gogit: Add new ForceGoGitImplementation FeatureGate

ForceGoGitImplementation ignores the value set for gitImplementation
and ensures that go-git is used for all GitRepository objects.
This can be used to confirm that Flux instances won't break if/when
the libgit2 implementation was to be deprecated.

When enabled, libgit2 won't be initialized, nor will any git2go cgo
code be called.

Signed-off-by: Paulo Gomes <paulo.gomes@weave.works>

controllers/imageupdateautomation_controller.go

@@ -60,6 +60,7 @@ import (
  sourcev1 "github.com/fluxcd/source-controller/api/v1beta2"
 
  imagev1 "github.com/fluxcd/image-automation-controller/api/v1beta1"
+ "github.com/fluxcd/image-automation-controller/internal/features"
  "github.com/fluxcd/image-automation-controller/pkg/update"
 )
 
@@ -85,6 +86,8 @@ type ImageUpdateAutomationReconciler struct {
  helper.Metrics
 
  NoCrossNamespaceRef bool
+
+ features map[string]bool
 }
 
 type ImageUpdateAutomationReconcilerOptions struct {
@@ -254,14 +257,19 @@ func (r *ImageUpdateAutomationReconciler) Reconcile(ctx context.Context, req ctr
  return failWithError(err)
  }
 
+ gitImplementation := origin.Spec.GitImplementation
+ if goGitOnly, _ := r.features[features.ForceGoGitImplementation]; goGitOnly {
+ gitImplementation = sourcev1.GoGitImplementation
+ }
+
  var gitClient git.RepositoryClient
- switch origin.Spec.GitImplementation {
+ switch gitImplementation {
  case sourcev1.LibGit2Implementation:
  gitClient, err = libgit2.NewClient(tmp, authOpts)
  case sourcev1.GoGitImplementation, "":
  gitClient, err = gogit.NewClient(tmp, authOpts)
  default:
- err = fmt.Errorf("failed to create git client; referred GitRepository has invalid implementation: %s", origin.Spec.GitImplementation)
+ err = fmt.Errorf("failed to create git client; referred GitRepository has invalid implementation: %s", gitImplementation)
  }
  if err != nil {
  return failWithError(err)
@@ -416,6 +424,10 @@ func (r *ImageUpdateAutomationReconciler) SetupWithManager(mgr ctrl.Manager, opt
  return err
  }
 
+ if r.features == nil {
+ r.features = features.FeatureGates()
+ }
+
  return ctrl.NewControllerManagedBy(mgr).
  For(&imagev1.ImageUpdateAutomation{}, builder.WithPredicates(
  predicate.Or(predicate.GenerationChangedPredicate{}, predicates.ReconcileRequestedPredicate{}))).

controllers/suite_test.go

@@ -35,6 +35,7 @@ import (
  sourcev1 "github.com/fluxcd/source-controller/api/v1beta2"
 
  imagev1 "github.com/fluxcd/image-automation-controller/api/v1beta1"
+ "github.com/fluxcd/image-automation-controller/internal/features"
  // +kubebuilder:scaffold:imports
 )
 
@@ -60,19 +61,34 @@ func TestMain(m *testing.M) {
  utilruntime.Must(sourcev1.AddToScheme(scheme.Scheme))
  utilruntime.Must(imagev1.AddToScheme(scheme.Scheme))
 
+ if err := transport.InitManagedTransport(); err != nil {
+ panic(fmt.Sprintf("failed to initialize libgit2 managed transport: %v", err))
+ }
+
+ code := runTestsWithFeatures(m, nil)
+ if code != 0 {
+ fmt.Println("failed with default feature values")
+ os.Exit(code)
+ }
+
+ code = runTestsWithFeatures(m, map[string]bool{
+ features.ForceGoGitImplementation: false,
+ })
+
+ os.Exit(code)
+}
+
+func runTestsWithFeatures(m *testing.M, feats map[string]bool) int {
  testEnv = testenv.New(testenv.WithCRDPath(
  filepath.Join("..", "config", "crd", "bases"),
  filepath.Join("testdata", "crds"),
  ))
 
- if err := transport.InitManagedTransport(); err != nil {
- panic(fmt.Sprintf("failed to initialize libgit2 managed transport: %v", err))
- }
-
  controllerName := "image-automation-controller"
  if err := (&ImageUpdateAutomationReconciler{
  Client: testEnv,
  EventRecorder: testEnv.GetEventRecorderFor(controllerName),
+ features: feats,
  }).SetupWithManager(testEnv, ImageUpdateAutomationReconcilerOptions{}); err != nil {
  panic(fmt.Sprintf("failed to start ImageUpdateAutomationReconciler: %v", err))
  }
@@ -92,7 +108,7 @@ func TestMain(m *testing.M) {
  panic(fmt.Sprintf("failed to stop the test environment: %v", err))
  }
 
- os.Exit(code)
+ return code
 }
 
 // This provides a regression assurance for image-automation-controller/#339.

internal/features/features.go

@@ -22,16 +22,19 @@ package features
 import feathelper "github.com/fluxcd/pkg/runtime/features"
 
 const (
- // GitManagedTransport implements a managed transport for GitRepository
- // objects that use the libgit2 implementation.
+ // ForceGoGitImplementation ignores the value set for gitImplementation
+ // of a GitRepository object and ensures that go-git is used for all git operations.
  //
- // When enabled, improves the reliability of libgit2 reconciliations,
- // by enforcing timeouts and ensuring libgit2 cannot hijack the process
- // and hang it indefinitely.
- GitManagedTransport = "GitManagedTransport"
+ // When enabled, libgit2 won't be initialized, nor will any git2go cgo
+ // code be called.
+ ForceGoGitImplementation = "ForceGoGitImplementation"
 )
 
-var features = map[string]bool{}
+var features = map[string]bool{
+ // ForceGoGitImplementation
+ // opt-out from v0.32
+ ForceGoGitImplementation: true,
+}
 
 // DefaultFeatureGates contains a list of all supported feature gates and
 // their default values.

main.go

@@ -163,9 +163,11 @@ func main() {
  }
  // +kubebuilder:scaffold:builder
 
- if err = transport.InitManagedTransport(); err != nil {
- setupLog.Error(err, "unable to initialize libgit2 managed transport")
- os.Exit(1)
+ if gogitOnly, _ := features.Enabled(features.ForceGoGitImplementation); !gogitOnly {
+ if err = transport.InitManagedTransport(); err != nil {
+ setupLog.Error(err, "unable to initialize libgit2 managed transport")
+ os.Exit(1)
+ }
  }
 
  setupLog.Info("starting manager")