If you are on a team of a few people and you are working together on a product, you will sooner or later need to integrate each team member's work with that of the other team members. You will likely also have a customer who wants to see progress and try out what you're making before releasing a new version to the end-users. This likely means you'll need to keep several versions of your project running at all times.
Different teams choose different strategies, but in this workshop we will teach you a basic technique which is useful in most small projects.
To get you started, we've set up a small project for you.
You need to create a user at GitHub
Before you start, you need to:
If you run into problems pushing to github or heroku using https, you may also want to:
It's useful to keep a browser pointed at the Heroku dashboard at all times during the workshop. Most of the commands you execute in the terminal will trigger an immediate response in the Heroku Dashboard, so you'll know you're doing it right. If you're not particularly keen on writing lots of commands, you can also do most of the things by using the Heroku Dashboard user interface.
All the commands in this workshop are shown as they appear on a unix console:
$ echo Hello, World!
Hello, World!
You're not supposed to write the $ character - that's part of the prompt.
If you're on a Windows computer, you may be used to seeing it like this:
C:\> echo Hello, World!
Hello, World!
If we want you to replace part of the command with something else, we'll enclose that in angle brackets like so:
$ echo Hello, <username>!
and then you're supposed to write
$ echo Hello, monty!
(if your username is monty). Don't include the brackets.
All good? Let's start!
Go to https://github.com/kantega/heroku-demo and fork the repo into your personal account. Then, clone the repository from your fork:
$ git clone https://github.com/<username>/heroku-demo.git
$ cd heroku-demo
Now you have the demo app git repository on your own computer. It's time to launch it on your own personal Heroku cloud. After doing this, you'll be able to open the app in your browser and see it running.
Note Heroku apps must have unique names, since they're available as a URL on the Internet. To avoid naming conflicts, please add your name to the name of the apps you create in this workshop.
It is important that you are now in the heroku-demo directory.
Change directory to heroku-demo if you have not already done so.
$ heroku apps:create --region eu <username>-heroku-dev
$ git push heroku
Counting objects: 18, done.
Delta compression using up to 8 threads.
Compressing objects: 100% (18/18), done.
Writing objects: 100% (18/18), 173.15 KiB | 6.41 MiB/s, done.
Total 18 (delta 0), reused 0 (delta 0)
remote: Compressing source files... done.
remote: Building source:
remote:
remote: -----> Node.js app detected
remote:
remote: -----> Creating runtime environment
...
remote: -----> Launching...
remote: Released v3
remote: https://<username>-heroku-dev.herokuapp.com/ deployed to Heroku
remote:
remote: Verifying deploy... done.
To https://git.heroku.com/<username>-heroku-dev.git
* [new branch] master -> master
You should now see an app in the Heroku Dashboard. You may need to refresh the page. Use the dashboard to open the app (there's a button in the upper right corner that says "Open app"), and you should see a spinning React logo.
Now that you have an app, you can add it to a pipeline. A pipeline is where you
keep your development, staging and production apps. The app you just created
had a name that ended in -dev. That's because it's the app that we're going
to put in the development stage of your pipeline.
Let's create the development stage now:
$ heroku pipelines:create --app <username>-heroku-dev --stage development <username>-heroku
You should see something like this:
Creating oven-heroku pipeline... done
Adding ⬢ oven-heroku-dev to oven-heroku pipeline as development... done
And the Heroku Dashboard should look something like this:
This command also added the <username>-heroku-dev app to the newly created stage.
To be able to keep a separate environment for development and testing purposes, you'll need to create another app. This is often referred to as a "staging" app. It's mainly used as a preview of what will be deployed to production.
Let's create the app, and add it to the pipeline:
$ heroku apps:create --region eu <username>-heroku-staging
$ heroku pipelines:add --app <username>-heroku-staging --stage staging <username>-heroku
And the Heroku Dashboard should look something like this:
At the moment, there's nothing running on the staging app. You need to deploy something. You've already created, compiled and run a development version of your app. To copy that (without rebuilding), you can simply promote the app from the development stage to the staging stage.
$ heroku pipelines:promote --app <username>-heroku-dev
Visit https://username-heroku-staging.herokuapp.com/ to see your staging app (or open it from the Heroku Dashboard)
Make a small change to src/App.js. You can use any editor you like. I use vim.
$ vim src/App.js
Then commit and push to heroku. You are now pushing to the development version, since heroku apps:create created the heroku remote for you, and subsequent calls to heroku apps:create does not overwrite that.
$ git add .
$ git commit -m "ove was here"
$ git push heroku
Then, reload https://username-heroku-dev.herokuapp.com/ - You should be able to see your changes. Also, reload https://username-heroku-staging.herokuapp.com/ and observe that the changes are not there.
You've now completed development of your new feature, and you'd like to share it with your customer. To do this, you promote the app again, like you did before.
$ heroku pipelines:promote --app <username>-heroku-dev
Create a production app, connect it to the pipeline and promote staging to production.
Bring up the Heroku console, and observe the following banner on top:
"Connect this pipeline to GitHub to enable additional features such as review apps, automatic deploys, and Heroku CI"
Click "Connect to GitHub" to do just that. Enter heroku as the name of the repository to connect to, and return to the pipeline view.
It is considered a best practice to always keep the master branch deployed to the development environment. To set it up so that Heroku automatically deploys master to the development stage, go to the Heroku Dashboard, click the arrow next to "-heroku-dev" and select "Configure automatic deploys...". Choose the master branch, and click "Enable Automatic Deploys".
Now, make a small change to src/App.js, save and push to github. After a few seconds. you should see
"Building app" in the Heroku console.
Heroku can automatically deploy any pull requests you make on github. This enables anyone who is reviewing your pull request to see the changes in action. In the Heroku console, click "Enable Review Apps...".
Heroku will ask you for a parent app to copy settings from. Select "-heroku-dev" and click "Create an app.json file". You can review the settings it proposes, and select "Commit to repo". Then, select "-heroku-dev" as the app to inherit config vars from, and finally check the box next to "Create new review apps for new pull requests automatically". Click "Enable" to save your changes.
You should now see a message saying "There are no open pull requests on /heroku".
Since you committed a new app.json file in the previous step, you need to pull that commit before
carrying on.
$ git pull
Then, create a branch with some changes
$ git checkout -b my-pr-1
$ vim src/App.js ## make some changes
$ git commit -a -m "I made some changes"
$ git push -u origin my-pr-1
Now you can create a pull request from your branch. Note Make sure you select your own master branch as the base, otherwise the pull request will be made against the repository you forked from, and that repository is not connected to your Heroku.
Visit this URL to create the pull request: https://github.com/username/heroku-demo/pull/new/my-pr-1
Again, make sure you select your own master branch as the base, not Kantega.
Then, head back to the heroku console, where you should find that Heroku is already busy building and deploying an app for your pull request.
Now you're ready to do a proper code review. Look to the person sitting next to you, and go through the pull request on GitHub together. Demonstrate the changes by pulling up your review app in the browser, and show how the running review app differs from the running development version.
When you've done the code review, head on over to github and approve and merge the pull request. Heroku will immediately remove the review app. Since you also configured automatic deployments to development, you will also see a progress indicator next to "Building app" in the development stage.
When this is done, you can refresh the development app, and you should see that your changes have been published.
Happy hacking!