MM-21722 - Repository synchronization tool (#86)

build/sync/plan/setup.go

@@ -0,0 +1,80 @@
+package plan
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	git "gopkg.in/src-d/go-git.v4"
+)
+
+// RepoID identifies a repository - either plugin or template.
+type RepoID string
+
+const (
+	// SourceRepo is the id of the template repository (source).
+	SourceRepo RepoID = "source"
+	// TargetRepo is the id of the plugin repository (target).
+	TargetRepo RepoID = "target"
+)
+
+// Setup contains information about both parties
+// in the sync: the plugin repository being updated
+// and the source of the update - the template repo.
+type Setup struct {
+	Source         RepoSetup
+	Target         RepoSetup
+	VerboseLogging bool
+}
+
+// Logf logs the provided message.
+// If verbose output is not enabled, the message will not be printed.
+func (c Setup) Logf(tpl string, args ...interface{}) {
+	if c.VerboseLogging {
+		fmt.Fprintf(os.Stderr, tpl+"\n", args...)
+	}
+}
+
+// LogErrorf logs the provided error message.
+func (c Setup) LogErrorf(tpl string, args ...interface{}) {
+	fmt.Fprintf(os.Stderr, tpl+"\n", args...)
+}
+
+// GetRepo is a helper to get the required repo setup.
+// If the target parameter is not one of "plugin" or "template",
+// the function panics.
+func (c Setup) GetRepo(r RepoID) RepoSetup {
+	switch r {
+	case TargetRepo:
+		return c.Target
+	case SourceRepo:
+		return c.Source
+	default:
+		panic(fmt.Sprintf("cannot get repository setup %q", r))
+	}
+}
+
+// PathInRepo returns the full path of a file in the specified repository.
+func (c Setup) PathInRepo(repo RepoID, path string) string {
+	r := c.GetRepo(repo)
+	return filepath.Join(r.Path, path)
+}
+
+// RepoSetup contains relevant information
+// about a single repository (either source or target).
+type RepoSetup struct {
+	Git  *git.Repository
+	Path string
+}
+
+// GetRepoSetup returns the repository setup for the specified path.
+func GetRepoSetup(path string) (RepoSetup, error) {
+	repo, err := git.PlainOpen(path)
+	if err != nil {
+		return RepoSetup{}, fmt.Errorf("failed to access git repository at %q: %v", path, err)
+	}
+	return RepoSetup{
+		Git:  repo,
+		Path: path,
+	}, nil
+}