Abstract git logic

Author: ChappIO

cmd/git-backup/main.go

@@ -9,28 +9,27 @@ import (
 
 func main() {
 	config := loadConfig()
-	for _, githubConfig := range config.Github {
-		me, err := githubConfig.GetMe()
-		if err != nil {
-			log.Printf("Communication Error: %s", err)
-			os.Exit(100)
+	for _, source := range config.GetSources() {
+		sourceName := source.GetName()
+		log.Printf("=== %s ===", sourceName)
+		if err := source.Test(); err != nil {
+			log.Printf("Failed to verify connection to job [%s]: %s", sourceName, err)
+			os.Exit(110)
 		}
-		log.Printf("=== %s ===", githubConfig.JobName)
-		log.Printf("Authenticated as: %s", *me.Login)
-		repos, err := githubConfig.GetRepos()
+		repos, err := source.ListRepositories()
 		if err != nil {
 			log.Printf("Communication Error: %s", err)
 			os.Exit(100)
 		}
 		for _, repo := range repos {
-			log.Println(*repo.FullName)
-			targetPath := filepath.Join("backup", githubConfig.JobName, *repo.FullName)
+			log.Printf("Discovered %s", repo.FullName)
+			targetPath := filepath.Join("backup", sourceName, repo.FullName)
 			err := os.MkdirAll(targetPath, os.ModePerm)
 			if err != nil {
 				log.Printf("Failed to create directory: %s", err)
 				os.Exit(100)
 			}
-			err = githubConfig.CloneInto(repo, targetPath)
+			err = repo.CloneInto(targetPath)
 			if err != nil {
 				log.Printf("Failed to clone: %s", err)
 				os.Exit(100)

config.go

@@ -10,6 +10,18 @@ type Config struct {
 	Github []*GithubConfig `yaml:"github"`
 }
 
+func (c *Config) GetSources() []RepositorySource {
+	sources := make([]RepositorySource, len(c.Github))
+
+	offset := 0;
+	for i := 0; i < len(c.Github); i++ {
+		sources[i + offset] = c.Github[i]
+		offset++
+	}
+
+	return sources
+}
+
 func (c *Config) setDefaults() {
 	if c.Github != nil {
 		for _, config := range c.Github {
@@ -37,4 +49,4 @@ func LoadReader(reader io.Reader) (out Config, err error) {
 	err = dec.Decode(&out)
 	out.setDefaults()
 	return
-}
+}

github.go

@@ -8,6 +8,7 @@ import (
 	"github.com/go-git/go-git/v5/plumbing/transport/http"
 	"github.com/google/go-github/v43/github"
 	"golang.org/x/oauth2"
+	"net/url"
 	"os"
 )
 
@@ -18,6 +19,36 @@ type GithubConfig struct {
 	client      *github.Client
 }
 
+func (c *GithubConfig) Test() error {
+	me, err := c.getMe()
+	if err != nil {
+		return err
+	}
+	fmt.Printf("Authenticated with github as: %s", me.Login)
+	return nil
+}
+
+func (c *GithubConfig) GetName() string {
+	return c.JobName
+}
+
+func (c *GithubConfig) ListRepositories() ([]*Repository, error) {
+	repos, err := c.getAllRepos()
+	if err != nil {
+		return nil, err
+	}
+	out := make([]*Repository, len(repos))
+	for i, repo := range repos {
+		gitUrl, err := url.Parse(*repo.CloneURL)
+		if err != nil {
+			return out, err
+		}
+		gitUrl.User = url.UserPassword("github", c.AccessToken)
+		out[i] = &Repository{GitURL: *gitUrl}
+	}
+	return out, nil
+}
+
 func (c *GithubConfig) setDefaults() {
 	if c.JobName == "" {
 		c.JobName = "GitHub"
@@ -33,12 +64,13 @@ func (c *GithubConfig) setDefaults() {
 		}
 	}
 }
-func (c *GithubConfig) GetMe() (*github.User, error) {
+
+func (c *GithubConfig) getMe() (*github.User, error) {
 	response, _, err := c.client.Users.Get(context.Background(), "")
 	return response, err
 }
 
-func (c *GithubConfig) GetRepos() ([]*github.Repository, error) {
+func (c *GithubConfig) getAllRepos() ([]*github.Repository, error) {
 	all := make([]*github.Repository, 0)
 	var err error
 

repository.go

@@ -0,0 +1,76 @@
+package git_backup
+
+import (
+	"github.com/go-git/go-git/v5"
+	"github.com/go-git/go-git/v5/plumbing/transport"
+	"github.com/go-git/go-git/v5/plumbing/transport/http"
+	"net/url"
+	"os"
+)
+
+type RepositorySource interface {
+	GetName() string
+	Test() error
+	ListRepositories() ([]*Repository, error)
+}
+
+type Repository struct {
+	GitURL   url.URL
+	FullName string
+}
+
+func (r *Repository) CloneInto(path string) error {
+	var auth http.AuthMethod
+	if r.GitURL.User != nil {
+		password, _ := r.GitURL.User.Password()
+		auth = &http.BasicAuth{
+			Username: r.GitURL.User.Username(),
+			Password: password,
+		}
+	}
+	gitRepo, err := git.PlainClone(path, false, &git.CloneOptions{
+		URL:      r.GitURL.String(),
+		Auth:     auth,
+		Progress: os.Stdout,
+	})
+
+	if err == git.ErrRepositoryAlreadyExists {
+		// Pull instead of clone
+		if gitRepo, err = git.PlainOpen(path); err == nil {
+			if w, wErr := gitRepo.Worktree(); wErr != nil {
+				err = wErr
+			} else {
+				err = w.Pull(&git.PullOptions{
+					Auth:     auth,
+					Progress: os.Stdout,
+				})
+			}
+		}
+	}
+
+	switch err {
+	case transport.ErrEmptyRemoteRepository:
+		//  Empty repo does not need backup
+		return nil
+	default:
+		return err
+	case git.NoErrAlreadyUpToDate:
+		// Already up to date on current branch, still need to refresh other branches
+		fallthrough
+	case nil:
+		// No errors, continue
+		err = gitRepo.Fetch(&git.FetchOptions{
+			Auth:     auth,
+			Progress: os.Stdout,
+			Tags:     git.AllTags,
+			Force:    true,
+		})
+	}
+
+	switch err {
+	case git.NoErrAlreadyUpToDate:
+		return nil
+	default:
+		return err
+	}
+}