.. currentmodule:: asyncio
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.. _asyncio-exceptions:
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==========
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Exceptions
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==========
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.. exception:: TimeoutError
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The operation has exceeded the given deadline.
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.. important::
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This exception is different from the builtin :exc:`TimeoutError`
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exception.
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.. exception:: CancelledError
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The operation has been cancelled.
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This exception can be caught to perform custom operations
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when asyncio Tasks are cancelled. In almost all situations the
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exception must be re-raised.
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.. important::
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This exception is a subclass of :exc:`Exception`, so it can be
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accidentally suppressed by an overly broad ``try..except`` block::
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try:
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await operation
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except Exception:
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# The cancellation is broken because the *except* block
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# suppresses the CancelledError exception.
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log.log('an error has occurred')
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Instead, the following pattern should be used::
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try:
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await operation
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except asyncio.CancelledError:
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raise
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except Exception:
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log.log('an error has occurred')
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.. exception:: InvalidStateError
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Invalid internal state of :class:`Task` or :class:`Future`.
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Can be raised in situations like setting a result value for a
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*Future* object that already has a result value set.
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.. exception:: SendfileNotAvailableError
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The "sendfile" syscall is not available for the given
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socket or file type.
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A subclass of :exc:`RuntimeError`.
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.. exception:: IncompleteReadError
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The requested read operation did not complete fully.
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Raised by the :ref:`asyncio stream APIs<asyncio-streams>`.
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This exception is a subclass of :exc:`EOFError`.
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.. attribute:: expected
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The total number (:class:`int`) of expected bytes.
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.. attribute:: partial
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A string of :class:`bytes` read before the end of stream was reached.
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.. exception:: LimitOverrunError
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Reached the buffer size limit while looking for a separator.
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Raised by the :ref:`asyncio stream APIs <asyncio-streams>`.
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.. attribute:: consumed
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The total number of to be consumed bytes.
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