open-policy-agent / open-policy-agent/java-opa-sdk

Implement string templating builtins

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builtins enhancement evaluator
Dominant language
Java
Stars
16
Forks
24
Avg merge
8h 17m
Merged PRs (30d)
15

Description

Missing builtins

  • strings.render_template
  • internal.template_string

Context

These OPA builtins are not implemented in the SDK. Most are exercised by the Rego compliance suite (opa-evaluator/src/test/resources/compliance/.../TestData) and currently raise FunctionNotFoundError; implementing them makes those cases pass.

Implementation notes

Register each builtin with an @OpaBuiltin-annotated static method (see io.github.open_policy_agent.opa.ast.builtin.impls). Core builtins are listed in BuiltinRegistry.BUILTIN_CLASSES; domain-specific ones live in an opa-builtins-* module exposed via the BuiltinProvider SPI (e.g. RegexBuiltins, CidrBuiltins, SemverBuiltins).

Reference: https://www.openpolicyagent.org/docs/policy-reference/#built-in-functions

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reading BuiltinRegistry.BUILTIN_CLASSES and existing @OpaBuiltin implementations in io.github.open_policy_agent.opa.ast.builtin.impls, then inspect the Rego compliance cases under opa-evaluator/src/test/resources/compliance/.../TestData. Implement and register strings.render_template and internal.template_string through the appropriate builtin provider, with the compliance cases no longer raising FunctionNotFoundError.

Written by the indexing model from the issue text.

Assessment

Tech stack
java
Domain
backend
Issue type
Feature
Difficulty
4/5
Estimated time
3-5 days
Activity status
Quiet
Clarity
Mostly clear
Newbie friendliness
58/100

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