Add support for Kustomize components

Fix fluxcd#753

Signed-off-by: Kristian Klausen <kristian@klausen.dk>

api/v1beta2/kustomization_types.go

@@ -153,6 +153,11 @@ type KustomizationSpec struct {
 	// +kubebuilder:validation:Enum=none;client;server
 	// +optional
 	Validation string `json:"validation,omitempty"`
+
+	// Components specifies relative paths to specifications of other Components
+	// via relative paths, absolute paths, or URLs.
+	// +optional
+	Components []string `json:"components,omitempty"`
 }
 
 // Decryption defines how decryption is handled for Kubernetes manifests.

config/crd/bases/kustomize.toolkit.fluxcd.io_kustomizations.yaml

@@ -585,6 +585,12 @@ spec:
             description: KustomizationSpec defines the configuration to calculate
               the desired state from a Source using Kustomize.
             properties:
+              components:
+                description: Components specifies relative paths to specifications
+                  of other Components via relative paths, absolute paths, or URLs.
+                items:
+                  type: string
+                type: array
               decryption:
                 description: Decrypt Kubernetes secrets before applying them on the
                   cluster.

internal/generator/generator.go

@@ -79,6 +79,10 @@ func (kg *KustomizeGenerator) WriteFile(dirPath string) (string, error) {
 		})
 	}
 
+	for _, m := range kg.kustomization.Spec.Components {
+		kus.Components = append(kus.Components, m)
+	}
+
 	for _, m := range kg.kustomization.Spec.PatchesStrategicMerge {
 		kus.PatchesStrategicMerge = append(kus.PatchesStrategicMerge, kustypes.PatchStrategicMerge(m.Raw))
 	}

internal/generator/generator_test.go

@@ -93,3 +93,52 @@ func TestGenerator_WriteFile(t *testing.T) {
 		})
 	}
 }
+
+func TestGenerator_Components(t *testing.T) {
+	tests := []struct {
+		name               string
+		dir                string
+		fluxComponents     []string
+		expectedComponents []string
+	}{
+		{
+			name:               "test kustomization.yaml with components and Flux Kustomization without components",
+			dir:                "components",
+			fluxComponents:     []string{},
+			expectedComponents: []string{"componentA"},
+		},
+		{
+			name:               "test kustomization.yaml without components and Flux Kustomization with components",
+			dir:                "zero-components",
+			fluxComponents:     []string{"componentB", "componentC"},
+			expectedComponents: []string{"componentB", "componentC"},
+		},
+		{
+			name:               "test kustomization.yaml with components and Flux Kustomization with components",
+			dir:                "components",
+			fluxComponents:     []string{"componentB", "componentC"},
+			expectedComponents: []string{"componentA", "componentB", "componentC"},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			g := NewWithT(t)
+			tmpDir := t.TempDir()
+			g.Expect(copy.Copy("./testdata/components", tmpDir)).To(Succeed())
+			ks := v1beta2.Kustomization{
+				Spec: v1beta2.KustomizationSpec{
+					Components: tt.fluxComponents,
+				},
+			}
+			kfile, err := NewGenerator(filepath.Join(tmpDir, tt.dir), &ks).WriteFile(filepath.Join(tmpDir, tt.dir))
+			g.Expect(err).ToNot(HaveOccurred())
+
+			kfileYAML, err := os.ReadFile(kfile)
+			g.Expect(err).ToNot(HaveOccurred())
+			var k kustypes.Kustomization
+			g.Expect(k.Unmarshal(kfileYAML)).To(Succeed())
+			g.Expect(k.Components).Should(Equal(tt.expectedComponents))
+		})
+	}
+}