As of December 14, 2023, Dagger has officially discontinued support for its CUE SDK. CUE is a powerful configuration language created by Marcel van Lohuizen who co-created the Borg Configuration Language (BCL)—the language used to deploy all applications at Google. It is the result of years of experience writing configuration languages at Google, and seeks to improve the developer experience while avoiding some nasty pitfalls.

CUE is a superset of JSON, with additional features to make declarative, data-driven programming as pleasant and productive as regular imperative programming.

CUE is ultimately used to export data, and is most useful when that data has been validated against a well-defined schema.

“Since we released multi-language support, we have seen a steep decline in usage of our original CUE configuration syntax, and have made it clear that feature parity with newer SDKs would not be a priority. After a year of keeping the lights on and collecting feedback from our community, we’ve concluded that there simply is not enough interest. Therefore, as of 14 Dec 2023, we are discontinuing support for our CUE SDK,” the official blog post reads.