Periodically calling a HTTP endpoint using AWS cron rule

08/01/2022 - AWS

In this example we are going to create a HTTP endpoint and send POST requests to it every minute using AWS EventBridge cron rule. The request can have parameters, query strings, headers and body. In case of any conflicting keys, values from the Connection take precedence over Target.


Rule


$ aws --profile localstack --endpoint-url http://localhost:4566 events put-rule \
    --name users-api-cron-rule \
    --schedule-expression "cron(* * * * *)"

{
    "RuleArn": "arn:aws:events:eu-west-1:000000000000:rule/users-api-cron-rule"
}

$ aws --profile localstack --endpoint-url http://localhost:4566 events list-rules

{
    "Rules": [
        {
            "Name": "users-api-cron-rule",
            "Arn": "arn:aws:events:eu-west-1:000000000000:rule/users-api-cron-rule",
            "State": "ENABLED",
            "ScheduleExpression": "cron(* * * * *)",
            "EventBusName": "default"
        }
    ]
}

Connection


$ aws --profile localstack --endpoint-url http://localhost:4566 events create-connection \
    --name users-api-connection \
    --authorization-type BASIC \
    --auth-parameters "{\"BasicAuthParameters\":{\"Username\":\"hello\",\"Password\":\"world\"},\"InvocationHttpParameters\":{\"HeaderParameters\":[{\"Key\":\"hdr-c\",\"Value\":\"val-c\",\"IsValueSecret\":false},{\"Key\":\"hdr-x\",\"Value\":\"val-c\",\"IsValueSecret\":false}],\"QueryStringParameters\":[{\"Key\":\"qry-c\",\"Value\":\"val-c\",\"IsValueSecret\":false},{\"Key\":\"qry-x\",\"Value\":\"val-c\",\"IsValueSecret\":false}],\"BodyParameters\":[{\"Key\":\"bdy-c\",\"Value\":\"val-c\",\"IsValueSecret\":false}]}}"

{
    "ConnectionArn": "arn:aws:events:eu-west-1:000000000000:connection/users-api-connection/314c648e-0905-4e3b-9731-5144e6c99616",
    "ConnectionState": "AUTHORIZED",
    "CreationTime": "2022-03-12T12:12:16.384584+00:00",
    "LastModifiedTime": "2022-03-12T12:12:16.384584+00:00"
}

Destination


$ aws --profile localstack --endpoint-url http://localhost:4566 events create-api-destination \
    --name users-api-destination \
    --connection-arn "arn:aws:events:eu-west-1:000000000000:connection/users-api-connection/314c648e-0905-4e3b-9731-5144e6c99616" \
    --http-method POST \
    --invocation-endpoint "https://webhook.site/357c5571-fb00-4f48-bddc-9b03417a044e/api/v1/users"

{
    "ApiDestinationArn": "arn:aws:events:eu-west-1:000000000000:api-destination/users-api-destination/448f2e65-222a-4dbf-8602-a5219dc9529b",
    "ApiDestinationState": "ACTIVE",
    "CreationTime": "2022-03-12T12:12:47.789677+00:00",
    "LastModifiedTime": "2022-03-12T12:12:47.789677+00:00"
}

Target


$ aws --profile localstack --endpoint-url http://localhost:4566 events put-targets \
    --rule users-api-cron-rule \
    --targets '[{"Id":"1","Arn":"arn:aws:events:eu-west-1:000000000000:api-destination/users-api-destination/448f2e65-222a-4dbf-8602-a5219dc9529b","Input":"{\"bdy-t\":\"val-t\"}","HttpParameters":{"PathParameterValues":["par-t"],"HeaderParameters":{"hdr-t":"val-t","hdr-x":"val-t"},"QueryStringParameters":{"qry-t":"val-t","qry-x":"val-t"}}}]'

Logs



localstack    | 2022-03-12T12:20:50.104:DEBUG:localstack.services.events.events_listener: Notifying 1 targets in response to triggered Events rule users-api-cron-rule
localstack    | 2022-03-12T12:20:50.123:DEBUG:localstack.utils.aws.message_forwarding: Calling EventBridge API destination (state "ACTIVE"): POST https://webhook.site/357c5571-fb00-4f48-bddc-9b03417a044e/api/v1/users

Request dump



curl \
  -X 'POST' 'https://webhook.site/5c2b623f-a9d5-439a-833c-6ab632e57d9d/api/v1/users/par-t?qry-c=val-c&qry-x=val-c&qry-t=val-t' \
  -H 'hdr-t: val-t' \
  -H 'hdr-x: val-c' \
  -H 'hdr-c: val-c' \
  -H 'authorization: Basic aGVsbG86d29ybGQ=' \
  -H 'content-type: application/json; charset=utf-8' \
  -H 'php-auth-user: hello' \
  -H 'php-auth-pw: world' \
  -d $'{"bdy-t": "val-t", "bdy-c": "val-c"}'