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79 lines
2.6 KiB
JavaScript
79 lines
2.6 KiB
JavaScript
5 years ago
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// simple node web server that displays hello world
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// optimized for Docker image
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var express = require('express');
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// this example uses express web framework so we know what longer build times
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// do and how Dockerfile layer ordering matters. If you mess up Dockerfile ordering
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// you'll see long build times on every code change + build. If done correctly,
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// code changes should be only a few seconds to build locally due to build cache.
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var morgan = require('morgan');
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// morgan provides easy logging for express, and by default it logs to stdout
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// which is a best practice in Docker. Friends don't let friends code their apps to
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// do app logging to files in containers.
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// Constants
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const PORT = process.env.PORT || 8080;
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// if you're not using docker-compose for local development, this will default to 8080
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// to prevent non-root permission problems with 80. Dockerfile is set to make this 80
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// because containers don't have that issue :)
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// Appi
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var app = express();
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app.use(morgan('common'));
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app.get('/', function (req, res) {
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res.send('Hello Docker World\n');
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});
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app.get('/healthz', function (req, res) {
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// do app logic here to determine if app is truly healthy
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// you should return 200 if healthy, and anything else will fail
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// if you want, you should be able to restrict this to localhost (include ipv4 and ipv6)
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res.send('I am happy and healthy\n');
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});
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var server = app.listen(PORT, function () {
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console.log('Webserver is ready');
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});
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//
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// need this in docker container to properly exit since node doesn't handle SIGINT/SIGTERM
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// this also won't work on using npm start since:
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// https://github.com/npm/npm/issues/4603
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// https://github.com/npm/npm/pull/10868
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// https://github.com/RisingStack/kubernetes-graceful-shutdown-example/blob/master/src/index.js
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// if you want to use npm then start with `docker run --init` to help, but I still don't think it's
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// a graceful shutdown of node process
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//
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// quit on ctrl-c when running docker in terminal
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process.on('SIGINT', function onSigint () {
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console.info('Got SIGINT (aka ctrl-c in docker). Graceful shutdown ', new Date().toISOString());
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shutdown();
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});
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// quit properly on docker stop
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process.on('SIGTERM', function onSigterm () {
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console.info('Got SIGTERM (docker container stop). Graceful shutdown ', new Date().toISOString());
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shutdown();
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})
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// shut down server
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function shutdown() {
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server.close(function onServerClosed (err) {
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if (err) {
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console.error(err);
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process.exitCode = 1;
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}
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process.exit();
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})
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}
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//
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// need above in docker container to properly exit
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//
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module.exports = app;
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