README.md

go-githubauth

go-githubauth is a Go package that provides utilities for GitHub authentication, including generating and using GitHub App tokens and installation tokens.

Features

go-githubauth package provides implementations of the TokenSource interface from the golang.org/x/oauth2 package. This interface has a single method, Token, which returns an *oauth2.Token.

• Generate GitHub Application JWT Generating a jwt for a github app
• Obtain GitHub App installation tokens Authenticating as a GitHub App

This package is designed to be used with the golang.org/x/oauth2 package, which provides support for OAuth2 authentication.

Installation

To use go-githubauth in your project, you need to have Go installed. You can get the package via:

go get -u github.com/jferrl/go-githubauth

Usage

Usage with go-github and oauth2

package main

import (
 "context"
 "fmt"
 "os"
 "strconv"

 "github.com/google/go-github/v62/github"
 "github.com/jferrl/go-githubauth"
 "golang.org/x/oauth2"
)

func main() {
 privateKey := []byte(os.Getenv("GITHUB_APP_PRIVATE_KEY"))
 appID, _ := strconv.ParseInt(os.Getenv("GITHUB_APP_ID"), 10, 64)
 installationID, _ := strconv.ParseInt(os.Getenv("GITHUB_INSTALLATION_ID"), 10, 64)

 appTokenSource, err := githubauth.NewApplicationTokenSource(appID, privateKey)
 if err != nil {
  fmt.Println("Error creating application token source:", err)
  return
 }

 installationTokenSource := githubauth.NewInstallationTokenSource(installationID, appTokenSource)

 // oauth2.NewClient create a new http.Client that adds an Authorization header with the token.
 // Transport src use oauth2.ReuseTokenSource to reuse the token.
 // The token will be reused until it expires.
 // The token will be refreshed if it's expired.
 httpClient := oauth2.NewClient(context.Background(), installationTokenSource)

 githubClient := github.NewClient(httpClient)

 _, _, err = githubClient.PullRequests.CreateComment(context.Background(), "owner", "repo", 1, &github.PullRequestComment{
  Body: github.String("Awesome comment!"),
 })
 if err != nil {
  fmt.Println("Error creating comment:", err)
  return
 }
}

Generate GitHub Application Token

First of all you need to create a GitHub App and generate a private key.

To authenticate as a GitHub App, you need to generate a JWT. Generating a jwt for a github app

package main

import (
 "fmt"
 "os"
 "time"

 "github.com/jferrl/go-githubauth"
)

func main() {
 privateKey := []byte(os.Getenv("GITHUB_APP_PRIVATE_KEY"))
 appID, _ := strconv.ParseInt(os.Getenv("GITHUB_APP_ID"), 10, 64)

 tokenSource, err := githubauth.NewApplicationTokenSource(appID, privateKey, githubauth.WithApplicationTokenExpiration(5*time.Minute))
 if err != nil {
  fmt.Println("Error creating token source:", err)
  return
 }

 token, err := tokenSource.Token()
 if err != nil {
  fmt.Println("Error generating token:", err)
  return
 }

 fmt.Println("Generated token:", token.AccessToken)
}

Generate GitHub App Installation Token

To authenticate as a GitHub App installation, you need to obtain an installation token.

package main

import (
 "fmt"
 "os"
 "strconv"

 "github.com/jferrl/go-githubauth"
)

func main() {
 privateKey := []byte(os.Getenv("GITHUB_APP_PRIVATE_KEY"))
 appID, _ := strconv.ParseInt(os.Getenv("GITHUB_APP_ID"), 10, 64)
 installationID, _ := strconv.ParseInt(os.Getenv("GITHUB_INSTALLATION_ID"), 10, 64)

 appTokenSource, err := githubauth.NewApplicationTokenSource(appID, privateKey)
 if err != nil {
  fmt.Println("Error creating application token source:", err)
  return
 }

 installationTokenSource := githubauth.NewInstallationTokenSource(installationID, appTokenSource)

 token, err := installationTokenSource.Token()
 if err != nil {
  fmt.Println("Error generating installation token:", err)
  return
 }

 fmt.Println("Generated installation token:", token.AccessToken)
}

Contributing

Contributions are welcome! Please open an issue or submit a pull request on GitHub.

License

This project is licensed under the MIT License. See the LICENSE file for details.