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/ unidist / sharedcounter.py
sharedcounter
Shared Counter module. Get access to shared counters. Numeric values, which
can be atomically get/set, or atomically incremented.
TODO(g): Implement serialization, archiving, snapshotting, and replication to
sharestate. This will allow us flexibility in many things. This is not
necessarily going to be the best scaling solution, but it will work and provide
a way to keep state and distribute. Name spaces should have this specified
individually. If not specified, state will not be archived, serialized,
snapshotted or replicated.
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Functions
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Set
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Set ( name, value )
Sets the named counter to this value. Should be numeric, but is not tested.
Args:
name: string, name of the counter
value: int, value to set this counter. This is using the counter as a
numeric state, not a real counter, but it's here for functionality not
being strictly semantic about what a counter is.
Returns: int, value after setting (for consistency between other functions).
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GetAllCounters
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GetAllCounters ()
Returns a dict (copy) of all the counters we have.
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Get
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Get ( name )
Returns the value of this counter, or CounterDoesntExist class.
If named counter does not exist, starts counter value at zero.
Args:
name: string, name of the counter
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_UnlockCounter
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_UnlockCounter ( name )
Unlock a counter after operations.
Args:
name: string, name of the counter
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Exceptions
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CounterDoesntExist( 'Not found: %s' % name )
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_LockCounter
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_LockCounter ( name )
Lock a counter for operations.
Args:
name: string, name of the counter
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Increment
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Increment ( name, value=1 )
Increments the named counter by value (default is 1). Returns the new
value. If named counter does not exist, starts counter value at zero.
Args:
name: string, name of the counter
value: int (optional), value to increment this counter by. Default is 1.
Returns: int, value of the counter after it has been incremented
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GetIncrement
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GetIncrement ( name, value=1 )
Increments the named counter to this value. Returns the previous value.
If named counter does not exist, starts counter value at zero.
Args:
name: string, name of the counter
value: int (optional), value to increment this counter by. Default is 1.
Returns: int, value of counter before it was incremented.
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GetSet
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GetSet ( name, value )
Sets the named counter to this value. Returns the previous value.
Args:
name: string, name of the counter
value: int, value to set this counter. This is using the counter as a
numeric state, not a real counter, but it's here for functionality not
being strictly semantic about what a counter is.
Returns: int, value of the counter, before the new value was set
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