Add diagnostic channels

API.md

@@ -5030,3 +5030,73 @@ const plugin = {
     }
 };
 ```
+
+## Diagnostic Channels
+
+Diagnostic Channels allows Hapi to report events to other modules. This is useful for APM vendors to collect data from Hapi for diagnostics purposes. 
+This not intended to be used in your own server or plugin, use [extension methods](#server.ext()) or [events](#server.events) instead.  
+
+See [the official documentation](https://nodejs.org/docs/latest/api/diagnostics_channel.html) for more information.
+
+### `hapi.onServer`
+
+This event is sent when a new server is created. The [`server`](#server) object is passed as the message.
+
+```js
+const DC = require('diagnostics_channel');
+const channel = DC.channel('hapi.onServer');
+
+channel.subscribe((server) => {
+
+    // Do something with the server
+    console.log(server.version);
+});
+```
+
+### `hapi.onRoute`
+
+This event is sent when a new route is added to the server. The [`route`](#request.route) object is passed as the message. 
+Similar to `server.events.on('route', (route) => {})`.
+
+```js
+const DC = require('diagnostics_channel');
+const channel = DC.channel('hapi.onRoute');
+
+channel.subscribe((route) => {
+
+    // Do something with the route
+    console.log(route.path);
+});
+```
+
+### `hapi.onRequest`
+
+This event is sent when a request is generated by the framework. The [`request`](#request) object is passed as the message.
+Similar to `server.events.on('request', (request) => {})`.
+
+```js
+const DC = require('diagnostics_channel');
+const channel = DC.channel('hapi.onRequest');
+
+channel.subscribe((request) => {
+
+    // Do something with the request
+    console.log(request.info.id);
+});
+```
+
+### `hapi.onResponse`
+
+This event is sent after the response is sent back to the client. The [`response`](#request.response) object is passed as the message.
+Similar to `server.events.on('response', ({ response }) => {})`.
+
+```js
+const DC = require('diagnostics_channel');
+const channel = DC.channel('hapi.onResponse');
+
+channel.subscribe((response) => {
+
+    // Do something with the response
+    console.log(response.statusCode);
+});
+```

lib/channels.js

@@ -0,0 +1,11 @@
+'use strict';
+
+const DC = require('diagnostics_channel');
+
+exports.server = DC.channel('hapi.onServer');
+
+exports.route = DC.channel('hapi.onRoute');
+
+exports.response = DC.channel('hapi.onResponse');
+
+exports.request = DC.channel('hapi.onRequest');

lib/core.js

@@ -17,6 +17,7 @@ const Podium = require('@hapi/podium');
 const Statehood = require('@hapi/statehood');
 
 const Auth = require('./auth');
+const Channels = require('./channels');
 const Compression = require('./compression');
 const Config = require('./config');
 const Cors = require('./cors');
@@ -510,6 +511,8 @@ exports = module.exports = internals.Core = class {
 
             const request = Request.generate(this.root, req, res, options);
 
+            Channels.request.publish(request);
+
             // Track socket request processing state
 
             if (this.settings.operations.cleanStop &&

lib/request.js

@@ -8,6 +8,7 @@ const Bounce = require('@hapi/bounce');
 const Hoek = require('@hapi/hoek');
 const Podium = require('@hapi/podium');
 
+const Channels = require('./channels');
 const Cors = require('./cors');
 const Toolkit = require('./toolkit');
 const Transmit = require('./transmit');
@@ -510,6 +511,8 @@ exports = module.exports = internals.Request = class {
 
         this._core.events.emit('response', this);
 
+        Channels.response.publish(this.response);
+
         if (this._route._extensions.onPostResponse.nodes) {
             this._invoke(this._route._extensions.onPostResponse, { ignoreResponse: true });
         }

lib/server.js

@@ -4,6 +4,7 @@ const Hoek = require('@hapi/hoek');
 const Shot = require('@hapi/shot');
 const Teamwork = require('@hapi/teamwork');
 
+const Channels = require('./channels');
 const Config = require('./config');
 const Core = require('./core');
 const Cors = require('./cors');
@@ -83,6 +84,8 @@ internals.Server = class {
         }
 
         core.registerServer(this);
+
+        Channels.server.publish(this);
     }
 
     _clone(name) {
@@ -532,6 +535,9 @@ internals.Server = class {
         }
 
         this.events.emit('route', route.public);
+
+        Channels.route.publish(route.public);
+
         Cors.options(route.public, server);
     }
 

test/channels.js

@@ -0,0 +1,101 @@
+'use strict';
+
+const DC = require('diagnostics_channel');
+
+const Code = require('@hapi/code');
+const Lab = require('@hapi/lab');
+
+const Hapi = require('..');
+
+const { describe, it } = exports.lab = Lab.script();
+const expect = Code.expect;
+
+describe('DiagnosticChannel', () => {
+
+    describe('hapi.onServer', () => {
+
+        const channel = DC.channel('hapi.onServer');
+
+        it('server should be exposed on creation through the channel hapi.onServer', async () => {
+
+            let server;
+
+            const exposedServer = await new Promise((resolve) => {
+
+                channel.subscribe(resolve);
+
+                server = Hapi.server();
+            });
+
+            expect(exposedServer).to.shallow.equal(server);
+        });
+    });
+
+    describe('hapi.onRoute', () => {
+
+        const channel = DC.channel('hapi.onRoute');
+
+        it('route should be exposed on creation through the channel hapi.onRoute', async () => {
+
+            const server = Hapi.server();
+
+            const exposedRoute = await new Promise((resolve) => {
+
+                channel.subscribe(resolve);
+
+                server.route({
+                    method: 'GET',
+                    path: '/',
+                    options: { app: { x: 'o' } },
+                    handler: () => 'ok'
+                });
+            });
+
+            expect(exposedRoute).to.be.an.object();
+            expect(exposedRoute.settings.app.x).to.equal('o');
+        });
+    });
+
+    describe('hapi.onResponse', () => {
+
+        const channel = DC.channel('hapi.onResponse');
+
+        it('response should be exposed on creation through the channel hapi.onResponse', async () => {
+
+            const server = Hapi.server();
+
+            server.route({ method: 'GET', path: '/', handler: () => 'ok' });
+
+            const event = new Promise((resolve) => {
+
+                channel.subscribe(resolve);
+            });
+
+            const response = await server.inject('/');
+            const responseExposed = await event;
+
+            expect(response.request.response).to.shallow.equal(responseExposed);
+        });
+    });
+
+    describe('hapi.onRequest', () => {
+
+        const channel = DC.channel('hapi.onRequest');
+
+        it('request should be exposed on creation through the channel hapi.onRequest', async () => {
+
+            const server = Hapi.server();
+
+            server.route({ method: 'GET', path: '/', handler: () => 'ok' });
+
+            const event = new Promise((resolve) => {
+
+                channel.subscribe(resolve);
+            });
+
+            const response = await server.inject('/');
+            const requestExposed = await event;
+            expect(response.request).to.shallow.equal(requestExposed);
+        });
+    });
+});