Ensure git remotes for local repositories (#22)

Issue N/A

Description of changes:
This patch adds more logic to `pkg/repository.Manager` to ensure that
the local repositories remotes point to the right URLs.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

Author: a-hilaly

pkg/repository/manager.go

@@ -299,6 +299,44 @@ func (m *Manager) EnsureRepository(ctx context.Context, name string) error {
 		return err
 	}
 
+	err = m.EnsureRemotes(ctx, repo)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// EnsureRemotes ensures that the local repositories have both origin and upstream
+// remotes setup and point to the correct URLs.
+func (m *Manager) EnsureRemotes(ctx context.Context, repo *Repository) error {
+	remotes, err := util.GetRepositoryRemotes(repo.gitRepo)
+	if err != nil {
+		return err
+	}
+
+	expecetedOriginURL := m.urlBuilder(m.cfg.Github.Username, repo.ExpectedForkName)
+	// First check that one fo the  origin URLs points to the fork url
+	originURLs, ok := remotes[originRemoteName]
+	if !ok || !util.InStrings(expecetedOriginURL, originURLs) {
+		originURLs = append(originURLs, expecetedOriginURL)
+		err = util.UpdateRepositoryRemotes(repo.gitRepo, originRemoteName, originURLs)
+		if err != nil {
+			return fmt.Errorf("error updating origin URL: %v", err)
+		}
+	}
+
+	expectedUpstreamURL := m.urlBuilder(github.ACKOrg, repo.Name)
+	// Then check that one of the upstream URLs points to the original
+	// repository
+	upstreamURLs, ok := remotes[upstreamRemoteName]
+	if !ok || !util.InStrings(expectedUpstreamURL, upstreamURLs) {
+		upstreamURLs = append(upstreamURLs, expectedUpstreamURL)
+		err = util.UpdateRepositoryRemotes(repo.gitRepo, upstreamRemoteName, upstreamURLs)
+		if err != nil {
+			return fmt.Errorf("error updating origin URL: %v", err)
+		}
+	}
 	return nil
 }
 
@@ -314,6 +352,11 @@ func (m *Manager) EnsureAll(ctx context.Context) error {
 		if err != nil {
 			return err
 		}
+
+		err = m.EnsureRemotes(ctx, repo)
+		if err != nil {
+			return err
+		}
 	}
 	return nil
 }

pkg/util/git.go

@@ -0,0 +1,38 @@
+package util
+
+import (
+	"fmt"
+
+	git "gopkg.in/src-d/go-git.v4"
+	gitconfig "gopkg.in/src-d/go-git.v4/config"
+)
+
+// GetRepositoryRemotes returns a map containing the remote names and the URLs they
+// point to.
+func GetRepositoryRemotes(repo *git.Repository) (map[string][]string, error) {
+	gitRemotes, err := repo.Remotes()
+	if err != nil {
+		return nil, fmt.Errorf("cannot list remotes: %v", err)
+	}
+
+	remotes := map[string][]string{}
+	for _, remote := range gitRemotes {
+		remoteCfg := remote.Config()
+		remotes[remoteCfg.Name] = remoteCfg.URLs
+	}
+	return remotes, nil
+}
+
+// UpdateRepositoryRemotes updates the URLs list for a specific remote.
+func UpdateRepositoryRemotes(repo *git.Repository, name string, URLs []string) error {
+	cfg, err := repo.Storer.Config()
+	if err != nil {
+		return err
+	}
+
+	cfg.Remotes[name] = &gitconfig.RemoteConfig{
+		Name: name,
+		URLs: URLs,
+	}
+	return repo.Storer.SetConfig(cfg)
+}