Add test case for image generation (#42693)

This PR adds a basic test case to ensure Next.js and Edge Runtime
changes don't break the image generation feature, as well as record the
usage.

## Bug

- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have a helpful link attached, see `contributing.md`

## Feature

- [ ] Implements an existing feature request or RFC. Make sure the
feature request has been accepted for implementation before opening a
PR.
- [ ] Related issues linked using `fixes #number`
- [x] Integration tests added
- [ ] Documentation added
- [x] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have a helpful link attached, see `contributing.md`

## Documentation / Examples

- [ ] Make sure the linting passes by running `pnpm build && pnpm lint`
- [ ] The "examples guidelines" are followed from [our contributing
doc](https://github.com/vercel/next.js/blob/canary/contributing/examples/adding-examples.md)

package.json

@@ -90,6 +90,7 @@
     "@typescript-eslint/eslint-plugin": "4.29.1",
     "@typescript-eslint/parser": "4.29.1",
     "@vercel/fetch": "6.1.1",
+    "@vercel/og": "0.0.20",
     "@webassemblyjs/ast": "1.11.1",
     "@webassemblyjs/floating-point-hex-parser": "1.11.1",
     "@webassemblyjs/helper-api-error": "1.11.1",

packages/next/build/webpack/plugins/middleware-plugin.ts

@@ -27,6 +27,7 @@ import {
 } from '../../analysis/get-page-static-info'
 import { Telemetry } from '../../../telemetry/storage'
 import { traceGlobals } from '../../../trace/shared'
+import { EVENT_BUILD_FEATURE_USAGE } from '../../../telemetry/events'
 
 export interface EdgeFunctionDefinition {
   env: string[]
@@ -686,6 +687,25 @@ function getExtractMetadata(params: {
       for (const module of modules) {
         const buildInfo = getModuleBuildInfo(module)
 
+        /**
+         * Check if it uses the image generation feature.
+         */
+        if (!dev) {
+          const resource = module.resource
+          const hasOGImageGeneration =
+            resource &&
+            /[\\/]node_modules[\\/]@vercel[\\/]og[\\/]dist[\\/]index.js$/.test(
+              resource
+            )
+          telemetry.record({
+            eventName: EVENT_BUILD_FEATURE_USAGE,
+            payload: {
+              featureName: 'vercelImageGeneration',
+              invocationCount: hasOGImageGeneration ? 1 : 0,
+            },
+          })
+        }
+
         /**
          * When building for production checks if the module is using `eval`
          * and in such case produces a compilation error. The module has to

packages/next/telemetry/events/build.ts

@@ -153,6 +153,7 @@ export type EventBuildFeatureUsage = {
     | `swc/target/${SWC_TARGET_TRIPLE}`
     | 'turbotrace'
     | 'build-lint'
+    | 'vercelImageGeneration'
   invocationCount: number
 }
 export function eventBuildFeatureUsage(

test/integration/image-generation/app/pages/api/image.jsx

@@ -0,0 +1,9 @@
+import { ImageResponse } from '@vercel/og'
+
+export default async () => {
+  return new ImageResponse(<div tw="w-full h-full text-5xl">hello</div>)
+}
+
+export const config = {
+  runtime: 'experimental-edge',
+}

test/integration/image-generation/test/index.test.ts

@@ -0,0 +1,42 @@
+/* eslint-env jest */
+import {
+  fetchViaHTTP,
+  findPort,
+  killApp,
+  nextBuild,
+  nextStart,
+} from 'next-test-utils'
+import { join } from 'path'
+
+const appDir = join(__dirname, '../app')
+
+describe('Image Generation', () => {
+  describe('Prod', () => {
+    let app
+    let appPort
+
+    beforeAll(async () => {
+      await nextBuild(appDir)
+      appPort = await findPort()
+      app = await nextStart(appDir, appPort)
+    })
+    afterAll(async () => {
+      await killApp(app)
+    })
+
+    it('should generate the image without errors', async () => {
+      const res = await fetchViaHTTP(appPort, '/api/image')
+      expect(res.status).toBe(200)
+      expect(res.headers.get('Content-Type')).toBe('image/png')
+
+      const buffer = await res.buffer()
+
+      // It should be a PNG
+      expect(
+        [0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a].every(
+          (b, i) => buffer[i] === b
+        )
+      ).toBeTrue()
+    })
+  })
+})

test/integration/telemetry/pages/api/og.jsx

@@ -0,0 +1,9 @@
+import { ImageResponse } from '@vercel/og'
+
+export default async () => {
+  return new ImageResponse(<div tw="w-full h-full text-5xl">hello</div>)
+}
+
+export const config = {
+  runtime: 'experimental-edge',
+}

test/integration/telemetry/test/index.test.js

@@ -331,9 +331,9 @@ describe('Telemetry CLI', () => {
     const event1 = /NEXT_BUILD_OPTIMIZED[\s\S]+?{([\s\S]+?)}/.exec(stderr).pop()
     expect(event1).toMatch(/"staticPropsPageCount": 2/)
     expect(event1).toMatch(/"serverPropsPageCount": 2/)
-    expect(event1).toMatch(/"ssrPageCount": 1/)
+    expect(event1).toMatch(/"ssrPageCount": 2/)
     expect(event1).toMatch(/"staticPageCount": 4/)
-    expect(event1).toMatch(/"totalPageCount": 9/)
+    expect(event1).toMatch(/"totalPageCount": 10/)
   })
 
   it('detects isSrcDir dir correctly for `next dev`', async () => {
@@ -970,4 +970,19 @@ describe('Telemetry CLI', () => {
       invocationCount: 1,
     })
   })
+
+  it('emits telemetry for usage of @vercel/og', async () => {
+    const { stderr } = await nextBuild(appDir, [], {
+      stderr: true,
+      env: { NEXT_TELEMETRY_DEBUG: 1 },
+    })
+    const featureUsageEvents = findAllTelemetryEvents(
+      stderr,
+      'NEXT_BUILD_FEATURE_USAGE'
+    )
+    expect(featureUsageEvents).toContainEqual({
+      featureName: 'vercelImageGeneration',
+      invocationCount: 1,
+    })
+  })
 })