Can you say what specifically isn't working? One thing I noticed is that the prefix has uploads/* which means that key name would have to start with the literal characters uploads/* (prefix/suffix aren't globs). You'd probably want uploads/ instead.

With that change, everything is working when I try it out:

from chalice import Chalice

app = Chalice(app_name='s3-events-test')
app.debug = True


@app.on_s3_event(bucket='dfasdjfhasjhasdf', events=['s3:ObjectCreated:*'],
                 prefix='uploads/', suffix='.txt')
def index(event):
    app.log.debug('Handler called.')
    app.log.debug(event.key)

chalice deploy
...

aws s3 cp requirements.txt s3://dfasdjfhasjhasdf/uploads/test3.txt
upload: ./requirements.txt to s3://dfasdjfhasjhasdf/uploads/test3.txt

Then verify the handler was called:

$ chalice logs -n index
2019-08-09 15:06:13.755000 caec42 s3-events-test - DEBUG - Handler called.
2019-08-09 15:06:13.755000 caec42 s3-events-test - DEBUG - uploads/test3.txt

It might be nice to add some warnings if the prefix/suffix has *, but * is a valid char to use with a prefix/suffix, it just means the literal char *. Perhaps we can have a lint command.

Thank you James, you were right, using the * wildcard does not work with Chalice while it is supported by the AWS Management Console. Dropping it solves the issue, you can close this now.

The idea of the lint command or to support wildcards might be an interesting feature, I'll let you decide on that 😄

Thanks!

Closing out old issue, a note was added in the docs about wildcards in #1210.