Setup

If you are using GitHub Actions, you can skip this guide and refer to the GitHub Actions guide instead.

Continuous Integration/Continuous Deployment (CI/CD) is a software development practice that automates building, testing, and deploying software. If you are working with Protobuf, then buf should be part of all three of these development stages.

This guide illustrates how to integrate buf into general CI/CD solutions, such as CircleCI and TravisCI. If you are using GitHub Actions, you can skip this guide and refer to the GitHub Actions guide instead.

This guide is also supplemented by the buf-example repository, which provides a functional example for integrating buf into CircleCI, TravisCI, or GitHub Actions. For a quick solution that uses a Makefile, see to buf-example!

Installation

For a functional example, see the buf-example repository.

The first step is to get buf running on your CI/CD worker. In order to do so, you'll need an install script. buf can be downloaded from a release or built from source.

#!/bin/bash

PROJECT=<your-project-name>
# Use your desired buf version
BUF_VERSION=1.15.1
# buf is installed to ~/bin/your-project-name.
BIN_DIR=$HOME/bin/$PROJECT

curl -sSL \
	"https://github.com/bufbuild/buf/releases/download/v$BUF_VERSION/buf-$(uname -s)-$(uname -m)" \
	-o "$BIN_DIR/buf"
chmod +x "$BIN_DIR/buf"

Running lint and breaking change detection

For a functional example, see the buf-example repository.

To run lint checks with your job, simply add buf lint to it and you're good to go!

If your buf.yaml is defined at the root of your repository, you can run the linter with this command:

$ buf lint

If, on the other hand, your buf.yaml is defined in a nested directory, such as the proto directory, the command looks like this:

$ buf lint proto

For buf breaking, the process is similar, but be sure to set the full https or ssh remote as the target. If your buf.yaml is defined at the root of your repository, the command looks like this:

$ buf breaking --against "https://github.com/<your-org>/<your-repo>.git#branch=main"

Also valid:

$ buf breaking --against "ssh://git@github.com/<your-org>/<your-repo>.git#branch=main"

Again, if your buf.yaml is defined in a nested directory, such as the proto directory, the command looks like this (notice the subdir parameter):

$ buf breaking proto --against "https://github.com/<your-org>/<your-repo>.git#branch=main,subdir=proto"

Also valid:

$ buf breaking proto --against "ssh://git@github.com/<your-org>/<your-repo>.git#branch=main,subdir=proto"

If you are on TravisCI or CircleCI they do not clone any branches outside of the one being tested, so this enables buf to clone using the remote and run the breaking change detector.

CI authentication (Optional)

If you wish to authenticate a CI/CD job to access the BSR (for example, push a module, create tags, etc.), we recommend you store your BUF_TOKEN in your CI/CD provider's secret environment variable storage.

For example:

• TravisCI
• CircleCI
• GitHub Actions

You can then access the token in your job using an environment variable, which enables you to create a .netrc file for your job during setup. Here's an example assuming you've stored your token as BUF_API_TOKEN and your username as BUF_USER:

$ echo ${BUF_API_TOKEN} | buf registry login --username ${BUF_USER} --token-stdin

For more details on authenticating to the BSR, see Authentication.

CI caching

To enable caching of modules downloaded by the buf CLI, you can either configure caching of the ~/.cache directory, or set the BUF_CACHE_DIR environment variable to a directory of your choice and cache that directory.

For more information about module caching, see the Module Cache docs.

Wrapping up

Now that you've set up buf to run lint checks and detect breaking changes in your CI/CD environment, your APIs will always remain consistent, and you won't need to waste any more time understanding the complex backwards compatibility rules to ensure that you never break your customers.