Deploy your Dockerised app to Fly.io with BitBucket Pipelines in 15 minutes

Fly.io pitches itself as a quick and hassle-free way to deploy and host web infrastructure for your web applications. Here I will give a quick walkthrough of how I set up a CD pipeline for Fly with BitBucket Pipelines. Feel free to skip around the article to the part that you might need help with!

Do some Coding!

It’s time to code the thing you want to deploy - this could be anything as Fly supports deployment via Dockerfile. I’m assuming you’ve got something you want to deploy in mind.

Ensure that your application runs inside a Dockerfile locally.

I was deploying a lightweight API in Java, so my Dockerfile looked something like:


FROM openjdk:11

COPY . /usr/src/api
WORKDIR /usr/src/api
ENV CLASSPATH=/usr/src/api
RUN find . -name "*.class" -exec rm {} \;
RUN javac opt/api/Server.java
ENTRYPOINT ["java", "opt.api.Server"]

I built this image with docker build . -t api and run a container with something like docker run -p 8080:8080 --name java-api api.

Deploy to Fly.io Locally with the flyctl CLI

Create an account on Fly.io and sign in to see your dashboard (you won’t have anything deployed yet)!

Install flyctl CLI:


# Mac
brew install flyctl
# Linux
curl -L https://fly.io/install.sh | sh
# Windows
pwsh -Command "iwr https://fly.io/install.ps1 -useb | iex"

Now you need to create a fly.toml in your repo which will tell fly the configuration that you’re using to deploy. You can do this automatically with fly launch!

You can deploy right away when launch asks you Would you like to deploy now?. Once the command is finished deploying, you should see the new app appear in your dashboard.

Setup your BitBucket Repository

I’m not going to go through all the details, but hopefully the links will help:

Create a new repo.

Setup SSH keys and Two Factor Authentication (you need to setup 2FA to enable pipelines in your repo).

Enable the pipelines feature in your repo: Repository Settings > Pipelines > Settings.

Add your FLY_API_TOKEN as a Repository Secret

Get an API key from fly with:


fly auth token

Go to Repository Settings > Pipelines > Repository Variables and add in your variable and call it FLY_API_TOKEN (or something).

Create your Bitbucket Pipeline Definition

Create a file (which must be in the root of your repo) called bitbucket-pipelines.yml.

I wanted my deployment to run on commits to develop and master:


image: ubuntu # Using the latest ubuntu image

definitions:
  steps:
		# Define a reusable step which we can call from different branches
    - step: &deploy-to-fly
        name: Deploy to Fly IO
        script:
          - apt-get update && apt-get install -y curl
          - curl -L https://fly.io/install.sh | sh  # Install flyclt in the container
          - export FLYCTL_INSTALL="/root/.fly"
          - export PATH="$FLYCTL_INSTALL/bin:$PATH" # Make flyctl available in the path
          - export FLY_API_TOKEN=$FLY_API_TOKEN     # Get the FLY_API_TOKEN from our env
          - flyctl deploy --remote-only --dockerfile <path-to-dockerfile> --config <path-to-fly.toml>

pipelines:
  branches:
    master:
      - step: *deploy-to-fly
    develop:
      - step: *deploy-to-fly

When running flyctl deploy, we can pass in optional locations for the Dockerfile and fly.toml files which I needed in my case.

💡

This pipelines uses YAML Anchors and Aliases to avoid duplication:

Anchors (&): Anchors are used to mark a YAML data structure that you want to reuse later. An anchor is denoted by an ampersand (&) followed by a name. The anchor is placed on the line of the data structure you want to reference later.

Aliases (*): Aliases are used to reference an anchor within the YAML document. An alias is denoted by an asterisk (*) followed by the name of the anchor you want to reuse. The alias can be used in place of the full data structure, which simplifies the YAML file and prevents redundancy.

Summary

Whenever you push new commits to your develop or master branches (e.g. on merge of a pull request), the changes made in that pull request should be reflected live on your deployment of Fly.io automatically!

Reach out and let me know if I missed anything!