This is an example of creating a function that runs as a cron job using the serverless schedule
event. It retrieves weather information at 10am (UTC) and emails it to a predefined recipient. For more information on schedule
event check out the Serverless docs on schedule.
cron(Minutes Hours Day-of-month Month Day-of-week Year)
All fields are required and time zone is UTC only.
Field | Values | Wildcards |
---|---|---|
Minutes | 0-59 | , - * / |
Hours | 0-23 | , - * / |
Day-of-month | 1-31 | , - * ? / L W |
Month | 1-12 or JAN-DEC | , - * / |
Day-of-week | 1-7 or SUN-SAT | , - * ? / L # |
Year | 192199 | , - * / |
Read the AWS cron expression syntax docs for more info on how to setup cron
Please visit https://darksky.net/dev/ to register for a free API token.
Please visit https://postmarkapp.com to register for a free Postmark account.
Upon setting up access to both external services, you'll be required to update the environment variables in serverless.yml
:
environment:
RECIPIENT: tom@carrotcreative.com
DARK_SKY_API_KEY: abc123
POSTMARK_API_KEY: abc123
POSTMARK_SENDER: devops@carrotcreative.com
LATITUDE: 40.702637
LONGITUDE: -73.989406
In order to deploy the you endpoint simply run
serverless deploy
The expected result should be similar to:
Serverless: Packaging service...
Serverless: Uploading CloudFormation file to S3...
Serverless: Uploading service .zip file to S3 (1.87 MB)...
Serverless: Updating Stack...
Serverless: Checking Stack update progress...
...........
Serverless: Stack update finished...
Serverless: Removing old service versions...
Service Information
service: scheduled-weather-example
stage: dev
region: us-east-1
api keys:
None
endpoints:
None
functions:
scheduled-weather-example-dev-weather: arn:aws:lambda:us-east-1:219106525755:function:scheduled-weather-example-dev-weather
There is no additional step required. Your defined schedule becomes active right away after deployment.
To test your function remotely:
sls invoke -f weather
The expected result should be similar to:
{
"success": true
}
For more information on running cron with Serverless check out the Tutorial: Serverless Scheduled Tasks by Parallax.