142 lines
6.1 KiB
Markdown
142 lines
6.1 KiB
Markdown
---
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title: "Build your first serverless app using only JavaScript"
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authors: ["marc-holmes"]
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tags: ["Serverless"]
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meta_desc: "This tutorial shows how to use Pulumi to build a complete serverless application using JavaScript. No YAML needed."
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date: "2018-07-05"
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meta_image: "code-completion.png"
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---
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In this tutorial, we'll use Pulumi to build a
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complete serverless application using only JavaScript. When we say 'using
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only JavaScript', we're not kidding:
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- write code just like an Express app... but end up with a fully
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deployable serverless app
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- lambdas are... just lambdas
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- no YAML required... freedom from indentation
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- all the features of the V8 runtime... async await ahoy
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- all the behaviors of immutable infrastructure as code tools... but
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we really mean 'as code'
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Pulumi also supports containers (including Kubernetes), managed
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services, infrastructure and everything else in between that you might
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need for building cloud applications. Better than that, you can even
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[combine them all in the same program](/blog/build-a-video-thumbnailer-with-pulumi-using-lambdas-containers-and-infrastructure-on-aws/).
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<!--more-->
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## Our first serverless app in 5 lines of JavaScript
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After [installing the Pulumi CLI](/docs/install/), just run
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the following to create your new serverless JavaScript app:
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mkdir firstapp && cd firstapp
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pulumi new hello-aws-javascript
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This template creates a small `index.js` file (the main Pulumi code)
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that is a simple but complete serverless application:
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```javascript
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// Add the required package
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const cloud = require("@pulumi/cloud-aws");
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// Declare an HTTP endpoint
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const endpoint = new cloud.API("hello");
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// Serve up some static content on that endpoint
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endpoint.static("/", "www");
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// Create a simple serverless function responding to GET
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endpoint.get("/source", (req, res) => res.json({name: "AWS"}));
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// Publish the URL so we can easily access our app
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exports.url = endpoint.publish().url;
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```
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So what's happening here? This code creates a `cloud.API` which exposes
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an HTTP endpoint to the internet. It serves static content at the root
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of the API from what's in the `www` folder on your local machine. And it
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serves a REST API on `GET /source` which runs the JavaScript callback to
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return the JSON object `{name: “AWS”}` (our serverless function).
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Finally, it exports the URL where the HTTP API is exposed.
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Now just run `pulumi update` to deploy the application. Before the app
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deploys, you'll get a preview of what will be deployed and you can
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choose to go ahead with the full deployment. Pulumi figures out all of
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the cloud resources needed to run the code above and prepares that for
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deployment.
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Once deployed, your application will run in the cloud. Use
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`pulumi stack output url` to get the URL where your app is running, and
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open it up in your browser:
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With Pulumi, we've built a serverless JavaScript app in just a few lines of code.
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This approach avoided significant amounts of configuration (YAML, or
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point-and-click). Pulumi also supports containers (including
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Kubernetes), managed services, infrastructure and everything else in
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between that you might need for building cloud applications.
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[Get started with Pulumi](/docs/get-started/).
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## Why JavaScript for serverless programming?
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There are many great reasons to use JavaScript for serverless
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programming (and cloud programming generally). Pulumi also supports
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TypeScript, Python, and Go with more languages on the way.
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Pulumi uses NPM, Express, and supports modern JavaScript features like
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async await, module etc. and so you can bring your JavaScript skills
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directly to cloud programming.
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### Code is the best Config
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Serverless platforms such as AWS Lambda offer an easy and cost-effective
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way to run your code in the cloud. But using these serverless platforms
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often requires learning lots of finicky details of the cloud platform,
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and using esoteric YAML configuration files to tell the cloud platform
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how to run your app. Often, the work needed to configure the app can
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outweigh the work needed to code the app.
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Pulumi changes that, and lets you create serverless
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cloud applications using **only** JavaScript (or TypeScript). These
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applications can use all the features of cloud platforms like Amazon Web Services (AWS), Azure
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or Google Cloud Platform (GCP) - but exposed as simple JavaScript APIs on NPM.
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This means that you can write code that contains logic alongside code
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that defines the services and infrastructure needed to run it and Pulumi
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can then deployed the app in seconds and run as a managed, scalable and -
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in the case of serverless apps such as this one - extremely low cost
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service on your chosen cloud.
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### Code is more productive, expressive, and... fun
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One of the biggest advantages of a pure code approach is the automatic
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gains from better tooling support. In particular:
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- **Code completion.** There are a lot of services in each cloud.
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Wouldn't it be great to be able to autocomplete?
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- **Error checking.** Less worry about correctly indented YAML, more
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real error checking.
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- **Versioning and Packaging.** Much improved versioning and packaging
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scenarios through Github and NPM workflows.
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- **Reusable components.** Build on top of base classes, and share for
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easy reuse, standard configurations and so on.
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## Want more?
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To learn more take a look at more tutorials and example code:
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- Our origin story: [Hello, Pulumi!](http://joeduffyblog.com/2018/06/18/hello-pulumi/)
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- Tutorial: [Deploying Containers with Pulumi](/blog/deploying-production-ready-containers-with-pulumi/)
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- Tutorial: [Build a video thumbnailer using AWS Lambda, Fargate, and S3 in JavaScript](/blog/build-a-video-thumbnailer-with-pulumi-using-lambdas-containers-and-infrastructure-on-aws/)
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- [Pulumi Quickstart](/docs/get-started/)
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- [Pulumi Community Slack](https://slack.pulumi.com)
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- [Pulumi Examples on GitHub](https://github.com/pulumi/examples)
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- [Node.js and Pulumi](/docs/languages-sdks/javascript/)
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- [Node.js Examples for AWS and Azure](/blog/running-a-serverles-nodejs-http-server-on-aws-and-azure/)
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