Restart browser if killed on Mermaid

mermaid/src/browser-instance.js

@@ -2,6 +2,8 @@ import puppeteer from 'puppeteer'
 
 import { logger } from './logger.js'
 
+let INSTANCE
+
 const createBrowser = async () => {
  const browser = await puppeteer.launch({
  headless: 'new',
@@ -30,8 +32,9 @@ const createBrowser = async () => {
  '--disable-software-rasterizer'
  ]
  })
-
  const browserProcess = browser.process()
+ logger.info(`Chrome instance launched with pid ${browserProcess.pid}`)
+
  browserProcess.stdout.unpipe()
  browserProcess.stderr.unpipe()
  browserProcess.stdout.on('data', (data) => {
@@ -50,6 +53,9 @@ const createBrowser = async () => {
  })
  browserProcess.on('exit', (code, signal) => {
  logger.error({ code, signal }, 'chrome process exited')
+ browserProcess.kill()
+ browser.close()
+ INSTANCE = undefined
  })
  browserProcess.on('message', (message) => {
  logger.warn({ message }, 'chrome process message')
@@ -60,10 +66,14 @@ const createBrowser = async () => {
  await browser.close()
  throw err
  } finally {
- browser.disconnect()
+ await browser.disconnect()
  }
 }
 
-export async function create () {
- return createBrowser()
+export async function getBrowserWSEndpoint () {
+ if (INSTANCE === undefined) {
+ INSTANCE = await createBrowser()
+ logger.info(`Chrome accepting connections on endpoint ${INSTANCE.wsEndpoint()}`)
+ }
+ return INSTANCE.wsEndpoint()
 }

mermaid/src/index.js

@@ -5,13 +5,10 @@ import http from 'node:http'
 import micro from 'micro'
 import { SyntaxError, TimeoutError, Worker } from './worker.js'
 import Task from './task.js'
-import { create } from './browser-instance.js'
 
 (async () => {
  // QUESTION: should we create a pool of Chrome instances ?
- const browser = await create()
- logger.info(`Chrome accepting connections on endpoint ${browser.wsEndpoint()}`)
- const worker = new Worker(browser)
+ const worker = new Worker()
  const server = new http.Server(
  micro.serve(async (req, res) => {
  // Add a /health route that renders a sample diagram by calling the worker

mermaid/src/worker.js

@@ -4,6 +4,7 @@ import path from 'node:path'
 import puppeteer, { HTTPResponse, Page } from 'puppeteer'
 import { logger } from './logger.js'
 import { updateConfig } from './config.js'
+import { getBrowserWSEndpoint } from './browser-instance.js'
 
 const __dirname = fileURLToPath(new URL('.', import.meta.url))
 
@@ -22,8 +23,7 @@ export class SyntaxError extends Error {
 }
 
 export class Worker {
- constructor (browserInstance) {
- this.browserWSEndpoint = browserInstance.wsEndpoint()
+ constructor () {
  this.pageUrl = process.env.KROKI_MERMAID_PAGE_URL || `file://${path.join(__dirname, '..', 'assets', 'index.html')}`
  this.convertTimeout = process.env.KROKI_MERMAID_CONVERT_TIMEOUT || '10000'
  }
@@ -109,8 +109,9 @@ export class Worker {
  * @private
  */
  async _connect () {
+ const browserWSEndpoint = await getBrowserWSEndpoint()
  return await puppeteer.connect({
- browserWSEndpoint: this.browserWSEndpoint,
+ browserWSEndpoint,
  ignoreHTTPSErrors: true
  })
  }