Use shallow clone to speed up performance

* Only git fetch the one target revision that we need
* This does not utilize the history so there is no reason to clone it
* For large repos, this will speed up performance significantly

Signed-off-by: Joshua Novick <[email protected]>

ext/git/client.go

@@ -65,6 +65,7 @@ type Client interface {
 	Root() string
 	Init() error
 	Fetch(revision string) error
+	ShallowFetch(revision string, depth int) error
 	Submodule() error
 	Checkout(revision string, submoduleEnabled bool) error
 	LsRefs() (*Refs, error)
@@ -384,6 +385,40 @@ func (m *nativeGitClient) Fetch(revision string) error {
 	return err
 }
 
+func (m *nativeGitClient) shallowFetch(revision string, depth int) error {
+	var err error
+	if revision != "" {
+		err = m.runCredentialedCmd("fetch", "origin", revision, "--force", "--prune", "--depth", strconv.Itoa(depth))
+	} else {
+		err = m.runCredentialedCmd("fetch", "origin", "--force", "--prune", "--depth", strconv.Itoa(depth))
+	}
+	return err
+}
+
+// Fetch fetches latest updates from origin
+func (m *nativeGitClient) ShallowFetch(revision string, depth int) error {
+	if m.OnFetch != nil {
+		done := m.OnFetch(m.repoURL)
+		defer done()
+	}
+
+	err := m.shallowFetch(revision, depth)
+
+	// When we have LFS support enabled, check for large files and fetch them too.
+	// No shallow fetch is possible here
+	if err == nil && m.IsLFSEnabled() {
+		largeFiles, err := m.LsLargeFiles()
+		if err == nil && len(largeFiles) > 0 {
+			err = m.runCredentialedCmd("lfs", "fetch", "--all")
+			if err != nil {
+				return err
+			}
+		}
+	}
+
+	return err
+}
+
 // LsFiles lists the local working tree, including only files that are under source control
 func (m *nativeGitClient) LsFiles(path string, enableNewGitFileGlobbing bool) ([]string, error) {
 	if enableNewGitFileGlobbing {

ext/git/git_test.go

@@ -322,6 +322,25 @@ func TestVerifyCommitSignature(t *testing.T) {
 	}
 }
 
+func TestVerifyShallowFetchCheckout(t *testing.T) {
+	p := t.TempDir()
+
+	client, err := NewClientExt("https://github.com/argoproj/argo-cd.git", p, NopCreds{}, false, false, "")
+	assert.NoError(t, err)
+
+	err = client.Init()
+	assert.NoError(t, err)
+
+	err = client.ShallowFetch("HEAD", 1)
+	assert.NoError(t, err)
+
+	commitSHA, err := client.LsRemote("HEAD")
+	assert.NoError(t, err)
+
+	err = client.Checkout(commitSHA, true)
+	assert.NoError(t, err)
+}
+
 func TestNewFactory(t *testing.T) {
 	addBinDirToPath := path.NewBinDirToPath()
 	defer addBinDirToPath.Close()

pkg/argocd/git.go

@@ -157,10 +157,6 @@ func commitChangesGit(app *v1alpha1.Application, wbc *WriteBackConfig, changeLis
 	if err != nil {
 		return err
 	}
-	err = gitC.Fetch("")
-	if err != nil {
-		return err
-	}
 
 	// Set username and e-mail address used to identify the commiter
 	if wbc.GitCommitUser != "" && wbc.GitCommitEmail != "" {
@@ -186,6 +182,10 @@ func commitChangesGit(app *v1alpha1.Application, wbc *WriteBackConfig, changeLis
 			return err
 		}
 	}
+	err = gitC.ShallowFetch(checkOutBranch, 1)
+	if err != nil {
+		return err
+	}
 
 	// The push branch is by default the same as the checkout branch, unless
 	// specified after a : separator git-branch annotation, in which case a