[SOLVED] What is the chalice @app.schedule syntax for cron events?

What is the chalice @app.schedule syntax for cron events?

I am trying to follow the documentation from https://chalice.readthedocs.io/en/latest/topics/events.html

I tried this

@app.schedule('0 0 * * ? *')
def dataRefresh(event):
    print(event.to_dict())

and got this error:

botocore.exceptions.ClientError: An error occurred (ValidationException) when calling the PutRule operation: Parameter ScheduleExpression is not valid.

and so tried this:

@app.schedule(Cron('0 0 * * ? *'))
def dataRefresh(event):
    print(event.to_dict())

and got this other error:

NameError: name 'Cron' is not defined

Nothing works... what's the correct syntax?

Solution

If you want to use the Cron object you have to import it from the chalice package, and then each value is a positional parameter to the Cron object:

from chalice import Chalice, Cron

app = Chalice(app_name='sched')


@app.schedule(Cron(0, 0, '*', '*', '?', '*'))
def my_schedule():
    return {'hello': 'world'}

Here's the docs for Cron that has more info.

Or alternatively use this syntax, which works without the extra import:

@app.schedule('cron(0 0 * * ? *)')
def dataRefresh(event):
    print(event.to_dict())