return non-zero exitcode when encountering any change on upgrade (#65)

An attempt at resolving #54, maybe someone can pick it up and build on it?

Author: cmeury

README.md

@@ -76,6 +76,7 @@ Examples:
 
 Flags:
   -h, --help                   help for upgrade
+      --detailed-exitcode      return a non-zero exit code when there are changes
       --reset-values           reset the values to the ones built into the chart and merge in any new values
       --reuse-values           reuse the last release's values and merge in any new values
       --set stringArray        set values on the command line (can specify multiple or separate values with commas: key1=val1,key2=val2)

cmd/upgrade.go

@@ -9,20 +9,22 @@ import (
 	"github.com/databus23/helm-diff/manifest"
 	"github.com/spf13/cobra"
 	"k8s.io/helm/pkg/helm"
+	"errors"
 )
 
 type diffCmd struct {
-	release         string
-	chart           string
-	chartVersion    string
-	client          helm.Interface
-	valueFiles      valueFiles
-	values          []string
-	reuseValues     bool
-	resetValues     bool
-	allowUnreleased bool
-	suppressedKinds []string
-	outputContext   int
+	release           string
+	chart             string
+	chartVersion      string
+	client            helm.Interface
+	detailedExitCode 	bool
+	valueFiles        valueFiles
+	values            []string
+	reuseValues       bool
+	resetValues       bool
+	allowUnreleased   bool
+	suppressedKinds   []string
+	outputContext     int
 }
 
 const globalUsage = `Show a diff explaining what a helm upgrade would change.
@@ -61,6 +63,7 @@ func newChartCommand() *cobra.Command {
 
 	f := cmd.Flags()
 	f.StringVar(&diff.chartVersion, "version", "", "specify the exact chart version to use. If this is not specified, the latest version is used")
+	f.BoolVar(&diff.detailedExitCode, "detailed-exitcode", false, "return a non-zero exit code when there are changes")
 	f.BoolP("suppress-secrets", "q", false, "suppress secrets in the output")
 	f.VarP(&diff.valueFiles, "values", "f", "specify values in a YAML file (can specify multiple)")
 	f.StringArrayVar(&diff.values, "set", []string{}, "set values on the command line (can specify multiple or separate values with commas: key1=val1,key2=val2)")
@@ -139,7 +142,11 @@ func (d *diffCmd) run() error {
 		newSpecs = manifest.Parse(upgradeResponse.Release.Manifest, upgradeResponse.Release.Namespace)
 	}
 
-	diff.DiffManifests(currentSpecs, newSpecs, d.suppressedKinds, d.outputContext, os.Stdout)
+	seenAnyChanges := diff.DiffManifests(currentSpecs, newSpecs, d.suppressedKinds, d.outputContext, os.Stdout)
+
+	if d.detailedExitCode && seenAnyChanges {
+		return errors.New("identified at least one change, exiting with non-zero exit code (detailed-exitcode parameter enabled)")
+	}
 
 	return nil
 }

diff/diff.go

@@ -12,31 +12,51 @@ import (
 	"github.com/databus23/helm-diff/manifest"
 )
 
-func DiffManifests(oldIndex, newIndex map[string]*manifest.MappingResult, suppressedKinds []string, context int, to io.Writer) {
+func DiffManifests(oldIndex, newIndex map[string]*manifest.MappingResult, suppressedKinds []string, context int, to io.Writer) bool {
+	seenAnyChanges := false
+	emptyMapping := &manifest.MappingResult{}
 	for key, oldContent := range oldIndex {
 		if newContent, ok := newIndex[key]; ok {
 			if oldContent.Content != newContent.Content {
 				// modified
 				fmt.Fprintf(to, ansi.Color("%s has changed:", "yellow")+"\n", key)
-				printDiff(suppressedKinds, oldContent.Kind, context, oldContent.Content, newContent.Content, to)
+				diffs := generateDiff(oldContent, newContent)
+				if len(diffs) > 0 {
+					seenAnyChanges = true
+				}
+				printDiff(suppressedKinds, oldContent.Kind, context, diffs, to)
 			}
 		} else {
 			// removed
 			fmt.Fprintf(to, ansi.Color("%s has been removed:", "yellow")+"\n", key)
-			printDiff(suppressedKinds, oldContent.Kind, context, oldContent.Content, "", to)
+			diffs := generateDiff(oldContent, emptyMapping)
+			if len(diffs) > 0 {
+				seenAnyChanges = true
+			}
+			printDiff(suppressedKinds, oldContent.Kind, context, diffs, to)
 		}
 	}
 
 	for key, newContent := range newIndex {
 		if _, ok := oldIndex[key]; !ok {
 			// added
 			fmt.Fprintf(to, ansi.Color("%s has been added:", "yellow")+"\n", key)
-			printDiff(suppressedKinds, newContent.Kind, context, "", newContent.Content, to)
+			diffs := generateDiff(emptyMapping, newContent)
+			if len(diffs) > 0 {
+				seenAnyChanges = true
+			}
+			printDiff(suppressedKinds, newContent.Kind, context, diffs, to)
 		}
 	}
+	return seenAnyChanges
+}
+
+func generateDiff(oldContent *manifest.MappingResult, newContent *manifest.MappingResult) []difflib.DiffRecord {
+	const sep = "\n"
+	return difflib.Diff(strings.Split(oldContent.Content, sep), strings.Split(newContent.Content, sep))
 }
 
-func printDiff(suppressedKinds []string, kind string, context int, before, after string, to io.Writer) {
+func printDiff(suppressedKinds []string, kind string, context int, diffs []difflib.DiffRecord, to io.Writer) {
 	diffs := difflib.Diff(strings.Split(before, "\n"), strings.Split(after, "\n"))
 
 	for _, ckind := range suppressedKinds {

main.go

@@ -2,12 +2,14 @@ package main
 
 import (
 	"os"
+	"fmt"
 
 	"github.com/databus23/helm-diff/cmd"
 )
 
 func main() {
 	if err := cmd.New().Execute(); err != nil {
+		fmt.Println(err)
 		os.Exit(1)
 	}
 }