On Fri, Jul 22, 2016 at 6:27 PM, Marco S. via Python-list
<python-list@python.org> wrote:
> Furthermore I have a question about exceptions in asyncio. If I
> understand well how it works, tasks exceptions can be caught only if
> you wait for task completion, with yield from, await or
> loop.run_until_complete(future). But in this case the coroutine blocks
> the execution of the program until it returns. On the contrary you can
> execute the coroutine inside an asyncio task and it will be
> non-blocking, but in this case exceptions can't be caught in a try
> statement.
If you don't want to block the current function on the task, then spin
off another task to do the error handling. Instead of this:
async def do_something():
try:
await do_something_else()
except DidNothingError as e:
handle_error(e)
...
Consider this:
async def do_something():
get_event_loop().create_task(await_and_handle(do_something_else()))
...
async def await_and_handle(awaitable):
try:
await awaitable
except DidNothingError as e:
handle_error(e)
If you want, you could generalize that further by passing in the
exception class and error handler as well:
async def do_something():
get_event_loop().create_task(await_and_handle(
do_something_else(), DidNothingError, handle_error))
...
async def await_and_handle(awaitable, error_class, handler):
try:
await awaitable
except error_class as e:
handler(e)
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