Implement generate-document lambda (WIP)

Implement lambda to generate documents (e.g., DOW) that returns
a base64 encoded string of the pdf binary. Template files are
contained in a layer and are under the /templates folder. Juice
is a third-party package to combine the html and css files.

Still troubleshooting trying to get puppeteer to run inside of
lambda using puppeteer-core and having a compressed chromium
binary added as a dependency or some alternative. The
chrome-aws-lambda package does not appear to be maintained
anymore, but someone has forked the repo and has been updating
recent versions of node (v16) and puppeteer (v14).
- https://acloudguru.com/blog/engineering/serverless-browser-automation-with-aws-lambda-and-puppeteer
- https://github.com/alixaxel/chrome-aws-lambda
- https://github.com/Sparticuz/chrome-aws-lambda
- alixaxel/chrome-aws-lambda#264
- alixaxel/chrome-aws-lambda#275

Tikcet: AT-7345

document-generation/generate-document.test.ts

@@ -0,0 +1,17 @@
+import { handler } from "./generate-document";
+
+describe("Success", () => {
+  it("should return successful", async () => {
+    // GIVEN / ARRANGE
+    // WHEN / ACT
+    // THEN / ASSERT
+  });
+});
+
+describe("Failure", () => {
+  it("should return errors", async () => {
+    // GIVEN / ARRANGE
+    // WHEN / ACT
+    // THEN / ASSERT
+  });
+});

document-generation/generate-document.ts

@@ -0,0 +1,100 @@
+import { APIGatewayProxyEvent, APIGatewayProxyResult } from "aws-lambda";
+import { injectLambdaContext } from "@aws-lambda-powertools/logger";
+import middy from "@middy/core";
+import httpJsonBodyParser from "@middy/http-json-body-parser";
+import inputOutputLogger from "@middy/input-output-logger";
+import errorLogger from "@middy/error-logger";
+import { logger } from "../utils/logging";
+import { ApiBase64SuccessResponse, SuccessStatusCode } from "../utils/response";
+import { IpCheckerMiddleware } from "../utils/middleware/ip-logging";
+import { errorHandlingMiddleware } from "../utils/middleware/error-handling-middleware";
+import JSONErrorHandlerMiddleware from "middy-middleware-json-error-handler";
+import validator from "@middy/validator";
+import { wrapSchema } from "../utils/middleware/schema-wrapper";
+import {
+  generateDocumentSchema,
+  RequestEvent,
+  GenerateDocumentRequest,
+  DocumentType,
+} from "../models/document-generation";
+import * as fs from "fs";
+import handlebars from "handlebars";
+// import puppeteer from "puppeteer";
+import * as puppeteer from "puppeteer-core";
+import { PDFOptions } from "puppeteer";
+import chromium from "chrome-aws-lambda";
+import juice from "juice";
+
+async function baseHandler(
+  event: RequestEvent<GenerateDocumentRequest>
+): Promise<ApiBase64SuccessResponse<APIGatewayProxyResult>> {
+  const lookingAtFiles = fs.readdirSync("/var/task/", { withFileTypes: true });
+  // logger.debug not work ?
+  console.debug("FILES: " + JSON.stringify(lookingAtFiles));
+
+  // small sample to ensure data populated in template
+  const { documentType, templatePayload } = event.body;
+
+  // get files to generate documents
+  let html, css, htmlWithCss;
+  if (documentType === DocumentType.DESCRIPTION_OF_WORK) {
+    html = fs.readFileSync("/opt/dow-template.html", "utf-8");
+    css = fs.readFileSync("/opt/dow-style.css", "utf-8");
+    htmlWithCss = juice.inlineContent(html, css);
+  }
+
+  // use handlebars to populate data into template
+  const template = handlebars.compile(htmlWithCss);
+  const templateWithData = template(templatePayload);
+
+  // use puppeteer to generate pdf
+  let browser, pdf;
+
+  try {
+    // ! chromium module does not seem to be added, troubleshoot
+    console.debug("PUPPET: " + JSON.stringify(chromium.defaultViewport));
+    console.debug("PUPPET: " + JSON.stringify(chromium.defaultViewport));
+    console.debug("PUPPET: " + JSON.stringify(chromium.executablePath)); // ! empty object
+    console.debug("PUPPET: " + JSON.stringify(chromium.headless)); // true
+    console.debug("PUPPET: " + JSON.stringify(chromium.puppeteer)); // ! undefined
+
+    browser = await chromium.puppeteer.launch({
+      args: chromium.args,
+      defaultViewport: chromium.defaultViewport,
+      executablePath: await chromium.executablePath,
+      headless: chromium.headless,
+      ignoreHTTPSErrors: true,
+    });
+    logger.debug("BROWSER: " + JSON.stringify(browser));
+    const page = await browser.newPage();
+    logger.debug("PAGE: " + JSON.stringify(page));
+
+    const options: any = { format: "A4" }; // PDFOptions still gives typescript error
+
+    await page.setContent(templateWithData);
+    await page.emulateMediaType("screen");
+    pdf = await page.pdf(options);
+
+    logger.info("Document generation complete");
+    logger.debug("PDF: " + pdf);
+  } catch (error) {
+    logger.error(error as any);
+  } finally {
+    if (browser !== null) {
+      await browser?.close();
+    }
+  }
+
+  const headers = { "Content-type": "application/pdf" };
+  return new ApiBase64SuccessResponse<string | undefined>(pdf?.toString("base64"), SuccessStatusCode.OK, headers);
+}
+
+export const handler = middy(baseHandler)
+  .use(injectLambdaContext(logger))
+  .use(inputOutputLogger({ logger: (message) => logger.info("Event/Result", message) }))
+  .use(errorLogger({ logger: (err) => logger.error("An error occurred during the request", err as Error) }))
+  .use(httpJsonBodyParser())
+  .use(validator({ eventSchema: wrapSchema(generateDocumentSchema) }));
+// TODO: fix middleware inputs/outputs
+// .use(IpCheckerMiddleware())
+// .use(errorHandlingMiddleware);