From 6b59b30846ab65d36a6869f548e068f1f80082b4 Mon Sep 17 00:00:00 2001
From: Mateusz Kwasniewski <kwasniewski.mateusz@gmail.com>
Date: Wed, 15 May 2024 12:47:01 +0200
Subject: [PATCH] feat: backfill current stage on startup (#7057)

---
 .../fake-feature-lifecycle-store.ts           |  2 ++
 .../feature-lifecycle-service.ts              |  1 +
 .../feature-lifecycle-store-type.ts           |  1 +
 .../feature-lifecycle-store.ts                | 10 ++++++++++
 .../feature-lifecycle.e2e.test.ts             | 20 +++++++++++++++++++
 5 files changed, 34 insertions(+)

diff --git a/src/lib/features/feature-lifecycle/fake-feature-lifecycle-store.ts b/src/lib/features/feature-lifecycle/fake-feature-lifecycle-store.ts
index d15b1f9f4923..bf545e899f99 100644
--- a/src/lib/features/feature-lifecycle/fake-feature-lifecycle-store.ts
+++ b/src/lib/features/feature-lifecycle/fake-feature-lifecycle-store.ts
@@ -16,6 +16,8 @@ export class FakeFeatureLifecycleStore implements IFeatureLifecycleStore {
         );
     }
 
+    async backfill() {}
+
     private async insertOne(
         featureLifecycleStage: FeatureLifecycleStage,
     ): Promise<void> {
diff --git a/src/lib/features/feature-lifecycle/feature-lifecycle-service.ts b/src/lib/features/feature-lifecycle/feature-lifecycle-service.ts
index ff976d6e8de9..164690307dc1 100644
--- a/src/lib/features/feature-lifecycle/feature-lifecycle-service.ts
+++ b/src/lib/features/feature-lifecycle/feature-lifecycle-service.ts
@@ -87,6 +87,7 @@ export class FeatureLifecycleService extends EventEmitter {
     }
 
     listen() {
+        void this.checkEnabled(() => this.featureLifecycleStore.backfill());
         this.eventStore.on(FEATURE_CREATED, async (event) => {
             await this.checkEnabled(() =>
                 this.featureInitialized(event.featureName),
diff --git a/src/lib/features/feature-lifecycle/feature-lifecycle-store-type.ts b/src/lib/features/feature-lifecycle/feature-lifecycle-store-type.ts
index a0659ffa8a43..d8ff0b88599c 100644
--- a/src/lib/features/feature-lifecycle/feature-lifecycle-store-type.ts
+++ b/src/lib/features/feature-lifecycle/feature-lifecycle-store-type.ts
@@ -21,4 +21,5 @@ export interface IFeatureLifecycleStore {
     stageExists(stage: FeatureLifecycleStage): Promise<boolean>;
     delete(feature: string): Promise<void>;
     deleteStage(stage: FeatureLifecycleStage): Promise<void>;
+    backfill(): Promise<void>;
 }
diff --git a/src/lib/features/feature-lifecycle/feature-lifecycle-store.ts b/src/lib/features/feature-lifecycle/feature-lifecycle-store.ts
index 89076e7f3088..6e3586a72f1e 100644
--- a/src/lib/features/feature-lifecycle/feature-lifecycle-store.ts
+++ b/src/lib/features/feature-lifecycle/feature-lifecycle-store.ts
@@ -26,6 +26,16 @@ export class FeatureLifecycleStore implements IFeatureLifecycleStore {
         this.db = db;
     }
 
+    async backfill(): Promise<void> {
+        await this.db.raw(`
+            INSERT INTO feature_lifecycles (feature, stage, created_at)
+            SELECT features.name, 'initial', features.created_at
+            FROM features
+                LEFT JOIN feature_lifecycles ON features.name = feature_lifecycles.feature
+            WHERE feature_lifecycles.feature IS NULL
+        `);
+    }
+
     async insert(
         featureLifecycleStages: FeatureLifecycleStage[],
     ): Promise<void> {
diff --git a/src/lib/features/feature-lifecycle/feature-lifecycle.e2e.test.ts b/src/lib/features/feature-lifecycle/feature-lifecycle.e2e.test.ts
index 65e207958a2a..8e5effacf19e 100644
--- a/src/lib/features/feature-lifecycle/feature-lifecycle.e2e.test.ts
+++ b/src/lib/features/feature-lifecycle/feature-lifecycle.e2e.test.ts
@@ -10,6 +10,7 @@ import {
     FEATURE_CREATED,
     FEATURE_REVIVED,
     type IEventStore,
+    type IFeatureLifecycleStore,
     type StageName,
 } from '../../types';
 import type EventEmitter from 'events';
@@ -24,6 +25,7 @@ import type { IFeatureLifecycleReadModel } from './feature-lifecycle-read-model-
 let app: IUnleashTest;
 let db: ITestDb;
 let featureLifecycleService: FeatureLifecycleService;
+let featureLifecycleStore: IFeatureLifecycleStore;
 let eventStore: IEventStore;
 let eventBus: EventEmitter;
 let featureLifecycleReadModel: IFeatureLifecycleReadModel;
@@ -45,6 +47,7 @@ beforeAll(async () => {
     eventBus = app.config.eventBus;
     featureLifecycleService = app.services.featureLifecycleService;
     featureLifecycleReadModel = new FeatureLifecycleReadModel(db.rawDatabase);
+    featureLifecycleStore = db.stores.featureLifecycleStore;
 
     await app.request
         .post(`/auth/demo/login`)
@@ -186,3 +189,20 @@ test('should be able to toggle between completed/uncompleted', async () => {
 
     expect(body).toEqual([]);
 });
+
+test('should backfill initial stage when no stages', async () => {
+    await app.createFeature('my_feature_c');
+
+    await featureLifecycleStore.delete('my_feature_c');
+
+    const currentStage = await getCurrentStage('my_feature_c');
+    expect(currentStage).toBe(undefined);
+
+    await featureLifecycleStore.backfill();
+
+    const backfilledCurrentStage = await getCurrentStage('my_feature_c');
+    expect(backfilledCurrentStage).toEqual({
+        stage: 'initial',
+        enteredStageAt: expect.any(Date),
+    });
+});