CDK Mixins (Preview)

---

cdk-constructs: Experimental

The APIs of higher level constructs in this module are experimental and under active development. They are subject to non-backward compatible changes or removal in any future version. These are not subject to the Semantic Versioning model and breaking changes will be announced in the release notes. This means that while you may use them, you may need to update your source code when upgrading to a newer version of this package.

Note: The core Mixins mechanism (Mixins, Mixin, IMixin, MixinApplicator, ConstructSelector) is now available in constructs and aws-cdk-lib. All service Mixins are now available in aws-cdk-lib. Please update your imports.

This package continues to provide Logs Delivery Mixins and EventBridge Event Facades.

CDK Mixins provide a new, advanced way to add functionality through composable abstractions. Unlike traditional L2 constructs that bundle all features together, Mixins allow you to pick and choose exactly the capabilities you need for constructs. Mixins can be applied during or after construct construction. Mixins are an addition, not a replacement for construct properties. By itself, they cannot change optionality of properties or change defaults.

Usage and documentation

See the documentation for CDK Mixins in aws-cdk-lib.

Built-in Mixins

Logs Delivery

Configures vended logs delivery for supported resources to various destinations:

import aws_cdk.mixins_preview.aws_cloudfront.mixins as cloudfront_mixins

# Create CloudFront distribution
# origin: s3.IBucket

distribution = cloudfront.Distribution(scope, "Distribution",
    default_behavior=cloudfront.BehaviorOptions(
        origin=origins.S3BucketOrigin.with_origin_access_control(origin)
    )
)

# Create log destination
log_group = logs.LogGroup(scope, "DeliveryLogGroup")

# Configure log delivery using the mixin
distribution.with(cloudfront_mixins.CfnDistributionLogsMixin.CONNECTION_LOGS.to_log_group(log_group,
    output_format=cloudfront_mixins.CfnDistributionConnectionLogsOutputFormat.LogGroup.JSON,
    record_fields=[cloudfront_mixins.CfnDistributionConnectionLogsRecordFields.CONNECTIONSTATUS, cloudfront_mixins.CfnDistributionConnectionLogsRecordFields.CLIENTIP, cloudfront_mixins.CfnDistributionConnectionLogsRecordFields.SERVERIP, cloudfront_mixins.CfnDistributionConnectionLogsRecordFields.TLSPROTOCOL
    ]
))

Configures vended logs delivery for supported resources when a pre-created destination is provided:

import aws_cdk.mixins_preview.aws_cloudfront.mixins as cloudfront_mixins

# Create CloudFront distribution
# origin: s3.IBucket

distribution = cloudfront.Distribution(scope, "Distribution",
    default_behavior=cloudfront.BehaviorOptions(
        origin=origins.S3BucketOrigin.with_origin_access_control(origin)
    )
)

# Create destination bucket
dest_bucket = s3.Bucket(scope, "DeliveryBucket")
# Add permissions to bucket to facilitate log delivery
bucket_policy = s3.BucketPolicy(scope, "DeliveryBucketPolicy",
    bucket=dest_bucket,
    document=iam.PolicyDocument()
)
# Create S3 delivery destination for logs
destination = logs.CfnDeliveryDestination(scope, "Destination",
    destination_resource_arn=dest_bucket.bucket_arn,
    name="unique-destination-name",
    delivery_destination_type="S3"
)

distribution.with(cloudfront_mixins.CfnDistributionLogsMixin.CONNECTION_LOGS.to_destination(destination))

Vended Logs Configuration for Cross Account delivery (only supported for S3 and Firehose destinations)

from aws_cdk import Environment, Environment
import aws_cdk.mixins_preview.aws_logs as log_destinations
import aws_cdk.mixins_preview.aws_cloudfront.mixins as cloudfront_mixins

# Create CloudFront distribution
# origin: s3.IBucket


destination_account = "123456789012"
source_account = "234567890123"
region = "us-east-1"

app = App()

dest_stack = Stack(app, "destination-stack",
    env=Environment(
        account=destination_account,
        region=region
    )
)

# Create destination bucket
dest_bucket = s3.Bucket(dest_stack, "DeliveryBucket")
log_destinations.S3DeliveryDestination(dest_stack, "Destination",
    bucket=dest_bucket,
    source_account_id=source_account
)

source_stack = Stack(app, "source-stack",
    env=Environment(
        account=source_account,
        region=region
    )
)
distribution = cloudfront.Distribution(source_stack, "Distribution",
    default_behavior=cloudfront.BehaviorOptions(
        origin=origins.S3BucketOrigin.with_origin_access_control(origin)
    )
)

destination = logs.CfnDeliveryDestination.from_delivery_destination_arn(source_stack, "Destination", "arn of Delivery Destination in destinationAccount")

distribution.with(cloudfront_mixins.CfnDistributionLogsMixin.CONNECTION_LOGS.to_destination(destination))

EventBridge Event Patterns

CDK Mixins automatically generates typed EventBridge event patterns for AWS resources. These patterns work with both L1 and L2 constructs, providing a consistent interface for creating EventBridge rules.

Event Patterns Basic Usage

from aws_cdk.mixins_preview.aws_s3.events.ObjectType import ObjectType, ObjectType
from aws_cdk.mixins_preview.aws_s3.events import BucketEvents
import aws_cdk.aws_events as events
import aws_cdk.aws_events_targets as targets
# fn: lambda.Function


# Works with L2 constructs
my_bucket = s3.Bucket(scope, "Bucket")
bucket_events = BucketEvents.from_bucket(my_bucket)

events.Rule(scope, "Rule",
    event_pattern=bucket_events.object_created_pattern(
        object=ObjectType(key=events.Match.wildcard("uploads/*"))
    ),
    targets=[targets.LambdaFunction(fn)]
)

# Also works with L1 constructs
cfn_bucket = s3.CfnBucket(scope, "CfnBucket")
cfn_bucket_events = BucketEvents.from_bucket(cfn_bucket)

events.CfnRule(scope, "CfnRule",
    state="ENABLED",
    event_pattern=cfn_bucket_events.object_created_pattern(
        object=ObjectType(key=events.Match.wildcard("uploads/*"))
    ),
    targets=[events.CfnRule.TargetProperty(arn=fn.function_arn, id="L1")]
)

Event Pattern Features

Automatic Resource Injection: Resource identifiers are automatically included in patterns

from aws_cdk.mixins_preview.aws_s3.events import BucketEvents

bucket_events = BucketEvents.from_bucket(bucket)

# Bucket name is automatically injected from the bucket reference
pattern = bucket_events.object_created_pattern()

Event Metadata Support: Control EventBridge pattern metadata

from aws_cdk import AWSEventMetadataProps
from aws_cdk.mixins_preview.aws_s3.events import BucketEvents
import aws_cdk.aws_events as events


bucket_events = BucketEvents.from_bucket(bucket)

pattern = bucket_events.object_created_pattern(
    event_metadata=AWSEventMetadataProps(
        region=events.Match.prefix("us-"),
        version=["0"]
    )
)

Available Events

Event patterns are generated for EventBridge events available in the AWS Event Schema Registry. Common examples:

S3 Events:

objectCreatedPattern() - Object creation events
objectDeletedPattern() - Object deletion events
objectTagsAddedPattern() - Object tagging events
awsAPICallViaCloudTrailPattern() - CloudTrail API calls

Import events from service-specific modules:

from aws_cdk.mixins_preview.aws_s3.events import BucketEvents