Timestream access from Appsync API using an HTTP resolver?

AWS AppSync supports AWS Lambda, Amazon DynamoDB, relational databases (Amazon Aurora Serverless), Amazon OpenSearch Service, and HTTP endpoints as data sources as mentioned in the documentation here:

[+] https://docs.aws.amazon.com/appsync/latest/devguide/tutorials.html

Unfortunately, it is not possible to use HTTP resolver to query Timestream, as at this point of time HTTP resolver supports public endpoints. Also, currently AWS Timestream is not supported as a native integration with AppSync. However, there is an existing feature request in the backlog to support the Timestream as a native Database:

[+] https://github.com/aws/aws-appsync-community/issues/136

While I am unable to comment on if/when this feature may get released, I request you to keep an eye on the Github issues page or our What's New and Blog pages for any new feature announcements.

As a workaround, you can use Lambda resolver to perform the query to the Timestream Database. A similar approach is described in this blog where you can use Amazon Timestream as a data source instead of Amazon ElastiCache and Amazon Neptune. You can find more details and sample code regarding Lambda's interaction with Timestream here.