CODEWITHSUNDEEP
python-asyncio
Nick
Nick

Reputation: 406

Asyncio: appending return values to a list

I am trying to implement asyncio in a previously working program but my functions are returning coroutines instead of the objects I expect.

Example:

async def requester(things):

    async def adder(item):
        output = {}
        output['timestamp'] = datetime.datetime.now().timestamp()
        output['key'] = item
        return output

    to_insert = []
    for thing in things:
        to_insert.append(adder(thing))

    mongodbcollection.insert_many(to_insert) # This throws the error

loop = asyncio.get_event_loop()
loop.run_until_complete(requester(['a', 'b', 'c']))

In this example, instead of objects being returned from the adder function, coroutines are returned, and naturally when I try to insert them into a database it throws TypeError: document must be an instance of dict, bson.son.SON, bson.raw_bson.RawBSONDocument, or a type that inherits from collections.MutableMapping. There are other asynchronous things happening in each of these functions, that is why they are async. How can I get this internal function to return the object as intended?

Upvotes: 0

Views: 3605

Answers (1)

Mikhail Gerasimov
Mikhail Gerasimov

Reputation: 39636

You should use await to execute a coroutine and get a result of the execution:

to_insert = []
for thing in things:
    res = await adder(thing)
    to_insert.append(res)

There's also a chance insert_many should also be awaited if it's a coroutine.

Upvotes: 2

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