chore(mollifier): address CodeRabbit review for phase-1 PR

- changeset: drop "deferred" wording — phase-1 actively dual-writes + runs
  the drainer ack loop.
- worker.server.ts: wrap mollifier drainer init in try/catch + register
  SIGTERM/SIGINT handlers so the polling loop stops cleanly on shutdown.
- bufferedTriggerPayload: only serialise idempotencyKeyExpiresAt when an
  idempotencyKey is present (avoid impossible orphan-expiry payloads).
- mollifierTelemetry: narrow recordDecision reason to DecisionReason union
  to keep OTEL attribute cardinality bounded.
- mollifierGate: rename resolveOrgFlag → resolveFlag. The underlying
  FeatureFlag table is global by key, so the "org" prefix was misleading;
  per-org gating is out of scope for phase-1.
- tests: drop vi.fn mocks. mollifierGate now uses plain closure spies;
  mollifierTripEvaluator runs against a real MollifierBuffer backed by a
  redisTest container (closed client exercises the fail-open path).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: d-cs

.changeset/mollifier-redis-worker-primitives.md

@@ -2,4 +2,4 @@
 "@trigger.dev/redis-worker": patch
 ---
 
-Add MollifierBuffer (with `accept`, `pop`, `ack`, `requeue`, `fail`, and `evaluateTrip`) and MollifierDrainer primitives for trigger burst smoothing. `evaluateTrip` is an atomic Lua sliding-window trip evaluator used by the webapp gate to detect per-env trigger bursts. Webapp shadow-mode logging is wired; buffer writes and drainer activation are deferred to a follow-up.
+Add MollifierBuffer (with `accept`, `pop`, `ack`, `requeue`, `fail`, and `evaluateTrip`) and MollifierDrainer primitives for trigger burst smoothing. `evaluateTrip` is an atomic Lua sliding-window trip evaluator used by the webapp gate to detect per-env trigger bursts. Phase 1 wires MollifierBuffer dual-write monitoring alongside the real trigger path and runs MollifierDrainer's pop/ack loop end-to-end with a no-op handler; full buffering and replayed drainer-side triggers land in later phases.

apps/webapp/app/services/worker.server.ts

@@ -130,7 +130,24 @@ export async function init() {
     await workerQueue.initialize();
   }
 
-  getMollifierDrainer();
+  try {
+    const drainer = getMollifierDrainer();
+    if (drainer) {
+      // The drainer owns a polling loop and a Redis client; let it drain
+      // in-flight pops on shutdown rather than tearing the process down
+      // mid-handler. Idempotent — `drainer.stop()` short-circuits if already
+      // stopped, so registering on both signals is safe.
+      const stopDrainer = () => {
+        drainer.stop().catch((error) => {
+          logger.error("Failed to stop mollifier drainer", { error });
+        });
+      };
+      process.once("SIGTERM", stopDrainer);
+      process.once("SIGINT", stopDrainer);
+    }
+  } catch (error) {
+    logger.error("Failed to initialise mollifier drainer", { error });
+  }
 }
 
 function getWorkerQueue() {

apps/webapp/app/v3/mollifier/bufferedTriggerPayload.server.ts

@@ -92,9 +92,10 @@ export function buildBufferedTriggerPayload(input: {
     taskId: input.taskId,
     body: input.body,
     idempotencyKey: input.idempotencyKey,
-    idempotencyKeyExpiresAt: input.idempotencyKeyExpiresAt
-      ? input.idempotencyKeyExpiresAt.toISOString()
-      : null,
+    idempotencyKeyExpiresAt:
+      input.idempotencyKey && input.idempotencyKeyExpiresAt
+        ? input.idempotencyKeyExpiresAt.toISOString()
+        : null,
     tags: input.tags,
     parentRunFriendlyId: input.parentRunFriendlyId,
     traceContext: input.traceContext,

apps/webapp/app/v3/mollifier/mollifierGate.server.ts

@@ -4,7 +4,11 @@ import { flag } from "~/v3/featureFlags.server";
 import { FEATURE_FLAG } from "~/v3/featureFlags";
 import { getMollifierBuffer } from "./mollifierBuffer.server";
 import { createRealTripEvaluator } from "./mollifierTripEvaluator.server";
-import { recordDecision, type DecisionOutcome } from "./mollifierTelemetry.server";
+import {
+  recordDecision,
+  type DecisionOutcome,
+  type DecisionReason,
+} from "./mollifierTelemetry.server";
 
 // `count` is the *single-instance* sliding-window counter, not a fleet-wide
 // aggregate. Each webapp instance maintains its own Redis key, so the fleet
@@ -37,7 +41,7 @@ export type TripEvaluator = (inputs: GateInputs) => Promise<TripDecision>;
 export type GateDependencies = {
   isMollifierEnabled: () => boolean;
   isShadowModeOn: () => boolean;
-  resolveOrgFlag: () => Promise<boolean>;
+  resolveFlag: () => Promise<boolean>;
   evaluator: TripEvaluator;
   logShadow: (
     inputs: GateInputs,
@@ -47,7 +51,7 @@ export type GateDependencies = {
     inputs: GateInputs,
     decision: Extract<TripDecision, { divert: true }>,
   ) => void;
-  recordDecision: (outcome: DecisionOutcome, reason?: string) => void;
+  recordDecision: (outcome: DecisionOutcome, reason?: DecisionReason) => void;
 };
 
 // `options` is a thunk so env reads happen per-evaluation, not at module load.
@@ -82,7 +86,7 @@ function logDivertDecision(
 export const defaultGateDependencies: GateDependencies = {
   isMollifierEnabled: () => env.MOLLIFIER_ENABLED === "1",
   isShadowModeOn: () => env.MOLLIFIER_SHADOW_MODE === "1",
-  resolveOrgFlag: () =>
+  resolveFlag: () =>
     flag({ key: FEATURE_FLAG.mollifierEnabled, defaultValue: false }),
   evaluator: defaultEvaluator,
   logShadow: (inputs, decision) =>
@@ -103,10 +107,10 @@ export async function evaluateGate(
     return { action: "pass_through" };
   }
 
-  const orgFlagEnabled = await d.resolveOrgFlag();
+  const flagEnabled = await d.resolveFlag();
   const shadowOn = d.isShadowModeOn();
 
-  if (!orgFlagEnabled && !shadowOn) {
+  if (!flagEnabled && !shadowOn) {
     d.recordDecision("pass_through");
     return { action: "pass_through" };
   }
@@ -117,7 +121,7 @@ export async function evaluateGate(
     return { action: "pass_through" };
   }
 
-  if (orgFlagEnabled) {
+  if (flagEnabled) {
     d.logMollified(inputs, decision);
     d.recordDecision("mollify", decision.reason);
     return { action: "mollify", decision };

apps/webapp/app/v3/mollifier/mollifierTelemetry.server.ts

@@ -7,8 +7,9 @@ export const mollifierDecisionsCounter = meter.createCounter("mollifier.decision
 });
 
 export type DecisionOutcome = "pass_through" | "shadow_log" | "mollify";
+export type DecisionReason = "per_env_rate";
 
-export function recordDecision(outcome: DecisionOutcome, reason?: string): void {
+export function recordDecision(outcome: DecisionOutcome, reason?: DecisionReason): void {
   mollifierDecisionsCounter.add(1, {
     outcome,
     ...(reason ? { reason } : {}),

apps/webapp/test/bufferedTriggerPayload.test.ts

@@ -50,6 +50,16 @@ describe("buildBufferedTriggerPayload", () => {
     const noKey = buildBufferedTriggerPayload(baseInput);
     expect(noKey.idempotencyKey).toBeNull();
     expect(noKey.idempotencyKeyExpiresAt).toBeNull();
+
+    // Defensive: an expiresAt without an accompanying key is an impossible
+    // idempotency state — drop the expiresAt rather than serialise it.
+    const orphanExpiry = buildBufferedTriggerPayload({
+      ...baseInput,
+      idempotencyKey: null,
+      idempotencyKeyExpiresAt: new Date("2026-05-13T10:00:00.000Z"),
+    });
+    expect(orphanExpiry.idempotencyKey).toBeNull();
+    expect(orphanExpiry.idempotencyKeyExpiresAt).toBeNull();
   });
 
   it("preserves customer body byte-equivalent (drainer replay must match Postgres)", () => {

apps/webapp/test/mollifierGate.test.ts

@@ -1,39 +1,56 @@
-import { describe, expect, it, vi } from "vitest";
+import { describe, expect, it } from "vitest";
 import {
   evaluateGate,
   type GateDependencies,
   type GateInputs,
   type TripDecision,
 } from "~/v3/mollifier/mollifierGate.server";
+import type { DecisionOutcome, DecisionReason } from "~/v3/mollifier/mollifierTelemetry.server";
 
+// We deliberately don't use vi.fn here. Per repo policy tests shouldn't lean on
+// mock frameworks for behaviours that are pure functions of the inputs — the
+// gate is pure decision logic, so a hand-rolled "deps + spy log" wired with
+// plain closures gives exactly the assertions we need without the indirection.
 type Spies = {
-  [K in keyof GateDependencies]: ReturnType<typeof vi.fn>;
+  evaluatorCalls: number;
+  logShadowCalls: Array<{ inputs: GateInputs; decision: Extract<TripDecision, { divert: true }> }>;
+  logMollifiedCalls: Array<{ inputs: GateInputs; decision: Extract<TripDecision, { divert: true }> }>;
+  recordDecisionCalls: Array<{ outcome: DecisionOutcome; reason?: DecisionReason }>;
 };
 
-function makeDeps(overrides: Partial<GateDependencies> = {}): {
-  deps: GateDependencies;
-  spies: Spies;
-} {
-  const defaults: GateDependencies = {
-    isMollifierEnabled: () => false,
-    isShadowModeOn: () => false,
-    resolveOrgFlag: async () => false,
-    evaluator: async () => ({ divert: false }) as TripDecision,
-    logShadow: () => {},
-    logMollified: () => {},
-    recordDecision: () => {},
+type Toggles = {
+  enabled: boolean;
+  shadow: boolean;
+  flag: boolean;
+  decision: TripDecision;
+};
+
+function makeDeps(toggles: Toggles): { deps: GateDependencies; spies: Spies } {
+  const spies: Spies = {
+    evaluatorCalls: 0,
+    logShadowCalls: [],
+    logMollifiedCalls: [],
+    recordDecisionCalls: [],
+  };
+  const deps: GateDependencies = {
+    isMollifierEnabled: () => toggles.enabled,
+    isShadowModeOn: () => toggles.shadow,
+    resolveFlag: async () => toggles.flag,
+    evaluator: async () => {
+      spies.evaluatorCalls += 1;
+      return toggles.decision;
+    },
+    logShadow: (inputs, decision) => {
+      spies.logShadowCalls.push({ inputs, decision });
+    },
+    logMollified: (inputs, decision) => {
+      spies.logMollifiedCalls.push({ inputs, decision });
+    },
+    recordDecision: (outcome, reason) => {
+      spies.recordDecisionCalls.push({ outcome, reason });
+    },
   };
-  const merged = { ...defaults, ...overrides };
-  const spies = {
-    isMollifierEnabled: vi.fn(merged.isMollifierEnabled),
-    isShadowModeOn: vi.fn(merged.isShadowModeOn),
-    resolveOrgFlag: vi.fn(merged.resolveOrgFlag),
-    evaluator: vi.fn(merged.evaluator),
-    logShadow: vi.fn(merged.logShadow),
-    logMollified: vi.fn(merged.logMollified),
-    recordDecision: vi.fn(merged.recordDecision),
-  } satisfies Spies;
-  return { deps: spies, spies };
+  return { deps, spies };
 }
 
 const trippedDecision = {
@@ -101,53 +118,49 @@ describe("evaluateGate cascade — exhaustive truth table", () => {
     "row $id: enabled=$enabled shadow=$shadow flag=$flag divert=$divert → action=$expected.action",
     async (row) => {
       const { deps, spies } = makeDeps({
-        isMollifierEnabled: () => row.enabled,
-        isShadowModeOn: () => row.shadow,
-        resolveOrgFlag: async () => row.flag,
-        evaluator: async () => (row.divert ? trippedDecision : passDecision),
+        enabled: row.enabled,
+        shadow: row.shadow,
+        flag: row.flag,
+        decision: row.divert ? trippedDecision : passDecision,
       });
 
       const outcome = await evaluateGate(inputs, deps);
 
       expect(outcome.action).toBe(row.expected.action);
-      expect(spies.evaluator).toHaveBeenCalledTimes(row.expected.evaluatorCalls);
-      expect(spies.logShadow).toHaveBeenCalledTimes(row.expected.logShadowCalls);
-      expect(spies.logMollified).toHaveBeenCalledTimes(row.expected.logMollifiedCalls);
+      expect(spies.evaluatorCalls).toBe(row.expected.evaluatorCalls);
+      expect(spies.logShadowCalls).toHaveLength(row.expected.logShadowCalls);
+      expect(spies.logMollifiedCalls).toHaveLength(row.expected.logMollifiedCalls);
 
       // Every evaluation records exactly one decision.
-      expect(spies.recordDecision).toHaveBeenCalledTimes(1);
-      if (row.expected.expectedReason === undefined) {
-        expect(spies.recordDecision).toHaveBeenCalledWith(row.expected.recordedOutcome);
-      } else {
-        expect(spies.recordDecision).toHaveBeenCalledWith(
-          row.expected.recordedOutcome,
-          row.expected.expectedReason,
-        );
-      }
+      expect(spies.recordDecisionCalls).toHaveLength(1);
+      expect(spies.recordDecisionCalls[0].outcome).toBe(row.expected.recordedOutcome);
+      expect(spies.recordDecisionCalls[0].reason).toBe(row.expected.expectedReason);
     },
   );
 
   it("divert log carries the full decision (envId, orgId, taskId, reason, count, threshold, windowMs, holdMs)", async () => {
     const { deps, spies } = makeDeps({
-      isMollifierEnabled: () => true,
-      isShadowModeOn: () => true,
-      evaluator: async () => trippedDecision,
+      enabled: true,
+      shadow: true,
+      flag: false,
+      decision: trippedDecision,
     });
 
     await evaluateGate(inputs, deps);
 
-    expect(spies.logShadow).toHaveBeenCalledWith(inputs, trippedDecision);
+    expect(spies.logShadowCalls).toEqual([{ inputs, decision: trippedDecision }]);
   });
 
   it("mollify log carries the full decision (mirrors shadow log)", async () => {
     const { deps, spies } = makeDeps({
-      isMollifierEnabled: () => true,
-      resolveOrgFlag: async () => true,
-      evaluator: async () => trippedDecision,
+      enabled: true,
+      shadow: false,
+      flag: true,
+      decision: trippedDecision,
     });
 
     await evaluateGate(inputs, deps);
 
-    expect(spies.logMollified).toHaveBeenCalledWith(inputs, trippedDecision);
+    expect(spies.logMollifiedCalls).toEqual([{ inputs, decision: trippedDecision }]);
   });
 });