feat: scaffold OpenFeature Go SDK feature-flag support

[devantler]

🤖 Generated by the Daily AI Assistant

Why

The Go template ships no feature-flag scaffolding, so every service generated from it starts without a standard way to land features behind a flag — the opposite of the portfolio-wide feature-flag-first delivery direction.

What

Wires the portable OpenFeature Go SDK as the standard flag API in a small, replaceable pkg/featureflag package: an example feature gated default-off, with tests covering both states. Ships with an in-memory provider so it works out of the box; a real service swaps in flagd or a managed backend without touching call sites. AGENTS.md documents the convention and the mandatory flag lifecycle (release flags are removed after rollout). Dependency footprint stays minimal.

Fixes #145
Part of devantler-tech/monorepo#2059

[coderabbitai]

📝 Walkthrough

Walkthrough

This pull request adds a feature-flag-first scaffold for Go templates. It introduces pkg/featureflag with an OpenFeature in-memory provider, a client constructor, a boolean helper that defaults off on missing or failed evaluations, and an example feature branch. It also updates go.mod and .golangci.yml for the OpenFeature SDK, adds table-driven tests for enabled, disabled, and absent flags, and documents the convention in AGENTS.md and README.md.

Changes

Related issues: #145

Suggested labels: enhancement, dependencies, documentation

Suggested reviewers: devantler

Sequence Diagram(s)

sequenceDiagram
  participant Caller
  participant ExampleFeature
  participant Enabled
  participant OpenFeatureClient
  participant InMemoryProvider

  Caller->>ExampleFeature: ExampleFeature(ctx, client)
  ExampleFeature->>Enabled: Enabled(ctx, client, ExampleFlag)
  Enabled->>OpenFeatureClient: Boolean(ctx, ExampleFlag, false, ...)
  OpenFeatureClient->>InMemoryProvider: evaluate flag
  InMemoryProvider-->>OpenFeatureClient: variant value
  OpenFeatureClient-->>Enabled: boolean result
  Enabled-->>ExampleFeature: true/false
  ExampleFeature-->>Caller: "new feature output" or "default output"

Loading

Poem
A rabbit hops with flags in tow,
Default off, but ready to grow.

---

Caution

Pre-merge checks failed

Please resolve all errors before merging. Addressing warnings is optional.

• Ignore

❌ Failed checks (1 error)

Check name	Status	Explanation	Resolution
Linked Issues check	❌ Error	Most requirements are met, but #145 also asks for a flagd provider stub, which is not present in the changes.	Add a flagd provider stub aligned with the platform layer, or document and implement the issue's provider requirement explicitly.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Out of Scope Changes check	✅ Passed	The changes stay focused on feature-flag scaffolding, docs, and dependency setup with no clear unrelated additions.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Title check	✅ Passed	The title clearly matches the main change: scaffolding OpenFeature-based feature-flag support.
Description check	✅ Passed	The description is directly related to the changeset and accurately explains the feature-flag scaffold and docs updates.

---

_{Comment @coderabbitai help to get the list of available commands.}

[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@AGENTS.md`:
- Around line 93-105: The feature-flag guidance only documents the OpenFeature
path and is missing the CLI-only exception for lightweight static boolean flags.
Update the AGENTS.md guidance near the feature-flag section to explicitly
mention the cobra Hidden / --experimental route, and clarify that templates
needing only static CLI gating should use that dependency-free approach instead
of the OpenFeature SDK. Refer to the feature-flag-first delivery section and its
package guidance so the exception is clearly tied to the existing flag policy.

In `@README.md`:
- Line 12: The README feature-flag bullet only mentions the OpenFeature SDK
flow; update that bullet to also mention the non-SDK Cobra path using the Hidden
or --experimental option so readers understand when a generated CLI can stay
dependency-free. Keep the existing Feature-flag-first entry in the README, but
expand its wording to cover both the pkg/featureflag/OpenFeature approach and
the cobra Hidden/--experimental alternative.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: 62ba90e6-d6cd-47cf-83e3-81f91a9b978a

📥 Commits

Reviewing files that changed from the base of the PR and between f06c9c1 and 3417964.

⛔ Files ignored due to path filters (1)

• go.sum is excluded by !**/*.sum

📒 Files selected for processing (6)

• .golangci.yml
• AGENTS.md
• README.md
• go.mod
• pkg/featureflag/featureflag.go
• pkg/featureflag/featureflag_test.go

🔗 Linked repositories identified

CodeRabbit considers these linked repositories for cross-repo context during reviews:

• devantler-tech/actions (auto-detected)

📜 Review details

⏰ Context from checks skipped due to timeout. (1)

• GitHub Check: zizmor

🧰 Additional context used

📓 Path-based instructions (3)

{go.mod,.github/workflows/copilot-setup-steps.yml,README.md}

📄 CodeRabbit inference engine (AGENTS.md)

Do not hard-code a second Go version elsewhere; copilot-setup-steps.yml must read the version from go.mod, and the README should refer to go.mod instead of duplicating the floor.

Files:

• README.md
• go.mod

pkg/featureflag/**/*.go

📄 CodeRabbit inference engine (AGENTS.md)

New features should be guarded behind pkg/featureflag.Enabled, default to the old path when the flag is off or errors, and include table-driven tests covering both enabled and disabled states.

Files:

• pkg/featureflag/featureflag_test.go
• pkg/featureflag/featureflag.go

go.mod

📄 CodeRabbit inference engine (AGENTS.md)

Keep the Go minimum version in go.mod as the single source of truth, and raise it only when a shared tooling requirement or security/EOL reason forces it.

Files:

• go.mod

🔇 Additional comments (7)

.golangci.yml (1)

38-41: LGTM!

pkg/featureflag/featureflag.go (4)

1-32: LGTM!

---

40-57: LGTM!

---

59-70: LGTM!

---

72-89: LGTM!

pkg/featureflag/featureflag_test.go (1)

1-52: LGTM! Table-driven subtests correctly cover enabled, disabled, and absent-flag default-off states, and per-subtest unique domain names avoid provider registration collisions under t.Parallel().

go.mod (1)

4-10: 🗄️ Data Integrity & Integration

Check the go directive against the new SDK’s Go 1.24 floor. github.com/open-feature/go-sdk v1.17.2 requires Go 1.24, so go.mod should still be the single source of truth for the minimum supported version.

[devantler]

@coderabbitai review

🤖 Generated by the Daily AI Assistant

[coderabbitai]

@devantler I'll review the changes now.

✅ Action performed

Review finished.

Note: CodeRabbit is an incremental review system and does not re-review already reviewed commits. This command is applicable only when automatic reviews are paused.

Superseded: every requested change was addressed in a80f196 (concrete memprovider return + un-inlined error + CLI experimental-flag guidance in AGENTS.md/README) and all review threads are resolved. CodeRabbit's subsequent reviews on the current head are COMMENTED-only with no new change requests. Dismissing this stale review from commit 3417964.