google.appengine.api.datastore.RunInReadOnlyTransactionOptions

Runs a function inside a read-only datastore transaction.

google.appengine.api.datastore.RunInReadOnlyTransactionOptions(
    options, function, *args, **kwargs
)

A read-only transaction cannot perform writes, but may be able to execute more efficiently.

Like RunInTransactionOptions, but with a read-only transaction.

options TransactionOptions specifying options (number of retries, etc) for this transaction
function a function to be run inside the transaction on all remaining arguments *args: positional arguments for function. **kwargs: keyword arguments for function.

the function's return value, if any

TransactionFailedError, if the transaction could not be committed.