Fix 'helm template' to also print invalid yaml

Signed-off-by: Reinhard Naegele <unguiculus@gmail.com>

cmd/helm/template.go

@@ -64,10 +64,10 @@ func newTemplateCmd(cfg *action.Configuration, out io.Writer) *cobra.Command {
 			client.APIVersions = chartutil.VersionSet(extraAPIs)
 			client.IncludeCRDs = includeCrds
 			rel, err := runInstall(args, client, valueOpts, out)
-			if err != nil {
-				return err
-			}
 
+			// We ignore a potential error here because we always want to print the YAML,
+			// even if it is not valid. The error is still returned afterwards.
+			if rel != nil {
 				var manifests bytes.Buffer
 				fmt.Fprintln(&manifests, strings.TrimSpace(rel.Manifest))
 
@@ -113,8 +113,9 @@ func newTemplateCmd(cfg *action.Configuration, out io.Writer) *cobra.Command {
 				} else {
 					fmt.Fprintf(out, "%s", manifests.String())
 				}
+			}
 
-			return nil
+			return err
 		},
 	}
 

cmd/helm/template_test.go

@@ -102,6 +102,12 @@ func TestTemplateCmd(t *testing.T) {
 			// don't accidentally get the expected result.
 			repeat: 10,
 		},
+		{
+			name:      "chart with template with invalid yaml",
+			cmd:       fmt.Sprintf("template '%s'", "testdata/testcharts/chart-with-template-with-invalid-yaml"),
+			wantError: true,
+			golden:    "output/template-with-invalid-yaml.txt",
+		},
 	}
 	runTestCmd(t, tests)
 }

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

@@ -0,0 +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
+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 ':'

cmd/helm/testdata/testcharts/chart-with-template-with-invalid-yaml/Chart.yaml

@@ -0,0 +1,8 @@
+apiVersion: v1
+description: Deploy a basic Alpine Linux pod
+home: https://helm.sh/helm
+name: chart-with-template-with-invalid-yaml
+sources:
+  - https://github.com/helm/helm
+version: 0.1.0
+type: application

cmd/helm/testdata/testcharts/chart-with-template-with-invalid-yaml/README.md

@@ -0,0 +1,13 @@
+#Alpine: A simple Helm chart
+
+Run a single pod of Alpine Linux.
+
+This example was generated using the command `helm create alpine`.
+
+The `templates/` directory contains a very simple pod resource with a
+couple of parameters.
+
+The `values.yaml` file contains the default values for the
+`alpine-pod.yaml` template.
+
+You can install this example using `helm install ./alpine`.

cmd/helm/testdata/testcharts/chart-with-template-with-invalid-yaml/templates/alpine-pod.yaml

@@ -0,0 +1,10 @@
+apiVersion: v1
+kind: Pod
+metadata:
+  name: "{{.Release.Name}}-{{.Values.Name}}"
+spec:
+  containers:
+  - name: waiter
+    image: "alpine:3.9"
+    command: ["/bin/sleep","9000"]
+invalid

cmd/helm/testdata/testcharts/chart-with-template-with-invalid-yaml/values.yaml

@@ -0,0 +1 @@
+Name: my-alpine