add EventEmitter

packages/ckan/package.json

@@ -37,6 +37,7 @@
     "xmlbuilder2": "^3.1.1"
   },
   "devDependencies": {
+    "@types/node": "^20.11.16",
     "c8": "^9.1.0",
     "chai": "^5.0.3",
     "chai-subset": "^1.6.0",

packages/core/index.js

@@ -1,4 +1,5 @@
 // @ts-check
+import EventEmitter from 'node:events'
 import express from 'express'
 import { pino } from 'pino'
 import cors from 'cors'
@@ -41,6 +42,7 @@ export {
  * }>} Trifid instance.
  */
 const trifid = async (config, additionalMiddlewares = {}) => {
+  const trifidEvents = new EventEmitter()
   const fullConfig = await handler(config)
   const server = express()
   server.disable('x-powered-by')
@@ -63,6 +65,15 @@ const trifid = async (config, additionalMiddlewares = {}) => {
   // Add support for absolute URLs, so that we can use `req.absoluteUrl()` in any middleware to get the absolute URL
   server.use(absoluteUrl())
 
+  // Forward server events to the Trifid middlewares
+  server.on('ready', () => {
+    trifidEvents.emit('ready')
+  })
+
+  server.on('close', () => {
+    trifidEvents.emit('close')
+  })
+
   // Configure Express server
   if (fullConfig?.server?.express) {
     for (const expressSettingKey in fullConfig.server.express) {
@@ -104,6 +115,7 @@ const trifid = async (config, additionalMiddlewares = {}) => {
     logger,
     templateEngineInstance,
     `http://${host}:${portNumber}/`,
+    trifidEvents,
   )
 
   const start = async () => {

packages/core/lib/middlewares/apply.js

@@ -2,7 +2,7 @@ import merge from 'lodash/merge.js'
 import vhost from 'vhost'
 import { initQuery } from '../sparql.js'
 
-const apply = async (server, globals, middlewares, logger, templateEngine, instanceHostname) => {
+const apply = async (server, globals, middlewares, logger, templateEngine, instanceHostname, trifidEvents) => {
   const { query: querySparql } = initQuery(logger, globals.endpoints, instanceHostname)
 
   for (const middleware of middlewares) {
@@ -28,6 +28,7 @@ const apply = async (server, globals, middlewares, logger, templateEngine, insta
       render,
       query,
       registerTemplateHelper: registerHelper,
+      trifidEvents,
     })
 
     // default path is '/' (see: https://github.com/expressjs/express/blob/d854c43ea177d1faeea56189249fff8c24a764bd/lib/router/index.js#L425)

packages/core/types/index.js

@@ -74,6 +74,7 @@
  * @property {Object.<string, any>} config The Trifid configuration.
  * @property {(templatePath: string, context: Object.<string, any>, options: Object.<string, any>) => Promise<string>} render The render function.
  * @property {TrifidQuery} query The SPARQL query function.
+ * @property {import('node:events').EventEmitter} trifidEvents The Trifid events emitter.
  */
 
 /**

packages/handler-fetch/index.js

@@ -6,7 +6,7 @@ import { waitForVariableToBeTrue } from './lib/utils.js'
 
 /** @type {import('trifid-core/dist/types/index.d.ts').TrifidMiddleware} */
 export const factory = async (trifid) => {
-  const { config, logger } = trifid
+  const { config, logger, trifidEvents } = trifid
   const { contentType, url, baseIri, graphName, unionDefaultGraph } = config
 
   const queryTimeout = 30000
@@ -17,6 +17,18 @@ export const factory = async (trifid) => {
 
   let ready = false
 
+  logger.warn('Listening to Trifid events…')
+
+  trifidEvents.on('ready', async () => {
+    logger.warn('Got "ready" event from Trifid')
+  })
+
+  trifidEvents.on('close', async () => {
+    logger.warn('Got "close" event from Trifid ; closing worker…')
+    await worker.terminate()
+    logger.debug('Worker terminated')
+  })
+
   worker.on('message', async (message) => {
     const { type, data } = message
     if (type === 'log') {