Automatically reload the server when it changes (badges#3401)

While working on badges#2428 I found myself wanting to reload the server frequently. This is working great and reducing my iteration time significantly. I should have tackled this way sooner! 🙊 

I’ve left `verbose` on which seems useful, at least in the short term while we’re tuning the configuration.

Close badges#2426

Procfile

@@ -1 +1 @@
-web: node server
+web: npm run start:server:prod

README.md

@@ -98,9 +98,15 @@ You can read a [tutorial on how to add a badge][tutorial].
    Tests need to pass in Node 8 and 10.
 2. Clone this repository.
 3. Run `npm ci` to install the dependencies.
-4. Run `npm start` to start the server.
+4. Run `npm start` to start the badge server and the frontend dev server.
 5. Open `http://localhost:3000/` to view the frontend.
 
+When server source files change, the badge server should automatically restart
+itself (using [nodemon][]). When the frontend files change, the frontend dev
+server (`gatsby dev`) should also automatically reload. However the badge
+definitions are built only before the server first starts. To regenerate those,
+either run `npm run defs` or manually restart the server.
+
 To debug a badge from the command line, run `npm run badge -- /npm/v/nock.svg`.
 It also works with full URLs like
 `npm run badge -- https://img.shields.io/npm/v/nock.svg`.
@@ -130,6 +136,7 @@ Daily tests, including a full run of the service tests and overall code coverage
 [sentry]: https://sentry.io/
 [sentry configuration]: doc/self-hosting.md#sentry
 [daily-tests]: https://github.com/badges/daily-tests
+[nodemon]: https://nodemon.io/
 
 ## Hosting your own server
 

doc/TUTORIAL.md

@@ -35,7 +35,7 @@ install node and npm: https://nodejs.org/en/download/
 3. `cd shields`
 4. Install project dependencies
    `npm ci`
-5. Run the server
+5. Run the badge server and the frontend dev server
    `npm start`
 6. Visit the website to check the front-end is loaded:
    [http://localhost:3000/](http://localhost:3000/)
@@ -152,10 +152,9 @@ The process of turning this object into an image is handled automatically by the
 To try out this example badge:
 
 1. Copy and paste this code into a new file in `/services/example/example.service.js`
-2. Quit the running server with `Control+C`.
-3. Start the server again.
-   `npm start`
-4. Visit the badge at <http://localhost:8080/example/foo.svg>.
+2. The server should restart on its own. (If it doesn't for some reason, quit
+   the running server with `Control+C`, then start it again with `npm start`.)
+3. Visit the badge at <http://localhost:8080/example/foo.svg>.
    It should look like this: ![](https://img.shields.io/badge/example-foo-blue.svg)
 
 [path-to-regexp]: https://github.com/pillarjs/path-to-regexp#parameters

package.json

@@ -103,12 +103,14 @@
     "defs": "node scripts/export-service-definitions-cli.js > service-definitions.yml",
     "build": "run-s defs features && gatsby build",
     "heroku-postbuild": "run-s --silent build",
-    "start:server": "cross-env NODE_CONFIG_ENV=development node server 8080",
-    "now-start": "node server",
+    "start:server:prod": "node server",
+    "now-start": "npm run start:server:prod",
+    "start:server:e2e-on-build": "node server 8080",
+    "start:server": "cross-env NODE_CONFIG_ENV=development nodemon server 8080",
     "prestart": "run-s --silent depcheck defs features",
     "start": "concurrently --names server,frontend \"npm run start:server\" \"cross-env GATSBY_BASE_URL=http://localhost:8080 gatsby develop --port 3000\"",
     "e2e": "start-server-and-test start http://localhost:3000 test:e2e",
-    "e2e-on-build": "cross-env CYPRESS_baseUrl=http://localhost:8080 start-server-and-test start:server http://localhost:8080 test:e2e",
+    "e2e-on-build": "cross-env CYPRESS_baseUrl=http://localhost:8080 start-server-and-test start:server:e2e-on-build http://localhost:8080 test:e2e",
     "badge": "cross-env NODE_CONFIG_ENV=test TRACE_SERVICES=true node scripts/badge-cli.js"
   },
   "lint-staged": {
@@ -122,6 +124,20 @@
       "git add"
     ]
   },
+  "nodemonConfig": {
+    "verbose": true,
+    "ext": "js",
+    "ignore": [
+       "package.json",
+       "**/*.spec.js",
+       "**/*.tester.js",
+       "**/*.integration.js",
+       "frontend/",
+       "public/",
+       "build/",
+       "cypress/"
+    ]
+  },
   "devDependencies": {
     "@babel/core": "^7.4.3",
     "@babel/plugin-proposal-class-properties": "^7.4.0",
@@ -193,6 +209,7 @@
     "nock": "11.0.0-beta.10",
     "node-fetch": "^2.3.0",
     "node-mocks-http": "^1.7.3",
+    "nodemon": "^1.18.11",
     "npm-run-all": "^4.1.5",
     "nyc": "^14.0.0",
     "opn-cli": "^4.1.0",