AWS Serverless Replay Cache (Beta)

AWS Serverless Replay Cache is a serverless implementation of cache solution for dynamic and static content using Lambda@Edge.

Solution Blueprint

Requirements

• AWS CLI installed and configured
• SAM CLI installed and configured
• CloudFront Distribution created and with Behavior(s) configured

⚠️ CloudFront requires the deployment to be made in the US East (N. Virginia) Region.

Git Clone

git clone https://github.com/aws-samples/aws-serverless-replay-cache.git

Copy configuration file (FOR WINDOWS USERS ONLY)

cp conf/config.json content-manager/
cp conf/config.json origin-request/
cp conf/config.json origin-response/

Create SAM Bucket

aws s3 mb s3://<SAM_BUCKET_NAME>

Deploy SAM Application

sam deploy --stack-name replay-cache --s3-bucket <SAM_BUCKET_NAME> --capabilities CAPABILITY_NAMED_IAM --parameter-overrides BucketName=<CACHE_BUCKET_NAME>

Configure CloudFront

1. Open the CloudFront console at https://console.aws.amazon.com/cloudfront
2. In the navigation panel select Distributions, and then click in the ID of the CloudFront Distribution to be configured
3. Under Origins and Origin Groups tab, click on Create Origin button
4. Origin Domain Name select the bucket specified in the parameter <CACHE_BUCKET_NAME> of SAM deployment
5. Restrict Bucket Access select Yes
6. Origin Access Identity select Create a New Identity
7. Grant Read Permissions Bucket select Yes, Update Bucket Policy
8. Click on Create button
9. Under Origins and Origin Groups tab, click on Create Origin Group button
10. Origins select the website Origin and click on Add button
11. Origins select the S3 Cache Bucket Origin and click on Add button
12. Failover criteria select all 5xx errors
13. Origin Group ID enter ReplayCache-OriginGroup
14. Click on Create button
15. Under Behaviors tab, edit or create a new Behavior that will serve cached content in case of a failover
16. Origin or Origin Group select ReplayCache-OriginGroup
17. Cache and origin request settings select Use legacy cache setting
18. Cache Based on Selected Request Headers select Whitelist
19. Whitelist Headers input enter Host value and click on Add Custom >> button
20. Whitelist Headers list CloudFront-Forwarded-Proto and click on Add >> button
21. Click on Create or Yes, Edit button

Deploy Origin Request Lambda@Edge

1. Open the Lambda console at https://console.aws.amazon.com/lambda
2. In the navigation panel select Functions, and then open replay-cache-origin-request function
3. Click on Action button and select Deploy to Lambda@Edge option
4. Select the appropriated Distribution and Behavior
5. CloudFront event select Origin request
6. Check the acknowledge checkbox
7. Click on Deploy button

Deploy Origin Response Lambda@Edge

1. Open the Lambda console at https://console.aws.amazon.com/lambda
2. In the navigation panel select Functions, and then open replay-cache-origin-response function
3. Click on Action button and select Deploy to Lambda@Edge option
4. Select the appropriated Distribution and Behavior
5. CloudFront event select Origin response
6. Check the acknowledge checkbox
7. Click on Deploy button

Add Region(s) on DynamoDB Global Table

1. Open the DynamoDB console at https://console.aws.amazon.com/dynamodb
2. In the navigation panel select Tables, and then open replay-cache table
3. Under Global Tables tab, click on Add region
4. Select the appropriated Region
5. Click on Create replica button

Cleanup

1. Remove Lambda@Edge function associations. Please note it may take a few hours to be completed.
2. Delete the DynamoDB Global Table regions
3. Empty S3 content bucket:

aws s3 rm s3://<CACHE_BUCKET_NAME> --recursive

4. Delete the CloudFormation Stack

aws cloudformation delete-stack --stack-name replay-cache

Application Design

Troubleshooting

1. I can't see anything being cached.

It's likely you didn't created a DynamoDB Global Table replica in the region that Amazon CloudFront is serving you. In each region you'd like to trigger the caching process must have its own replica. Notice, by default the table is created in us-east-1 region.

You can additionaly confirm this in the Origin Response function logs at Amazon CloudWatch in the respective region.

License

This library is licensed under the MIT-0 License. See the LICENSE file.