPTYSTRING = ''
 class MessageStore:
     implements(IMessageStore)
 
-    def add(self, message):
+    @dbconnection
+    def add(self, store, message):
         # Ensure that the message has the requisite headers.
         message_ids = message.get_all('message-id', [])
         if len(message_ids) <> 1:
@@ -57,8 +58,7 @@ class MessageStore:
         # Calculate and insert the X-Message-ID-Hash.
         message_id = message_ids[0]
         # Complain if the Message-ID already exists in the storage.
-        existing = config.db.store.find(Message,
-                                        Message.message_id == message_id).one()
+        existing = store.find(Message, Message.message_id == message_id).one()
         if existing is not None:
             raise ValueError(
                 'Message ID already exists in message store: {0}'.format(
@@ -104,34 +104,37 @@ class MessageStore:
         with open(path) as fp:
             return pickle.load(fp)
 
-    def get_message_by_id(self, message_id):
-        row = config.db.store.find(Message, message_id=message_id).one()
+    @dbconnection
+    def get_message_by_id(self, store, message_id):
+        row = store.find(Message, message_id=message_id).one()
         if row is None:
             return None
         return self._get_message(row)
 
-    def get_message_by_hash(self, message_id_hash):
+    @dbconnection
+    def get_message_by_hash(self, store, message_id_hash):
         # It's possible the hash came from a message header, in which case it
         # will be a Unicode.  However when coming from source code, it may be
         # an 8-string.  Coerce to the latter if necessary; it must be
         # US-ASCII.
         if isinstance(message_id_hash, unicode):
             message_id_hash = message_id_hash.encode('ascii')
-        row = config.db.store.find(Message,
-                                   message_id_hash=message_id_hash).one()
+        row = store.find(Message, message_id_hash=message_id_hash).one()
         if row is None:
             return None
         return self._get_message(row)
 
     @property
-    def messages(self):
-        for row in config.db.store.find(Message):
+    @dbconnection
+    def messages(self, store):
+        for row in store.find(Message):
             yield self._get_message(row)
 
-    def delete_message(self, message_id):
-        row = config.db.store.find(Message, message_id=message_id).one()
+    @dbconnection
+    def delete_message(self, store, message_id):
+        row = store.find(Message, message_id=message_id).one()
         if row is None:
             raise LookupError(message_id)
         path = os.path.join(config.MESSAGES_DIR, row.path)
         os.remove(path)
-        config.db.store.remove(row)
+        store.remove(row)
diff --git a/src/mailman/model/pending.py b/src/mailman/model/pending.py
index 557361c6f..39845e0bf 100644
--- a/src/mailman/model/pending.py
+++ b/src/mailman/model/pending.py
@@ -17,7 +17,7 @@
 
 """Implementations of the IPendable and IPending interfaces."""
 
-from __future__ import absolute_import, unicode_literals
+from __future__ import absolute_import, print_function, unicode_literals
 
 __metaclass__ = type
 __all__ = [
@@ -37,6 +37,7 @@ from zope.interface.verify import verifyObject
 
 from mailman.config import config
 from mailman.database.model import Model
+from mailman.database.transaction import dbconnection
 from mailman.interfaces.pending import (
     IPendable, IPended, IPendedKeyValue, IPendings)
 from mailman.utilities.datetime import now
@@ -86,7 +87,8 @@ class Pendings:
 
     implements(IPendings)
 
-    def add(self, pendable, lifetime=None):
+    @dbconnection
+    def add(self, store, pendable, lifetime=None):
         verifyObject(IPendable, pendable)
         # Calculate the token and the lifetime.
         if lifetime is None:
@@ -104,7 +106,7 @@ class Pendings:
             token = hashlib.sha1(repr(x)).hexdigest()
             # In practice, we'll never get a duplicate, but we'll be anal
             # about checking anyway.
-            if config.db.store.find(Pended, token=token).count() == 0:
+            if store.find(Pended, token=token).count() == 0:
                 break
         else:
             raise AssertionError('Could not find a valid pendings token')
@@ -129,11 +131,11 @@ class Pendings:
                          '\2'.join(value))
             keyval = PendedKeyValue(key=key, value=value)
             pending.key_values.add(keyval)
-        config.db.store.add(pending)
+        store.add(pending)
         return token
 
-    def confirm(self, token, expunge=True):
-        store = config.db.store
+    @dbconnection
+    def confirm(self, store, token, expunge=True):
         # Token can come in as a unicode, but it's stored in the database as
         # bytes.  They must be ascii.
         pendings = store.find(Pended, token=str(token))
@@ -158,8 +160,8 @@ class Pendings:
             store.remove(pending)
         return pendable
 
-    def evict(self):
-        store = config.db.store
+    @dbconnection
+    def evict(self, store):
         right_now = now()
         for pending in store.find(Pended):
             if pending.expiration_date < right_now:
diff --git a/src/mailman/model/requests.py b/src/mailman/model/requests.py
index 4a3efa67f..030c630b9 100644
--- a/src/mailman/model/requests.py
+++ b/src/mailman/model/requests.py
@@ -17,7 +17,7 @@
 
 """Implementations of the pending requests interfaces."""
 
-from __future__ import absolute_import, unicode_literals
+from __future__ import absolute_import, print_function, unicode_literals
 
 __metaclass__ = type
 __all__ = [
@@ -29,8 +29,8 @@ from storm.locals import AutoReload, Int, RawStr, Reference, Unicode
 from zope.component import getUtility
 from zope.interface import implements
 
-from mailman.config import config
 from mailman.database.model import Model
+from mailman.database.transaction import dbconnection
 from mailman.database.types import Enum
 from mailman.interfaces.pending import IPendable, IPendings
 from mailman.interfaces.requests import IListRequests, RequestType
@@ -49,30 +49,33 @@ class ListRequests:
         self.mailing_list = mailing_list
 
     @property
-    def count(self):
-        return config.db.store.find(
-            _Request, mailing_list=self.mailing_list).count()
+    @dbconnection
+    def count(self, store):
+        return store.find(_Request, mailing_list=self.mailing_list).count()
 
-    def count_of(self, request_type):
-        return config.db.store.find(
+    @dbconnection
+    def count_of(self, store, request_type):
+        return store.find(
             _Request,
             mailing_list=self.mailing_list, request_type=request_type).count()
 
     @property
-    def held_requests(self):
-        results = config.db.store.find(
-            _Request, mailing_list=self.mailing_list)
+    @dbconnection
+    def held_requests(self, store):
+        results = store.find(_Request, mailing_list=self.mailing_list)
         for request in results:
             yield request
 
-    def of_type(self, request_type):
-        results = config.db.store.find(
+    @dbconnection
+    def of_type(self, store, request_type):
+        results = store.find(
             _Request,
             mailing_list=self.mailing_list, request_type=request_type)
         for request in results:
             yield request
 
-    def hold_request(self, request_type, key, data=None):
+    @dbconnection
+    def hold_request(self, store, request_type, key, data=None):
         if request_type not in RequestType:
             raise TypeError(request_type)
         if data is None:
@@ -87,11 +90,12 @@ class ListRequests:
             token = getUtility(IPendings).add(pendable, timedelta(days=5000))
             data_hash = token
         request = _Request(key, request_type, self.mailing_list, data_hash)
-        config.db.store.add(request)
+        store.add(request)
         return request.id
 
-    def get_request(self, request_id, request_type=None):
-        result = config.db.store.get(_Request, request_id)
+    @dbconnection
+    def get_request(self, store, request_id, request_type=None):
+        result = store.get(_Request, request_id)
         if result is None:
             return None
         if request_type is not None and result.request_type != request_type:
@@ -104,13 +108,14 @@ class ListRequests:
         data.update(pendable)
         return result.key, data
 
-    def delete_request(self, request_id):
-        request = config.db.store.get(_Request, request_id)
+    @dbconnection
+    def delete_request(self, store, request_id):
+        request = store.get(_Request, request_id)
         if request is None:
             raise KeyError(request_id)
         # Throw away the pended data.
         getUtility(IPendings).confirm(request.data_hash)
-        config.db.store.remove(request)
+        store.remove(request)
 
 
 
diff --git a/src/mailman/model/roster.py b/src/mailman/model/roster.py
index 48d434ab1..84ed12930 100644
--- a/src/mailman/model/roster.py
+++ b/src/mailman/model/roster.py
@@ -22,7 +22,7 @@ the ones that fit a particular role.  These are used as the member, owner,
 moderator, and administrator roster filters.
 """
 
-from __future__ import absolute_import, unicode_literals
+from __future__ import absolute_import, print_function, unicode_literals
 
 __metaclass__ = type
 __all__ = [
@@ -40,7 +40,7 @@ __all__ = [
 from storm.expr import And, Or
 from zope.interface import implements
 
-from mailman.config import config
+from mailman.database.transaction import dbconnection
 from mailman.interfaces.member import DeliveryMode, MemberRole
 from mailman.interfaces.roster import IRoster
 from mailman.model.address import Address
@@ -64,8 +64,9 @@ class AbstractRoster:
     def __init__(self, mlist):
         self._mlist = mlist
 
-    def _query(self):
-        return config.db.store.find(
+    @dbconnection
+    def _query(self, store):
+        return store.find(
             Member,
             mailing_list=self._mlist.fqdn_listname,
             role=self.role)
@@ -101,9 +102,10 @@ class AbstractRoster:
         for member in self.members:
             yield member.address
 
-    def get_member(self, address):
+    @dbconnection
+    def get_member(self, store, address):
         """See `IRoster`."""
-        results = config.db.store.find(
+        results = store.find(
             Member,
             Member.mailing_list == self._mlist.fqdn_listname,
             Member.role == self.role,
@@ -157,16 +159,18 @@ class AdministratorRoster(AbstractRoster):
 
     name = 'administrator'
 
-    def _query(self):
-        return config.db.store.find(
+    @dbconnection
+    def _query(self, store):
+        return store.find(
             Member,
             Member.mailing_list == self._mlist.fqdn_listname,
             Or(Member.role == MemberRole.owner,
                Member.role == MemberRole.moderator))
 
-    def get_member(self, address):
+    @dbconnection
+    def get_member(self, store, address):
         """See `IRoster`."""
-        results = config.db.store.find(
+        results = store.find(
                 Member,
                 Member.mailing_list == self._mlist.fqdn_listname,
                 Or(Member.role == MemberRole.moderator,
@@ -194,7 +198,8 @@ class DeliveryMemberRoster(AbstractRoster):
         # checking the delivery mode to a query parameter.
         return len(tuple(self.members))
 
-    def _get_members(self, *delivery_modes):
+    @dbconnection
+    def _get_members(self, store, *delivery_modes):
         """The set of members for a mailing list, filter by delivery mode.
 
         :param delivery_modes: The modes to filter on.
@@ -202,7 +207,7 @@ class DeliveryMemberRoster(AbstractRoster):
         :return: A generator of members.
         :rtype: generator
         """
-        results = config.db.store.find(
+        results = store.find(
             Member,
             And(Member.mailing_list == self._mlist.fqdn_listname,
                 Member.role == MemberRole.member))
@@ -244,10 +249,9 @@ class Subscribers(AbstractRoster):
 
     name = 'subscribers'
 
-    def _query(self):
-        return config.db.store.find(
-            Member,
-            mailing_list=self._mlist.fqdn_listname)
+    @dbconnection
+    def _query(self, store):
+        return store.find(Member, mailing_list=self._mlist.fqdn_listname)
 
 
 
@@ -261,8 +265,9 @@ class Memberships:
     def __init__(self, user):
         self._user = user
 
-    def _query(self):
-        results = config.db.store.find(
+    @dbconnection
+    def _query(self, store):
+        results = store.find(
             Member,
             Or(Member.user_id == self._user.id,
                And(Address.user_id == self._user.id,
@@ -291,9 +296,10 @@ class Memberships:
         for address in self._user.addresses:
             yield address
 
-    def get_member(self, address):
+    @dbconnection
+    def get_member(self, store, address):
         """See `IRoster`."""
-        results = config.db.store.find(
+        results = store.find(
             Member,
             Member.address_id == Address.id,
             Address.user_id == self._user.id)
diff --git a/src/mailman/model/uid.py b/src/mailman/model/uid.py
index c3564aa40..08eae8aff 100644
--- a/src/mailman/model/uid.py
+++ b/src/mailman/model/uid.py
@@ -17,7 +17,7 @@
 
 """Unique IDs."""
 
-from __future__ import absolute_import, unicode_literals
+from __future__ import absolute_import, print_function, unicode_literals
 
 __metaclass__ = type
 __all__ = [
@@ -28,8 +28,8 @@ __all__ = [
 from storm.locals import Int
 from storm.properties import UUID
 
-from mailman.config import config
 from mailman.database.model import Model
+from mailman.database.transaction import dbconnection
 
 
 
@@ -48,23 +48,29 @@ class UID(Model):
     id = Int(primary=True)
     uid = UUID()
 
-    def __init__(self, uid):
+    @dbconnection
+    def __init__(self, store, uid):
         super(UID, self).__init__()
         self.uid = uid
-        config.db.store.add(self)
+        store.add(self)
 
     def __repr__(self):
         return '<UID {0} at {1}>'.format(self.uid, id(self))
 
     @staticmethod
-    def record(uid):
+    @dbconnection
+    # Note that the parameter order is deliberate reversed here.  Normally,
+    # `store` is the first parameter after `self`, but since this is a
+    # staticmethod and there is no self, the decorator will see the uid in
+    # arg[0].
+    def record(uid, store):
         """Record the uid in the database.
 
         :param uid: The unique id.
         :type uid: unicode
         :raises ValueError: if the id is not unique.
         """
-        existing = config.db.store.find(UID, uid=uid)
+        existing = store.find(UID, uid=uid)
         if existing.count() != 0:
             raise ValueError(uid)
         return UID(uid)
diff --git a/src/mailman/model/user.py b/src/mailman/model/user.py
index 9ca9b5aea..15ed9170f 100644
--- a/src/mailman/model/user.py
+++ b/src/mailman/model/user.py
@@ -17,7 +17,7 @@
 
 """Model for users."""
 
-from __future__ import absolute_import, unicode_literals
+from __future__ import absolute_import, print_function, unicode_literals
 
 __metaclass__ = type
 __all__ = [
@@ -30,8 +30,8 @@ from storm.properties import UUID
 from zope.event import notify
 from zope.interface import implements
 
-from mailman.config import config
 from mailman.database.model import Model
+from mailman.database.transaction import dbconnection
 from mailman.interfaces.address import (
     AddressAlreadyLinkedError, AddressNotLinkedError)
 from mailman.interfaces.user import (
@@ -64,16 +64,17 @@ class User(Model):
     preferences_id = Int()
     preferences = Reference(preferences_id, 'Preferences.id')
 
-    def __init__(self, display_name=None, preferences=None):
+    @dbconnection
+    def __init__(self, store, display_name=None, preferences=None):
         super(User, self).__init__()
         self._created_on = date_factory.now()
         user_id = uid_factory.new_uid()
-        assert config.db.store.find(User, _user_id=user_id).count() == 0, (
+        assert store.find(User, _user_id=user_id).count() == 0, (
             'Duplicate user id {0}'.format(user_id))
         self._user_id = user_id
         self.display_name = ('' if display_name is None else display_name)
         self.preferences = preferences
-        config.db.store.add(self)
+        store.add(self)
 
     def __repr__(self):
         short_user_id = self.user_id.int
@@ -135,18 +136,20 @@ class User(Model):
         """See `IUser`."""
         self._preferred_address = None
 
-    def controls(self, email):
+    @dbconnection
+    def controls(self, store, email):
         """See `IUser`."""
-        found = config.db.store.find(Address, email=email)
+        found = store.find(Address, email=email)
         if found.count() == 0:
             return False
         assert found.count() == 1, 'Unexpected count'
         return found[0].user is self
 
-    def register(self, email, display_name=None):
+    @dbconnection
+    def register(self, store, email, display_name=None):
         """See `IUser`."""
         # First, see if the address already exists
-        address = config.db.store.find(Address, email=email).one()
+        address = store.find(Address, email=email).one()
         if address is None:
             if display_name is None:
                 display_name = ''
diff --git a/src/mailman/model/usermanager.py b/src/mailman/model/usermanager.py
index c8a5c65a2..2c4158b90 100644
--- a/src/mailman/model/usermanager.py
+++ b/src/mailman/model/usermanager.py
@@ -17,7 +17,7 @@
 
 """A user manager."""
 
-from __future__ import absolute_import, unicode_literals
+from __future__ import absolute_import, print_function, unicode_literals
 
 __metaclass__ = type
 __all__ = [
@@ -27,7 +27,7 @@ __all__ = [
 
 from zope.interface import implements
 
-from mailman.config import config
+from mailman.database.transaction import dbconnection
 from mailman.interfaces.address import ExistingAddressError
 from mailman.interfaces.usermanager import IUserManager
 from mailman.model.address import Address
@@ -48,33 +48,38 @@ class UserManager:
             user.link(address)
         return user
 
-    def delete_user(self, user):
+    @dbconnection
+    def delete_user(self, store, user):
         """See `IUserManager`."""
-        config.db.store.remove(user)
+        store.remove(user)
 
-    def get_user(self, email):
+    @dbconnection
+    def get_user(self, store, email):
         """See `IUserManager`."""
-        addresses = config.db.store.find(Address, email=email.lower())
+        addresses = store.find(Address, email=email.lower())
         if addresses.count() == 0:
             return None
         return addresses.one().user
 
-    def get_user_by_id(self, user_id):
+    @dbconnection
+    def get_user_by_id(self, store, user_id):
         """See `IUserManager`."""
-        users = config.db.store.find(User, _user_id=user_id)
+        users = store.find(User, _user_id=user_id)
         if users.count() == 0:
             return None
         return users.one()
 
     @property
-    def users(self):
+    @dbconnection
+    def users(self, store):
         """See `IUserManager`."""
-        for user in config.db.store.find(User):
+        for user in store.find(User):
             yield user
 
-    def create_address(self, email, display_name=None):
+    @dbconnection
+    def create_address(self, store, email, display_name=None):
         """See `IUserManager`."""
-        addresses = config.db.store.find(Address, email=email.lower())
+        addresses = store.find(Address, email=email.lower())
         if addresses.count() == 1:
             found = addresses[0]
             raise ExistingAddressError(found.original_email)
@@ -85,32 +90,36 @@ class UserManager:
         # constructor will do the right thing.
         address = Address(email, display_name)
         address.preferences = Preferences()
-        config.db.store.add(address)
+        store.add(address)
         return address
 
-    def delete_address(self, address):
+    @dbconnection
+    def delete_address(self, store, address):
         """See `IUserManager`."""
         # If there's a user controlling this address, it has to first be
         # unlinked before the address can be deleted.
         if address.user:
             address.user.unlink(address)
-        config.db.store.remove(address)
+        store.remove(address)
 
-    def get_address(self, email):
+    @dbconnection
+    def get_address(self, store, email):
         """See `IUserManager`."""
-        addresses = config.db.store.find(Address, email=email.lower())
+        addresses = store.find(Address, email=email.lower())
         if addresses.count() == 0:
             return None
         return addresses.one()
 
     @property
-    def addresses(self):
+    @dbconnection
+    def addresses(self, store):
         """See `IUserManager`."""
-        for address in config.db.store.find(Address):
+        for address in store.find(Address):
             yield address
 
     @property
-    def members(self):
+    @dbconnection
+    def members(self, store):
         """See `IUserManager."""
-        for member in config.db.store.find(Member):
+        for member in store.find(Member):
                 yield member