CloudFront Origins for the CDK CloudFront Library

---

cdk-constructs: Stable


This library contains convenience methods for defining origins for a CloudFront distribution. You can use this library to create origins from S3 buckets, Elastic Load Balancing v2 load balancers, or any other domain name.

S3 Bucket

An S3 bucket can be added as an origin. If the bucket is configured as a website endpoint, the distribution can use S3 redirects and S3 custom error documents.

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
import aws_cdk.aws_cloudfront as cloudfront
import aws_cdk.aws_cloudfront_origins as origins

my_bucket = s3.Bucket(self, "myBucket")
cloudfront.Distribution(self, "myDist",
    default_behavior=BehaviorOptions(origin=origins.S3Origin(my_bucket))
)

The above will treat the bucket differently based on if IBucket.isWebsite is set or not. If the bucket is configured as a website, the bucket is treated as an HTTP origin, and the built-in S3 redirects and error pages can be used. Otherwise, the bucket is handled as a bucket origin and CloudFront’s redirect and error handling will be used. In the latter case, the Origin will create an origin access identity and grant it access to the underlying bucket. This can be used in conjunction with a bucket that is not public to require that your users access your content using CloudFront URLs and not S3 URLs directly. Alternatively, a custom origin access identity can be passed to the S3 origin in the properties.

Adding Custom Headers

You can configure CloudFront to add custom headers to the requests that it sends to your origin. These custom headers enable you to send and gather information from your origin that you don’t get with typical viewer requests. These headers can even be customized for each origin. CloudFront supports custom headers for both for custom and Amazon S3 origins.

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
import aws_cdk.aws_cloudfront as cloudfront
import aws_cdk.aws_cloudfront_origins as origins

my_bucket = s3.Bucket(self, "myBucket")
cloudfront.Distribution(self, "myDist",
    default_behavior=BehaviorOptions(origin=origins.S3Origin(my_bucket,
        custom_headers={
            "Foo": "bar"
        }
    ))
)

ELBv2 Load Balancer

An Elastic Load Balancing (ELB) v2 load balancer may be used as an origin. In order for a load balancer to serve as an origin, it must be publicly accessible (internetFacing is true). Both Application and Network load balancers are supported.

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
import aws_cdk.aws_ec2 as ec2
import aws_cdk.aws_elasticloadbalancingv2 as elbv2

vpc = ec2.Vpc(...)
# Create an application load balancer in a VPC. 'internetFacing' must be 'true'
# for CloudFront to access the load balancer and use it as an origin.
lb = elbv2.ApplicationLoadBalancer(self, "LB",
    vpc=vpc,
    internet_facing=True
)
cloudfront.Distribution(self, "myDist",
    default_behavior={"origin": origins.LoadBalancerV2Origin(lb)}
)

The origin can also be customized to respond on different ports, have different connection properties, etc.

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
origin = origins.LoadBalancerV2Origin(load_balancer,
    connection_attempts=3,
    connection_timeout=Duration.seconds(5),
    protocol_policy=cloudfront.OriginProtocolPolicy.MATCH_VIEWER
)

From an HTTP endpoint

Origins can also be created from any other HTTP endpoint, given the domain name, and optionally, other origin properties.

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
cloudfront.Distribution(self, "myDist",
    default_behavior={"origin": origins.HttpOrigin("www.example.com")}
)

See the documentation of @aws-cdk/aws-cloudfront for more information.

Failover Origins (Origin Groups)

You can set up CloudFront with origin failover for scenarios that require high availability. To get started, you create an origin group with two origins: a primary and a secondary. If the primary origin is unavailable, or returns specific HTTP response status codes that indicate a failure, CloudFront automatically switches to the secondary origin. You achieve that behavior in the CDK using the OriginGroup class:

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
cloudfront.Distribution(self, "myDist",
    default_behavior={
        "origin": origins.OriginGroup(
            primary_origin=origins.S3Origin(my_bucket),
            fallback_origin=origins.HttpOrigin("www.example.com"),
            # optional, defaults to: 500, 502, 503 and 504
            fallback_status_codes=[404]
        )
    }
)