CI Pipeline for FFlags.com

This is a write-up of the initial CI pipeline I set up for FFlags.com. With fflags.com I wanted to keep things clean and simple as much as possible. The pipeline is built using Github Actions, GHCR, and Railway.

The Stack

• Golang Web Server
• Postgres Database
• React Frontend

The React frontend is built and embedded into the Golang binary using go:embed.

The Pipeline

The pipeline is triggered on a new release which builds the docker image, pushes it to GHCR. The workflow file looks something like this:

# release.yml
name: Release Workflow

on:
  release:
    types: [created]

env:
  REGISTRY: ghcr.io
  IMAGE_NAME: ${{ github.repository }}

jobs:
  build-and-push:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write

    steps:
      - name: Checkout repository
        uses: actions/checkout@v3

      - name: Setup Node.js
        uses: actions/setup-node@v3
        with:
          node-version: "20"

      - name: Install pnpm
        uses: pnpm/action-setup@v2
        with:
          version: 8

      - name: Build dashboard app
        working-directory: ./dashboard
        run: |
          pnpm install
          pnpm run build

      - name: Setup Go
        uses: actions/setup-go@v4
        with:
          go-version: "1.23"

      - name: Build Go binary
        run: CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -a -ldflags '-extldflags "-static"' -o bin/fflags cmd/web-server/main.go

      - name: Log in to the Container registry
        uses: docker/login-action@v2
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Extract metadata (tags, labels) for Docker
        id: meta
        uses: docker/metadata-action@v4
        with:
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}

      - name: Build and push Docker image
        uses: docker/build-push-action@v4
        with:
          context: .
          push: true
          tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.outputs.labels }}

The pipeline builds the React frontend, the Golang binary, and pushes the docker image to GHCR. The Dockerfile for the Golang server looks like this:

# Dockerfile
FROM alpine:latest

WORKDIR /app
COPY --chmod=0755 bin/fflags /app/

EXPOSE 8081

CMD ["/app/fflags"]

Mistakes and Learnings

Initially, I had the following build command for the Go executable:

go build -o bin/fflags cmd/web-server/main.go

This command worked fine on my local machine and on the CI. But, the binary was not executing on the alpine image and throwing the following error:

exec /app/fflags: no such file or directory

The problem here was I was building the binary on a Debian-based OS and trying to run it on an Alpine-based image. The solution was to build the binary with the following command:

CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -a -ldflags '-extldflags "-static"' -o bin/fflags cmd/web-server/main.go

Here, CGO_ENABLED=0 disables the use of cgo which is required to build a static binary. GOOS=linux and GOARCH=amd64 specify the target OS and architecture respectively. and -ldflags '-extldflags "-static"' is used to link the binary statically.

Deploying to Railway

After the docker image is pushed to GHCR, I manually deploy the image to Railway. I am planning to automate this step as well in the future when the application becomes a little stable.