feat: add local subcommand to compare two chart folders

Author: bo0tzz

README.md

@@ -74,6 +74,7 @@ Usage:
 
 Available Commands:
   completion  Generate the autocompletion script for the specified shell
+  local       Shows diff between two local chart directories
   release     Shows diff between release's manifests
   revision    Shows diff between revision's manifests
   rollback    Show a diff explaining what a helm rollback could perform
@@ -134,6 +135,63 @@ Use "diff [command] --help" for more information about a command.
 
 ## Commands:
 
+### local:
+
+```
+$ helm diff local -h
+
+This command compares the manifests of two local chart directories.
+
+It renders both charts using 'helm template' and shows the differences
+between the resulting manifests.
+
+This is useful for:
+ - Comparing different versions of a chart
+ - Previewing changes before committing
+ - Validating chart modifications
+
+Usage:
+  diff local [flags] CHART1 CHART2
+
+Examples:
+  helm diff local ./chart-v1 ./chart-v2
+  helm diff local ./chart-v1 ./chart-v2 -f values.yaml
+  helm diff local /path/to/chart-a /path/to/chart-b --set replicas=3
+
+Flags:
+  -a, --api-versions stringArray                 Kubernetes api versions used for Capabilities.APIVersions
+  -C, --context int                              output NUM lines of context around changes (default -1)
+      --detailed-exitcode                        return a non-zero exit code when there are changes
+      --enable-dns                               enable DNS lookups when rendering templates
+  -D, --find-renames float32                     Enable rename detection if set to any value greater than 0. If specified, the value denotes the maximum fraction of changed content as lines added + removed compared to total lines in a diff for considering it a rename. Only objects of the same Kind are attempted to be matched
+  -h, --help                                     help for local
+      --include-crds                             include CRDs in the diffing
+      --include-tests                            enable the diffing of the helm test hooks
+      --kube-version string                      Kubernetes version used for Capabilities.KubeVersion
+      --namespace string                         namespace to use for template rendering
+      --normalize-manifests                      normalize manifests before running diff to exclude style differences from the output
+      --output string                            Possible values: diff, simple, template, dyff. When set to "template", use the env var HELM_DIFF_TPL to specify the template. (default "diff")
+      --post-renderer string                     the path to an executable to be used for post rendering. If it exists in $PATH, the binary will be used, otherwise it will try to look for the executable at the given path
+      --post-renderer-args stringArray           an argument to the post-renderer (can specify multiple)
+      --release string                           release name to use for template rendering (default "release")
+      --set stringArray                          set values on the command line (can specify multiple or separate values with commas: key1=val1,key2=val2)
+      --set-file stringArray                     set values from respective files specified via the command line (can specify multiple or separate values with commas: key1=path1,key2=path2)
+      --set-json stringArray                     set JSON values on the command line (can specify multiple or separate values with commas: key1=jsonval1,key2=jsonval2)
+      --set-literal stringArray                  set STRING literal values on the command line
+      --set-string stringArray                   set STRING values on the command line (can specify multiple or separate values with commas: key1=val1,key2=val2)
+      --show-secrets                             do not redact secret values in the output
+      --show-secrets-decoded                     decode secret values in the output
+      --strip-trailing-cr                        strip trailing carriage return on input
+      --suppress stringArray                     allows suppression of the kinds listed in the diff output (can specify multiple, like '--suppress Deployment --suppress Service')
+      --suppress-output-line-regex stringArray   a regex to suppress diff output lines that match
+  -q, --suppress-secrets                         suppress secrets in the output
+  -f, --values valueFiles                        specify values in a YAML file (can specify multiple) (default [])
+
+Global Flags:
+      --color      color output. You can control the value for this flag via HELM_DIFF_COLOR=[true|false]. If both --no-color and --color are unspecified, coloring enabled only when the stdout is a term and TERM is not "dumb"
+      --no-color   remove colors from the output. If both --no-color and --color are unspecified, coloring enabled only when the stdout is a term and TERM is not "dumb"
+```
+
 ### upgrade:
 
 ```

cmd/local.go

@@ -0,0 +1,234 @@
+package cmd
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"strings"
+
+	"github.com/spf13/cobra"
+
+	"github.com/databus23/helm-diff/v3/diff"
+	"github.com/databus23/helm-diff/v3/manifest"
+)
+
+type local struct {
+	chart1             string
+	chart2             string
+	release            string
+	namespace          string
+	detailedExitCode   bool
+	includeTests       bool
+	includeCRDs        bool
+	normalizeManifests bool
+	enableDNS          bool
+	valueFiles         valueFiles
+	values             []string
+	stringValues       []string
+	stringLiteralValues []string
+	jsonValues         []string
+	fileValues         []string
+	postRenderer       string
+	postRendererArgs   []string
+	extraAPIs          []string
+	kubeVersion        string
+	diff.Options
+}
+
+const localCmdLongUsage = `
+This command compares the manifests of two local chart directories.
+
+It renders both charts using 'helm template' and shows the differences
+between the resulting manifests.
+
+This is useful for:
+ - Comparing different versions of a chart
+ - Previewing changes before committing
+ - Validating chart modifications
+`
+
+func localCmd() *cobra.Command {
+	diff := local{
+		release: "release",
+	}
+
+	localCmd := &cobra.Command{
+		Use:   "local [flags] CHART1 CHART2",
+		Short: "Shows diff between two local chart directories",
+		Long:  localCmdLongUsage,
+		Example: strings.Join([]string{
+			"  helm diff local ./chart-v1 ./chart-v2",
+			"  helm diff local ./chart-v1 ./chart-v2 -f values.yaml",
+			"  helm diff local /path/to/chart-a /path/to/chart-b --set replicas=3",
+		}, "\n"),
+		RunE: func(cmd *cobra.Command, args []string) error {
+			// Suppress the command usage on error. See #77 for more info
+			cmd.SilenceUsage = true
+
+			if v, _ := cmd.Flags().GetBool("version"); v {
+				fmt.Println(Version)
+				return nil
+			}
+
+			if err := checkArgsLength(len(args), "chart1 path", "chart2 path"); err != nil {
+				return err
+			}
+
+			ProcessDiffOptions(cmd.Flags(), &diff.Options)
+
+			diff.chart1 = args[0]
+			diff.chart2 = args[1]
+
+			if diff.namespace == "" {
+				diff.namespace = os.Getenv("HELM_NAMESPACE")
+			}
+
+			return diff.run()
+		},
+	}
+
+	localCmd.Flags().StringVar(&diff.release, "release", "release", "release name to use for template rendering")
+	localCmd.Flags().StringVar(&diff.namespace, "namespace", "", "namespace to use for template rendering")
+	localCmd.Flags().BoolVar(&diff.detailedExitCode, "detailed-exitcode", false, "return a non-zero exit code when there are changes")
+	localCmd.Flags().BoolVar(&diff.includeTests, "include-tests", false, "enable the diffing of the helm test hooks")
+	localCmd.Flags().BoolVar(&diff.includeCRDs, "include-crds", false, "include CRDs in the diffing")
+	localCmd.Flags().BoolVar(&diff.normalizeManifests, "normalize-manifests", false, "normalize manifests before running diff to exclude style differences from the output")
+	localCmd.Flags().BoolVar(&diff.enableDNS, "enable-dns", false, "enable DNS lookups when rendering templates")
+	localCmd.Flags().VarP(&diff.valueFiles, "values", "f", "specify values in a YAML file (can specify multiple)")
+	localCmd.Flags().StringArrayVar(&diff.values, "set", []string{}, "set values on the command line (can specify multiple or separate values with commas: key1=val1,key2=val2)")
+	localCmd.Flags().StringArrayVar(&diff.stringValues, "set-string", []string{}, "set STRING values on the command line (can specify multiple or separate values with commas: key1=val1,key2=val2)")
+	localCmd.Flags().StringArrayVar(&diff.stringLiteralValues, "set-literal", []string{}, "set STRING literal values on the command line")
+	localCmd.Flags().StringArrayVar(&diff.jsonValues, "set-json", []string{}, "set JSON values on the command line (can specify multiple or separate values with commas: key1=jsonval1,key2=jsonval2)")
+	localCmd.Flags().StringArrayVar(&diff.fileValues, "set-file", []string{}, "set values from respective files specified via the command line (can specify multiple or separate values with commas: key1=path1,key2=path2)")
+	localCmd.Flags().StringVar(&diff.postRenderer, "post-renderer", "", "the path to an executable to be used for post rendering. If it exists in $PATH, the binary will be used, otherwise it will try to look for the executable at the given path")
+	localCmd.Flags().StringArrayVar(&diff.postRendererArgs, "post-renderer-args", []string{}, "an argument to the post-renderer (can specify multiple)")
+	localCmd.Flags().StringArrayVarP(&diff.extraAPIs, "api-versions", "a", []string{}, "Kubernetes api versions used for Capabilities.APIVersions")
+	localCmd.Flags().StringVar(&diff.kubeVersion, "kube-version", "", "Kubernetes version used for Capabilities.KubeVersion")
+
+	AddDiffOptions(localCmd.Flags(), &diff.Options)
+
+	localCmd.SuggestionsMinimumDistance = 1
+
+	return localCmd
+}
+
+func (l *local) run() error {
+	manifest1, err := l.renderChart(l.chart1)
+	if err != nil {
+		return fmt.Errorf("Failed to render chart %s: %w", l.chart1, err)
+	}
+
+	manifest2, err := l.renderChart(l.chart2)
+	if err != nil {
+		return fmt.Errorf("Failed to render chart %s: %w", l.chart2, err)
+	}
+
+	excludes := []string{manifest.Helm3TestHook, manifest.Helm2TestSuccessHook}
+	if l.includeTests {
+		excludes = []string{}
+	}
+
+	specs1 := manifest.Parse(string(manifest1), l.namespace, l.normalizeManifests, excludes...)
+	specs2 := manifest.Parse(string(manifest2), l.namespace, l.normalizeManifests, excludes...)
+
+	seenAnyChanges := diff.Manifests(specs1, specs2, &l.Options, os.Stdout)
+
+	if l.detailedExitCode && seenAnyChanges {
+		return Error{
+			error: errors.New("identified at least one change, exiting with non-zero exit code (detailed-exitcode parameter enabled)"),
+			Code:  2,
+		}
+	}
+
+	return nil
+}
+
+func (l *local) renderChart(chartPath string) ([]byte, error) {
+	flags := []string{}
+
+	if l.includeCRDs {
+		flags = append(flags, "--include-crds")
+	}
+
+	if l.namespace != "" {
+		flags = append(flags, "--namespace", l.namespace)
+	}
+
+	if l.postRenderer != "" {
+		flags = append(flags, "--post-renderer", l.postRenderer)
+	}
+
+	for _, arg := range l.postRendererArgs {
+		flags = append(flags, "--post-renderer-args", arg)
+	}
+
+	for _, valueFile := range l.valueFiles {
+		if strings.TrimSpace(valueFile) == "-" {
+			bytes, err := io.ReadAll(os.Stdin)
+			if err != nil {
+				return nil, err
+			}
+
+			tmpfile, err := os.CreateTemp("", "helm-diff-stdin-values")
+			if err != nil {
+				return nil, err
+			}
+			defer func() {
+				_ = os.Remove(tmpfile.Name())
+			}()
+
+			if _, err := tmpfile.Write(bytes); err != nil {
+				_ = tmpfile.Close()
+				return nil, err
+			}
+
+			if err := tmpfile.Close(); err != nil {
+				return nil, err
+			}
+
+			flags = append(flags, "--values", tmpfile.Name())
+		} else {
+			flags = append(flags, "--values", valueFile)
+		}
+	}
+
+	for _, value := range l.values {
+		flags = append(flags, "--set", value)
+	}
+
+	for _, stringValue := range l.stringValues {
+		flags = append(flags, "--set-string", stringValue)
+	}
+
+	for _, stringLiteralValue := range l.stringLiteralValues {
+		flags = append(flags, "--set-literal", stringLiteralValue)
+	}
+
+	for _, jsonValue := range l.jsonValues {
+		flags = append(flags, "--set-json", jsonValue)
+	}
+
+	for _, fileValue := range l.fileValues {
+		flags = append(flags, "--set-file", fileValue)
+	}
+
+	if l.enableDNS {
+		flags = append(flags, "--enable-dns")
+	}
+
+	for _, a := range l.extraAPIs {
+		flags = append(flags, "--api-versions", a)
+	}
+
+	if l.kubeVersion != "" {
+		flags = append(flags, "--kube-version", l.kubeVersion)
+	}
+
+	args := []string{"template", l.release, chartPath}
+	args = append(args, flags...)
+
+	cmd := exec.Command(os.Getenv("HELM_BIN"), args...)
+	return outputWithRichError(cmd)
+}

cmd/local_test.go

@@ -0,0 +1,82 @@
+package cmd
+
+import (
+	"os"
+	"testing"
+)
+
+func TestLocalCmdArgValidation(t *testing.T) {
+	cases := []struct {
+		name        string
+		args        []string
+		expectError bool
+	}{
+		{
+			name:        "no arguments",
+			args:        []string{},
+			expectError: true,
+		},
+		{
+			name:        "one argument",
+			args:        []string{"chart1"},
+			expectError: true,
+		},
+		{
+			name:        "three arguments",
+			args:        []string{"chart1", "chart2", "chart3"},
+			expectError: true,
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			cmd := localCmd()
+			cmd.SetArgs(tc.args)
+			err := cmd.Execute()
+
+			if tc.expectError && err == nil {
+				t.Errorf("Expected error but got none")
+			}
+			if !tc.expectError && err != nil {
+				t.Errorf("Expected no error but got: %v", err)
+			}
+		})
+	}
+}
+
+func TestLocalCmdExecution(t *testing.T) {
+	tmpDir := t.TempDir()
+	fakeHelm := tmpDir + "/helm"
+	manifestYAML := `---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: test-config
+  namespace: default
+data:
+  key: value
+`
+
+	err := os.WriteFile(fakeHelm, []byte(`#!/bin/sh
+cat <<EOF
+`+manifestYAML+`
+EOF
+`), 0755)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	t.Setenv("HELM_BIN", fakeHelm)
+
+	chart1 := t.TempDir()
+	chart2 := t.TempDir()
+
+	cmd := localCmd()
+	cmd.SetArgs([]string{chart1, chart2})
+
+	err = cmd.Execute()
+	if err != nil {
+		t.Errorf("Expected no error but got: %v", err)
+	}
+}
+

cmd/root.go

@@ -94,6 +94,7 @@ func New() *cobra.Command {
 		revisionCmd(),
 		rollbackCmd(),
 		releaseCmd(),
+		localCmd(),
 	)
 	cmd.SetHelpCommand(&cobra.Command{}) // Disable the help command
 	return cmd