Extending OPA Golang SDK Builtins

[victoraugustolls]

Hi! I'm having a hard time trying to figure out how to extend OPA to include a new builtin function when using the Golang SDK. Is it possible at all? I know you can do it using the low level packages, but it seems to add a lot of extra work just to add a builtin function.

Thanks in advance!

[charlieegan3]

Hi @victoraugustolls, thanks for asking this question. It's come up a few times before in slack, but I can't seem to find an issue for it.

Would you be able to create a new issue for this as a feature request outlining your use case and the value this would offer? 🙏

https://github.com/open-policy-agent/opa/issues/new?template=feature_request.md

Please @ me on the issue too so I can keep tabs and promote it.

[victoraugustolls]

Hey @charlieegan3 I got it working as my comment here. Do you still want me to open a feature request so the docs can reflect the changes?

[charlieegan3]

Hey, sorry @victoraugustolls. I've been out on annual leave.

I'll get a new issue open to remind us to document this more clearly. Do you remember where the non v1 docs were that you followed?

[anderseknert]

There may not be a convenience function for doing this via the SDK directly (and perhaps there should be), but built-ins registered globally should be picked up by the SDK just as anywhere else.

Here's an example of this being done in a test. If you grep for those two calls, you should find other examples to browse. I just picked the first one that came up.

Convenience function or not, we should have the docs on the SDK updated to cover this.

[charlieegan3]

Ahh thanks. I’d forgotten that option.

[victoraugustolls]

I forgot to update here but it ended up working yesterday. I think my initial mistake was I was following the docs and they weren't updated to use the v1 package. After noticing that and changing it, everything started working.

[charlieegan3]

For now, I’ll just make a note and get this updated. No need for an issue!

Glad you got it sorted.