Google Git
Sign in
cue / cue / 03aab97182e8457cefea9e1b43037c639d317230
commit03aab97182e8457cefea9e1b43037c639d317230[log] [tgz]
authorPaul Jolly <paul@myitcv.io>Thu Jan 14 05:57:12 2021 +0000
committerMarcel van Lohuizen <mpvl@golang.org>Thu Jan 14 08:31:24 2021 +0000
tree1187112eedb429dd26151b613f07e4e52578b99d
parent867f71fec51611b96fcf5bbbf2921a6c8c2bf660 [diff]
internal/core: re-allow new definitions in closed structs

This is a partial revert of CL 8062, specifically the implementation
change that disallowed new definitions in closed structs. The spec part
of CL 8062 remains.

This change is being reverted until fixes for #635 and other issues
discovered as part of the beta.1 release are resolved. #635 is a fairly
major problem - it's not unlikely people will run into correctness
issues as a result of it. The change to disallow new definitions in
closed structs will likely require changes from users (changes that
cannot safely be automatically rewritten). At this stage, getting
exposure to the other changes made as part of beta.1 is more important.
Hence the focus is on fixing #635 and friends, providing a more solid
baseline release in the form of beta.2 (which should generally speaking
be a more apples-to-apples comparison with whatever people were using
before beta.1) and _then_ make the breaking change that disallows new
definitions in closed structs.

Change-Id: I7294a2e6156ec4fe1356e489e7937355c11c56f8
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/8201
Reviewed-by: CUE cueckoo <cueckoo@gmail.com>
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
2 files changed
tree: 1187112eedb429dd26151b613f07e4e52578b99d
  1. .github/
  2. cmd/
  3. cue/
  4. cue.mod/
  5. cuego/
  6. doc/
  7. encoding/
  8. internal/
  9. pkg/
  10. tools/
  11. .dockerignore
  12. .gitattributes
  13. .gitignore
  14. .goreleaser.yml
  15. AUTHORS
  16. codereview.cfg
  17. CONTRIBUTING.md
  18. Dockerfile
  19. gen.go
  20. genpkgtests.go
  21. go.mod
  22. go.sum
  23. LICENSE
  24. README.md
  25. tmp.cue
  26. tools.go
README.md

GoDoc Github GolangCI Go 1.13+ platforms

The CUE Data Constraint Language

Configure, Unify, Execute

CUE is an open source data constraint language which aims to simplify tasks involving defining and using data.

It is a superset of JSON, allowing users familiar with JSON to get started quickly.

What is it for?

You can use CUE to

  • define a detailed validation schema for your data (manually or automatically from data)
  • reduce boilerplate in your data (manually or automatically from schema)
  • extract a schema from code
  • generate type definitions and validation code
  • merge JSON in a principled way
  • define and run declarative scripts

How?

CUE merges the notion of schema and data. The same CUE definition can simultaneously be used for validating data and act as a template to reduce boilerplate. Schema definition is enriched with fine-grained value definitions and default values. At the same time, data can be simplified by removing values implied by such detailed definitions. The merging of these two concepts enables many tasks to be handled in a principled way.

Constraints provide a simple and well-defined, yet powerful, alternative to inheritance, a common source of complexity with configuration languages.

CUE Scripting

The CUE scripting layer defines declarative scripting, expressed in CUE, on top of data. This solves three problems: working around the closedness of CUE definitions (we say CUE is hermetic), providing an easy way to share common scripts and workflows for using data, and giving CUE the knowledge of how data is used to optimize validation.

There are many tools that interpret data or use a specialized language for a specific domain (Kustomize, Ksonnet). This solves dealing with data on one level, but the problem it solves may repeat itself at a higher level when integrating other systems in a workflow. CUE scripting is generic and allows users to define any workflow.

Tooling

CUE is designed for automation. Some aspects of this are:

  • convert existing YAML and JSON
  • automatically simplify configurations
  • rich APIs designed for automated tooling
  • formatter
  • arbitrary-precision arithmetic
  • generate CUE templates from source code
  • generate source code from CUE definitions (TODO)

Download and Install

Install using Homebrew

Using Homebrew, you can install using the CUE Homebrew tap:

brew install cuelang/tap/cue

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.

Learning CUE

The fastest way to learn the basics is to follow the tutorial on basic language constructs.

A more elaborate tutorial demonstrating of how to convert and restructure an existing set of Kubernetes configurations is available in written form.

References

Contributing

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

To contribute, please read the Contribution Guide.

To report issues or make a feature request, use the issue tracker.

Changes can be contributed using Gerrit or Github pull requests.

Contact

You can get in touch with the cuelang community in the following ways:

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

This is not an officially supported Google product.