feat: lifecycle prometheus metrics per project (#7032)

When we pushed metrics per feature, it had too many datapoints and
grafana could not handle it. Now I am taking median for a project.

src/lib/features/feature-lifecycle/calculate-stage-durations.test.ts

@@ -0,0 +1,89 @@
+import {
+    calculateMedians,
+    calculateStageDurations,
+} from './calculate-stage-durations';
+
+test('can find feature lifecycle stage timings', async () => {
+    const now = new Date();
+    const oneHourAgo = new Date(now.getTime() - 60 * 60 * 1000);
+    const twentyMinutesAgo = new Date(now.getTime() - 20 * 60 * 1000);
+    const tenMinutesAgo = new Date(now.getTime() - 10 * 60 * 1000);
+    const fiveMinutesAgo = new Date(now.getTime() - 5 * 60 * 1000);
+
+    const durations = calculateStageDurations([
+        {
+            feature: 'a',
+            stage: 'initial',
+            project: 'default',
+            enteredStageAt: oneHourAgo,
+        },
+        {
+            feature: 'b',
+            stage: 'initial',
+            project: 'default',
+            enteredStageAt: oneHourAgo,
+        },
+        {
+            feature: 'a',
+            stage: 'pre-live',
+            project: 'default',
+            enteredStageAt: twentyMinutesAgo,
+        },
+        {
+            feature: 'b',
+            stage: 'live',
+            project: 'default',
+            enteredStageAt: tenMinutesAgo,
+        },
+        {
+            feature: 'c',
+            stage: 'initial',
+            project: 'default',
+            enteredStageAt: oneHourAgo,
+        },
+        {
+            feature: 'c',
+            stage: 'pre-live',
+            project: 'default',
+            enteredStageAt: fiveMinutesAgo,
+        },
+    ]);
+
+    expect(durations).toMatchObject([
+        {
+            project: 'default',
+            stage: 'initial',
+            duration: 50,
+        },
+        {
+            project: 'default',
+            stage: 'pre-live',
+            duration: 12.5,
+        },
+        {
+            project: 'default',
+            stage: 'live',
+            duration: 10,
+        },
+    ]);
+});
+
+test('should calculate median durations', () => {
+    const groupedData = {
+        'Project1/Development': [180, 120, 10],
+        'Project1/Testing': [240, 60],
+    };
+    const medians = calculateMedians(groupedData);
+    expect(medians).toMatchObject([
+        {
+            project: 'Project1',
+            stage: 'Development',
+            duration: 120,
+        },
+        {
+            project: 'Project1',
+            stage: 'Testing',
+            duration: 150,
+        },
+    ]);
+});

src/lib/features/feature-lifecycle/calculate-stage-durations.ts

@@ -0,0 +1,50 @@
+import type { IProjectLifecycleStageDuration, StageName } from '../../types';
+import type { FeatureLifecycleProjectItem } from './feature-lifecycle-store-type';
+import { differenceInMinutes } from 'date-fns';
+import { median } from '../../util/median';
+
+export function calculateStageDurations(
+    featureLifeCycles: FeatureLifecycleProjectItem[],
+) {
+    const sortedLifeCycles = featureLifeCycles.sort(
+        (a, b) => a.enteredStageAt.getTime() - b.enteredStageAt.getTime(),
+    );
+
+    const groupedByProjectAndStage = sortedLifeCycles.reduce<{
+        [key: string]: number[];
+    }>((acc, curr, index, array) => {
+        const key = `${curr.project}/${curr.stage}`;
+        if (!acc[key]) {
+            acc[key] = [];
+        }
+
+        const nextItem = array
+            .slice(index + 1)
+            .find(
+                (item) =>
+                    item.feature === curr.feature && item.stage !== curr.stage,
+            );
+        const endTime = nextItem ? nextItem.enteredStageAt : new Date();
+        const duration = differenceInMinutes(endTime, curr.enteredStageAt);
+        acc[key].push(duration);
+        return acc;
+    }, {});
+
+    return calculateMedians(groupedByProjectAndStage);
+}
+
+export const calculateMedians = (groupedByProjectAndStage: {
+    [key: string]: number[];
+}) => {
+    const medians: IProjectLifecycleStageDuration[] = [];
+    Object.entries(groupedByProjectAndStage).forEach(([key, durations]) => {
+        const [project, stage] = key.split('/');
+        const duration = median(durations);
+        medians.push({
+            project,
+            stage: stage as StageName,
+            duration,
+        });
+    });
+    return medians;
+};

src/lib/features/feature-lifecycle/feature-lifecycle-service.test.ts

@@ -128,76 +128,3 @@ test('ignores lifecycle state updates when flag disabled', async () => {
 
     expect(lifecycle).toEqual([]);
 });
-
-test('can find feature lifecycle stage timings', async () => {
-    const eventBus = new EventEmitter();
-    const { featureLifecycleService, eventStore, environmentStore } =
-        createFakeFeatureLifecycleService({
-            flagResolver: { isEnabled: () => false },
-            eventBus,
-            getLogger: noLoggerProvider,
-        } as unknown as IUnleashConfig);
-    const now = new Date();
-    const minusOneMinute = new Date(now.getTime() - 1 * 60 * 1000);
-    const minusTenMinutes = new Date(now.getTime() - 10 * 60 * 1000);
-    const durations = featureLifecycleService.calculateStageDurations([
-        {
-            feature: 'a',
-            stage: 'initial',
-            project: 'default',
-            enteredStageAt: minusTenMinutes,
-        },
-        {
-            feature: 'b',
-            stage: 'initial',
-            project: 'default',
-            enteredStageAt: minusTenMinutes,
-        },
-        {
-            feature: 'a',
-            stage: 'pre-live',
-            project: 'default',
-            enteredStageAt: minusOneMinute,
-        },
-        {
-            feature: 'b',
-            stage: 'live',
-            project: 'default',
-            enteredStageAt: minusOneMinute,
-        },
-        {
-            feature: 'c',
-            stage: 'initial',
-            project: 'default',
-            enteredStageAt: minusTenMinutes,
-        },
-    ]);
-
-    expect(durations).toMatchObject([
-        {
-            feature: 'a',
-            stage: 'initial',
-            duration: 9,
-        },
-        {
-            feature: 'a',
-            stage: 'pre-live',
-            duration: 1,
-        },
-        {
-            feature: 'b',
-            stage: 'initial',
-            duration: 9,
-        },
-        {
-            feature: 'b',
-            stage: 'live',
-            duration: 1,
-        },
-        {
-            feature: 'c',
-            stage: 'initial',
-            duration: 10,
-        },
-    ]);
-});

src/lib/features/feature-lifecycle/feature-lifecycle-service.ts

@@ -9,12 +9,11 @@ import {
     type IEnvironmentStore,
     type IEventStore,
     type IFeatureEnvironmentStore,
-    type IFeatureLifecycleStageDuration,
+    type IProjectLifecycleStageDuration,
     type IFlagResolver,
     type IUnleashConfig,
 } from '../../types';
 import type {
-    FeatureLifecycleProjectItem,
     FeatureLifecycleView,
     IFeatureLifecycleStore,
 } from './feature-lifecycle-store-type';
@@ -22,8 +21,8 @@ import EventEmitter from 'events';
 import type { Logger } from '../../logger';
 import type EventService from '../events/event-service';
 import type { ValidatedClientMetrics } from '../metrics/shared/schema';
-import { differenceInMinutes } from 'date-fns';
 import type { FeatureLifecycleCompletedSchema } from '../../openapi';
+import { calculateStageDurations } from './calculate-stage-durations';
 
 export const STAGE_ENTERED = 'STAGE_ENTERED';
 
@@ -215,50 +214,9 @@ export class FeatureLifecycleService extends EventEmitter {
     }
 
     public async getAllWithStageDuration(): Promise<
-        IFeatureLifecycleStageDuration[]
+        IProjectLifecycleStageDuration[]
     > {
         const featureLifeCycles = await this.featureLifecycleStore.getAll();
-        return this.calculateStageDurations(featureLifeCycles);
+        return calculateStageDurations(featureLifeCycles);
-    }
-
-    public calculateStageDurations(
-        featureLifeCycles: FeatureLifecycleProjectItem[],
-    ) {
-        const groupedByFeature = featureLifeCycles.reduce<{
-            [feature: string]: FeatureLifecycleProjectItem[];
-        }>((acc, curr) => {
-            if (!acc[curr.feature]) {
-                acc[curr.feature] = [];
-            }
-            acc[curr.feature].push(curr);
-            return acc;
-        }, {});
-
-        const times: IFeatureLifecycleStageDuration[] = [];
-        Object.values(groupedByFeature).forEach((stages) => {
-            stages.sort(
-                (a, b) =>
-                    a.enteredStageAt.getTime() - b.enteredStageAt.getTime(),
-            );
-
-            stages.forEach((stage, index) => {
-                const nextStage = stages[index + 1];
-                const endTime = nextStage
-                    ? nextStage.enteredStageAt
-                    : new Date();
-                const duration = differenceInMinutes(
-                    endTime,
-                    stage.enteredStageAt,
-                );
-
-                times.push({
-                    feature: stage.feature,
-                    stage: stage.stage,
-                    project: stage.project,
-                    duration,
-                });
-            });
-        });
-        return times;
     }
 }

src/lib/features/instance-stats/instance-stats-service.ts

@@ -22,7 +22,7 @@ import {
     FEATURES_EXPORTED,
     FEATURES_IMPORTED,
     type IApiTokenStore,
-    type IFeatureLifecycleStageDuration,
+    type IProjectLifecycleStageDuration,
     type IFlagResolver,
 } from '../../types';
 import { CUSTOM_ROOT_ROLE_TYPE } from '../../util';
@@ -63,7 +63,7 @@ export interface InstanceStats {
         enabledCount: number;
         variantCount: number;
     };
-    featureLifeCycles: IFeatureLifecycleStageDuration[];
+    featureLifeCycles: IProjectLifecycleStageDuration[];
 }
 
 export type InstanceStatsSigned = Omit<InstanceStats, 'projects'> & {
@@ -349,7 +349,7 @@ export class InstanceStatsService {
         return { ...instanceStats, sum, projects: totalProjects };
     }
 
-    async getAllWithStageDuration(): Promise<IFeatureLifecycleStageDuration[]> {
+    async getAllWithStageDuration(): Promise<IProjectLifecycleStageDuration[]> {
         if (this.flagResolver.isEnabled('featureLifecycleMetrics')) {
             return this.featureLifecycleService.getAllWithStageDuration();
         }

src/lib/metrics.ts

@@ -261,7 +261,7 @@ export default class MetricsMonitor {
 
         const featureLifecycleStageDuration = createHistogram({
             name: 'feature_lifecycle_stage_duration',
-            labelNames: ['feature_id', 'stage', 'project_id'],
+            labelNames: ['stage', 'project_id'],
             help: 'Duration of feature lifecycle stages',
         });
 
@@ -292,7 +292,6 @@ export default class MetricsMonitor {
                 stats.featureLifeCycles.forEach((stage) => {
                     featureLifecycleStageDuration
                         .labels({
-                            feature_id: stage.feature,
                             stage: stage.stage,
                             project_id: stage.project,
                         })

src/lib/routes/admin-api/instance-admin.ts

@@ -127,7 +127,6 @@ class InstanceAdminController extends Controller {
             },
             featureLifeCycles: [
                 {
-                    feature: 'feature1',
                     project: 'default',
                     stage: 'archived',
                     duration: 2000,

src/lib/types/model.ts

@@ -7,7 +7,6 @@ import type { IProjectStats } from '../features/project/project-service';
 import type { CreateFeatureStrategySchema } from '../openapi';
 import type { ProjectEnvironment } from '../features/project/project-store-type';
 import type { FeatureSearchEnvironmentSchema } from '../openapi/spec/feature-search-environment-schema';
-import type { FeatureLifecycleStage } from '../features/feature-lifecycle/feature-lifecycle-store-type';
 
 export type Operator = (typeof ALL_OPERATORS)[number];
 
@@ -166,9 +165,10 @@ export interface IFeatureLifecycleStage {
     enteredStageAt: Date;
 }
 
-export type IFeatureLifecycleStageDuration = FeatureLifecycleStage & {
+export type IProjectLifecycleStageDuration = {
     duration: number;
     project: string;
+    stage: StageName;
 };
 
 export interface IFeatureDependency {

src/lib/util/median.test.ts

@@ -0,0 +1,21 @@
+import { median } from './median';
+
+test('calculateMedian with an odd number of elements', () => {
+    expect(median([1, 3, 5])).toBe(3);
+});
+
+test('calculateMedian with an even number of elements', () => {
+    expect(median([1, 2, 3, 4])).toBe(2.5);
+});
+
+test('calculateMedian with negative numbers', () => {
+    expect(median([-5, -1, -3, -2, -4])).toBe(-3);
+});
+
+test('calculateMedian with one element', () => {
+    expect(median([42])).toBe(42);
+});
+
+test('calculateMedian with an empty array', () => {
+    expect(median([])).toBe(Number.NaN);
+});

src/lib/util/median.ts

@@ -0,0 +1,9 @@
+export const median = (numbers: number[]): number => {
+    numbers.sort((a, b) => a - b);
+    const midIndex = Math.floor(numbers.length / 2);
+    if (numbers.length % 2 === 0) {
+        return (numbers[midIndex - 1] + numbers[midIndex]) / 2;
+    } else {
+        return numbers[midIndex];
+    }
+};