feature-flag

name: feature-flag description: > Decision guide and implementation patterns for Gram's two feature-gating systems: productfeatures (org-level, admin-configurable, entitlement-tied) vs PostHog feature flags (per-user/per-group rollout, engineering-controlled). Activate whenever the task involves gating a feature behind a flag, dogfooding a change, deciding which system to use, or adding a new product feature or PostHog flag. metadata: relevant_files: - "server/internal/productfeatures//*.go" - "server/internal/productfeatures/queries.sql" - "server/design/productfeatures/design.go" - "server/internal/feature/flags.go" - "server/internal/feature/provider.go" - "server/internal/thirdparty/posthog/posthog.go" - "client/dashboard/src/pages/"

Two systems, two purposes

Gram has two distinct feature-gating mechanisms. They are not interchangeable — pick based on the semantics of the flag, not on convenience.

Decision rule

Use productfeatures when the toggle represents a durable, org-level capability that admins control or that maps to what the customer purchased (entitlement). Think: GCP's per-project API enablement.

Use PostHog flags when you're rolling something out gradually, dogfooding a change internally, or need per-user granularity. The flag is expected to disappear once the feature ships to everyone.

If you're gating a dev-phase UI change that you only want your dogfooding org to see → PostHog. If you're shipping a capability that some customers pay for and others don't → productfeatures.

productfeatures

Concepts

• Feature constants live in server/internal/productfeatures/features.go as typed string constants (Feature type).
• State is stored in organization_features (PostgreSQL). Soft-deletes track removal.
• productfeatures.Client checks Redis first (15 min TTL), falls back to Postgres, and returns errors on lookup failures — use PlatformFeatureCheck when you want silent false-on-error degradation.
• The management API (/rpc/productFeatures.get and /rpc/productFeatures.set) exposes the state to the dashboard and Speakeasy ops.

Adding a new product feature

1. Declare the constant in server/internal/productfeatures/features.go:

const (
    FeatureMyNewFeature Feature = "my_new_feature"
)

2. Add it to the Goa design in server/design/productfeatures/design.go:

// In the setProductFeature method's Enum constraint:
Enum("logs", "tool_io_logs", ..., "my_new_feature")

// In the getProductFeatures Result:
Attribute("my_new_feature_enabled", Boolean, "Whether my new feature is enabled")

3. Wire the result in server/internal/productfeatures/impl.go:

MyNewFeatureEnabled: isEnabled(FeatureMyNewFeature),

4. Regenerate with mise generate (Goa codegen updates gen/).

Checking a feature at runtime (Go)

// inject *productfeatures.Client — it's already wired in cmd/gram/start.go
enabled, err := pf.IsFeatureEnabled(ctx, organizationID, productfeatures.FeatureMyNewFeature)
if err != nil {
    return fmt.Errorf("check my_new_feature: %w", err)
}

Use PlatformFeatureCheck (returns bool, logs errors, degrades to false) only in non-critical paths where you want silent degradation.

Checking in the React dashboard

const { data: features } = useProductFeatures();
if (features?.myNewFeatureEnabled) { ... }

PostHog feature flags

Concepts

• Flag constants live in server/internal/feature/flags.go as a typed Flag string.
• The feature.Provider interface (IsFlagEnabled(ctx, flag, distinctID)) is the only server-side API — inject it, don't call PostHog directly.
• The PostHog implementation polls the PostHog platform; a noop stub is used in tests.
• distinctID is typically the user's ID or email. For org-level targeting you can use the org ID and configure matching groups in PostHog.

Adding a new PostHog flag

1. Declare the constant in server/internal/feature/flags.go:

const (
    FlagMyNewFeature Flag = "my-new-feature"  // must match the key in PostHog
)

2. Create the flag in PostHog — set release conditions (e.g., "users in group X") via the PostHog console. The string key must match exactly.

3. Check at runtime by injecting feature.Provider:

enabled, err := featureProvider.IsFlagEnabled(ctx, feature.FlagMyNewFeature, userDistinctID)
if err != nil || !enabled {
    // flag off or unavailable
}

Checking in the React dashboard

Use the useTelemetry() hook from client/dashboard/src/contexts/Telemetry.tsx — never import PostHog hooks directly:

const telemetry = useTelemetry();
const myFeatureEnabled = telemetry.isFeatureEnabled("my-new-feature") ?? false;

Common mistakes

• Don't use productfeatures for a temporary dogfood gate. It creates API surface (getProductFeatures result field, Goa enum) that must be maintained indefinitely.
• Don't use PostHog for entitlements. PostHog is engineer-controlled and ephemeral; entitlement checks belong in productfeatures so org admins and billing can manage them.
• Don't hardcode PostHog flag strings in multiple places. Always declare them as constants in feature/flags.go.
• Don't call the PostHog SDK directly from Go handlers. Always go through the feature.Provider interface so tests can inject a noop.