The CUE Configuration Language

Configure, Unify, Execute

CUE is an open source configuration language which aims to make complex configurations more manageable and usable.

CUE is a constrained-based language. Constraints provide a powerful yet simple alternative to inheritance, a common source of complexity with other languages. The CUE tooling also provides powerful integrated scripting aimed at improving the overall experience of putting configurations to good use.

Some highlights:

  • JSON superset: get started quickly
  • convert existing YAML and JSON
  • arbitrary-precision arithmetic
  • reformatter
  • automatically simplify configurations
  • powerful scripting
  • rich APIs designed for automated tooling
  • a formalism conducive to automated reasoning
  • generate CUE templates from source code

Download and Install

Install From Source

If you already have Go installed, the short version is:

go get -u cuelang.org/go/cmd/cue

This will install the cue command line tool.

For more details see [Installing CUE][./doc/install.md].

Learning CUE

A demonstration of how to convert and restructure and existing set of Kubernetes configurations is available in [written form][./doc/demo/kubernetes/Readme.md] or as video.

References

  • [Language Specification][./doc/ref/spec.md]: official CUE Language specification.

  • API: the API on godoc.org

  • Builtin packages: builtins available from CUE programs

  • [cue Command line reference][./doc/cmd/cue.md]: the cue command

Contributing

Our canonical Git repository is located at https://cue.googlesource.com.

To contribute, please read the [Contribution Guidelines][./CONTRIBUTING.md]

Note that we do not accept pull requests and that we use the issue tracker for bug reports and proposals only.

Unless otherwise noted, the CUE source files are distributed under the Apache 2.0 license found in the LICENSE file.