Add line numbers for debugging invalid yaml

Signed-off-by: Artem Mikhalitsin <artemmikhalitsin@gmail.com>

cmd/helm/testdata/output/template-with-invalid-yaml-debug.txt

@@ -1,13 +1,13 @@
 ---
 # Source: chart-with-template-with-invalid-yaml/templates/alpine-pod.yaml
-apiVersion: v1
-kind: Pod
-metadata:
-  name: "release-name-my-alpine"
-spec:
-  containers:
-  - name: waiter
-    image: "alpine:3.9"
-    command: ["/bin/sleep","9000"]
-invalid
+ 1 apiVersion: v1
+ 2 kind: Pod
+ 3 metadata:
+ 4   name: "release-name-my-alpine"
+ 5 spec:
+ 6   containers:
+ 7   - name: waiter
+ 8     image: "alpine:3.9"
+ 9     command: ["/bin/sleep","9000"]
+10 invalid
 Error: YAML parse error on chart-with-template-with-invalid-yaml/templates/alpine-pod.yaml: error converting YAML to JSON: yaml: line 11: could not find expected ':'

pkg/action/action.go

@@ -17,12 +17,14 @@ limitations under the License.
 package action
 
 import (
+	"bufio"
 	"bytes"
 	"fmt"
 	"os"
 	"path"
 	"path/filepath"
 	"regexp"
+	"strconv"
 	"strings"
 
 	"github.com/pkg/errors"
@@ -173,6 +175,7 @@ func (cfg *Configuration) renderResources(ch *chart.Chart, values chartutil.Valu
 			if strings.TrimSpace(content) == "" {
 				continue
 			}
+			content = addLineNumbers(content)
 			fmt.Fprintf(b, "---\n# Source: %s\n%s\n", name, content)
 		}
 		return hs, b, "", err
@@ -225,6 +228,45 @@ func (cfg *Configuration) renderResources(ch *chart.Chart, values chartutil.Valu
 	return hs, b, notes, nil
 }
 
+// getResourceLines separates a resource into individual lines
+func getResourceLines(resource string) []string {
+	result := []string{}
+	in := strings.NewReader(resource)
+	scanner := bufio.NewScanner(in)
+	for scanner.Scan() {
+		result = append(result, scanner.Text())
+	}
+
+	return result
+}
+
+// addLineNumbers numbers the lines of a resource
+func addLineNumbers(resource string) string {
+	resourceLines := getResourceLines(resource)
+	lineFormat := getNumberedLineFormat(len(resourceLines))
+	var result bytes.Buffer
+
+	for index, line := range resourceLines {
+		lineNumber := index + 1
+		lineWithNum := fmt.Sprintf(lineFormat, lineNumber, line)
+		fmt.Fprintln(&result, lineWithNum)
+	}
+	return result.String()
+}
+
+// getNumberedLineFormat determines which format to use
+// when printing lines of a resource based on the
+// max possible number of digits
+func getNumberedLineFormat(maxLineNumber int) string {
+	strBuilder := strings.Builder{}
+	numDigits := len(strconv.Itoa(maxLineNumber))
+	// Format is like "%3d %s"
+	strBuilder.WriteString("%")
+	strBuilder.WriteString(strconv.Itoa(numDigits))
+	strBuilder.WriteString("d %s")
+	return strBuilder.String()
+}
+
 // RESTClientGetter gets the rest client
 type RESTClientGetter interface {
 	ToRESTConfig() (*rest.Config, error)

pkg/action/action_test.go

@@ -217,6 +217,16 @@ func withSampleIncludingIncorrectTemplates() chartOption {
 	}
 }
 
+func withBadYaml() chartOption {
+	return func(opts *chartOptions) {
+		badYamlTemplate := []*chart.File{
+			{Name: "templates/goodyaml", Data: []byte("goodbye:world")},
+			{Name: "templates/badyaml", Data: []byte("this:isn't:\nhow:you_write_yaml")},
+		}
+		opts.Templates = append(opts.Templates, badYamlTemplate...)
+	}
+}
+
 func withMultipleManifestTemplate() chartOption {
 	return func(opts *chartOptions) {
 		sampleTemplates := []*chart.File{

pkg/action/install_test.go

@@ -291,6 +291,34 @@ func TestInstallReleaseIncorrectTemplate_DryRun(t *testing.T) {
 	}
 }
 
+func TestInstallRelease_LineNumbers(t *testing.T) {
+	is := assert.New(t)
+	t.Run("Should print line numbers on incorrect yaml when flag is set", func(t *testing.T) {
+		instAction := installAction(t)
+		instAction.DryRun = true
+		dummyVals := map[string]interface{}{}
+		badChart := buildChart(withBadYaml())
+		res, _ := instAction.Run(badChart, dummyVals)
+
+		// Should have line numbers for bad yaml
+		is.Contains(res.Manifest, "1 this:isn't:")
+		is.Contains(res.Manifest, "2 how:you_write_yaml")
+		// Should have line numbers for every other resource
+		is.Contains(res.Manifest, "1 kind: ConfigMap")
+	})
+
+	t.Run("Should not print line numbers on well-formatted yaml", func(t *testing.T) {
+		instAction := installAction(t)
+		instAction.DryRun = true
+		dummyVals := map[string]interface{}{}
+		goodChart := buildChart(withSampleTemplates())
+		res, _ := instAction.Run(goodChart, dummyVals)
+
+		is.Contains(res.Manifest, "hello: world")
+		is.NotContains(res.Manifest, "1 hello: Earth")
+	})
+}
+
 func TestInstallRelease_NoHooks(t *testing.T) {
 	is := assert.New(t)
 	instAction := installAction(t)