Travis CI is a cloud hosted continuous integration service that works with GitHub repositories for supported languages. Heroku is a cloud hosted platform as a service, enabling you to deploy applications without creating or maintaining server infrastructure for supported languages.
If you have an application you wish to use for this exercise already in a GitHub repository, skip ahead to the Travis CI section. You may need to do some adjustments to your code to meet with Heroku expectations (specifically, using the requested port number from
If you don’t have an existing Node.js application, and instead want to deploy a sample one, there’s one on the Heroku documentation you can use. On that page you’ll also find that you need to use
npm init to create a valid
package.json file, as well as information about engines if you want to control what version of Node.js is deployed (by default, it will deploy the latest stable version).
Browse to https://travis-ci.org/ and flip the appropriate toggle switch, instructing Travis CI which GitHub repository to build. You’ll need to authorize Travis CI to interact with your GitHub account if you haven’t done so already.
Travis CI uses a
.travis.yml configuration file in the root of your repository. You’ll want to create this file before moving on. Here’s an example
.travis.yml you can use, which will initiate a separate build for each of the specified versions of Node.js.
Anytime you modify the
.travis.yml file, you may wish to run it through a linter to verify its validity before you commit it.
Now is a good time to ensure Travis CI builds. Push your code to the GitHub repo to get this process started. Then, navigate to Travis CI in a web browser and ensure everything looks good. Also, if you have automated tests, you may want to get these working now – but I’ll leave that to you.
heroku login to setup the Heroku Toolbelt. If you’ve done this before, you may be able to skip this step.
Next, create a new Heroku application with
heroku create yourappname. For subsequent
heroku commands interacting with this application – if you are outside your repository directory (or, you don’t have the Heroku Toolbelt configured for your local repository), you will need to append
--app yourappname to your
heroku commands to instruct the Heroku Toolbelt which application you wish to target.
travis setup heroku. During this process you’ll need to provide your Heroku API key. Use the secure API key option. At no point should you commit or otherwise reveal your non-encrypted Heroku API key.
Create the Heroku
Procfile pointing to the main application entry point. Assuming
web.js is your application entry point, use:
1 web: node web.js
Everything should now be setup in your local repository. Commit and push your changes to GitHub, then wait for Travis CI to complete its operations.
By default, Heroku doesn’t assign you a dyno to run your application on. To start one, run
heroku ps:scale web=1. At the time of this post a single dyno can be ran for free.
Now, browse to your application at the expected Heroku hosted address to see if it works. If everything appears working, good job and well done! If it doesn’t, don’t panic. Run
heroku logs to try to find your issue.
If no Node.js version information was explicitly specified, Heroku should deploy using the latest stable version of Node.js.
As a reward for a working cloud CI build, add the Travis CI build status badge to your GitHub
README.md to show off the (hopefully passing) status of your Travis CI build. Simply add
![Travis CI Build Status](the_image_url_here) to the
README.md to display the image. If you don’t have a
README.md or equivalent file, now is a great time to create one!