Implement PVC-backed Git workspace cache (design-pvc-workspace.md)

Add pkg/workspace.Manager that provides Acquire/Release semantics for Git
repos. When GIT_CACHE_DIR is set and a GitRepository has spec.cache.enabled,
controllers use on-disk bare clones with incremental fetch; otherwise they
fall back to the existing in-memory clone behavior.

Key changes:
- New pkg/workspace package with Manager, Workspace, GC, Deepen, and
  context-based injection (WithManager/GetManager)
- GitRepository API gains spec.cache (CacheConfig) and status.cache
  (CacheStatus) with deepcopy and CRD schema updates
- Push, sync, and resolver reconcilers now use workspace.Acquire/Release
  instead of inline memory.NewStorage + git.CloneContext
- Shallow clone by default; sync/resolver deepen as needed for merge-base
- New Prometheus metrics: workspace_acquire_duration_seconds,
  workspace_cache_hit_total, workspace_cache_miss_total
- Deployment manifests include commented-out PVC configuration
- Comprehensive unit tests for workspace package (21 tests)
- E2E tests for cache-free and cache-enabled push flows

https://claude.ai/code/session_01NULGxaCLPMT1yDVEAsffc5

pkg/apis/git/v1alpha1/types.go

@@ -35,6 +35,18 @@ type GitRepositorySpec struct {
 	// If unset, the controller's default poll interval is used.
 	// +optional
 	PollInterval *metav1.Duration `json:"pollInterval,omitempty"`
+
+	// Cache configures on-disk caching for this repository.
+	// When enabled, controllers with a PVC mounted will use a persistent
+	// bare clone instead of cloning into memory each time.
+	// +optional
+	Cache *CacheConfig `json:"cache,omitempty"`
+}
+
+// CacheConfig configures on-disk caching for a GitRepository.
+type CacheConfig struct {
+	// Enabled indicates whether on-disk caching should be used for this repo.
+	Enabled bool `json:"enabled"`
 }
 
 // GitAuth contains authentication details for accessing a Git repository.
@@ -58,6 +70,25 @@ type GitRepositoryStatus struct {
 	// LastFetchTime is the timestamp of the last successful fetch.
 	// +optional
 	LastFetchTime *metav1.Time `json:"lastFetchTime,omitempty"`
+
+	// Cache contains cache health information.
+	// +optional
+	Cache *CacheStatus `json:"cache,omitempty"`
+}
+
+// CacheStatus reports the current state of the on-disk cache for a repository.
+type CacheStatus struct {
+	// LastCloneTime is the timestamp of the initial clone to disk.
+	// +optional
+	LastCloneTime *metav1.Time `json:"lastCloneTime,omitempty"`
+
+	// LastFetchTime is the timestamp of the last git fetch on the cached repo.
+	// +optional
+	LastFetchTime *metav1.Time `json:"lastFetchTime,omitempty"`
+
+	// SizeBytes is the approximate size of the cached repo on disk.
+	// +optional
+	SizeBytes int64 `json:"sizeBytes,omitempty"`
 }
 
 // +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object

pkg/apis/git/v1alpha1/zz_generated.deepcopy.go

@@ -10,6 +10,44 @@ import (
 	runtime "k8s.io/apimachinery/pkg/runtime"
 )
 
+// DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
+func (in *CacheConfig) DeepCopyInto(out *CacheConfig) {
+	*out = *in
+}
+
+// DeepCopy is an autogenerated deepcopy function, copying the receiver, creating a new CacheConfig.
+func (in *CacheConfig) DeepCopy() *CacheConfig {
+	if in == nil {
+		return nil
+	}
+	out := new(CacheConfig)
+	in.DeepCopyInto(out)
+	return out
+}
+
+// DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
+func (in *CacheStatus) DeepCopyInto(out *CacheStatus) {
+	*out = *in
+	if in.LastCloneTime != nil {
+		in, out := &in.LastCloneTime, &out.LastCloneTime
+		*out = (*in).DeepCopy()
+	}
+	if in.LastFetchTime != nil {
+		in, out := &in.LastFetchTime, &out.LastFetchTime
+		*out = (*in).DeepCopy()
+	}
+}
+
+// DeepCopy is an autogenerated deepcopy function, copying the receiver, creating a new CacheStatus.
+func (in *CacheStatus) DeepCopy() *CacheStatus {
+	if in == nil {
+		return nil
+	}
+	out := new(CacheStatus)
+	in.DeepCopyInto(out)
+	return out
+}
+
 // DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
 func (in *GitAuth) DeepCopyInto(out *GitAuth) {
 	*out = *in
@@ -85,6 +123,11 @@ func (in *GitRepositorySpec) DeepCopyInto(out *GitRepositorySpec) {
 		*out = new(metav1.Duration)
 		**out = **in
 	}
+	if in.Cache != nil {
+		in, out := &in.Cache, &out.Cache
+		*out = new(CacheConfig)
+		**out = **in
+	}
 }
 
 // DeepCopy is an autogenerated deepcopy function, copying the receiver, creating a new GitRepositorySpec.
@@ -105,6 +148,11 @@ func (in *GitRepositoryStatus) DeepCopyInto(out *GitRepositoryStatus) {
 		in, out := &in.LastFetchTime, &out.LastFetchTime
 		*out = (*in).DeepCopy()
 	}
+	if in.Cache != nil {
+		in, out := &in.Cache, &out.Cache
+		*out = new(CacheStatus)
+		(*in).DeepCopyInto(*out)
+	}
 }
 
 // DeepCopy is an autogenerated deepcopy function, copying the receiver, creating a new GitRepositoryStatus.