feat(capsules): Implement AttachCapsuleToDeployment and dependency management (#18)

Completes the implementation of Resource Capsules attachment to Kubernetes
This enables versioned resources to be attached to container automatically.

Key changes:
- Complete AttachCapsuleToDeployment to modify K8s Deployments with volumes
- Create test suite for validating both real and mock implementations

Part of #17

Author: j143

kubernetes.go

@@ -190,17 +190,107 @@ func (kcm *KubernetesCapsuleManager) DeleteCapsule(name, version string) error {
 
 // AttachCapsuleToDeployment attaches a Resource Capsule to a Kubernetes Deployment
 func (kcm *KubernetesCapsuleManager) AttachCapsuleToDeployment(deploymentName, capsuleName, capsuleVersion string) error {
-	// This would involve updating a Deployment to mount the ConfigMap/Secret
-	// For this implementation, we'll simulate the attachment
-	fmt.Printf("[Kubernetes] Attaching capsule %s:%s to deployment %s\n", capsuleName, capsuleVersion, deploymentName)
-	
-	// In a real implementation, this would:
-	// 1. Get the existing Deployment
+    // 1. Get the existing Deployment
+    deployment, err := kcm.client.AppsV1().Deployments(kcm.namespace).Get(context.TODO(), deploymentName, metav1.GetOptions{})
+    if err != nil {
+        return fmt.Errorf("failed to get deployment %s: %v", deploymentName, err)
+    }
+
+	// does capsule exists as a ConfigMap or Secret
+    configMapName := fmt.Sprintf("%s-%s", capsuleName, capsuleVersion)
+    secretName := configMapName
+    
+    // First, determine if the capsule exists as a ConfigMap or Secret
+    _, configMapErr := kcm.GetConfigMapCapsule(capsuleName, capsuleVersion)
+    _, secretErr := kcm.GetSecretCapsule(capsuleName, capsuleVersion)
+    
 	// 2. Add a volume for the ConfigMap/Secret
+    var volumeName string
+    var volumeSource v1.VolumeSource
+    var mountPath string
+    
+    if configMapErr == nil {
+        // It's a ConfigMap capsule
+        volumeName = fmt.Sprintf("capsule-%s-%s", capsuleName, capsuleVersion)
+        volumeSource = v1.VolumeSource{
+            ConfigMap: &v1.ConfigMapVolumeSource{
+                LocalObjectReference: v1.LocalObjectReference{
+                    Name: configMapName,
+                },
+            },
+        }
+        mountPath = fmt.Sprintf("/capsules/%s/%s", capsuleName, capsuleVersion)
+    } else if secretErr == nil {
+        // It's a Secret capsule
+        volumeName = fmt.Sprintf("capsule-%s-%s", capsuleName, capsuleVersion)
+        volumeSource = v1.VolumeSource{
+            Secret: &v1.SecretVolumeSource{
+                SecretName: secretName,
+            },
+        }
+        mountPath = fmt.Sprintf("/capsules/%s/%s", capsuleName, capsuleVersion)
+    } else {
+        return fmt.Errorf("capsule %s:%s not found", capsuleName, capsuleVersion)
+    }
+    
+    volumeExists := false
+    for _, volume := range deployment.Spec.Template.Spec.Volumes {
+        if volume.Name == volumeName {
+            volumeExists = true
+            break
+        }
+    }
+    
+    // Add the volume if it doesn't exist
+    if !volumeExists {
+        deployment.Spec.Template.Spec.Volumes = append(
+            deployment.Spec.Template.Spec.Volumes,
+            v1.Volume{
+                Name:         volumeName,
+                VolumeSource: volumeSource,
+            },
+        )
+    }
+    
 	// 3. Add a volumeMount to the container spec
-	// 4. Update the Deployment
-	
-	return nil
+    for i := range deployment.Spec.Template.Spec.Containers {
+        container := &deployment.Spec.Template.Spec.Containers[i]
+        
+		// check if this container already has the mount
+		mountExists := false
+		for _, mount := range container.VolumeMounts {
+            if mount.Name == volumeName {
+                mountExists = true
+                break
+            }
+        }
+
+		if !mountExists {
+            container.VolumeMounts = append(
+                container.VolumeMounts,
+                v1.VolumeMount{
+                    Name:      volumeName,
+                    MountPath: mountPath,
+                    ReadOnly:  true,
+                },
+            )
+        }
+        
+    }
+    
+    //4. Update the deployment
+    _, err = kcm.client.AppsV1().Deployments(kcm.namespace).Update(
+        context.TODO(), 
+        deployment, 
+        metav1.UpdateOptions{},
+    )
+    if err != nil {
+        return fmt.Errorf("failed to update deployment %s: %v", deploymentName, err)
+    }
+    
+    fmt.Printf("[Kubernetes] Capsule %s:%s attached to deployment %s at path %s\n", 
+        capsuleName, capsuleVersion, deploymentName, mountPath)
+    return nil
 }
 
 // BenchmarkKubernetesResourceAccess benchmarks access to Kubernetes resources

kubernetes_test.go

@@ -6,6 +6,7 @@ import (
 	"os"
 	"testing"
 
+	appsv1 "k8s.io/api/apps/v1"
 	v1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/client-go/kubernetes/fake"
@@ -175,6 +176,126 @@ func TestAddKubernetesResourceCapsule(t *testing.T) {
 	}
 }
 
+func TestAttachCapsuleToDeployment(t *testing.T) {
+	clientset := fake.NewSimpleClientset()
+
+	deployment := &appsv1.Deployment {
+		ObjectMeta: metav1.ObjectMeta {
+			Name: "test-deployment",
+			Namespace: "default",
+		},
+		Spec: appsv1.DeploymentSpec {
+			Selector: &metav1.LabelSelector {
+				MatchLabels: map[string]string {
+					"app": "test",
+				},
+			},
+			Template: v1.PodTemplateSpec {
+				ObjectMeta: metav1.ObjectMeta {
+					Labels: map[string] string {
+						"app": "test",
+					},
+				},
+				Spec: v1.PodSpec {
+					Containers: []v1.Container {
+						{
+							Name: "test-container",
+							Image: "nginx:latest",
+						},
+					},
+				},
+			},
+		},
+	}
+
+	// Create the deployment in the fake clientset
+    _, err := clientset.AppsV1().Deployments("default").Create(
+        context.TODO(), 
+        deployment, 
+        metav1.CreateOptions{},
+    )
+    if err != nil {
+        t.Fatalf("Failed to create test deployment: %v", err)
+    }
+    
+    // Create a test ConfigMap capsule
+    configMap := &v1.ConfigMap{
+        ObjectMeta: metav1.ObjectMeta{
+            Name:      "test-capsule-1.0",
+            Namespace: "default",
+            Labels: map[string]string{
+                "capsule.docker.io/name":    "test-capsule",
+                "capsule.docker.io/version": "1.0",
+            },
+        },
+        Data: map[string]string{
+            "test-data": "test value",
+        },
+    }
+    
+    // Create the ConfigMap in the fake clientset
+    _, err = clientset.CoreV1().ConfigMaps("default").Create(
+        context.TODO(), 
+        configMap, 
+        metav1.CreateOptions{},
+    )
+    if err != nil {
+        t.Fatalf("Failed to create test ConfigMap: %v", err)
+    }
+    
+    // Create a KubernetesCapsuleManager with the fake clientset
+    kcm := &KubernetesCapsuleManager{
+        client:    clientset,
+        namespace: "default",
+    }
+    
+    // Attach the capsule to the deployment
+    err = kcm.AttachCapsuleToDeployment("test-deployment", "test-capsule", "1.0")
+    if err != nil {
+        t.Fatalf("Failed to attach capsule to deployment: %v", err)
+    }
+    
+    // Get the updated deployment
+    updatedDeployment, err := clientset.AppsV1().Deployments("default").Get(
+        context.TODO(), 
+        "test-deployment", 
+        metav1.GetOptions{},
+    )
+    if err != nil {
+        t.Fatalf("Failed to get updated deployment: %v", err)
+    }
+    
+    // Check that the volume was added
+    volumeFound := false
+    for _, volume := range updatedDeployment.Spec.Template.Spec.Volumes {
+        if volume.Name == "capsule-test-capsule-1.0" {
+            volumeFound = true
+            break
+        }
+    }
+    if !volumeFound {
+        t.Errorf("Volume for capsule was not added to the deployment")
+    }
+    
+    // Check that the volume mount was added to the container
+    container := &updatedDeployment.Spec.Template.Spec.Containers[0]
+    mountFound := false
+    for _, mount := range container.VolumeMounts {
+        if mount.Name == "capsule-test-capsule-1.0" {
+            mountFound = true
+            if mount.MountPath != "/capsules/test-capsule/1.0" {
+                t.Errorf("Unexpected mount path: got %s, want /capsules/test-capsule/1.0", mount.MountPath)
+            }
+            break
+        }
+    }
+    if !mountFound {
+        t.Errorf("Volume mount for capsule was not added to the container")
+    }
+    
+    t.Log("Successfully attached capsule to deployment and verified volume and mount")
+}
+
 // BenchmarkKubernetesConfigMapAccess benchmarks ConfigMap access performance
 func BenchmarkKubernetesConfigMapAccess(b *testing.B) {
 	mockKCM := NewMockKubernetesCapsuleManager()