Source Code for Module Products.ZenUtils.transaction_contextmanagers

 1  ############################################################################## 
 2  #  
 3  # Copyright (C) Zenoss, Inc. 2010, all rights reserved. 
 4  #  
 5  # This content is made available according to terms specified in 
 6  # License.zenoss under the directory where your Zenoss product is installed. 
 7  #  
 8  ############################################################################## 
 9   
10   
11  # context managers for transaction and state commit/rollback 
12  from contextlib import contextmanager 
13   
14  import transaction 
15   
16  # define exception type to catch cases where current transaction is explicitly 
17  # committed or aborted with in the body of the with statement (only necessary on 
18  # abort) 
19 -class InvalidTransactionError(Exception): pass 
20   
21  @contextmanager 
22 -def zodb_transaction(): 
23      try: 
24          txn = transaction.get() 
25          yield txn 
26      except: 
27          if txn is not transaction.get(): 
28              raise InvalidTransactionError( 
29                  "could not abort transaction, was already aborted/committed within 'with' body") 
30          try: 
31              txn.abort() 
32          # catch any internal exceptions that happen during abort 
33          except Exception: 
34              pass 
35          raise 
36      else: 
37          try: 
38              if txn is transaction.get(): 
39                  txn.commit() 
40          # catch any internal exceptions that happen during commit 
41          except Exception: 
42              pass 
43   
44  @contextmanager 
45 -def nested_transaction(xaDataManager=None): 
46      try: 
47          txn = transaction.get() 
48          sp = txn.savepoint() 
49          if xaDataManager is not None: 
50              txn.join(xaDataManager) 
51          yield 
52      except: 
53          try: 
54              sp.rollback() 
55              if xaDataManager is not None: 
56                  xaDataManager.abort(txn) 
57          except: 
58              pass 
59          raise 
60      else: 
61          pass 
62