Manages transaction lifecycle, participants, and metadata.
There is no predefined number of transactions that may exist, or
what they are associated with. Depending on the application
model, there may be one per application, one per transaction, one
per incoming connection (in server applications), or some other
number. The transaction package should, however, offer an API for
managing per-thread (or per-app, if threads aren't being used)
transactions, since this will probably be the most common usage
scenario.
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Methods
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__contains__
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__contains__ ( participant )
Has participant joined?
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abort
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abort ()
Abort the transaction, or raise OutsideTransaction if not in
progress.
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addInfo
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addInfo ( **info )
Update the transaction's metadata dictionary with the
supplied keyword arguments. This can be used to record
information such as a description of the transaction, the user
who performed it, etc. Note that the transaction itself does
nothing with this information. Transaction participants will
need to retrieve the information with getInfo() and record
it at the appropriate point during the transaction.
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begin
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begin ( **info )
Begin a transaction. Raise TransactionInProgress if
already begun. Any keyword arguments are passed on to the
setInfo() method. (See below.)
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commit
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commit ()
Commit the transaction, or raise OutsideTransaction if not in
progress.
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fail
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fail ()
Force transaction to fail (i.e. no commits allowed, only aborts)
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getInfo
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getInfo ()
Return a copy of the transaction's metadata dictionary
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getTimestamp
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getTimestamp ()
Return the time that the transaction began, in time.time()
format, or None if no transaction in progress.
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isActive
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isActive ()
Return True if transaction is in progress.
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join
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join ( participant )
Add participant to the set of objects that will receive
transaction messages. Note that no particular ordering of
participants should be assumed. If the transaction is already
active, participant will receive a begin_txn() message. If
a commit or savepoint is in progress, participant may also
receive other messages to "catch it up" to the other
participants. However, if the commit or savepoint has already
progressed too far for the new participant to join in, a
TransactionInProgress error will be raised.
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removeParticipant
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removeParticipant ( participant )
Force participant to be removed; for error handler use only
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