Draft: Implement logic to clone git remotes only once

api/internal/git/cloner.go

@@ -4,21 +4,39 @@
 package git
 
 import (
+	"sync"
+
 	"sigs.k8s.io/kustomize/kyaml/filesys"
 )
 
 // Cloner is a function that can clone a git repo.
 type Cloner func(repoSpec *RepoSpec) error
 
+var (
+	clones     = make(map[string]filesys.ConfirmedDir)
+	cloneCount = make(map[filesys.ConfirmedDir]uint16)
+	cloneMutex sync.Mutex
+)
+
 // ClonerUsingGitExec uses a local git install, as opposed
 // to say, some remote API, to obtain a local clone of
 // a remote repo.
 func ClonerUsingGitExec(repoSpec *RepoSpec) error {
+	if dir, found := clones[repoSpec.Raw()]; found {
+		repoSpec.Dir = dir
+		cloneCount[dir] += 1
+		return nil
+	}
+
+	cloneMutex.Lock()
+	defer cloneMutex.Unlock()
+
 	r, err := newCmdRunner(repoSpec.Timeout)
 	if err != nil {
 		return err
 	}
 	repoSpec.Dir = r.dir
+	cloneCount[r.dir] = 1
 	if err = r.run("init"); err != nil {
 		return err
 	}
@@ -41,6 +59,10 @@ func ClonerUsingGitExec(repoSpec *RepoSpec) error {
 	if repoSpec.Submodules {
 		return r.run("submodule", "update", "--init", "--recursive")
 	}
+
+	// save the location of the clone for later reuse
+	clones[repoSpec.Raw()] = r.dir
+
 	return nil
 }
 
@@ -54,3 +76,16 @@ func DoNothingCloner(dir filesys.ConfirmedDir) Cloner {
 		return nil
 	}
 }
+
+// DecrementCloneCount decrements the count of repoSpecs using a directory clone.
+func DecrementCloneCount(dir filesys.ConfirmedDir) uint16 {
+	cloneMutex.Lock()
+	defer cloneMutex.Unlock()
+
+	if count, exists := cloneCount[dir]; exists && count > 0 {
+		cloneCount[dir] -= 1
+		return cloneCount[dir]
+	}
+
+	return 0
+}

api/internal/git/repospec.go

@@ -72,7 +72,12 @@ func (x *RepoSpec) AbsPath() string {
 }
 
 func (x *RepoSpec) Cleaner(fSys filesys.FileSystem) func() error {
-	return func() error { return fSys.RemoveAll(x.Dir.String()) }
+	return func() error {
+		if DecrementCloneCount(x.Dir) == 0 {
+			return fSys.RemoveAll(x.Dir.String())
+		}
+		return nil
+	}
 }
 
 const (