cel-spec VS copybara

My employer uses a combination of Protocol Buffers (for the config schema definition) and Bazel/Starlark (for concrete instantiations). Configs are validated at build time and runtime using CEL (https://github.com/google/cel-spec).

The Common Expression Language (CEL) implements common semantics for expression evaluation, enabling different applications to more easily interoperate. https://github.com/google/cel-spec

Looks like Google invented a specification for a simple "expression language." -> https://github.com/google/cel-spec/blob/master/doc/langdef.md. Writing the expressions feels like writing Java, C++, Go, or TypeScript code. Google then released C++ and Go versions of this langauge as a library.

https://github.com/google/cel-spec unfortunately, it's in Go or C++. Of course I can write a binding to them. But is there any other similar that you would know of for Java? My other course of action would be to offload computation to another service using this library in Go, or Jsonnet or Open Policy Agent/Rego based evaluation, which I'd prefer not to. Executing JS in Java via Nashorn also an option but it'd be heavy weight.

Having a standard way to share expressions does seem quite useful, especially when it's multilingual.

[0]: https://github.com/google/cel-spec

There's more information about CEL and its specifications here

Especially when dealing with more complex match rules, I personally much prefer Caddy's matchers over building some weird-ass if constructs in Nginx. It also supports CEL for request matching, giving you access to extremely powerful logic, if you need it.

sure! it used a collection of tools, the main ones were

* copybara [https://github.com/google/copybara] to mirror between github and our internal repo and transform the source tree layout to our internal conventions

* mercurial patch queues [https://hgbook.red-bean.com/read/managing-change-with-mercur...] to apply internal changes

there are internal tools to automate the copybara configuration for python packages specifically, and to map between mercurial and google's version control system, but that's the main idea, and a specific review process for adding new packages.

the process is actually documented here though not all the referenced tools are available (or even applicable) externally: https://opensource.google/documentation/reference/thirdparty...

Step two of installing Copybara is to install Bazel [0], so that doesn't exactly contradict my claim that if you're not already using Bazel you probably won't use Starlark.

[0] https://github.com/google/copybara

> Also, they have a bunch of tooling to manage open source projects that mirror google3 projects. ... if I recall correctly the tool itself was open sourced too.

https://github.com/google/copybara

You can potentially use CopyBara https://github.com/google/copybara

We go much further than CopyBara by syncing CI / CD pipelines, syncing review comments and so on.

We are considering launching GitSlice as product on its own. If you are interested, email me and I can keep you updated when its ready to test (hamza [at] gitstart [dot] com)

I haven’t seen much info regarding their setup, aside from the bits about Pants and Bazel.

Are those actually the upstream repositories, though? And is it known how they interact with them?

Google has Copybara [1], which allows portions of a monorepo to live outside as an entirely separate repository without the need for things like Git submodules. It supports synchronization of histories, pull requests, path and file transformations, etc.

In that sense, something like Copybara would allow them to, relatively, easily open source those bits, receive outside commits, and then sync the changes back to the monorepo.

[1]: <https://github.com/google/copybara>

Take a look at https://github.com/Olivr/copybara-action and https://github.com/google/copybara

I use copybara to sync them, and once I go through and audit them making sure that they're not causing any breaking changes, will release it and then update the code that depends on it.

Another option is to use Copybara (https://github.com/google/copybara) to create a light-weight version of the repo from the local repo, and then push that. The problem is that it will be push-only. You won’t be able to pull. Again, a pain in the ass.

Also you may want to try developing in a monorepo. If you need to publish them you can use stuff like Copybara / Copybara action to push them to individual repos