Creating GitHub CLI Extensions

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• Creating GitHub CLI extensions

Creating GitHub CLI extensions

Learn how to share new GitHub CLI commands with other users by creating custom extensions for GitHub CLI.

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In this article

• About GitHub CLI extensions
• Creating an interpreted extension with gh extension create
• Creating a precompiled extension in Go with gh extension create
• Creating a non-Go precompiled extension with gh extension create
• Creating an interpreted extension manually
• Tips for writing interpreted GitHub CLI extensions
• Creating a precompiled extension manually
• Tips for writing precompiled GitHub CLI extensions
• Next steps

About GitHub CLI extensions

GitHub CLI extensions are custom GitHub CLI commands that anyone can create and use. For more information about how to use GitHub CLI extensions, see Using GitHub CLI extensions.

You need a repository for each extension that you create. The repository name must start with gh-. The rest of the repository name is the name of the extension. The repository must have an executable file at its root with the same name as the repository or a set of precompiled binary executables attached to a release.

Note

When relying on an executable script, we recommend using a bash script because bash is a widely available interpreter. You may use non-bash scripts, but the user must have the necessary interpreter installed in order to use the extension. If you would prefer to not rely on users having interpreters installed, consider a precompiled extension.

Creating an interpreted extension with gh extension create

Note

Running gh extension create with no arguments will start an interactive wizard.

You can use the gh extension create command to create a project for your extension, including a bash script that contains some starter code.

1. Set up a new extension by using the gh extension create subcommand. Replace EXTENSION-NAME with the name of your extension.

   gh extension create EXTENSION-NAME

2. Follow the printed instructions to finalize and optionally publish your extension.

Creating a precompiled extension in Go with gh extension create

You can use the --precompiled=go argument to create a Go-based project for your extension, including Go scaffolding, workflow scaffolding, and starter code.

1. Set up a new extension by using the gh extension create subcommand. Replace EXTENSION-NAME with the name of your extension and specify --precompiled=go.

   gh extension create --precompiled=go EXTENSION-NAME

2. Follow the printed instructions to finalize and optionally publish your extension.

Creating a non-Go precompiled extension with gh extension create

You can use the --precompiled=other argument to create a project for your non-Go precompiled extension, including workflow scaffolding.

1. Set up a new extension by using the gh extension create subcommand. Replace EXTENSION-NAME with the name of your extension and specify --precompiled=other.

   gh extension create --precompiled=other EXTENSION-NAME

2. Add some initial code for your extension in your compiled language of choice.

3. Fill in script/build.sh with code to build your extension to ensure that your extension can be built automatically.

4. Follow the printed instructions to finalize and optionally publish your extension.

Creating an interpreted extension manually

1. Create a local directory called gh-EXTENSION-NAME for your extension. Replace EXTENSION-NAME with the name of your extension. For example, gh-whoami.

2. In the directory that you created, add an executable file with the same name as the directory.

   Note

   Make sure that your file is executable. On Unix, you can execute chmod +x file_name in the command line to make file_name executable. On Windows, you can run git init -b main, git add file_name, then git update-index --chmod=+x file_name.

3. Write your script in the executable file. For example:

   #!/usr/bin/env bash set -e exec gh api user --jq '"You are @\(.login) (\(.name))."'

4. From your directory, install the extension as a local extension.

   gh extension install .

5. Verify that your extension works. Replace EXTENSION-NAME with the name of your extension. For example, whoami.

   gh EXTENSION-NAME

6. From your directory, create a repository to publish your extension. Replace EXTENSION-NAME with the name of your extension.

   git init -b main git add . && git commit -m "initial commit" gh repo create gh-EXTENSION-NAME --source=. --public --push

7. Optionally, to help other users discover your extension, add the repository topic gh-extension. This will make the extension appear on the gh-extension topic page. For more information about how to add a repository topic, see Classifying your repository with topics.

Tips for writing interpreted GitHub CLI extensions

Handling arguments and flags

All command line arguments following a gh my-extension-name command will be passed to the extension script. In a bash script, you can reference arguments with $1, $2, etc. You can use arguments to take user input or to modify the behavior of the script.

For example, this script handles multiple flags. When the script is called with the -h or --help flag, the script prints help text instead of continuing execution. When the script is called with the --name flag, the script sets the next value after the flag to name_arg. When the script is called with the --verbose flag, the script prints a different greeting.

#!/usr/bin/env bash set -e verbose="" name_arg="" while [ $# -gt 0 ]; do case "$1" in --verbose) verbose=1 ;; --name) name_arg="$2" shift ;; -h|--help) echo "Add help text here." exit 0 ;; esac shift done if [ -z "$name_arg" ] then echo "You haven't told us your name." elif [ -z "$verbose" ] then echo "Hi $name_arg" else echo "Hello and welcome, $name_arg" fi

Calling core commands in non-interactive mode

Some GitHub CLI core commands will prompt the user for input. When scripting with those commands, a prompt is often undesirable. To avoid prompting, supply the necessary information explicitly via arguments.

For example, to create an issue programmatically, specify the title and body:

gh issue create --title "My Title" --body "Issue description"

Fetching data programmatically

Many core commands support the --json flag for fetching data programmatically. For example, to return a JSON object listing the number, title, and mergeability status of pull requests:

gh pr list --json number,title,mergeStateStatus

If there is not a core command to fetch specific data from GitHub, you can use the gh api command to access the GitHub API. For example, to fetch information about the current user:

gh api user

All commands that output JSON data also have options to filter that data into something more immediately usable by scripts. For example, to get the current user's name:

gh api user --jq '.name'

For more information, see gh help formatting.

Creating a precompiled extension manually

1. Create a local directory called gh-EXTENSION-NAME for your extension. Replace EXTENSION-NAME with the name of your extension. For example, gh-whoami.

2. In the directory you created, add some source code. For example:

   package main import ( "github.com/cli/go-gh" "fmt" ) func main() { args := []string{"api", "user", "--jq", `"You are @\(.login) (\(.name))"` } stdOut, _, err := gh.Exec(args...) if err != nil { fmt.Println(err) return } fmt.Println(stdOut.String()) }

3. From your directory, install the extension as a local extension.

   gh extension install .

4. Build your code. For example, with Go, replacing YOUR-USERNAME with your GitHub username:

   go mod init github.com/YOUR-USERNAME/gh-whoami go mod tidy go build

5. Verify that your extension works. Replace EXTENSION-NAME with the name of your extension. For example, whoami.

   gh EXTENSION-NAME

6. From your directory, create a repository to publish your extension. Replace EXTENSION-NAME with the name of your extension.

   Note

   Be careful not to commit the binary produced by your compilation step to version control.

   git init -b main echo "gh-EXTENSION-NAME" >> .gitignore git add main.go go.* .gitignore && git commit -m 'Initial commit' gh repo create "gh-EXTENSION-NAME"

7. Create a release to share your precompiled extension with others. Compile for each platform you want to support, attaching each binary to a release as an asset. Binary executables attached to releases must follow a naming convention and have a suffix of OS-ARCHITECTURE[EXTENSION].

   For example, an extension named whoami compiled for Windows 64bit would have the name gh-whoami-windows-amd64.exe while the same extension compiled for Linux 32bit would have the name gh-whoami-linux-386. To see an exhaustive list of OS and architecture combinations recognized by gh, see this source code.

   Note

   For your extension to run properly on Windows, its asset file must have a .exe extension. No extension is needed for other operating systems.

   Releases can be created from the command line. For example:

   git tag v1.0.0 git push origin v1.0.0 GOOS=windows GOARCH=amd64 go build -o gh-EXTENSION-NAME-windows-amd64.exe GOOS=linux GOARCH=amd64 go build -o gh-EXTENSION-NAME-linux-amd64 GOOS=darwin GOARCH=amd64 go build -o gh-EXTENSION-NAME-darwin-amd64 gh release create v1.0.0 ./*amd64*

8. Optionally, to help other users discover your extension, add the repository topic gh-extension. This will make the extension appear on the gh-extension topic page. For more information about how to add a repository topic, see Classifying your repository with topics.

Tips for writing precompiled GitHub CLI extensions

Automating releases

Consider adding the gh-extension-precompile action to a workflow in your project. This action will automatically produce cross-compiled Go binaries for your extension and supplies build scaffolding for non-Go precompiled extensions.

Using GitHub CLI features from Go-based extensions

Consider using go-gh, a Go library that exposes pieces of gh functionality for use in extensions.

Next steps

To see more examples of GitHub CLI extensions, look at repositories with the gh-extension topic.