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FlagLint

flaglint-go Quickstart

Installation

Section titled “Installation”

Homebrew (macOS / Linux)

Terminal window
brew install flaglint/tap/flaglint-go

go install

Terminal window
go install github.com/flaglint/flaglint-go/cmd/flaglint-go@latest

Prebuilt release binaries are also available from the releases page.

Requirements

Section titled “Requirements”
  • A Go project using github.com/launchdarkly/go-server-sdk v6 or v7.
  • Nothing else — flaglint-go is a single static binary with no runtime dependencies. It does not need your project to build; it parses source with go/parser only.

1. Run an Audit

Section titled “1. Run an Audit”
Terminal window
flaglint-go audit ./services

Example output from a small service wiring the client through a package-level singleton getter (a pattern flaglint-go resolves across files — see Identity Model):

pkg/flags/client.go
var client *ld.LDClient


func Client() *ld.LDClient { return client }
checkout.go
client := flags.Client()
enabled, _ := client.BoolVariation("checkout-v2", ctx, false)
pct, _ := client.IntVariation("discount-percentage", ctx, 0)
Scan complete — 2 unique flag(s) across 2 call site(s) (0ms, 2 file(s))
Migration readiness: 100/100 · ready
  2 low risk · 0 medium risk · 0 high risk

The three commands and when to use each:

  • audit — risk-ranked overview with a migration-readiness score. Start here.
  • scan — structured, file-level inventory (JSON/Markdown) for automation or deeper review.
  • validate — CI gate that blocks new direct LaunchDarkly evaluation calls.

2. Inspect Detailed Inventory With Scan

Section titled “2. Inspect Detailed Inventory With Scan”
Terminal window
flaglint-go scan ./services --format json
{
  "scannedFiles": 2,
  "totalUsages": 2,
  "uniqueFlags": ["checkout-v2", "discount-percentage"],
  "usages": [
    {
      "flagKey": "checkout-v2",
      "isDynamic": false,
      "file": "checkout.go",
      "line": 13,
      "callType": "BoolVariation",
      "fingerprint": "launchdarkly:BoolVariation:checkout-v2:checkout.go",
      "risk": "low"
    }
  ]
}

3. Enforce a Policy in CI

Section titled “3. Enforce a Policy in CI”
Terminal window
flaglint-go validate ./services --no-direct-launchdarkly
✗ validate --no-direct-launchdarkly: 2 direct LaunchDarkly Go SDK call(s) found.


  checkout.go:13:16 — BoolVariation("checkout-v2")
  checkout.go:20:12 — IntVariation("discount-percentage")


These call sites must migrate to OpenFeature before this rule passes.

validate is the only command that ever exits 1 — scan and audit always exit 0 unless something breaks (a bad directory, malformed config).

4. Adopt Gradually With a Baseline

Section titled “4. Adopt Gradually With a Baseline”

Turning on --no-direct-launchdarkly immediately fails CI for every existing call site. To adopt flaglint-go without a big-bang migration, capture current debt as a baseline and only fail on new debt:

Terminal window
# Capture current findings once, commit the file
flaglint-go audit ./services --write-baseline .flaglint-baseline.json


# In CI: pass as long as no new debt was introduced
flaglint-go validate ./services --baseline .flaglint-baseline.json --fail-on-new
Scanned 2 file(s). Found 2 LaunchDarkly Go SDK usage(s).
✓ No new findings beyond baseline

--baseline/--fail-on-new runs independently of --no-direct-launchdarkly — most teams adopt with baseline mode alone, then turn on the strict policy later once existing debt is cleared.

Further reading: CLI reference · Identity Model · Enforce in CI guide

Feedback

Section titled “Feedback”