EventPattern

class aws_cdk.aws_events.EventPattern(*, account=None, detail=None, detail_type=None, id=None, region=None, resources=None, source=None, time=None, version=None)

Bases: object

Events in Amazon CloudWatch Events are represented as JSON objects. For more information about JSON objects, see RFC 7159.

Important: this class can only be used with a Rule class. In particular, do not use it with CfnRule class: your pattern will not be rendered correctly. In a CfnRule class, write the pattern as you normally would when directly writing CloudFormation.

Rules use event patterns to select events and route them to targets. A pattern either matches an event or it doesn’t. Event patterns are represented as JSON objects with a structure that is similar to that of events.

It is important to remember the following about event pattern matching:

For a pattern to match an event, the event must contain all the field names listed in the pattern. The field names must appear in the event with the same nesting structure.
Other fields of the event not mentioned in the pattern are ignored; effectively, there is a "*": "*" wildcard for fields not mentioned.
The matching is exact (character-by-character), without case-folding or any other string normalization.
The values being matched follow JSON rules: Strings enclosed in quotes, numbers, and the unquoted keywords true, false, and null.
Number matching is at the string representation level. For example, 300, 300.0, and 3.0e2 are not considered equal.

For custom events, some optional properties are required. For more information, see Minimum information needed for a valid custom event.

Parameters:

account (Optional[Sequence[str]]) – The 12-digit number identifying an AWS account. Default: - No filtering on account
detail (Optional[Mapping[str, Any]]) – A JSON object, whose content is at the discretion of the service originating the event. Default: - No filtering on detail
detail_type (Optional[Sequence[str]]) – Identifies, in combination with the source field, the fields and values that appear in the detail field. Represents the “detail-type” event field. Default: - No filtering on detail type
id (Optional[Sequence[str]]) – A unique value is generated for every event. This can be helpful in tracing events as they move through rules to targets, and are processed. Default: - No filtering on id
region (Optional[Sequence[str]]) – Identifies the AWS region where the event originated. Default: - No filtering on region
resources (Optional[Sequence[str]]) – This JSON array contains ARNs that identify resources that are involved in the event. Inclusion of these ARNs is at the discretion of the service. For example, Amazon EC2 instance state-changes include Amazon EC2 instance ARNs, Auto Scaling events include ARNs for both instances and Auto Scaling groups, but API calls with AWS CloudTrail do not include resource ARNs. Default: - No filtering on resource
source (Optional[Sequence[str]]) – Identifies the service that sourced the event. All events sourced from within AWS begin with “aws.” Customer-generated events can have any value here, as long as it doesn’t begin with “aws.” We recommend the use of Java package-name style reverse domain-name strings. To find the correct value for source for an AWS service, see the table in AWS Service Namespaces. For example, the source value for Amazon CloudFront is aws.cloudfront. Default: - No filtering on source
time (Optional[Sequence[str]]) – The event timestamp, which can be specified by the service originating the event. If the event spans a time interval, the service might choose to report the start time, so this value can be noticeably before the time the event is actually received. Default: - No filtering on time
version (Optional[Sequence[str]]) – By default, this is set to 0 (zero) in all events. Default: - No filtering on version

See:

https://docs.aws.amazon.com/AmazonCloudWatch/latest/events/CloudWatchEventsandEventPatterns.html

ExampleMetadata:

infused

Example:

import aws_cdk.aws_lambda as lambda_


fn = lambda_.Function(self, "MyFunc",
    runtime=lambda_.Runtime.NODEJS_LATEST,
    handler="index.handler",
    code=lambda_.Code.from_inline("exports.handler = handler.toString()")
)

rule = events.Rule(self, "rule",
    event_pattern=events.EventPattern(
        source=["aws.ec2"]
    )
)

queue = sqs.Queue(self, "Queue")

rule.add_target(targets.LambdaFunction(fn,
    dead_letter_queue=queue,  # Optional: add a dead letter queue
    max_event_age=Duration.hours(2),  # Optional: set the maxEventAge retry policy
    retry_attempts=2
))

Attributes

account

The 12-digit number identifying an AWS account.

Default:

No filtering on account

detail

A JSON object, whose content is at the discretion of the service originating the event.

Default:

No filtering on detail

detail_type

Identifies, in combination with the source field, the fields and values that appear in the detail field.

Represents the “detail-type” event field.

Default:

No filtering on detail type

id

A unique value is generated for every event.

This can be helpful in tracing events as they move through rules to targets, and are processed.

Default:

No filtering on id

region

Identifies the AWS region where the event originated.

Default:

No filtering on region

resources

This JSON array contains ARNs that identify resources that are involved in the event.

Inclusion of these ARNs is at the discretion of the service.

For example, Amazon EC2 instance state-changes include Amazon EC2 instance ARNs, Auto Scaling events include ARNs for both instances and Auto Scaling groups, but API calls with AWS CloudTrail do not include resource ARNs.

Default:

No filtering on resource

source

Identifies the service that sourced the event.

All events sourced from within AWS begin with “aws.” Customer-generated events can have any value here, as long as it doesn’t begin with “aws.” We recommend the use of Java package-name style reverse domain-name strings.

To find the correct value for source for an AWS service, see the table in AWS Service Namespaces. For example, the source value for Amazon CloudFront is aws.cloudfront.

Default:

No filtering on source

See:

http://docs.aws.amazon.com/general/latest/gr/aws-arns-and-namespaces.html#genref-aws-service-namespaces

time

The event timestamp, which can be specified by the service originating the event.

If the event spans a time interval, the service might choose to report the start time, so this value can be noticeably before the time the event is actually received.

Default:

No filtering on time

version

By default, this is set to 0 (zero) in all events.

Default:

No filtering on version