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CircleCI Convenience Images => Go

A Continuous Integration focused Go Docker image built to run on CircleCI

_This image is designed to supercede the legacy CircleCI Go image, circleci/golang._

cimg/go is a Docker image created by CircleCI with continuous integration builds in mind. Each tag contains a complete Go version and toolchain, the testing wrapper gotestsum, and any binaries and tools that are required for builds to complete successfully in a CircleCI environment.

Table of Contents

• Getting Started • How This Image Works • Changes From Legacy Image • Development • Contributing • Additional Resources • License

Getting Started

This image can be used with the CircleCI docker executor. For example:

In the above example, the CircleCI Go Docker image is used for the primary container. More specifically, the tag 1.17 is used meaning the version of Go will be Go v1.17. You can now use Go within the steps for this job.

How This Image Works

This image contains the Go programming language and its complete toolchain. This includes support for Go modules, the official Go Proxy Server, etc.

Changes From Legacy Image

If you're coming from the legacy version of this image, circleci/golang, here's any changes that you might want to be aware of:

• GOPATH - this envar has changed from /go to $HOME/go. The latter will expand to the full path of /home/circleci/go. On first run, this change may affect caching and some other commands if you don’t correct the page in your config.

Variants

Variant images typically contain the same base software, but with a few additional modifications.

Node.js

The Node.js variant is the same Go image but with Node.js also installed. The Node.js variant will be used by appending -node to the end of an existing cimg/go tag.

Browsers

The browsers variant is the same Go image but with Node.js, Java, Selenium, and browser dependencies pre-installed via apt. The browsers variant can be used by appending -browser to the end of an existing cimg/go tag. The browsers variant is designed to work in conjunction with the CircleCI Browser Tools orb. You can use the orb to install a version of Google Chrome and/or Firefox into your build. The image contains all of the supporting tools needed to use both the browser and its driver.

Tagging Scheme

This image has the following tagging scheme:

- The version of Go to use. This can be a full SemVer point release (such as 1.12.7) or just the minor release (such as 1.12.0). **Note: For some reason the Go Team releases the first minor release without the .0 at the end. So instead of releasing Go v1.18.0, they release v1.18. For this image, we add the .0 anyway so that the tagging scheme works with our tooling.** If you use the minor release tag, it will automatically point to future patch updates as they are released by the Go Team. For example, the tag 1.17 points to Go v1.17 now, but when the next release comes out, it will point to Go v1.17.1.

[-variant] - Variant tags, if available, can optionally be used. Once the Node.js variant is available, it could be used like this: cimg/go:1.17-node.

Development

Images can be built and run locally with this repository. This has the following requirements:

• local machine of Linux (Ubuntu tested) or macOS • modern version of Bash (v4+) • modern version of Docker Engine (v19.03+)

Cloning For Community Users (no write access to this repository)

Fork this repository on GitHub. When you get your clone URL, you'll want to add --recurse-submodules to the clone command in order to populate the Git submodule contained in this repo. It would look something like this:

If you missed this step and already cloned, you can just run git submodule update --init to populate the submodule. Then you can optionally add this repo as an upstream to your own:

Cloning For Maintainers ( you have write access to this repository)

Clone the project with the following command so that you populate the submodule:

Generating Dockerfiles

Dockerfiles can be generated for a specific Go version using the gen-dockerfiles.sh script. For example, to generate the Dockerfile for Go v1.18, you would run the following from the root of the repo:

The generated Dockerfile will be located at ./1.18/Dockefile. To build this image locally and try it out, you can run the following:

**Note: For some reason the Go Team releases the first minor release without the .0 at the end. So instead of releasing Go v1.18.0, they release v1.18. For this image, we add the .0 anyway so that the tagging scheme works with our tooling.**

Building the Dockerfiles

To build the Docker images locally as this repository does, you'll want to run the build-images.sh script:

This would need to be run after generating the Dockerfiles first. When releasing proper images for CircleCI, this script is run from a CircleCI pipeline and not locally.

Publishing Official Images (for Maintainers only)

The individual scripts (above) can be used to create the correct files for an image, and then added to a new git branch, committed, etc. A release script is included to make this process easier. To make a proper release for this image, let's use the fake Go version of Go v9.99, you would run the following from the repo root:

This will automatically create a new Git branch, generate the Dockerfile(s), stage the changes, commit them, and push them to GitHub. The commit message will end with the string [release]. This string is used by CircleCI to know when to push images to Docker Hub. All that would need to be done after that is:

• wait for build to pass on CircleCI • review the PR • merge the PR

The main branch build will then publish a release.

**Note: For some reason the Go Team releases the first minor release without the .0 at the end. So instead of releasing Go v1.18.0, they release v1.18. For this image, we add the .0 anyway so that the tagging scheme works with our tooling.**

Incorporating Changes…

Description from the Docker Hub listing.