Implement flux debug kustomization command

Signed-off-by: Stefan Prodan <stefan.prodan@gmail.com>

cmd/flux/debug_kustomization.go

@@ -0,0 +1,125 @@
+/*
+Copyright 2024 The Flux authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package main
+
+import (
+	"context"
+	"fmt"
+	"sort"
+	"strings"
+
+	kustomizev1 "github.com/fluxcd/kustomize-controller/api/v1"
+	"github.com/fluxcd/pkg/kustomize"
+	"github.com/spf13/cobra"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/types"
+	"sigs.k8s.io/yaml"
+
+	"github.com/fluxcd/flux2/v2/internal/utils"
+)
+
+var debugKustomizationCmd = &cobra.Command{
+	Use:     "kustomization [name]",
+	Aliases: []string{"ks"},
+	Short:   "Debug a Flux Kustomization resource",
+	Long: withPreviewNote(`The debug kustomization command can be used to troubleshoot failing Flux Kustomization reconciliations.
+WARNING: This command will print sensitive information if Kubernetes Secrets are referenced in the Kustomization .spec.postBuild.substituteFrom field.`),
+	Example: `  # Print the status of a Flux Kustomization
+  flux debug ks podinfo --show-status
+
+  # Export the final variables used for post-build substitutions composed from referred ConfigMaps and Secrets
+  flux debug ks podinfo --show-vars > vars.env`,
+	RunE: debugKustomizationCmdRun,
+	Args: cobra.ExactArgs(1),
+}
+
+type debugKustomizationFlags struct {
+	name       string
+	showStatus bool
+	showVars   bool
+}
+
+var debugKustomizationArgs debugKustomizationFlags
+
+func init() {
+	debugKustomizationCmd.Flags().BoolVar(&debugKustomizationArgs.showStatus, "show-status", false, "print the status of the Flux Kustomization")
+	debugKustomizationCmd.Flags().BoolVar(&debugKustomizationArgs.showVars, "show-vars", false, "print the final vars of the Flux Kustomization in dot env format")
+	debugCmd.AddCommand(debugKustomizationCmd)
+}
+
+func debugKustomizationCmdRun(cmd *cobra.Command, args []string) error {
+	name := args[0]
+
+	if (!debugKustomizationArgs.showStatus && !debugKustomizationArgs.showVars) ||
+		(debugKustomizationArgs.showStatus && debugKustomizationArgs.showVars) {
+		return fmt.Errorf("either --show-status or --show-vars must be set")
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), rootArgs.timeout)
+	defer cancel()
+
+	kubeClient, err := utils.KubeClient(kubeconfigArgs, kubeclientOptions)
+	if err != nil {
+		return err
+	}
+
+	ks := &kustomizev1.Kustomization{}
+	ksName := types.NamespacedName{Namespace: *kubeconfigArgs.Namespace, Name: name}
+	if err := kubeClient.Get(ctx, ksName, ks); err != nil {
+		return err
+	}
+
+	if debugKustomizationArgs.showStatus {
+		status, err := yaml.Marshal(ks.Status)
+		if err != nil {
+			return err
+		}
+		rootCmd.Print(string(status))
+		return nil
+	}
+
+	if debugKustomizationArgs.showVars {
+		ksObj, err := runtime.DefaultUnstructuredConverter.ToUnstructured(ks)
+		if err != nil {
+			return err
+		}
+
+		finalVars, err := kustomize.LoadVariables(ctx, kubeClient, unstructured.Unstructured{Object: ksObj})
+		if err != nil {
+			return err
+		}
+
+		if len(ks.Spec.PostBuild.Substitute) > 0 {
+			for k, v := range ks.Spec.PostBuild.Substitute {
+				finalVars[k] = strings.ReplaceAll(v, "\n", "")
+			}
+		}
+
+		keys := make([]string, 0, len(finalVars))
+		for k := range finalVars {
+			keys = append(keys, k)
+		}
+		sort.Strings(keys)
+
+		for _, k := range keys {
+			rootCmd.Println(k + "=" + finalVars[k])
+		}
+	}
+
+	return nil
+}

cmd/flux/debug_kustomization_test.go

@@ -0,0 +1,71 @@
+//go:build unit
+// +build unit
+
+/*
+Copyright 2024 The Flux authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package main
+
+import (
+	"testing"
+)
+
+func TestDebugKustomization(t *testing.T) {
+	namespace := allocateNamespace("debug")
+
+	objectFile := "testdata/debug_kustomization/objects.yaml"
+	tmpl := map[string]string{
+		"fluxns": namespace,
+	}
+	testEnv.CreateObjectFile(objectFile, tmpl, t)
+
+	cases := []struct {
+		name       string
+		arg        string
+		goldenFile string
+		tmpl       map[string]string
+	}{
+		{
+			"debug status",
+			"debug ks test --show-status --show-vars=false",
+			"testdata/debug_kustomization/status.golden.yaml",
+			tmpl,
+		},
+		{
+			"debug vars",
+			"debug ks test --show-vars --show-status=false",
+			"testdata/debug_kustomization/vars.golden.env",
+			tmpl,
+		},
+		{
+			"debug vars from",
+			"debug ks test-from --show-vars --show-status=false",
+			"testdata/debug_kustomization/vars-from.golden.env",
+			tmpl,
+		},
+	}
+
+	for _, tt := range cases {
+		t.Run(tt.name, func(t *testing.T) {
+			cmd := cmdTestCase{
+				args:   tt.arg + " -n=" + namespace,
+				assert: assertGoldenTemplateFile(tt.goldenFile, tmpl),
+			}
+
+			cmd.runTestCmd(t)
+		})
+	}
+}

cmd/flux/main_test.go

@@ -470,6 +470,7 @@ func resetCmdArgs() {
 	}
 	envsubstArgs = envsubstFlags{}
 	debugHelmReleaseArgs = debugHelmReleaseFlags{}
+	debugKustomizationArgs = debugKustomizationFlags{}
 }
 
 func isChangeError(err error) bool {

cmd/flux/testdata/debug_kustomization/objects.yaml

@@ -0,0 +1,63 @@
+apiVersion: v1
+kind: Namespace
+metadata:
+  name: {{ .fluxns }}
+---
+apiVersion: kustomize.toolkit.fluxcd.io/v1
+kind: Kustomization
+metadata:
+  name: test
+  namespace: {{ .fluxns }}
+spec:
+  sourceRef:
+    kind: GitRepository
+    name: test
+  interval: 1m
+  path: "./"
+  prune: true
+  postBuild:
+   substitute:
+     TEST_OVERRIDE: "in-line"
+     TEST_INLINE: "in-line"
+   substituteFrom:
+     - kind: ConfigMap
+       name: test
+     - kind: Secret
+       name: test
+---
+apiVersion: kustomize.toolkit.fluxcd.io/v1
+kind: Kustomization
+metadata:
+  name: test-from
+  namespace: {{ .fluxns }}
+spec:
+  sourceRef:
+    kind: GitRepository
+    name: test
+  interval: 1m
+  path: "./"
+  prune: true
+  postBuild:
+    substituteFrom:
+      - kind: ConfigMap
+        name: test
+      - kind: Secret
+        name: test
+---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: test
+  namespace: {{ .fluxns }}
+data:
+  TEST_OVERRIDE: "cm"
+  TEST_CM: "cm"
+---
+apiVersion: v1
+kind: Secret
+metadata:
+  name: test
+  namespace: {{ .fluxns }}
+stringData:
+  TEST_OVERRIDE: "secret"
+  TEST_SECRET: "secret"

cmd/flux/testdata/debug_kustomization/status.golden.yaml

@@ -0,0 +1 @@
+observedGeneration: -1

cmd/flux/testdata/debug_kustomization/vars-from.golden.env

@@ -0,0 +1,3 @@
+TEST_CM=cm
+TEST_OVERRIDE=secret
+TEST_SECRET=secret

cmd/flux/testdata/debug_kustomization/vars.golden.env

@@ -0,0 +1,4 @@
+TEST_CM=cm
+TEST_INLINE=in-line
+TEST_OVERRIDE=in-line
+TEST_SECRET=secret