Running Docker in your CI/CD pipeline

At Zippy we believe that Docker is an industry standard that needs to be supported out of the box. In this blog post we will set up a Docker CI/CD pipeline from scratch. The first run installs in a minute and after that it’s 4 seconds.

Writing Your First Dockerfile

Docker containers are created with a Dockerfile. A Dockerfile defines what the container looks like. In this example we will use go-lang that runs a small unit test.

FROM golang:1.23-alpine

WORKDIR /app

RUN go mod init demo

RUN printf 'package main\n\nimport "testing"\n\nfunc TestAdd(t *testing.T) {\n\tif 1+1 != 2 {\n\t\tt.Fatal("math is broken")\n\t}\n}\n' > math_test.go

CMD ["go", "test", "-v", "./..."]

Running it locally

Let’s try to run docker for the first time locally:

Great, our unit test works! Now let’s bring it to our Zippy pipeline.

Setting up the Zippy CI/CD Pipeline

Environment setup

Install docker on the ubuntu environment:

#!/bin/bash
set -e

apt-get update
apt-get install -y ca-certificates curl
install -m 0755 -d /etc/apt/keyrings
curl -fsSL https://download.docker.com/linux/ubuntu/gpg -o /etc/apt/keyrings/docker.asc
chmod a+r /etc/apt/keyrings/docker.asc

tee /etc/apt/sources.list.d/docker.sources <<EOF
Types: deb
URIs: https://download.docker.com/linux/ubuntu
Suites: noble
Components: stable
Architectures: $(dpkg --print-architecture)
Signed-By: /etc/apt/keyrings/docker.asc
EOF

apt-get update

apt-get install -y docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin

Zippy pipeline script

The pipeline script itself is quite minimal:

#!/bin/bash

set -e

docker build .

Subsequent runs, just 4 seconds!

The total docker set up only took around a minute. But knowing the environment only spins up once, the next time only takes 4 seconds.