Serverless trace target support

packages/lambda-at-edge/.gitignore

@@ -1,2 +1,3 @@
 !tests/fixtures/**
+!tests/serverless-trace/**
 dist/

packages/lambda-at-edge/package.json

@@ -43,6 +43,7 @@
     "next-aws-cloudfront": "file:../cloudfront-lambda@edge-compat"
   },
   "dependencies": {
+    "@zeit/node-file-trace": "^0.5.1",
     "execa": "^4.0.0",
     "fs-extra": "^9.0.0",
     "path-to-regexp": "^6.1.0"

packages/lambda-at-edge/src/build.ts

@@ -1,3 +1,4 @@
+import nodeFileTrace from "@zeit/node-file-trace";
 import execa from "execa";
 import fse from "fs-extra";
 import { join } from "path";
@@ -17,28 +18,32 @@ export const DEFAULT_LAMBDA_CODE_DIR = "default-lambda";
 export const API_LAMBDA_CODE_DIR = "api-lambda";
 
 type BuildOptions = {
-  args: string[];
-  cwd: string;
-  env: NodeJS.ProcessEnv;
-  cmd: string;
+  args?: string[];
+  cwd?: string;
+  env?: NodeJS.ProcessEnv;
+  cmd?: string;
+};
+
+const defaultBuildOptions = {
+  args: [],
+  cwd: process.cwd(),
+  env: {},
+  cmd: "./node_modules/.bin/next"
 };
 
 class Builder {
   nextConfigDir: string;
+  dotNextDirectory: string;
   outputDir: string;
-  buildOptions: BuildOptions = {
-    args: [],
-    cwd: process.cwd(),
-    env: {},
-    cmd: "./node_modules/.bin/next"
-  };
+  buildOptions: BuildOptions = defaultBuildOptions;
 
   constructor(
     nextConfigDir: string,
     outputDir: string,
     buildOptions?: BuildOptions
   ) {
     this.nextConfigDir = nextConfigDir;
+    this.dotNextDirectory = path.join(this.nextConfigDir, ".next");
     this.outputDir = outputDir;
     if (buildOptions) {
       this.buildOptions = buildOptions;
@@ -100,10 +105,65 @@ class Builder {
     return sortedPagesManifest;
   }
 
-  buildDefaultLambda(
+  get isServerlessTraceTarget(): boolean {
+    try {
+      // eslint-disable-next-line
+      const nextConfig = require(`${path.resolve(
+        path.join(this.nextConfigDir, "next.config.js")
+      )}`);
+
+      if (nextConfig.target === "experimental-serverless-trace") {
+        return true;
+      }
+    } catch (err) {
+      // ignore error, it just means we can't use the experimental serverless trace
+    }
+
+    return false;
+  }
+
+  async buildDefaultLambda(
     buildManifest: OriginRequestDefaultHandlerManifest
   ): Promise<void[]> {
+    let copyTraces: Promise<void>[] = [];
+
+    if (this.isServerlessTraceTarget) {
+      const ignoreAppAndDocumentPages = (page: string): boolean => {
+        const basename = path.basename(page);
+        return basename !== "_app.js" && basename !== "_document.js";
+      };
+
+      const allSsrPages = [
+        ...Object.values(buildManifest.pages.ssr.nonDynamic),
+        ...Object.values(buildManifest.pages.ssr.dynamic).map(
+          entry => entry.file
+        )
+      ].filter(ignoreAppAndDocumentPages);
+
+      const ssrPages = Object.values(allSsrPages).map(pageFile =>
+        path.join(this.dotNextDirectory, "serverless", pageFile)
+      );
+
+      const { fileList, reasons } = await nodeFileTrace(ssrPages, {
+        base: path.resolve(this.nextConfigDir)
+      });
+
+      copyTraces = fileList
+        .filter(file => {
+          // exclude "initial" files from lambda artefact. These are just the pages themselves
+          // which are copied over separately
+          return !reasons[file] || reasons[file].type !== "initial";
+        })
+        .map((filePath: string) => {
+          return fse.copy(
+            path.join(path.resolve(this.nextConfigDir), filePath),
+            join(this.outputDir, DEFAULT_LAMBDA_CODE_DIR, filePath)
+          );
+        });
+    }
+
     return Promise.all([
+      ...copyTraces,
       fse.copy(
         require.resolve("@sls-next/lambda-at-edge/dist/default-handler.js"),
         join(this.outputDir, DEFAULT_LAMBDA_CODE_DIR, "index.js")
@@ -144,10 +204,41 @@ class Builder {
     ]);
   }
 
-  buildApiLambda(
+  async buildApiLambda(
     apiBuildManifest: OriginRequestApiHandlerManifest
   ): Promise<void[]> {
+    let copyTraces: Promise<void>[] = [];
+
+    if (this.isServerlessTraceTarget) {
+      const allApiPages = [
+        ...Object.values(apiBuildManifest.apis.nonDynamic),
+        ...Object.values(apiBuildManifest.apis.dynamic).map(entry => entry.file)
+      ];
+
+      const apiPages = Object.values(allApiPages).map(pageFile =>
+        path.join(this.dotNextDirectory, "serverless", pageFile)
+      );
+
+      const { fileList, reasons } = await nodeFileTrace(apiPages, {
+        base: path.resolve(this.nextConfigDir)
+      });
+
+      copyTraces = fileList
+        .filter(file => {
+          // exclude "initial" files from lambda artefact. These are just the pages themselves
+          // which are copied over separately
+          return !reasons[file] || reasons[file].type !== "initial";
+        })
+        .map((filePath: string) => {
+          return fse.copy(
+            path.join(path.resolve(this.nextConfigDir), filePath),
+            join(this.outputDir, API_LAMBDA_CODE_DIR, filePath)
+          );
+        });
+    }
+
     return Promise.all([
+      ...copyTraces,
       fse.copy(
         require.resolve("@sls-next/lambda-at-edge/dist/api-handler.js"),
         join(this.outputDir, API_LAMBDA_CODE_DIR, "index.js")
@@ -275,7 +366,10 @@ class Builder {
   }
 
   async build(): Promise<void> {
-    const { cmd, args, cwd, env } = this.buildOptions;
+    const { cmd, args, cwd, env } = Object.assign(
+      defaultBuildOptions,
+      this.buildOptions
+    );
 
     // cleanup .next/ directory except for cache/ folder
     await this.cleanupDotNext();

packages/lambda-at-edge/tests/serverless-trace/.next/prerender-manifest.json

@@ -0,0 +1 @@
+{}

packages/lambda-at-edge/tests/serverless-trace/.next/serverless/pages-manifest.json

@@ -0,0 +1,8 @@
+{
+  "/api/test-page": "pages/api/test-api-page.js",
+  "/api/sub/[dynamic-test-api-page]": "pages/api/sub/[dynamic-test-api-page].js",
+  "/test-page": "pages/test-page.js",
+  "/sub/[dynamic-test-page]": "pages/sub/[dynamic-test-page].js",
+  "/_app": "pages/_app.js",
+  "/_document": "pages/_document.js"
+}

packages/lambda-at-edge/tests/serverless-trace/.next/serverless/pages/api/sub/[dynamic-test-api-page].js

@@ -0,0 +1,3 @@
+const apiDependencyB = require("api-dependency-b");
+
+module.exports = {};

packages/lambda-at-edge/tests/serverless-trace/.next/serverless/pages/api/test-api-page.js

@@ -0,0 +1,3 @@
+const apiDependency = require("api-dependency-a");
+
+module.exports = {};

packages/lambda-at-edge/tests/serverless-trace/.next/serverless/pages/sub/[dynamic-test-page].js

@@ -0,0 +1,6 @@
+// the following dependency is shared with other pages but should be copied over to artefact only once
+const someDependency = require("dependency-a");
+
+const anotherDependency = require("dependency-b");
+
+module.exports = {};

packages/lambda-at-edge/tests/serverless-trace/.next/serverless/pages/test-page.js

@@ -0,0 +1,3 @@
+const someDependency = require("dependency-a");
+
+module.exports = {};

packages/lambda-at-edge/tests/serverless-trace/next.config.js

@@ -0,0 +1,3 @@
+module.exports = {
+  target: "experimental-serverless-trace"
+};

packages/lambda-at-edge/tests/serverless-trace/test/serverless-trace.test.ts

@@ -0,0 +1,91 @@
+import fse from "fs-extra";
+import os from "os";
+import path from "path";
+import Builder from "../../../src/build";
+import {
+  DEFAULT_LAMBDA_CODE_DIR,
+  API_LAMBDA_CODE_DIR
+} from "../../../src/build";
+
+describe("Serverless Trace", () => {
+  const fixturePath = path.join(__dirname, "../");
+  let outputDir: string;
+  let fseRemoveSpy: jest.SpyInstance;
+
+  beforeEach(async () => {
+    outputDir = os.tmpdir();
+
+    fseRemoveSpy = jest.spyOn(fse, "remove").mockImplementation(() => {
+      return;
+    });
+
+    const builder = new Builder(fixturePath, outputDir);
+
+    await builder.build();
+  });
+
+  afterEach(() => {
+    fseRemoveSpy.mockRestore();
+  });
+
+  it("copies api page dependencies to api lambda artefact", async () => {
+    const nodeModulesPath = path.join(
+      outputDir,
+      API_LAMBDA_CODE_DIR,
+      "node_modules"
+    );
+
+    const nodeModulesExists = await fse.pathExists(nodeModulesPath);
+    expect(nodeModulesExists).toBe(true);
+
+    const nodeModulesFiles = await fse.readdir(nodeModulesPath);
+    expect(nodeModulesFiles).toEqual(
+      expect.arrayContaining(["api-dependency-a", "api-dependency-b"])
+    );
+
+    const dependencyAPath = path.join(nodeModulesPath, "api-dependency-a");
+    const dependencyAFiles = await fse.readdir(dependencyAPath);
+    expect(dependencyAFiles).toEqual(expect.arrayContaining(["index.js"]));
+
+    const dependencyBPath = path.join(nodeModulesPath, "api-dependency-b");
+    const dependencyBFiles = await fse.readdir(dependencyBPath);
+    expect(dependencyBFiles).toEqual(expect.arrayContaining(["index.js"]));
+  });
+
+  it("copies ssr page dependencies to lambda artefact", async () => {
+    const nodeModulesPath = path.join(
+      outputDir,
+      DEFAULT_LAMBDA_CODE_DIR,
+      "node_modules"
+    );
+
+    const nodeModulesExists = await fse.pathExists(nodeModulesPath);
+    expect(nodeModulesExists).toBe(true);
+
+    const nodeModulesFiles = await fse.readdir(nodeModulesPath);
+    expect(nodeModulesFiles).toEqual(
+      expect.arrayContaining(["dependency-a", "dependency-b"])
+    );
+
+    const dependencyAPath = path.join(nodeModulesPath, "dependency-a");
+    const dependencyAFiles = await fse.readdir(dependencyAPath);
+    expect(dependencyAFiles).toEqual(
+      expect.arrayContaining(["index.js", "sub-dependency.js"])
+    );
+
+    const dependencyBPath = path.join(nodeModulesPath, "dependency-b");
+    const dependencyBFiles = await fse.readdir(dependencyBPath);
+    expect(dependencyBFiles).toEqual(expect.arrayContaining(["index.js"]));
+  });
+
+  it("does not copy any .next/ files into lambda artefact", async () => {
+    const nodeModulesPath = path.join(
+      outputDir,
+      DEFAULT_LAMBDA_CODE_DIR,
+      ".next"
+    );
+
+    const dotNextDirExists = await fse.pathExists(nodeModulesPath);
+    expect(dotNextDirExists).toBe(false);
+  });
+});

packages/lambda-at-edge/tests/test-utils.ts

@@ -1,7 +1,7 @@
 import { remove } from "fs-extra";
 import { OriginRequestEvent } from "../src/types";
 
-export const cleanupDir = (dir): Promise<void> => {
+export const cleanupDir = (dir: string): Promise<void> => {
   return remove(dir);
 };
 

packages/serverless-plugin/lib/__tests__/rewritePageHandlers.js

@@ -5,20 +5,26 @@ const getFactoryHandlerCode = require("../getFactoryHandlerCode");
 const NextPage = require("../../classes/NextPage");
 const logger = require("../../utils/logger");
 
-jest.mock("fs");
 jest.mock("../../utils/logger");
 jest.mock("../getFactoryHandlerCode");
 
 describe("rewritePageHandlers", () => {
   describe("when compat layer is injected successfully", () => {
     const pagesDir = "build/serverless/pages";
     let rewritePageHandlersPromise;
+    let fsRenameSpy;
+    let fsWriteFileSpy;
 
     beforeEach(() => {
-      fs.rename.mockImplementation((fileName, newFileName, cb) => cb(null, ""));
-      fs.writeFile.mockImplementation((filePath, data, cb) => {
-        cb(null, undefined);
-      });
+      fsRenameSpy = jest
+        .spyOn(fs, "rename")
+        .mockImplementation((fileName, newFileName, cb) => cb(null, ""));
+
+      fsWriteFileSpy = jest
+        .spyOn(fs, "writeFile")
+        .mockImplementation((filePath, data, cb) => {
+          cb(null, {});
+        });
 
       getFactoryHandlerCode.mockReturnValue("module.exports.render={...}");
 
@@ -30,6 +36,11 @@ describe("rewritePageHandlers", () => {
       return rewritePageHandlersPromise;
     });
 
+    afterEach(() => {
+      fsRenameSpy.mockRestore();
+      fsWriteFileSpy.mockRestore();
+    });
+
     it("should log", () => {
       expect(logger.log).toBeCalledWith(
         expect.stringContaining(

packages/serverless-plugin/lib/rewritePageHandlers.js

@@ -3,10 +3,10 @@ const { promisify } = require("util");
 const getFactoryHandlerCode = require("./getFactoryHandlerCode");
 const logger = require("../utils/logger");
 
-const writeFileAsync = promisify(fs.writeFile);
-const renameAsync = promisify(fs.rename);
-
 const processJsHandler = async (nextPage, customHandler) => {
+  const writeFileAsync = promisify(fs.writeFile);
+  const renameAsync = promisify(fs.rename);
+
   const compatCodeContent = getFactoryHandlerCode(
     nextPage.pagePath,
     customHandler